PRA - 2211

• (2025). Self-induced josephson oscillations and self-trapping in a supersolid dipolar quantum gas. PRA, 112(5), L051302. (www)

  @article{ , abstract = {The Josephson effect characterizes superfluids and superconductors separated by a weak link, the so-called Josephson junction. A recent experiment has shown that Josephson oscillations can also be observed in a supersolid, where the weak link is not due to an external barrier, but is self-induced by interparticle interactions. Here we show theoretically that supersolids—despite their self-induced character—feature key properties of bosonic Josephson junction arrays, including macroscopic quantum self-trapping. We focus on the harmonically trapped dipolar supersolids of interest for current experiments and show that they can be described with a generalized Josephson model that takes into account spatial inhomogeneities. Our work sheds new light on the dynamics of supersolids and opens the way to the study of a novel class of Josephson junctions.}, archive = {J_PRA}, author = {Beatrice Donelli and Nicolò Antolini and Giulio Biagioni and Marco Fattori and Andrea Fioretti and Carlo Gabbanini and Massimo Inguscio and Luca Tanzi and Giovanni Modugno and Augusto Smerzi and Luca Pezzè}, doi = {10.1103/hy2k-vqxd}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {L051302}, shortjournal = {Phys. Rev. A}, title = {Self-induced josephson oscillations and self-trapping in a supersolid dipolar quantum gas}, volume = {112}, year = {2025}, }
• (2025). Proposal for realizing heisenberg-type quantum-spin models in rydberg-atom quantum simulators. PRA, 112(5), L051301. (www)

  @article{ , abstract = {We investigate the magnetic-field dependence of the interaction between two Rydberg atoms, and . In this setting, the effective spin-1/2 Hamiltonian takes the form of an XXZ model. We show that the anisotropy parameter of the XXZ model can be tuned by applying a magnetic field and, in particular, that it changes drastically near the Förster resonance points. Based on this result, we propose experimental realizations of spin-1/2 and spin-1 Heisenberg-type quantum spin models in Rydberg atom quantum simulators, without relying on Floquet engineering. Our results provide guidance for future experiments of Rydberg atom quantum simulators and offer insight into quantum many-body phenomena emerging in the Heisenberg model.}, archive = {J_PRA}, author = {Masaya Kunimi and Takafumi Tomita}, doi = {10.1103/c97b-my2w}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {L051301}, shortjournal = {Phys. Rev. A}, title = {Proposal for realizing heisenberg-type quantum-spin models in rydberg-atom quantum simulators}, volume = {112}, year = {2025}, }
• (2025). Emergence of pseudoresonance in high-intensity resonant inelastic x-ray scattering. PRA, 112(5), L051101. (www)

  @article{ , abstract = {We report resonant inelastic x-ray scattering (RIXS) spectra of neon atoms interacting with intense x-ray pulses generated using an x-ray free-electron laser (XFEL). We find that an unexpected peak emerges near the line of Ne, which does not coincide with any physical resonances of neon ions. We perform theoretical calculations based on a quantum-state-resolved rate-equation approach with x-ray-induced processes including possible resonant excitations. Our dynamics simulations demonstrate that a sequence of multiple resonant photoabsorption events are involved and the interplay of those multiple resonances in combination with the relatively large spectral bandwidth of XFEL radiation leads to the emergent resonance-like structure at a position where no resonances exist. Our finding offers critical guidance for future applications of high-intensity RIXS at XFEL facilities.}, archive = {J_PRA}, author = {Sang-Kil Son (손상길 and Thomas M. Baumann and Jacob Pedersen and Laura Budewig and Kai Li and Hans Ågren and Olle Björneholm and Rebecca Boll and John Bozek and Carl Caleman and Sebastian Cardoch and Lucas M. Cornetta and Alberto De Fanis and Emiliano De Santis and Simon Dold and Gilles Doumy and Ulrich Eichmann and Xiaochun Gong and Johan Gråsjö and Alice E. Green and Iyas Ismail and Ludvig Kjellsson and Eva Lindroth and Tommaso Mazza and Jacobo Montaño and Terry Mullins and Christian Ott and Yevheniy Ovcharenko and Thomas Pfeifer and Maria Novella Piancastelli and Ralph Püttner and Nils Rennhack and Nina Rohringer and Cecilia Sánchez-Hanke and Conny Såthe and Philipp Schmidt and Björn Senfftleben and Marc Simon and Nicuşor Tîmneanu and Moto Togawa and Kiyoshi Ueda and Sergey Usenko and Hans Jakob Wörner and Weiqing Xu and Zhong Yin and Linda Young and Joseph Nordgren and Marcus Agåker and Johan Söderström and Sonia Coriani and Michael Meyer and Robin Santra and Jan-Erik Rubensson}, doi = {10.1103/drmh-vmgk}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {L051101}, shortjournal = {Phys. Rev. A}, title = {Emergence of pseudoresonance in high-intensity resonant inelastic x-ray scattering}, volume = {112}, year = {2025}, }
• (2025). Fast mixed-species quantum logic gates for trapped-ion quantum networks. PRA, 112(5), L050601. (www)

  @article{ , abstract = {Quantum logic operations between physically distinct qubits is an essential aspect of large-scale quantum information processing. We propose an approach to high-speed mixed-species entangling operations in trapped-ion quantum computers, based on mechanical excitation of spin-dependent ion motion by ultrafast pulsed lasers. We develop the theory and machine design of pulse sequences that realize megahertz-speed "fast gates" between a range of mixed-isotope and mixed-species ion pairings with experimentally realistic laser controls. We demonstrate the robustness of the gate mechanism against expected experimental errors, and identify errors in ultrafast single-qubit control as the primary technical limitation. The proposed mixed-species gate mechanism can be used for fast transfer of quantum information between specialized qubits and quantum memories, which we show enables the protection of matter-photon interfaces against rapid spin dephasing in optical networks of trapped-ion processors.}, archive = {J_PRA}, author = {Zain Mehdi and Varun D. Vaidya and Isabelle Savill-Brown and Phoebe Grosser and Alexander K. Ratcliffe and Haonan Liu and Simon A. Haine and Joseph J. Hope and C. Ricardo Viteri}, doi = {10.1103/gyls-g198}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {L050601}, shortjournal = {Phys. Rev. A}, title = {Fast mixed-species quantum logic gates for trapped-ion quantum networks}, volume = {112}, year = {2025}, }
• (2025). Quantum thermal machines and the emergence of different thermodynamic functioning regimes from finite coupling to a load. PRA, 112(5), L050201. (www)

  @article{ , abstract = {Autonomous quantum thermal machines are particularly suited to understand how correlations between thermal baths, a load, and a thermal machine affect the overall thermodynamic functioning of the setup. Here, we show that by tuning the operating temperatures and the magnitude of the coupling between machine and load, the thermal machine can operate in four modes: engine, accelerator, heater, or refrigerator. In particular, we show that as we increase the coupling strength, the engine mode is suppressed and the refrigerator mode is no longer attainable, leaving the heater as the most pronounced functioning modality, followed by the accelerator. This regime switching can be amplified by quantum effects, such as the bosonic enhancement factor for a harmonic oscillator load, which effectively modifies the machine-load coupling, making the thermodynamic functioning sensitive to the initial preparation of the load.}, archive = {J_PRA}, author = {Gauthameshwar S and Noufal Jaseem and Dario Poletti}, doi = {10.1103/dr9b-5ryh}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {L050201}, shortjournal = {Phys. Rev. A}, title = {Quantum thermal machines and the emergence of different thermodynamic functioning regimes from finite coupling to a load}, volume = {112}, year = {2025}, }
• (2025). Erratum: Repulsive interatomic potentials calculated at three levels of theory [Phys. rev. a 111, 032818 (2025)]. PRA, 112(5), 059901. (www)

  @article{ , abstract = {In this erratum, we provide new parameters for the Na-O screening function that had an unphysical value at the limit of infinite distance in the original data set.}, archive = {J_PRA}, author = {Kai Nordlund and Susi Lehtola and Gerhard Hobler}, doi = {10.1103/cdrk-x7my}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {059901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Repulsive interatomic potentials calculated at three levels of theory [Phys. rev. a 111, 032818 (2025)]}, volume = {112}, year = {2025}, }
• (2025). Nonlinear squeezing of superpositions of quadrature eigenstates. PRA, 112(5), 053706. (www)

  @article{ , abstract = {We introduce a family of operators exploiting the symmetry of superpositions of quadrature eigenstates (SQEs) and demonstrate how the associated nonlinear squeezing, quantified by the expectation value of such operators, serves both as a witness of non-Gaussianity and as an indicator of the quality of SQE approximations. To establish the usefulness of this measure, we connect it to quantum state fidelity and evaluate its implications in breeding protocols. Finally, we construct optimal approximations of SQE states in truncated Fock spaces.}, archive = {J_PRA}, author = {Vojtěch Kuchař and Petr Marek}, doi = {10.1103/nlkq-2r7l}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053706}, shortjournal = {Phys. Rev. A}, title = {Nonlinear squeezing of superpositions of quadrature eigenstates}, volume = {112}, year = {2025}, }
• (2025). Adaptive non-gaussian quantum state engineering. PRA, 112(5), 053705. (www)

  @article{ , abstract = {Non-Gaussian quantum states of bosons are a key resource in quantum information science with applications ranging from quantum metrology to fault-tolerant quantum computation. Generation of photonic non-Gaussian resource states, such as Schrödinger's cat and Gottesman-Kitaev-Preskill states, is challenging. In this work, we go beyond existing passive architectures and explore a broad set of adaptive schemes. Our numerical results demonstrate a consistent improvement in the probability of success and fidelity of generating these non-Gaussian quantum states with equivalent resources. We also explore the effect of loss as the primary limiting factor and observe that adaptive schemes lead to more desirable outcomes in terms of overall probability of success and loss tolerance. Our work offers a versatile framework for non-Gaussian resource state generation with the potential to guide future experimental implementations.}, archive = {J_PRA}, author = {Valerio Crescimanna and Shang Yu and Khabat Heshami and Raj B. Patel}, doi = {10.1103/jhkz-84dz}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053705}, shortjournal = {Phys. Rev. A}, title = {Adaptive non-gaussian quantum state engineering}, volume = {112}, year = {2025}, }
• (2025). Distinct single-photon blockades based on topological edge states and bulk states in a dimer chain. PRA, 112(5), 053704. (www)

  @article{ , abstract = {Topological photonics, combining the advantages of topological properties with those of optical systems, is anticipated to be significant for various applications. However, how to leverage its benefits for realizing single-photon blockade (PB) remains rarely studied. Here, we propose schemes to generate single PBs in a dimer chain featuring multiple qubits and a two-photon Jaynes-Cummings interaction. We demonstrate that with specific intracell and intercell hopping amplitudes of the lattice, the quantum level lattices are characterized by the form of a one-dimensional array with topological edge states in both two-excitation and three-excitation spaces, resulting in suppressed two-photon excitations and enhanced single-photon excited states. This further leads to a remarkable single PB effect under the resonance-driven case. Interestingly, single PBs can be observed in the off-resonance scenario under coupling strengths with opposite trends, while satisfying that two-excitation and three-excitation transitions are resonant whereas single-photon transition is detuned. We refer to this as an abnormal mechanism compared to previous regimes. Moreover, we show the superiority of the multiqubit-cavity topological chain by comparing with scenarios with different numbers of qubits. Our study not only sheds light on the generation of the single PB effect based on an abnormal mechanism but also establishes a pathway for realizing quantum blockade in topological optical systems, with potential applications in quantum information processing and quantum communication.}, archive = {J_PRA}, author = {Wei Zhang and Shutian Liu and Wen-Xue Cui and Shou Zhang and Hong-Fu Wang}, doi = {10.1103/dg6g-7z9p}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053704}, shortjournal = {Phys. Rev. A}, title = {Distinct single-photon blockades based on topological edge states and bulk states in a dimer chain}, volume = {112}, year = {2025}, }
• (2025). Multiphoton blockade by frequency-matched multitone drive. PRA, 112(5), 053703. (www)

  @article{ , abstract = {Multiphoton blockade provides an efficient way to achieve entangled photon sources and leads to wide applications in modern quantum technologies. Here, we propose a scheme to realize multiphoton blockade by a multitone drive. Specifically, we demonstrate two-photon and three-photon blockades in a single- mode optical Kerr resonator using a two-tone and a three-tone drive, respectively. In comparison with the single-tone drive, except for the blockade of the photon excitation due to large detuning, the key mechanism in this scheme is the sequentially resonant excitations of all the -photon states by the -tone drive, which lead to the enhancement of photon generation and the demonstration of multiphoton blockade in the weak driving regime. Moreover, the photon distribution within the system can be adjusted on demand by tuning the relative amplitudes of the driving fields for different frequencies. The scheme can be extended to other bosonic systems and be applied to demonstrate other multiphoton physical effects.}, archive = {J_PRA}, author = {Guang-Yu Zhang and Zhi-Hao Liu and Jie-Qiao Liao and Xun-Wei Xu}, doi = {10.1103/pvws-4ybt}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053703}, shortjournal = {Phys. Rev. A}, title = {Multiphoton blockade by frequency-matched multitone drive}, volume = {112}, year = {2025}, }
• (2025). Controlling radiative properties of circular atomic arrays through nanofiber guided modes. PRA, 112(5), 053702. (www)

  @article{ , abstract = {We theoretically investigate the collective emission of one and two circular arrays of two-level atoms surrounding an optical nanofiber. We show that the radiation eigenmodes of a single ring selectively couple to specific guided modes of the fiber, according to their symmetry, and study how the physical parameters of the system control their nature. In particular, we identify situations in which the emission toward radiation modes is highly suppressed with respect to fiber guided modes while the lifetime of the atomic excitation is enhanced. We further address the case of two identical rings positioned at a distance from each other along the nanofiber. By contrast to free-space configurations, the rings can exchange an excitation even at large separation through nanofiber guided modes resulting in enhanced sub- and supper-radiance with respect to the single-ring case. Our findings suggest that the ring configuration is promising for the implementation of efficient and versatile light-matter nanofiber-based interfaces and the achievement of waveguide quantum electrodynamics.}, archive = {J_PRA}, author = {J. Jiménez-Jaimes and S. Nic Chormaic and E. Brion}, doi = {10.1103/91kf-xl7p}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053702}, shortjournal = {Phys. Rev. A}, title = {Controlling radiative properties of circular atomic arrays through nanofiber guided modes}, volume = {112}, year = {2025}, }
• (2025). Temporal SU(1,1) interferometer with broadband squeezed light injection. PRA, 112(5), 053701. (www)

  @article{ , abstract = {Temporal optics has attracted much attention due to its ability for lossless stretching of ultrafast temporal pulses. Concurrently, spatial SU(1,1) interferometers (SUIs) are widely utilized due to their high sensitivity to phase changes. Building on these concepts, we investigate a temporal SUI based on a temporal Fourier transform system, injecting broadband squeezed light for characterization. Our results show that the output spectral characteristics of the interferometer depend on the ratio of the focal group delay dispersion values of the two time lenses (defined as the scaling factor ) and the derivative of the applied phase. The scaling factor strongly influences both the bandwidth and the degree of squeezing in the output spectrum. Meanwhile, the phase derivative induces a frequency shift proportional to its magnitude. Furthermore, the output squeezed-state spectrum exhibits concentrated squeezing at both the center frequency and the shifted frequencies. As the scaling factor increases, the proportion of squeezing concentrated at the center frequency increases correspondingly. We also theoretically analyze and numerically calculate the phase sensitivity with respect to the phase derivative and the scaling factor , under both lossless and lossy conditions. This temporal SUI architecture opens new avenues for the control of nonclassical fields in the time-frequency domain and quantum information processing applications.}, archive = {J_PRA}, author = {Zepeng Liu and Tianyu Liu and Hongmei Ma and Chun-Hua Yuan}, doi = {10.1103/3fln-61hc}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053701}, shortjournal = {Phys. Rev. A}, title = {Temporal SU(1,1) interferometer with broadband squeezed light injection}, volume = {112}, year = {2025}, }
• (2025). Control of optical skyrmionic textures via the pancharatnam-berry phase. PRA, 112(5), 053507. (www)

  @article{ , abstract = {Skyrmions are topological quasiparticles characterized by nontrivial topological textures. The manipulation of topological textures has attracted plenty of attention in recent years. In this study we demonstrate a geometric-phase-based method for dynamically controlling optical skyrmionic textures. By introducing the Pancharatnam-Berry phase through engineering closed paths of polarization evolution on the Poincaré sphere using waveplate combinations, we achieved the conversion between different skyrmionic topological textures. This geometric-phase-dependent strategy enables flexible manipulation of topological textures, paving the way for understanding topology transformations and engineering optical skyrmions for applications in information processing.}, archive = {J_PRA}, author = {Guang Liu and Lujia Shi and Yanzhe Liu and Xinji Zeng and Jinwen Wang and Zhenbin Fu and Yingxin Zhang and Haixia Chen and Dong Wei}, doi = {10.1103/frvz-v9qq}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053507}, shortjournal = {Phys. Rev. A}, title = {Control of optical skyrmionic textures via the pancharatnam-berry phase}, volume = {112}, year = {2025}, }
• (2025). Optimization of optomechanical cooling and entanglement using semianalytic solutions to the lindblad master equation. PRA, 112(5), 053506. (www)

  @article{ , abstract = {We solve the Lindblad master equation for the quantum state of a pumped optomechanical system coupled to a thermal bath. We show that the solution to the state in the linear pumping regime is a beam-split thermal state when pumped on the red sideband of cavity resonance and a two-mode squeezed thermal state when pumped on the blue sideband. The time dependence of each state is fully described by four coupled differential equations. Using this formalism, we describe a process of first cooling the mechanical mode via the red-sideband pump, then entangling that mode using the blue-sideband pump. We find that there is an optimal strength of blue-sideband pumping to drive the correlation variance between the two modes below a desired threshold for a maximum amount of time. This optimal value depends both on the loss rates and equilibrium temperatures of the two modes, and we provide an approximate analytic expression for this relationship. We show that a long entanglement time is achievable, even at relatively high temperatures, as long as the optical loss rate is much higher than the mechanical one.}, archive = {J_PRA}, author = {Paul R. B. Hughes and Marc M. Dignam}, doi = {10.1103/hs66-hfxv}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053506}, shortjournal = {Phys. Rev. A}, title = {Optimization of optomechanical cooling and entanglement using semianalytic solutions to the lindblad master equation}, volume = {112}, year = {2025}, }
• (2025). Equalized hyperspin machine. PRA, 112(5), 053505. (www)

  @article{ , abstract = {The reliable simulation of spin models is of critical importance to tackle complex optimization problems that are intractable on conventional computing machines. The recently introduced hyperspin machine, which is a network of linearly and nonlinearly coupled parametric oscillators, provides a versatile simulator of general classical vector spin models in arbitrary dimension, finding the minimum of the simulated spin Hamiltonian and implementing novel annealing algorithms. In the hyperspin machine, oscillators evolve in time minimizing a cost function that must resemble the desired spin Hamiltonian in order for the system to reliably simulate the target spin model. This condition is met if the hyperspin amplitudes are equal in the steady state. Currently, no mechanism to enforce equal amplitudes exists. Here we bridge this gap and introduce a method to simulate the hyperspin machine with equalized amplitudes in the steady state. We employ an additional network of oscillators (named equalizers) that connect to the hyperspin machine via an antisymmetric nonlinear coupling and equalize the hyperspin amplitudes. We demonstrate the performance of such an equalized hyperspin machine by large-scale numerical simulations up to 10 000 hyperspins. Compared to the hyperspin machine without equalization, we find that (1) the equalized hyperspin machine reaches orders of magnitude lower spin energy and (2) its performance is significantly less sensitive to the system parameters. The equalized hyperspin machine offers a competitive spin Hamiltonian minimizer and opens the possibility to combine amplitude equalization with complex annealing protocols to further boost the performance of spin machines.}, archive = {J_PRA}, author = {Marcello Calvanese Strinati and Claudio Conti}, doi = {10.1103/cxjt-53qy}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053505}, shortjournal = {Phys. Rev. A}, title = {Equalized hyperspin machine}, volume = {112}, year = {2025}, }
• (2025). Quantized helicity in optical media. PRA, 112(5), 053504. (www)

  @article{ , abstract = {We present an alternative approach to the definition of optical helicity in a medium. Our approach resolves the problem that duality transformations which simultaneously combine with and with are incompatible with linear constitutive relations. We find that the helicity density in a medium, as the conserved quantity associated with duality transforms, must contain an explicit contribution associated with the polarization and magnetization of the matter, and that it can be expressed naturally in terms of the elementary polarized excitations of the system. In media for which the helicity is conserved, each circular excitation carries a well-defined helicity. However, in a medium for which the helicity is not conserved, we find that the time-varying helicity can be viewed in terms of oscillations between different helicity eigenstates, analogous to neutrino oscillations. Here we explicitly study the helicity in homogeneous and lossless media but we believe that, differently to other choices, this helicity is readily generalizable to media that may be inhomogeneous, lossy, chiral or nonreciprocal.}, archive = {J_PRA}, author = {Neel Mackinnon and Jörg B. Götte and Stephen M. Barnett and Niclas Westerberg}, doi = {10.1103/y5d5-6xxb}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053504}, shortjournal = {Phys. Rev. A}, title = {Quantized helicity in optical media}, volume = {112}, year = {2025}, }
• (2025). Generation of large tripartite entanglement in optomechanical systems. PRA, 112(5), 053503. (www)

  @article{ , abstract = {We theoretically propose a scheme to generate strong genuine tripartite entanglement among three mechanical oscillators in a multimode optomechanical system. In our setup, each mechanical oscillator is independently coupled to three optical modes supported by a single optical cavity, with each optical mode driven by a six-tone driving field. By appropriately tailoring the amplitudes of the driving fields, the mechanical steady state can be engineered into a three-mode squeezed vacuum state exhibiting significant genuine tripartite entanglement. We further investigate the effects of mechanical thermal reservoirs and demonstrate that the entanglement generated by our scheme persists at a significant level even at dilution refrigerator temperatures. Our results offer a feasible route toward the generation and utilization of multipartite entanglement in quantum optomechanical platforms, with potential applications in quantum devices.}, archive = {J_PRA}, author = {P. Liu and X. Y. Zhang and X. Z. Hao and Y. H. Zhou and X. X. Yi}, doi = {10.1103/r2nb-5w8h}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053503}, shortjournal = {Phys. Rev. A}, title = {Generation of large tripartite entanglement in optomechanical systems}, volume = {112}, year = {2025}, }
• (2025). Probing strong-field QED via angle-discriminated emissions from electrons traversing colliding laser pulses. PRA, 112(5), 053502. (www)

  @article{ , abstract = {Future laser-electron colliders will reach quantum parameters χ well in excess of unity, enabling studies of strong-field QED in extreme regimes. However, statistical inference in such experiments requires mitigating premature radiative losses of electrons to enable high- χ QED events, as well as separating the detectable signal of these events from that of lower- χ particles and photons produced by QED cascades. We propose a collider geometry in which electrons traverse the waist of two or four perpendicularly propagating, tightly focused laser pulses. This configuration suppresses both outlined difficulties by leveraging the short interaction length of the waist, rather than relying on the more technically demanding reduction of pulse duration. Moreover, altering the phase and polarization of each pulse causes the electrons to undergo helical motion where the deflection angle is correlated with the field strength, permitting an angle-based discrimination of the signal from high- χ events. Analysis and simulations show that the case of four circularly polarized pulses uniquely permits achieving helical motion throughout the entire focal region, leading to near-perfect high- χ angle-discrimination and thereby high signal-to-noise ratio. These findings support the consideration of the proposed concept as a viable layout for future experiments at PW laser facilities.}, archive = {J_PRA}, author = {Christoffer Olofsson and Arkady Gonoskov}, doi = {10.1103/hnz2-nmk9}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053502}, shortjournal = {Phys. Rev. A}, title = {Probing strong-field QED via angle-discriminated emissions from electrons traversing colliding laser pulses}, volume = {112}, year = {2025}, }
• (2025). Propagation and circulating modes of the reciprocal non-hermitian skin effect. PRA, 112(5), 053501. (www)

  @article{ , abstract = {The non-Hermitian skin effect (NHSE) is a novel localization phenomenon, in which all bulk states in a non-Hermitian system under certain conditions are localized at the edge of the system. Conventionally, most studies of NHSE have dealt with discrete lattice systems with nonreciprocal couplings. However, in recent years, NHSE in a reciprocal two-dimensional continuous medium, such as photonic crystal systems, has also been reported. In particular, we have previously shown that NHSE also occurs in two-dimensional uniform media. In such two-dimensional systems, skin modes propagate in a direction perpendicular to the localization direction and, in particular, they have the property of propagating in only one direction. In this paper, we show numerically an intriguing scattering phenomenon: when a scatterer is placed in the path of a skin mode, the scattering causes the skin mode to hop between opposing edges. In addition, we propose a unique method of generating circulating modes with orbital angular momentum (OAM) using this scattering phenomenon. Our work paves the way for more applications of NHSE as microsized optical devices manipulating or generating OAM.}, archive = {J_PRA}, author = {Issei Takeda and Taiki Yoda and Yuto Moritake and Kenta Takata and Masaya Notomi}, doi = {10.1103/gqlb-qxkl}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053501}, shortjournal = {Phys. Rev. A}, title = {Propagation and circulating modes of the reciprocal non-hermitian skin effect}, volume = {112}, year = {2025}, }
• (2025). Analytical study of a finite-range impurity in a one-dimensional bose gas. PRA, 112(5), 053306. (www)

  @article{ , abstract = {One-dimensional Bose gases present an interesting setting to study the physics of Bose polarons, as density fluctuations play an enhanced role due to reduced dimensionality. Theoretical descriptions of this system have predominantly relied on contact pseudopotentials to model the impurity-bath interaction, leading to unphysical results in the strongly coupled limit. In this work, we analytically solve the Gross-Pitaevskii equation, using a square-well potential instead of a zero-range potential, for the ground-state wave function of a static impurity. We compute perturbative corrections arising from infinitesimally slow impurity motion. The polaron energy and effective mass remain finite in the strongly coupled regime, in contrast to the divergent behavior obtained using a contact potential. In this limit, we characterize the polaron properties in terms of the dimensionless ratio between the interaction range of the impurity-bath potential and the coherence length of the Bose gas. The effective mass exhibits a scaling. The energy of the attractive polaron scales as , whereas the repulsive polaron features subleading corrections to the dark soliton energy at the order .}, archive = {J_PRA}, author = {T. Alper Yoğurt and Matthew T. Eiles}, doi = {10.1103/gqd6-t881}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053306}, shortjournal = {Phys. Rev. A}, title = {Analytical study of a finite-range impurity in a one-dimensional bose gas}, volume = {112}, year = {2025}, }
• (2025). Doped resonating-valence-bond states: Robustness of the spin-ice phases in three-dimensional rydberg arrays. PRA, 112(5), 053305. (www)

  @article{ , abstract = {Rydberg blockade effect provides a convenient platform for simulating locally constrained many-body systems, such as quantum dimer models and quantum loop models, especially their novel phases like topological orders and gapless quantum spin ice (QSI) phases. To discuss the possible phase diagram containing different QSIs in three-dimensional (3D) Rydberg arrays, we have constructed an extended Rokhsar-Kivelson (RK) Hamiltonian with equal weight superposition ground state in different fillings at the RK point. Therefore, the perfect QSIs with fixed local dimer filling and their monomer-doped states can be simulated directly by Monte Carlo sampling. Using single-mode approximation, the excitations of dimers and monomers have also been explored in different fillings. We find that, in the thermodynamical limit, even doping a small amount of monomers can disrupt the topological structure and lead to the existence of off-diagonal long-range order. However, in a finite size (as in cold-atom experiment), the property of QSI will be kept in a certain region like a crossover after doping. The phase diagram containing different QSIs and off-diagonal order phases is proposed.}, archive = {J_PRA}, author = {Jingya Wang and Changle Liu and Yan-Cheng Wang and Zheng Yan}, doi = {10.1103/f3n1-n6rg}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053305}, shortjournal = {Phys. Rev. A}, title = {Doped resonating-valence-bond states: Robustness of the spin-ice phases in three-dimensional rydberg arrays}, volume = {112}, year = {2025}, }
• (2025). Transition from disordered solid to bose glass in a bose-hubbard model with disorder and long-range interactions. PRA, 112(5), 053304. (www)

  @article{ , abstract = {The introduction of disorder in the extended Bose-Hubbard model gives rise to new glassy quantum phases, namely the Bose-glass and disordered solid phases. In this work, we present a rich phase diagram of interacting bosons in a disordered two-dimensional optical lattice, modeled by the disordered Bose-Hubbard model. We systematically probe the effect of long-range interaction truncated to the nearest neighbors and next-nearest neighbors on the phase diagram. We investigate the zero-temperature ground-state quantum phases using the single-site Gutzwiller mean-field theory. We also employ strong-coupling perturbative expansion to identify the nature of ground-state solid phases analytically. At sufficiently high disorder strength, we observe a quantum phase transition between the disordered solid and Bose-glass phases. We have investigated this transition in greater detail using cluster Gutzwiller mean-field theory to study the effect of intersite correlations which is absent in the single-site Gutzwiller mean-field theory. We have also studied this phase transition from the perspective of percolation theory.}, archive = {J_PRA}, author = {Kohenjit Pebam and Laxmi Angom and Bhumika Thoudam and Momin Hrangbung and Deepak Gaur and Dilip Angom}, doi = {10.1103/1f85-k2wm}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053304}, shortjournal = {Phys. Rev. A}, title = {Transition from disordered solid to bose glass in a bose-hubbard model with disorder and long-range interactions}, volume = {112}, year = {2025}, }
• (2025). Calculating propagators for relativistic wave equations. PRA, 112(5), 053303. (www)

  @article{ , abstract = {Here we examine the propagation of relativistic fields in space-time using the viewpoint applied to derive the Rayleigh–Sommerfeld diffraction integral in three-dimensional space. We use this theory to find the propagators for both the Klein–Gordon equation and the Dirac equation. Based on these results, we highlight some apparently overlooked aspects of the Feynman checkerboard model as it is usually applied to the Dirac equation.}, archive = {J_PRA}, author = {Mingjie Li and S. A. R. Horsley}, doi = {10.1103/9bbm-bf4p}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053303}, shortjournal = {Phys. Rev. A}, title = {Calculating propagators for relativistic wave equations}, volume = {112}, year = {2025}, }
• (2025). Non-abelian gauge enhances self-healing for non-hermitian su-schrieffer-heeger chain. PRA, 112(5), 053302. (www)

  @article{ , abstract = {We investigate a non-Hermitian extension of the Su-Schrieffer-Heeger model that incorporates spin-dependent SU(2) gauge fields, represented by non-Abelian couplings between lattice sites, as well as independent nonreciprocal hopping amplitudes. This framework gives rise to a rich phase structure characterized by complex-energy braiding and tunable non-Hermitian skin effects. By employing the generalized Brillouin zone approach, we analyze the bulk-boundary correspondence and identify topological transitions protected by chiral symmetry. Notably, we demonstrate that non-Abelian gauge fields significantly enhance the dynamical resilience of the system, enabling robust self-healing under a moving scattering potential. These results clarify the role of SU(2) gauge fields in stabilizing non-Hermitian topological phases and indicate that the proposed model can be realized with currently available photonic, atomic, and superconducting experimental platforms.}, archive = {J_PRA}, author = {Yazhuang Miao and Yiming Zhao and Yong Wang and Jie Qiao and Xiaolong Zhao and Xuexi Yi}, doi = {10.1103/148x-k5xd}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053302}, shortjournal = {Phys. Rev. A}, title = {Non-abelian gauge enhances self-healing for non-hermitian su-schrieffer-heeger chain}, volume = {112}, year = {2025}, }
• (2025). Parametric instability of ultracold bose gases with long-range interaction and quantum fluctuations trapped in optical lattices. PRA, 112(5), 053301. (www)

  @article{ , abstract = {We investigate the dynamical instabilities of a one-dimensional ultracold Bose-Bose mixture with long-range dipole-dipole interactions, trapped in deep optical lattices and subject to periodically varying contact interaction. The effect of beyond-mean-field corrections due to quantum fluctuations is considered. In the tight-binding regime, we employ Wannier functions to derive a discrete nonlinear Schrödinger equation that captures the dynamics of the system. Using linear stability analysis coupled to multiple scale expansion, we systematically study the modulational and parametric instabilities of the system in the miscible regime, identifying the conditions under which these instabilities emerge. The corresponding instability domains are found and examined. The roles of long-range interactions and quantum fluctuations are highlighted, demonstrating their significant impact on the stability and dynamics of the lattice system. Our analytical predictions are validated through direct numerical simulations, which confirm the instability diagrams through the effective onset of instabilities and reveal the intricate interplay between interaction strength, quantum fluctuation, and the long-range nature of the dipole-dipole forces. This work provides insights into the control and manipulation of ultracold quantum gases in optical lattices, which have potential applications in quantum simulation and condensed-matter physics.}, archive = {J_PRA}, author = {Etienne Wamba and Jérémie Bai and Aurélien S. Tchakoutio Nguetcho}, doi = {10.1103/15qz-q9vm}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053301}, shortjournal = {Phys. Rev. A}, title = {Parametric instability of ultracold bose gases with long-range interaction and quantum fluctuations trapped in optical lattices}, volume = {112}, year = {2025}, }
• (2025). Tunable enhancement of two-color-driven high-order harmonics from a gaseous medium. PRA, 112(5), 053106. (www)

  @article{ , abstract = {We theoretically demonstrate the two-color-driven selective enhancement of high-order harmonic generations (HHGs) across a broad frequency range, spanning from the extreme ultraviolet (EUV) to the near-soft x-rays. The enhancement of harmonics, particularly at a central wavelength of , is of significant interest in the field of lithography. We identify two distinct enhancement mechanisms for HHGs in argon (Ar) and neon (Ne) gases: the enhancement of the 42nd harmonic (H42) in Ar is attributed to a coherent superposition of enhanced single-atom response harmonics in the off-axis region, whereas the enhancement of H118 in Ne is due to phase-matching selection of harmonics in the off-axis region. Through quantum orbit analysis, we demonstrate that phase matching is primarily influenced by the control of the amplitudes of the most relevant orbits in the off-axis region, which is associated with the modulation of the third strong peak of the driving field within the gaseous medium. This work presents a purely optical methodology for producing table-top tunable coherent sources of EUV or soft x-ray light.}, archive = {J_PRA}, author = {Zhi-Hong Jiao and Tian-Xiang Ma and Jin-Xu Du and Guo-Li Wang and Song-Feng Zhao and Lu Li and Xiao-Xin Zhou}, doi = {10.1103/jzzc-zgdg}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053106}, shortjournal = {Phys. Rev. A}, title = {Tunable enhancement of two-color-driven high-order harmonics from a gaseous medium}, volume = {112}, year = {2025}, }
• (2025). Comparison of continuum-continuum and coulomb-laser-coupling delays from visible to midinfrared wavelengths. PRA, 112(5), 053105. (www)

  @article{ , abstract = {Attosecond photoionization delays yield time-resolved information about the dynamics of electrons within atoms and molecules. Over the past decade, two pump-probe techniques have become the primary experimental methods for extracting such delays. Both methods use an attosecond XUV pump pulse to initiate the photoionization process, while an infrared laser field is used to modify the photoelectron's final momentum and provide timing information. The initial photoionization step is described by the Wigner delay, which is specific to the ionization target. However, both experimental techniques must account for an additional contribution to the measured delay due to the presence of the infrared field. Such contributions are called the Continuum-Continuum (CC) and Coulomb-Laser-Coupling (CLC) delay for the Reconstruction of Attosecond Beating By Two-photon Transitions and streaking methods, respectively. Here, we compare the various proposed formulas for CLC and CC delays using analytical and numerical methods across a range of wavelengths spanning visible to midinfrared. We show that one of the CC definitions is nearly equal to the CLC delay over a range of photoelectron energies and wavelengths. We furthermore obtain alternate expressions for the CC delays. These expressions are simpler to use and show close correspondence to the CLC delays. Based on this correspondence, we suggest a correction to the CLC delay for low-energy electrons, where the currently used approximation breaks down. Our work provides guidance for when it is valid to treat CC and CLC delays as being equivalent.}, archive = {J_PRA}, author = {Brock Grafstrom and Alexandra S. Landsman}, doi = {10.1103/blds-x7v6}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053105}, shortjournal = {Phys. Rev. A}, title = {Comparison of continuum-continuum and coulomb-laser-coupling delays from visible to midinfrared wavelengths}, volume = {112}, year = {2025}, }
• (2025). High-efficiency quantum-state detection of ThF+ with resonance-enhanced multiphoton asymmetric dissociation. PRA, 112(5), 053104. (www)

  @article{ , abstract = {Efficient quantum-state detection is crucial for many precision control experiments, such as the ongoing effort to probe the electron's electric dipole moment using trapped molecular ions at JILA. While quantum-state detection through state-selective photodissociation has been successfully implemented on this molecule, progress has been hindered by low dissociation efficiency. In this work, we perform spectroscopy on the molecule to identify excited states that facilitate more efficient photodissociation. For the most favorable transition, we achieve a dissociation efficiency of 57(14)% with quantum-state selectivity. Additionally, we discuss several state detection protocols that leverage favorable excited states that will facilitate simultaneous readout of all EDM relevant states, allowing further improvement of overall statistics.}, archive = {J_PRA}, author = {Kia Boon Ng and Sun Yool Park and Anzhou Wang and Addison Hartman and Patricia Hector Hernandez and Rohan Kompella and Lan Cheng and Stephan Malbrunot-Ettenauer and Jun Ye and Eric A. Cornell}, doi = {10.1103/mzd6-9kml}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053104}, shortjournal = {Phys. Rev. A}, title = {High-efficiency quantum-state detection of ThF+ with resonance-enhanced multiphoton asymmetric dissociation}, volume = {112}, year = {2025}, }
• (2025). Analysis of extreme-ultraviolet vortex high-order harmonics generated by few-cycle laguerre-gaussian beams carrying orbital angular momentum. PRA, 112(5), 053103. (www)

  @article{ , abstract = {Recent advances in generating high-energy, few-cycle, carrier-envelope phase (CEP)-stabilized vortex lasers has opened the possibility of producing novel vortex light sources in the extreme ultraviolet (XUV) and soft x-ray regions via high-order harmonic generation (HHG) in gases. However, this area remians underexplored and poorly understood, both experimentally and theoretically. In this work, we investigate the characteristics of vortex high harmonics driven by few-cycle Laguerre-Gaussian (LG) beams using an improved three-dimensional propagation model in which the nonlinear polarization is efficiently computed via a two-dimensional interpolation method. We demonstrate that the intensity profiles of generated vortex high harmonics exhibit discontinuous bright-spot patterns along the azimuthal direction, and the orbital angular momentum (OAM) carried by the harmonic contains multiple modes with topological charges , where is the topological charge of the fundamental laser. These features are distinctly different from those observed with long-duration LG beams. Such phenomena arise from the strong CEP dependence of few-cycle laser waveforms, which induces variations in the quantum-trajectory phase accumulated during electron ionization and recombination, effects that are especially pronounced for long trajectories. Additionally, we show that the harmonic intensity profiles, OAM spectra, and helical attosecond pulses depend sensitively on the position of the gas medium. We expect that this work will stimulate further experimental and theoretical investigations into strong-field phenomena driven by few-cycle vortex laser pulses.}, archive = {J_PRA}, author = {Shengfei Wu and Zhiming Yin and Jiaxin Han and Xiangyu Tang and Bincheng Wang and Chi Zhang and Jiahao You and Bin Lu and Ziyang Guo and Tanji Chen and Cheng Jin}, doi = {10.1103/b9bc-gw49}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053103}, shortjournal = {Phys. Rev. A}, title = {Analysis of extreme-ultraviolet vortex high-order harmonics generated by few-cycle laguerre-gaussian beams carrying orbital angular momentum}, volume = {112}, year = {2025}, }
• (2025). Optical centrifuge with zero rotational acceleration. PRA, 112(5), 053102. (www)

  @article{ , abstract = {An optical centrifuge is a laser pulse which enables controlled rotational excitation of molecules. Centrifuged molecules rotating with well-defined angular frequencies are ideal candidates to probe many-body quantum systems at the nanoscale. Because the interaction with the quantum environment increases the effective moment of inertia of the embedded molecular probes, the required rotational acceleration of the optical centrifuge must be lowered to accommodate adiabatic spinning. We demonstrate a design of an optical centrifuge, based on the method of spectral focusing, which enables extremely low, down to zero, rotational accelerations. We discuss the potential of using such constant-frequency centrifuge to investigate molecular rotation inside helium nanodroplets.}, archive = {J_PRA}, author = {K. Wang and A. Hardikar and A. A. Milner and V. Milner}, doi = {10.1103/tznp-lsvm}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053102}, shortjournal = {Phys. Rev. A}, title = {Optical centrifuge with zero rotational acceleration}, volume = {112}, year = {2025}, }
• (2025). Role of plasma waves in rescattering processes in intense laser fields. PRA, 112(5), 053101. (www)

  @article{ , abstract = {Rescattering of the photoelectron at its parent ion underlies a number of phenomena in intense laser field interaction with matter, such as high harmonic generation, attosecond pulse production, nonsequential double ionization, and others. These processes are unavoidably accompanied by the medium photoionization. The interaction of the laser pulse with the photoionization-induced plasma excites wakefield waves, which are self-consistently coupled plasma density and Langmuir waves. We study theoretically the effect of the electric field of the plasma wave on the rescattering processes. We show that this field can compensate for the magnetic drift of the rescattering electron, which otherwise dramatically suppresses the rescattering efficiency in intense low-frequency laser fields. Moreover, the presence of the plasma-wave field leads to new lines in the spectrum emitted due to the XUV free-induction decay (XFID). Observation of these lines can allow, in particular, the detection of forbidden transition frequencies, thus providing new perspectives for XFID spectroscopy.}, archive = {J_PRA}, author = {V. V. Strelkov and S. A. Bondarenko and I. V. Smetanin}, doi = {10.1103/pnh1-nyjh}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {053101}, shortjournal = {Phys. Rev. A}, title = {Role of plasma waves in rescattering processes in intense laser fields}, volume = {112}, year = {2025}, }
• (2025). Antiprotonic atoms with nonperturbative inclusion of vacuum polarization and finite nuclear mass. PRA, 112(5), 052808. (www)

  @article{ , abstract = {We demonstrate that energy levels of excited states in a hydrogenic system consisting of an arbitrary nucleus and an antiproton can be calculated within the framework of nonrelativistic quantum electrodynamics, even for a large nuclear charge . It is because for rotational states the expansion parameter is . The main advantage of this approach is the possibility of exact inclusion of the finite nuclear mass, which we achieve up to the order. In addition, we include unperturbatively the one-loop and two-loop electron vacuum polarization (EVP) potentials in the nonrelativistic Hamiltonian, as well as in the leading relativistic correction. The obtained results for states of antiprotonic atoms with a spinless nucleus are the most accurate to date. We make available a user-friendly mathematica code for antiprotonic atoms pbarspectr , which can be further improved by combining EVP potentials with QED effects, by adding three-loop EVP, and by extending to an arbitrary nuclear spin. Finally, we note that rotational states of antiprotonic atoms can be used to determine the mean-square nuclear charge radius much more accurately than from electronic or muonic atoms.}, archive = {J_PRA}, author = {Vojtěch Patkóš and Krzysztof Pachucki}, doi = {10.1103/82t6-y58b}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052808}, shortjournal = {Phys. Rev. A}, title = {Antiprotonic atoms with nonperturbative inclusion of vacuum polarization and finite nuclear mass}, volume = {112}, year = {2025}, }
• (2025). Multipole decomposition of the thermal one-loop self-energy correction for a bound atomic electron. PRA, 112(5), 052807. (www)

  @article{ , abstract = {In this paper, we present a comprehensive analysis of the one-loop self-energy correction at finite temperature for the bound electron. In this approach, we study the influence of thermal radiation on atomic systems. Along the way, we find well-known effects, including thermal Stark and Zeeman shifts, as well as thermal quadrupole interactions and relativistic corrections to the multipole expansion of photon field operators. We show that the corresponding contributions arise from the decomposition of the fully relativistic expression in terms of the parameter. The presented analysis unambiguously determines the consistency of the quantum electrodynamics theory at finite temperature with the perturbation theory of quantum mechanics. Although our analysis mainly focuses on the hydrogen atom model, potential implications for precision spectroscopic experiments are discussed.}, archive = {J_PRA}, author = {J. J. Lopez-Rodriguez and A. Bobylev and P. Kvasov and T. Zalialiutdinov and D. Solovyev}, doi = {10.1103/vzqf-8261}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052807}, shortjournal = {Phys. Rev. A}, title = {Multipole decomposition of the thermal one-loop self-energy correction for a bound atomic electron}, volume = {112}, year = {2025}, }
• (2025). Electron capture in low-energy collisions of sn3+ ions with h2 and d2. PRA, 112(5), 052806. (www)

  @article{ , abstract = {We report experimental single-electron-capture cross sections for ions impacting on and molecules at low projectile energies, ranging from 0.8 to 153 eV/u. The data were obtained in a crossed-beam-type experiment with a decelerated ion beam and a gas target. Charge-state resolved Sn ion currents are measured with a retarding field analyzer. After an extensive description of the setup and measurement procedure, we present and discuss the results in comparison to model calculations. Ab initio calculations of potential energy curves, including spin-orbit interactions, are performed and used to fit a four-state diabatic model. The experimental and theoretical single-electron-capture cross sections show good agreement and are found to have values in the range of 20– with a shallow maximum around 10 eV/u. We do not observe a significant difference between the cross sections for and , as hinted at in our previous work at energies of 80–400 eV/u.}, archive = {J_PRA}, author = {K. Bijlsma and E. de Wit and J. L. Pascual and A. Kleinsmit and E. Lalkens and L. Assink and M. Salverda and L. Méndez and O. O. Versolato and I. Rabadán and R. Hoekstra}, doi = {10.1103/x84b-5kcn}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052806}, shortjournal = {Phys. Rev. A}, title = {Electron capture in low-energy collisions of sn3+ ions with h2 and d2}, volume = {112}, year = {2025}, }
• (2025). Ionization potential and electron affinity of superheavy element 119: Relativistic high-order coupled-cluster study with QED corrections. PRA, 112(5), 052805. (www)

  @article{ , abstract = {We report a highly accurate ab initio study of the ionization potential (IP) and electron affinity (EA) of element 119. Electronic correlation effects are treated within the relativistic coupled-cluster theory including excitations up to quadruples. The Gaunt electron-electron interaction and QED corrections are taken into account. The role of high-order correlation effects is analyzed in detail. Our recommended values for the IP and EA are 4.7839(56) and 0.6750(71) eV, respectively. These results tighten previous estimates and provide a reference point for future experiments probing periodic-law trends beyond oganesson.}, archive = {J_PRA}, author = {A. R. Saetgaraev and L. V. Skripnikov and I. I. Tupitsyn and D. P. Usov and A. V. Oleynichenko and I. M. Savelyev and N. K. Dulaev and V. M. Shabaev}, doi = {10.1103/jpj3-l4c3}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052805}, shortjournal = {Phys. Rev. A}, title = {Ionization potential and electron affinity of superheavy element 119: Relativistic high-order coupled-cluster study with QED corrections}, volume = {112}, year = {2025}, }
• (2025). Relativistic effects on the ground state of positronic lithium. PRA, 112(5), 052804. (www)

  @article{ , abstract = {Positronic lithium, the first theoretically predicted positronic atom, has yet to be observed experimentally due to its weakly bound nature and short lifetime. Consequently, studies of its structural and annihilation properties can provide valuable guidance for future experimental efforts. In this work, we investigate the relativistic effects on positron binding to atomic lithium by evaluating the expectation values of relativistic operators. Our calculations show that while the total relativistic correction of positronic lithium is comparable in magnitude to the binding energy, the corrections for the bound and dissociated states are nearly identical and largely cancel each other, resulting in only a minor effect on the binding energy. Specifically, the inclusion of relativistic corrections alters the binding energy of positronic lithium and its isotopes by less than 0.13% for spin-triplet states and 0.04% for spin-singlet states. We also calculate the annihilation rates and lifetimes for both spin-triplet and spin-singlet states of positronic lithium.}, archive = {J_PRA}, author = {D.-X. Zhao and K. Hu and M.-S. Wu and J.-Y. Zhang and K.-D. Wang and L.-M. Wang and Z.-C. Yan}, doi = {10.1103/v5g3-vthm}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052804}, shortjournal = {Phys. Rev. A}, title = {Relativistic effects on the ground state of positronic lithium}, volume = {112}, year = {2025}, }
• (2025). CaF+CaF interactions in the ground and excited electronic states: Implications for collisional losses. PRA, 112(5), 052803. (www)

  @article{ , abstract = {Accurate ab initio potential energy surfaces are essential to understand and predict collisional outcomes in ultracold molecular systems. In this study, we explore the intermolecular interactions between two laser-cooled CaF molecules, in both their ground and excited electronic states, aiming to understand the mechanisms behind the observed collisional losses on the nonreactive, spin-polarized surface of the system. Using state-of-the-art ab initio methods, we compute 12 electronic states of the complex within the rigid rotor approximation applied to CaF. Calculating the potential energy surfaces for the excited electronic states of is challenging and computationally expensive. Our approach employs the multireference configuration interaction method, restricted to single and double excitations, along with a reasonably large active space to ensure the convergence in the excited states. We also compute the spin-orbit coupling between the ground state and the lowest spin-polarized triplet state, as well as the spin-spin coupling within the lowest triplet state (1) . Additionally, we determine the electric transition dipole moments for the (1) –(2) and (1) –(1) transitions. Notably, we find that the lowest spin-polarized state (1) , shifted by 1064 nm of laser light from the optical dipole trap, intersects several electronically excited states. Finally, by analyzing the potential energy surfaces, we discuss two plausible pathways that may account for the observed collisional losses on the spin-polarized surface of the system.}, archive = {J_PRA}, author = {Dibyendu Sardar and Marcin Gronowski and Michał Tomza and John L. Bohn}, doi = {10.1103/f2gg-mdgy}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052803}, shortjournal = {Phys. Rev. A}, title = {CaF+CaF interactions in the ground and excited electronic states: Implications for collisional losses}, volume = {112}, year = {2025}, }
• (2025). Variational calculation of the hyperfine stark effect in atomic Rb87,Cs133, and tm169. PRA, 112(5), 052802. (www)

  @article{ , abstract = {An electronically variational approach to the calculation of atomic hyperfine structure transition energies under the influence of static external electric fields is presented. The method avoids the calculation of intermediate atomic states entirely and requires only the wave functions of the electronic states involved in the respective hyperfine levels. These wave functions are obtained through relativistic general-excitation-rank configuration-interaction theory. A variant of the method also enables calculations on atoms with the most complicated of shell structures. Applications to , and a specific clock transition in are presented. The final results and obtained under inclusion of up to quintuple excitations in the atomic wave-function expansion are compatible with previous calculations and, in the case of Cs, confirm that one of the earlier experimental measurements is not reliable. For that is used in the development of atomic clocks the differential static scalar electric dipole polarizability between ground levels and is calculated to be a.u. This result from a pure ab initio calculation supports the result of a.u. obtained recently [A. Golovizin, E. Fedorova, D. Tregubov, D. Sukachev, K. Khabarova, V. Sorokin, and N. Kolachevsky, Nat. Commun. 10 , 1724 (2019) ] where a combination of measurement and theoretical modeling has been used.}, archive = {J_PRA}, author = {Timo Fleig}, doi = {10.1103/cy87-s81k}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052802}, shortjournal = {Phys. Rev. A}, title = {Variational calculation of the hyperfine stark effect in atomic Rb87,Cs133, and tm169}, volume = {112}, year = {2025}, }
• (2025). Lifetimes of bound excited states of the lanthanum negative ion and implications for laser cooling: Experiment and theory. PRA, 112(5), 052801. (www)

  @article{ , abstract = {The negative ion of lanthanum has one of the richest bound-state spectra observed for an atomic negative ion and it has been proposed as a promising candidate for laser cooling, which has not yet been achieved for any negatively charged system. In the present study, radiative decays of low-lying excited states of were experimentally investigated at the DESIREE cryogenic electrostatic ion-beam storage ring facility using state-selective photodetachment over storage times of up to 800 s. Independently, the transition rates for the relevant states were calculated using a high-precision hybrid theoretical approach. The measured lifetime of the lowest excited state of of 132(20) s agrees very well with the theoretical calculations and previous predictions. However, a puzzling discrepancy exists for the next-higher state , with the experiments yielding a lifetime times shorter than calculated, highlighting the challenges for this complex ion. The results provide valuable insights into the prospects for laser cooling .}, archive = {J_PRA}, author = {C. W. Walter and F. E. Vassallo and J. Karls and D. Leimbach and D. Hanstorp and J. E. Navarro Navarrete and O. H. Lundgren and M. K. Kristiansson and M. Björkhage and R. D. Thomas and H. Zettergren and H. T. Schmidt and C. Cheung and M. S. Safronova and N. D. Gibson}, doi = {10.1103/6641-mdhr}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052801}, shortjournal = {Phys. Rev. A}, title = {Lifetimes of bound excited states of the lanthanum negative ion and implications for laser cooling: Experiment and theory}, volume = {112}, year = {2025}, }
• (2025). End-to-end entanglement of quantum network paths with multiparameter states. PRA, 112(5), 052610. (www)

  @article{ , abstract = {Long-range entanglement distribution in a quantum network relies on entanglement swapping at intermediate nodes along a network path to connect short-range entangled states established over the network edges. The end-to-end entanglement of a network path obtained via this process determines the utility of the network path for executing entanglement enabled tasks and for the design of entanglement routing protocols in the quantum network. Here we study the end-to-end entanglement of paths in a quantum network when the edges are characterized by multiparameter quantum states that may be considered to be the output of arbitrary and unknown quantum channels described by the network's edges. We find that over ensembles of multiparameter states with fixed concurrence but varying density matrix elements, the end-to-end entanglement takes a range of values upper bounded by a function of the concurrence of the network-edge states. The scaling behavior of the average end-to-end entanglement reveals that its distribution gets increasingly concentrated around the mean as the paths become longer. For a network path of a given length, the average end-to-end entanglement vanishes for edge concurrence values below a threshold that increases with the path length. Although, for edge concurrence values greater than the threshold the average end-to-end entanglement increases faster with the length of the path. As an implication of our results, we show that the optimal path for entanglement distribution between a pair of end nodes, connected by alternate paths with multiparameter states along the edges, can be indeterminate given only entanglement guarantees along the network edges.}, archive = {J_PRA}, author = {Md Sohel Mondal and Aniket Zambare and Siddhartha Santra}, doi = {10.1103/vvw7-chh8}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052610}, shortjournal = {Phys. Rev. A}, title = {End-to-end entanglement of quantum network paths with multiparameter states}, volume = {112}, year = {2025}, }
• (2025). Memory effects in a dynamical decoupling process. PRA, 112(5), 052609. (www)

  @article{ , abstract = {We establish a simple quantitative relationship between the environmental memory effects and the characteristics in a dynamical decoupling process. In contrast to previous works, our measures of non-Markovianity are tailored and extended to evaluate the strength of memory effects in dynamical decoupling. We find that if each kick commutes with the dynamical map of the uncontrolled system, then the change of the final dynamical map or the final state brought by the control (called the “effect of control”) is upper (lower) bounded by the summation (difference) of the strengths of memory effects with and without control. We propose sufficient conditions for the commutation relation for parity kicks and illustrate our finding with a dissipative quantum Rabi model by numerical simulations where one or many cycles of parity kicks are implemented on the qubit. Besides, the results show that under certain conditions, the effect of control or the increase of performance by the control may be simply proportional to the strength of memory effects with or without control.}, archive = {J_PRA}, author = {S. C. Hou and X. Y. Zhang and Si-wen Li and X. X. Yi}, doi = {10.1103/ydgk-ng9t}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052609}, shortjournal = {Phys. Rev. A}, title = {Memory effects in a dynamical decoupling process}, volume = {112}, year = {2025}, }
• (2025). Application of optimal control to the time-resolution protocol for quantum sensing. PRA, 112(5), 052608. (www)

  @article{ , abstract = {Time-resolution protocol of quantum sensing aims to measure the fast temporal variation of an external field and demands a high field sensitivity in a short interrogation time . Since any operation that evolves the quantum state takes time and is counted as part of the interrogation, evaluating the performance of the time-resolution protocol requires a complete end-to-end description of the measurement process. In particular, the initial state has to be one of the quantum sensor's eigenstates in the absence of external fields, and the final projective measurements must be performed in the same eigenstate basis. Building upon prior works which proposed limits for time-resolved sensing using a quantum sensor, we apply optimal control theory to optimize the time-resolution protocol. Our analysis indicates that there exists a critical interrogation time : When the optimal protocol is a purely bang-bang strategy; when the optimal protocol involves a singular control during the interrogation. In the short- regime, which is relevant to high time resolution, we propose a detune protocol that involves only smooth control during the entire interrogation. As the discontinuities of control pose the main obstacles to experimental realization, we expect the presented detune protocol to be practically useful. In the long- regime, the optimal protocol closely resembles the Ramsey sequence; protocols based on maximizing quantum Fisher information are constructed to highlight the difference between the theoretically optimal and practically implementable measurements. Effective use of the time-resolution protocol requires a setup where the unknown time-domain signal of interest can be identically and repeatedly generated. As a potentially relevant application, we outline the calibration of baseband flux pulse distortion in the control of superconducting qubits.}, archive = {J_PRA}, author = {Chungwei Lin and Qi Ding and Yanting Ma}, doi = {10.1103/1nsd-2574}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052608}, shortjournal = {Phys. Rev. A}, title = {Application of optimal control to the time-resolution protocol for quantum sensing}, volume = {112}, year = {2025}, }
• (2025). Detector noise in continuous-variable quantum key distribution. PRA, 112(5), 052607. (www)

  @article{ , abstract = {In continuous-variable (CV) QKD with optical coherent detection, the widely adopted trusted detector noise model improves both the secret key rate and the transmission distance. This model assumes that detector noise is inherently random and inaccessible to an adversary. While substantial research has focused on shielding the detector, it is far more difficult to justify the adversary's ignorance of the detector noise. In this paper, we introduce a calibrated detector noise model for CV-QKD, which relies solely on the isolation of the detector from the adversary's intervention. Specifically, our model applies even when detector noise is predictable to the adversary. We analyze the electrical noise of a commercial balanced photoreceiver and perform numerical simulations to compare different noise models. Our results show that when the detector noise variance is an order of magnitude below the vacuum noise, the proposed model achieves a secret key rate comparable to that of the trusted detector noise model, while eliminating the questionable assumption of “truly random” detector noise.}, archive = {J_PRA}, author = {Shihong Pan and Dimitri Monokandylos and Bing Qi}, doi = {10.1103/4h84-5tsg}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052607}, shortjournal = {Phys. Rev. A}, title = {Detector noise in continuous-variable quantum key distribution}, volume = {112}, year = {2025}, }
• (2025). Controlled-Z gate fidelity in neutral-atom arrays with finite blockade and near-degenerate rydberg pair states. PRA, 112(5), 052606. (www)

  @article{ , abstract = {Arrays of optically trapped neutral atoms are an emerging platform for scalable quantum computing, where achieving high-fidelity entangling gates remains a central challenge. We present a systematic analysis of the two-qubit controlled- Z (cz) gate under finite Rydberg blockade, paying particular attention to the influence of near-degenerate Rydberg pair states and resonant dipole-dipole interactions. Using the global two-pulse excitation protocol, we model the full gate dynamics, explicitly capturing population leakage into noncomputational states. By analyzing the interplay between the control parameters such as Rabi frequency, detuning, the Förster defect, and interaction strength, we identify conditions that enable fast, high-fidelity gate operation while minimizing leakage. We also quantify the impact of finite Rydberg-state lifetimes on gate error and further demonstrate that the optimal parameter regimes identified here are accessible in current rubidium-based tweezer experiments. These results provide practical guidance for optimizing two-qubit gate protocols in neutral-atom quantum processors with experimentally accessible conditions.}, archive = {J_PRA}, author = {Diksha Thapliyal and Ishitwa Kumar Das and Ajay Wasan}, doi = {10.1103/4pzb-9nlg}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052606}, shortjournal = {Phys. Rev. A}, title = {Controlled-Z gate fidelity in neutral-atom arrays with finite blockade and near-degenerate rydberg pair states}, volume = {112}, year = {2025}, }
• (2025). Superresolving collective quantum measurements. PRA, 112(5), 052605. (www)

  @article{ , abstract = {We demonstrate a method for superresolving signals encoded as finite mixtures of bosonic modes using collective measurements that exploit permutation symmetry. Specifically, we use multiple copies of the state ρ of the finite mixture to extract an estimate for the purity of ρ via a spectrum measurement, the weak Schur-sampling measurement. Depending on the outcome, we then further fine-grain the measurement to optimally extract an estimate of the relative intensity between the two incoherent mixtures. Our protocol furnishes simultaneous estimates for both the relative intensity and the separation of incoherent signals saturating the multiparameter Cramér-Rao bound and is robust against misalignment errors. We also provide viable experimental avenues for implementing such collective measurements in different setups.}, archive = {J_PRA}, author = {J. O. de Almeida and M. Lewenstein and M. Skotiniotis}, doi = {10.1103/9w4p-5d9j}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052605}, shortjournal = {Phys. Rev. A}, title = {Superresolving collective quantum measurements}, volume = {112}, year = {2025}, }
• (2025). Achieving optimal multiparameter quantum estimation in optomechanics. PRA, 112(5), 052604. (www)

  @article{ , abstract = {Accurate simultaneous estimation of temperature and effective detuning is crucial for understanding, controlling, and optimizing optomechanical systems. Temperature characterizes the thermal state and mechanical properties, while detuning governs the light-motion interaction, influencing stability and enabling diverse quantum applications. Precise estimates of these parameters are therefore essential to exploit the full potential of such systems in high-precision metrology and the exploration of macroscopic quantum phenomena. In this work we investigate the simultaneous estimation of the effective detuning Δ and the mirror temperature T in a Fabry-Pérot cavity system, with a particular focus on the performance of heterodyne detection. Using analytical expressions for the quantum Fisher information matrices (QFIM) derived from the symmetric logarithmic derivative (SLD) and the right logarithmic derivative (RLD), we demonstrate that the quantum Cramér-Rao bound associated with the RLD is consistently lower than that based on the SLD, highlighting superior estimation precision. This gap between the SLD- and RLD-based bounds becomes especially pronounced in certain physical regimes, emphasizing the relevance of choosing the appropriate formalism in noncommutative estimation scenarios. From a physical perspective, the improved estimation performance stems from the fact that temperature directly influences thermal fluctuations in the mechanical mode, while the effective detuning modulates the strength of the optomechanical interaction, shaping the information exchange between optical and mechanical subsystems. We showed that using higher optical power, greater cavity decay rate, increased photon and phonon numbers, and reduced coupling strength improves the precision of both parameter estimates. These physical mechanisms affect the available quantum resources in the system—such as squeezing, entanglement, and state purity—which in turn determine the ultimate sensitivity achievable. Furthermore, our analysis shows that heterodyne detection can, under certain conditions, approach the ultimate precision set by the QFIM. Thus, a measurement strategy based on heterodyne detection could enable the efficient estimation of temperature, achieving performance close to that of ideal quantum-limited strategies.}, archive = {J_PRA}, author = {A. Naimy and A. Slaoui and A. Lakhfif and H. El Hadfi and R. Ahl Laamara}, doi = {10.1103/sf3p-3g7n}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052604}, shortjournal = {Phys. Rev. A}, title = {Achieving optimal multiparameter quantum estimation in optomechanics}, volume = {112}, year = {2025}, }
• (2025). Monte carlo approach for finding optimally controlled quantum gates with differential geometry. PRA, 112(5), 052603. (www)

  @article{ , abstract = {A unitary evolution in time may be treated as a curve in the manifold of the special unitary group. The length of such a curve can be related to the energetic cost of the associated computation, meaning a geodesic curve identifies an energetically optimal path. In this work, we employ sub-Riemannian geometry on the manifold of the unitary group to obtain optimally designed Hamiltonians for generating single-qubit gates in an environment with the presence of dephasing noise as well as a two-qubit gate under a time-constant crosstalk interaction. The resulting geodesic equation involves knowing the initial conditions of the parameters that cannot be obtained analytically. We then introduce a random sampling method combined with a minimization function and a cost function to find initial conditions that lead to optimal control fields. We also compare the optimized control fields obtained from the solutions of the geodesic equation with those extracted from the well-known Krotov method. Both approaches provide high-fidelity values for the desired quantum gate implementation, but the geodesic method has the advantage of minimizing the required energy to execute the same task. These findings bring insights for the design of more efficient fields in the arsenal of optimal control theory.}, archive = {J_PRA}, author = {Adonai H. da Silva and Leonardo K. Castelano and Reginaldo de J. Napolitano}, doi = {10.1103/c76s-d7pw}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052603}, shortjournal = {Phys. Rev. A}, title = {Monte carlo approach for finding optimally controlled quantum gates with differential geometry}, volume = {112}, year = {2025}, }
• (2025). Enhancing distillability of secret keys with entanglement distillation and classical advantage distillation. PRA, 112(5), 052602. (www)

  @article{ , abstract = {Realizing secure communication between distant parties is one of the main goals of quantum technology. Although quantum key distribution (QKD) promises information-theoretic security for sharing a secret key, the key rate heavily depends on the level of noise in the quantum channel. To overcome the noise, both quantum and classical techniques exist, i.e., entanglement distillation and classical advantage distillation. So far, these techniques have only been used separately from each other. Herein, we present a two-stage distillation scheme concatenating entanglement distillation with classical advantage distillation. For the advantage distillation, we utilize a fixed protocol, specifically, the repetition code ; in the case of entanglement distillation, we employ an enumeration algorithm to find an optimal protocol. We test our scheme for noisy entangled states and demonstrate its quantitative advantage: Our two-stage distillation scheme achieves finite key rates even in a high-noise regime where entanglement distillation or advantage distillation alone cannot afford key sharing. We also calculate the security bounds for relevant QKD protocols with our key-distillation scheme and show that they exceed the previous security bounds on the critical quantum bit error rates with only advantage distillation. Since the advantage distillation part does not introduce further requirements for quantum resources other than those required for entanglement distillation, the proposed scheme is well suited for quantum key distribution tasks with entanglement distribution networks.}, archive = {J_PRA}, author = {Shin Sun and Kenneth Goodenough and Daniel Bhatti and Koji Azuma and David Elkouss}, doi = {10.1103/95k8-3zxd}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052602}, shortjournal = {Phys. Rev. A}, title = {Enhancing distillability of secret keys with entanglement distillation and classical advantage distillation}, volume = {112}, year = {2025}, }
• (2025). Quantum entanglement response to pulsed gate modulation. PRA, 112(5), 052601. (www)

  @article{ , abstract = {We examine the impact of time-dependent gate voltages on entanglement generation in two capacitively coupled charge qubits, with single-electron injection triggered on demand. The gate voltage modulates the tunnel coupling between the qubits and electronic reservoirs, initiating charge transport into the system. The formation of entangled states arises from the competition between interqubit Coulomb interactions and electron-hopping processes. Particular attention is paid to the temporal structure of the gate pulse, which plays a pivotal role in shaping the entanglement dynamics. By exploring a variety of pulse profiles, we uncover regimes of enhanced entanglement and identify optimal driving conditions. Additionally, we investigate how environmental dephasing deteriorates entanglement formation. Within the framework of the density-matrix formalism, we calculate fidelity, linear entropy, and negativity to identify robust operational windows. These results provide insights into controlling quantum correlations in mesoscopic systems and underscore the importance of error-mitigation strategies in realizing high-performance electronic quantum devices.}, archive = {J_PRA}, author = {E. M. Fernandes and L. Sanz and F. M. Souza}, doi = {10.1103/sjjp-syxx}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052601}, shortjournal = {Phys. Rev. A}, title = {Quantum entanglement response to pulsed gate modulation}, volume = {112}, year = {2025}, }
• (2025). Self-testing measurements in networks from star shaped to tree shaped based on genuine network nonlocality. PRA, 112(5), 052415. (www)

  @article{ , abstract = {Network self-testing enables the unique identification of unknown measurements in a network using only observed measurement statistics. In this work, we first establish the self-testing statements for measurements in a three-branch star-shaped network (3BSN) scenario based on genuine network nonlocality. In this network, the central node performs a single joint measurement, while each branch node implements three binary-outcome projective measurements. We propose a set of statistical constraints for one pair of measurements (the first and second) at each branch node, and, by exploiting the maximal violation of the Mermin inequality for another pair (the second and third), we demonstrate the self-testing of the measurements in this 3BSN scenario. Subsequently, by performing a joint measurement on branch nodes from two discussed 3BSNs, we construct a three-layer two-forked tree-shaped network. We then establish the self-testing protocol of the joint measurement in this newly formed network scenario. In conjunction with the self-testing statements for each individual 3BSN scenario, this establishment enables the self-testing of all measurements in the tree-shaped network scenario. Our self-testing approach does not rely on any network Bell inequalities, thus providing a different perspective for device-independent quantum information processing tasks in networks.}, archive = {J_PRA}, author = {Pu Jia and Fenzhuo Guo and Haifeng Dong and Sujuan Qin and Fei Gao}, doi = {10.1103/v1jp-167d}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052415}, shortjournal = {Phys. Rev. A}, title = {Self-testing measurements in networks from star shaped to tree shaped based on genuine network nonlocality}, volume = {112}, year = {2025}, }
• (2025). Estimating decoding graphs and hypergraphs of memory quantum error-correction experiments. PRA, 112(5), 052414. (www)

  @article{ , abstract = {Characterizing the error sources of quantum devices is essential for building reliable large-scale quantum architectures and tailoring error correction codes to the noise profile of the devices. Tomography techniques can provide detailed information on the noise or quality of quantum states but are typically both computationally and experimentally intensive with respect to the system's size. For quantum error correction experiments, however, the information captured by a detector error model is sufficient for extracting the success rate of the experiment, as well as some information about the underlying noise. In this work, we estimate Pauli noise on detector error models, including hypergraphs, using only the syndrome statistics. We apply this method to well-known codes such as the repetition, surface, and two-dimensional color codes. Under bare-ancilla syndrome extraction, two-point correlations are enough to reconstruct the detector error model for repetition or surface codes. For color codes or repetition codes under Steane-style syndrome extraction, we show how to extend the estimation method to multipoint correlators and extract the error rates of the hypergraphs. Finally, we find an increase in logical error suppression when we calibrate the decoder to noise fluctuations typically present in experiments.}, archive = {J_PRA}, author = {Evangelia Takou and Kenneth R. Brown}, doi = {10.1103/qcz4-nx4r}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052414}, shortjournal = {Phys. Rev. A}, title = {Estimating decoding graphs and hypergraphs of memory quantum error-correction experiments}, volume = {112}, year = {2025}, }
• (2025). Entanglement source preparation via three-photon quantum scissors enhanced by realistic conditions. PRA, 112(5), 052413. (www)

  @article{ , abstract = {In quantum information processing, the preparation and optimization of entanglement sources are critical steps. This paper explores reality-enhanced entanglement in two-mode squeezed vacuum states via three-photon quantum scissors (3-QS). Crucially, in realistic scenarios, the optimized 3-QS scheme achieves stronger entanglement than ideal scenarios while expanding the effective enhancement range. By adjusting beam-splitter transmittance in experimentally accessible weak squeezing regimes, we achieve enhanced entanglement and higher quantum teleportation fidelity compared to conventional strong squeezing approaches. This scheme provides a practical path toward long-distance quantum communication by transforming low-quality squeezed states into high-fidelity entanglement resources.}, archive = {J_PRA}, author = {Liangjun Zhou and Yinxuan Cai and Zekun Zhao and Cunjin Liu and Teng Zhao and Liyun Hu}, doi = {10.1103/l3wl-7qsh}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052413}, shortjournal = {Phys. Rev. A}, title = {Entanglement source preparation via three-photon quantum scissors enhanced by realistic conditions}, volume = {112}, year = {2025}, }
• (2025). Leveraging magic resources for quantum channel capacity enhancement under stabilizer convolution. PRA, 112(5), 052412. (www)

  @article{ , abstract = {In this paper, we focus on discrete-variable quantum systems of odd prime dimension. We investigate the quantum capacity of stabilizer convolution channels under a variety of environmental states. Inspired by the recent result of Bu and Jaffe [ Phys. Rev. Lett. 134 , 050202 (2025) ], our main contribution is to generalize the analysis beyond the discrete beam splitter—which is only applicable for odd prime dimensions d ≥ 7 —to broader classes of stabilizer convolutions, allowing us to explore the behavior of magic resources in lower dimensions such as d = 3 and d = 5 , where their role in enhancing quantum capacity has remained unclear. In fact, many of our mathematical results are derived under the broader setting of positive convolutions, not limited strictly to stabilizer convolutions.}, archive = {J_PRA}, author = {Wenlong Sun and Yuanfeng Jin}, doi = {10.1103/qnz3-4fsc}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052412}, shortjournal = {Phys. Rev. A}, title = {Leveraging magic resources for quantum channel capacity enhancement under stabilizer convolution}, volume = {112}, year = {2025}, }
• (2025). Features of preparable entangled states in gaussian quantum networks. PRA, 112(5), 052411. (www)

  @article{ , abstract = {Large-scale quantum networks have been employed to overcome practical constraints on transmission and storage for single entangled systems. The deterministic preparation of entangled states is one of the key factors for the realization of quantum networks. There is no efficient method to verify whether single multipartite entanglement can be prepared by multisource quantum networks. Here, we theoretically analyze under what conditions entangled states can be prepared in three kinds of basic Gaussian quantum networks, named triangle networks, star-shaped networks, and chain-type networks. Some necessary criteria are derived for all preparable entangled Gaussian states in such networks. They show that the network structure imposes strong constraints on the set of preparable entangled Gaussian states, which is fundamentally different from standard single multipartite entanglement. This study takes the first step towards understanding the network mechanism for preparing entangled Gaussian states.}, archive = {J_PRA}, author = {Shuanping Du and Zhaofang Bai}, doi = {10.1103/ncbr-lwby}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052411}, shortjournal = {Phys. Rev. A}, title = {Features of preparable entangled states in gaussian quantum networks}, volume = {112}, year = {2025}, }
• (2025). Quantum dual extended hamming code immune to collective coherent errors. PRA, 112(5), 052410. (www)

  @article{ , abstract = {Collective coherent (CC) errors are inevitable, as every physical qubit undergoes free evolution under its kinetic Hamiltonian. These errors can be more damaging than stochastic Pauli errors because they affect all qubits coherently, resulting in high-weight errors that standard quantum error-correcting (QEC) codes struggle to correct. In quantum memories and communication systems, especially when storage durations are long, CC errors often dominate over stochastic noise. Trapped-ion platforms, for example, exhibit strong CC errors with minimal stochastic Pauli components. In this work, we address the regime where immunity to CC errors, high code rate (due to limited qubit availability), and moderate distance (sufficient for correcting low-weight errors) are all essential. We construct a family of constant-excitation stabilizer codes with parameters . The smallest instance, the [[8,1,4]] code, improves the code rate and error threshold of the best previously known CE code by factors of approximately two and four, respectively.}, archive = {J_PRA}, author = {En-Jui Chang}, doi = {10.1103/qzd2-b2mx}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052410}, shortjournal = {Phys. Rev. A}, title = {Quantum dual extended hamming code immune to collective coherent errors}, volume = {112}, year = {2025}, }
• (2025). General-purpose quantum architecture search based on deep reinforcement learning. PRA, 112(5), 052409. (www)

  @article{ , abstract = {Reinforcement learning (RL) shows promise for automated quantum circuit design but often stalls due to a “fidelity trap”: by optimizing only state fidelity, agents overlook entanglement structure and become stranded in suboptimal, overly complex circuits, resulting in significantly reduced search efficiency. In this paper, we propose a scheme that overcomes this barrier by implementing an entanglement-aware learning framework and enhancing the agent's reward function with a direct, quantitative measure of entanglement. This approach offers a more comprehensive physical description of the state space. We demonstrate the efficacy of this principle on three- and four-qubit state-synthesis tasks within an expanded gate set. For this problem, where the fidelity-driven agent systematically fails to discover the minimal-depth circuit, our entanglement-aware agent consistently succeeds. This transformative result is highly robust against variations in initial random seeds and extends to multiqubit systems even in the presence of noise. Our findings establish a generalizable principle that incorporating entanglement as an auxiliary reward can significantly enhance RL-based solutions for a broad class of fidelity-centric tasks in quantum physics and pave the way for scalable, automated discovery on near-term quantum devices.}, archive = {J_PRA}, author = {Xiao-Yu Bi and Yi-Ming Yu and Ye-Hong Chen and Zhi-Rong Zhong}, doi = {10.1103/7rc4-p446}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052409}, shortjournal = {Phys. Rev. A}, title = {General-purpose quantum architecture search based on deep reinforcement learning}, volume = {112}, year = {2025}, }
• (2025). Stabilizer-accelerated quantum many-body ground-state estimation. PRA, 112(5), 052408. (www)

  @article{ , abstract = {We investigate how the stabilizer formalism, in particular highly entangled stabilizer states, can be used to describe the emergence of many-body shape collectivity from individual constituents in a symmetry-preserving and classically efficient way. The method that we adopt is based on determining an optimal separation of the Hamiltonian into a stabilizer component and a residual part inducing nonstabilizerness. The corresponding stabilizer ground state is efficiently prepared using techniques of graph states and stabilizer tableaux. We demonstrate this technique in context of the Lipkin-Meshkov-Glick model, a fully connected spin system presenting a second-order phase transition from spherical to deformed state. The resulting stabilizer ground state is found to capture to a large extent both bipartite and collective multipartite entanglement features of the exact solution in the region of large deformation. We also explore several methods for injecting nonstabilizerness into the system, including adaptive derivative-assembled pseudo-Trotter variational quantum eigensolver and imaginary-time evolution (ITE) techniques. Stabilizer ground states are found to accelerate ITE convergence due to a larger overlap with the exact ground state. While further investigations are required, the present work suggests that collective features may be associated with high but simple large-scale entanglement which can be captured by stabilizer states, while the interplay with single-particle motion may be responsible for inducing nonstabilizerness. This study motivates applications of the proposed approach to more realistic quantum many-body systems, whose stabilizer ground states can be used in combinations with powerful classical many-body techniques and/or quantum methods.}, archive = {J_PRA}, author = {Caroline E. P. Robin}, doi = {10.1103/5qr5-7jkz}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052408}, shortjournal = {Phys. Rev. A}, title = {Stabilizer-accelerated quantum many-body ground-state estimation}, volume = {112}, year = {2025}, }
• (2025). Measurement reduction for expectation values via fine-grained commutativity. PRA, 112(5), 052407. (www)

  @article{ , abstract = {We introduce a notion of commutativity between operators on a tensor product space, nominally Pauli strings on qubits, that interpolates between qubitwise commutativity and (full) commutativity. We apply this notion, which we call k -commutativity, to measuring expectation values of observables in quantum circuits and show a reduction in the number measurements at the cost of increased circuit depth. We discuss the asymptotic measurement complexity of k -commutativity for several families of n -qubit Hamiltonians, showing examples with O ( 1 ) , O ( n ) , and O ( n ) scaling.}, archive = {J_PRA}, author = {Ben DalFavero and Rahul Sarkar and Jeremiah Rowland and Daan Camps and Nicolas P. D. Sawaya and Ryan LaRose}, doi = {10.1103/y6hl-gzr4}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052407}, shortjournal = {Phys. Rev. A}, title = {Measurement reduction for expectation values via fine-grained commutativity}, volume = {112}, year = {2025}, }
• (2025). Entanglement-measure vectors with generalized entanglement axioms. PRA, 112(5), 052406. (www)

  @article{ , abstract = {Despite significant advances in quantum information theory, the well-known entanglement axiom cannot be used to completely distinguish between different types of entanglement. We address this fundamental limitation by proposing generalized entanglement axioms for the complete characterization of entanglement. We firstly extend entanglement axioms under vector majorization—a mathematical framework that extends beyond conventional scalar measures. We then introduce entanglement-measure vectors that enable comprehensive classification of all bipartite pure states under local unitary operations. We further demonstrate how this framework naturally extends to multipartite systems through marginal information analysis. This work establishes a unified, mathematically rigorous methodology for entanglement classification with implications for both quantum foundations and quantum technologies.}, archive = {J_PRA}, author = {Xue Yang and Yan-Han Yang and Xin-Zhu Liu and Jun-Li Jiang and Liu Liu and Zhihao Ma and Shao-Ming Fei and Ming-Xing Luo}, doi = {10.1103/bddv-hdc8}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052406}, shortjournal = {Phys. Rev. A}, title = {Entanglement-measure vectors with generalized entanglement axioms}, volume = {112}, year = {2025}, }
• (2025). Non-markovian noise limits for sustaining entanglement in multiparty quantum states. PRA, 112(5), 052405. (www)

  @article{ , abstract = {The principal resource in several quantum information-processing tasks is entanglement. Building practically useful versions of such tasks, one often needs to consider multipartite systems. And in such scenarios, it is impossible to eliminate the effects of the environment while distributing the resources. We show how information backflow from the environment due to non-Markovianity in the system dynamics affects the resources in multipartite systems, specifically multiparty entanglement. In particular, we find that the entanglement of multiqubit Greenberger-Horne-Zeilinger cat states saturates with time to a nonzero value for a non-Markovian dephasing noise. The multiqubit W states saturate to a higher value. Such nonzero time-saturated values are washed out if the non-Markovianity in the channel is removed. The multiqubit W states provide a richer set of features, including a nonzero value for an asymptotic number of qubits and an even-odd dichotomy in the entanglement with the number of qubits. Moving to a non-Markovian depolarizing channel, we find that both cat and W states exhibit a revival of entanglement after the collapse.}, archive = {J_PRA}, author = {Suchetana Goswami and Ujjwal Sen}, doi = {10.1103/s963-rsm5}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052405}, shortjournal = {Phys. Rev. A}, title = {Non-markovian noise limits for sustaining entanglement in multiparty quantum states}, volume = {112}, year = {2025}, }
• (2025). Non-markovian speedup dynamics via quantum cyclic n-switch. PRA, 112(5), 052404. (www)

  @article{ , abstract = {In this work, we investigate the dynamical process of an open quantum system under the action of quantum cyclic n -switch in generalized amplitude-damping channels and depolarizing channels. The quantum cyclic n -switch operation is introduced by an external control system. Our results show that the quantum switch can regulate the dynamical behavior of the system dynamics and achieve non-Markovian speedup dynamics. Increasing the dimension of the control system can significantly enhance the evolution speed of the system's non-Markovian dynamics. For the generalized amplitude-damping channels, when the influence of thermal noise is intense, the greater the quantum cyclic n -switch is, the lower the initial coherence is, and the more conducive it is to the acceleration of the quantum state evolution speed. In the depolarizing channels, under the action of quantum cyclic n -switch, the evolution speed of the system dynamics is directly related to the non-Markovianity and is independent of the initial coherence of the system.}, archive = {J_PRA}, author = {Zhen-Dong Wei and Wei Han and Ying-Jie Zhang and Wei-Bin Yan and Zhong-Xiao Man and Yun-Jie Xia and Qing-Yu Cai}, doi = {10.1103/g8y3-xhmq}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052404}, shortjournal = {Phys. Rev. A}, title = {Non-markovian speedup dynamics via quantum cyclic n-switch}, volume = {112}, year = {2025}, }
• (2025). Average correlation as a resource of quantum teleportation. PRA, 112(5), 052403. (www)

  @article{ , abstract = {Bell nonlocality and quantum steering are recognized as two important physical resources and offer quantum advantages in modern quantum information processing. Inspired by the asymmetric relations of teleportation to Bell nonlocality and quantum steering, in this paper we unify the maximal violation of Bell inequality and the maximal violation of the three-setting linear steering inequality by introducing the concept of average correlation and manage to establish the relation of average correlation to quantum teleportation. Particularly, we propose a necessary and sufficient condition for any two-qubit state with nonclassicality in terms of average correlation for teleportation. Our results suggest that average correlation is not only used to detect the nonclassicality of quantum states, but also can be useful as a potential resource for teleportation.}, archive = {J_PRA}, author = {Youneng Guo and Xiangjun Chen and Huping Peng and Qinglong Tian}, doi = {10.1103/lmdx-dk95}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052403}, shortjournal = {Phys. Rev. A}, title = {Average correlation as a resource of quantum teleportation}, volume = {112}, year = {2025}, }
• (2025). Exact quantification of bipartite entanglement in unresolvable spin ensembles. PRA, 112(5), 052402. (www)

  @article{ , abstract = {Quantifying mixed-state entanglement in many-body systems has been a formidable task. In this work, we quantify the entanglement of states in unresolvable spin ensembles, which are inherently mixed. By exploiting their permutationally invariant properties, we show that the bipartite entanglement of a wide range of unresolvable ensemble states can be calculated exactly. Our formalism is versatile; it can be used to evaluate the entanglement in an ensemble with an arbitrary number of particles, effective angular momentum, and bipartition. We apply our method to explore the characteristics of entanglement in different physically motivated scenarios, including states with definite magnetization and metrologically useful superpositions such as Greenberger-Horne-Zeilinger (GHZ) states and spin-squeezed states. Our method can help understand the role of entanglement in spin-ensemble-based quantum technologies.}, archive = {J_PRA}, author = {Tzu-Wei Kuo and Hoi-Kwan Lau}, doi = {10.1103/vcqj-xd7z}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052402}, shortjournal = {Phys. Rev. A}, title = {Exact quantification of bipartite entanglement in unresolvable spin ensembles}, volume = {112}, year = {2025}, }
• (2025). Local inaccessibility of random classical information and their implications in the change-point problem. PRA, 112(5), 052401. (www)

  @article{ , abstract = {Discrimination of quantum states under local operations and classical communication is an intriguing question in the context of local retrieval of classical information, encoded in the multipartite quantum systems. All the local quantum state discrimination premises considered so far mimic a basic communication setup, where the spatially separated decoding devices are independent of any additional input. Here, exploring a generalized communication scenario, we introduce a framework for input-dependent local quantum state discrimination, which we call local random authentication (LRA). We report that the impossibility of LRA certifies the presence of entangled states in the ensemble, a feature absent from erstwhile nonlocality arguments based on local state discrimination. Additionally, we explore the salient features of this state discrimination prototype for an arbitrary set of orthogonal quantum states and compare them with the traditional notion of local quantum state discrimination. Finally, our results reveal fundamental information-theoretic implications in the local estimation of quantum change-point problems.}, archive = {J_PRA}, author = {Snehasish Roy Chowdhury and Subhendu B. Ghosh and Tathagata Gupta and Anandamay Das Bhowmik and Sutapa Saha and Some Sankar Bhattacharya and Tamal Guha}, doi = {10.1103/ylng-5j64}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052401}, shortjournal = {Phys. Rev. A}, title = {Local inaccessibility of random classical information and their implications in the change-point problem}, volume = {112}, year = {2025}, }
• (2025). Fractional thouless pumping of solitons: A unique manifestation of bulk-edge correspondence of nonlinear eigenvalue problems. PRA, 112(5), 052207. (www)

  @article{ , abstract = {Recent foundational studies have established the bulk-edge correspondence for nonlinear eigenvalue problems using auxiliary eigenvalues , spanning both linear [T. Isobe et al. , Phys. Rev. Lett. 132 , 126601 (2024) ] and nonlinear [C. Bai and Z. Liang, Phys. Rev. A 111 , 042201 (2025) ] Hamiltionians. This progress prompts a fundamental question: Can eigenvalue nonlinearity generate observable physical phenomena absent in conventional approaches ( )? In this work, we address this question by demonstrating a uniquely nonlinear manifestation of the bulk-edge correspondence: fractional Thouless pumping of solitons. Through systematic investigation of nonlinear Thouless pumping in an extended Rice-Mele model incorporating next-nearest-neighbor (NNN) couplings, we uncover that NNN interaction parameters can induce fractional topological phases—even in the presence of quantized topological invariants as predicted by conventional linear approaches. Crucially, these fractional phases are naturally explained within the auxiliary eigenvalue framework, directly linking nonlinear spectral characteristics to the bulk-boundary correspondence. Our findings reveal emergent phenomena arising from the interplay between nonlinearity and NNN couplings, providing key insights for the design of topological insulators and the controlled manipulation of quantum edge states in nonlinear regimes.}, archive = {J_PRA}, author = {Chenxi Bai and Zhaoxin Liang}, doi = {10.1103/tgzz-1ngp}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052207}, shortjournal = {Phys. Rev. A}, title = {Fractional thouless pumping of solitons: A unique manifestation of bulk-edge correspondence of nonlinear eigenvalue problems}, volume = {112}, year = {2025}, }
• (2025). Sequential quantum maximum-confidence discrimination. PRA, 112(5), 052206. (www)

  @article{ , abstract = {Sequential quantum information processing may lie in the peaceful coexistence of no-go theorems on quantum operations, such as the no-cloning theorem, the monogamy of correlations, and the no-signalling principle. In this work, we investigate a sequential scenario of quantum state discrimination with maximum confidence, called maximum-confidence discrimination, which generalizes other strategies such as minimum-error and unambiguous discrimination. We show that sequential discrimination with equally high confidence can be realized if and only if positive-operator-valued measure elements for a maximum-confidence measurement can be unambiguously discriminated, i.e., linearly independent; otherwise, a party will have strictly less confidence in measurement outcomes than the previous one. We investigate the tradeoff between state disturbance and information gain in sequential state discrimination and show that the less guessing probability there is from conclusive outcomes for each party, the more parties can participate in the sequential scenario.}, archive = {J_PRA}, author = {Hanwool Lee and Kieran Flatt and Joonwoo Bae}, doi = {10.1103/wm73-g73w}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052206}, shortjournal = {Phys. Rev. A}, title = {Sequential quantum maximum-confidence discrimination}, volume = {112}, year = {2025}, }
• (2025). Attainable quantum speed limit for N-dimensional quantum systems. PRA, 112(5), 052205. (www)

  @article{ , abstract = {The quantum speed limit (QSL) is a fundamental concept in quantum mechanics, providing a lower bound on the evolution time. The attainability of the QSL, which greatly depends on the understanding of the QSL, is a long-standing open problem, especially for high-dimensional systems. In this paper, we solve this problem by establishing a QSL suitable and attainable for both open and closed quantum systems based on a new proposed state distance. It is shown that, given any initial state in a certain finite dimension, unitary and nonunitary dynamics can always be found to attain our QSL bound in the corresponding dimension, and for any given Hamiltonian for a unitary evolution a pair of states always exists, attaining the bound. As applications, we demonstrate the QSL time attained by various physical settings. This paper will shed light on the QSL problems.}, archive = {J_PRA}, author = {Zi-yi Mai and Chang-shui Yu}, doi = {10.1103/9xmb-dmlw}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052205}, shortjournal = {Phys. Rev. A}, title = {Attainable quantum speed limit for N-dimensional quantum systems}, volume = {112}, year = {2025}, }
• (2025). Family of exact and inexact quantum speed limits for completely positive and trace-preserving dynamics. PRA, 112(5), 052204. (www)

  @article{ , abstract = {Traditional quantum speed limits formulated in density matrix space are generally unattainable for a wide class of dynamics and it is difficult to characterize the fastest possible dynamics. To address this, we present two distinct quantum speed limits in Liouville space for completely positive and trace-preserving (CPTP) dynamics. The first bound saturates for time-optimal CPTP dynamics, while the second bound is exact for all states and all CPTP dynamics. Our bounds have a clear physical and geometric interpretation arising from the uncertainty relations for operators acting on Liouville space, and the geometry of quantum evolution in Liouville space. We also obtain the form of the Liouvillian, which generates the time-optimal CPTP dynamics that connects the given initial and target states. To illustrate our findings, we show that the speed of evolution in Liouville space bounds the growth of the spectral form factor and Krylov complexity of states, which are crucial for studying information scrambling and quantum chaos. In another important application, we show that our results can help us understand the counterintuitive phenomenon of the Mpemba effect in nonequilibrium open quantum dynamics, as the minimal relaxation time scale obtained by speed limits is dictated by the eigenmodes of the Liouvillian.}, archive = {J_PRA}, author = {Abhay Srivastav and Vivek Pandey and Brij Mohan and Arun Kumar Pati}, doi = {10.1103/npkr-c4vf}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052204}, shortjournal = {Phys. Rev. A}, title = {Family of exact and inexact quantum speed limits for completely positive and trace-preserving dynamics}, volume = {112}, year = {2025}, }
• (2025). Characterization of P-divisibility in two-level open quantum systems. PRA, 112(5), 052203. (www)

  @article{ , abstract = {We study different characterizations of positive (P) divisibility in two-level open quantum systems whose dynamics are governed by a time-local master equation with time-dependent relaxation rates. In the case of phase-covariant dynamics, necessary and sufficient conditions for the P-divisibility of the dynamical map are given in terms of inequalities on such relaxation rates. We propose a geometric P-divisibility criterion based on the Bloch coordinates. The connection to the Breuer-Laine-Piilo (BLP) measure of non-Markovianity is also established. We show how these results can be extended to a Redfield master equation. As an application of such characterizations, we study the open dynamics of a qubit interacting with a single bosonic mode. More precisely, we characterize the properties of the local map of the qubit generated by its interaction with the bosonic mode, playing the role of an extremely reduced bath. Interesting observations are made, opening perspectives for a deeper physical understanding of complete positive divisibility, P-divisibility, and BLP measure.}, archive = {J_PRA}, author = {G. Théret and C. Lombard-Latune and D. Sugny}, doi = {10.1103/ngjb-mcnt}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052203}, shortjournal = {Phys. Rev. A}, title = {Characterization of P-divisibility in two-level open quantum systems}, volume = {112}, year = {2025}, }
• (2025). Quantum-imaginarity-based quantum speed limit. PRA, 112(5), 052202. (www)

  @article{ , abstract = {The quantum speed limit sets a fundamental restriction on the evolution time of quantum systems. We explore the relationship between quantum imaginarity and the quantum speed limit by utilizing measures such as relative entropy, trace distance, and geometric imaginarity. These speed limits define the fundamental constraints on the minimum time necessary for quantum systems to evolve under various dynamical processes. As applications, the dephasing dynamics and dissipative dynamics are analyzed in detail. The quantum speed limit in stochastic-approximate transformations is also investigated. Our quantum speed limits provide lower bounds on how fast a physical system evolves to attain or lose certain imaginarity, with potential applications in efficient quantum computation designs, quantum control, and quantum sensing.}, archive = {J_PRA}, author = {Dong-Ping Xuan and Zhong-Xi Shen and Wen Zhou and Shao-Ming Fei and Zhi-Xi Wang}, doi = {10.1103/s7kr-8rrn}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052202}, shortjournal = {Phys. Rev. A}, title = {Quantum-imaginarity-based quantum speed limit}, volume = {112}, year = {2025}, }
• (2025). High-entanglement regimes in the weisskopf-wigner theory for spontaneous decay. PRA, 112(5), 052201. (www)

  @article{ , abstract = {In this work we review the Weisskopf-Wigner formalism for spontaneous emission considering the spatial modes of light as well as external atomic degrees of freedom, which we introduce in the theory by modeling the atom as a wave packet in momentum space with a given initial uncertainty. We perform a purity calculation in order to quantify the entanglement encoded in the momentum variables of the atom-photon system. Our purity calculations reveal two high-entanglement regimes depending on the initial atomic momentum uncertainty: (1) the Recoil entanglement regime (which arises in the small momentum uncertainty region) where recoil effects dominate the mechanisms that originate entanglement, and (2) the Doppler entanglement regime (in the large momentum uncertainty region) where homogeneous Doppler shifts in the emitted photon's frequency play the fundamental part in the build up of quantum correlations in the system. Physical considerations are made to explain the nature of each entanglement regime as well as provide their respective thresholds.}, archive = {J_PRA}, author = {J. C. C. Capella and Alejandro Fonseca and Pablo L. Saldanha and D. Felinto}, doi = {10.1103/wmy8-jpvp}, journal = {Physical Review a}, month = {11}, number = {5}, pages = {052201}, shortjournal = {Phys. Rev. A}, title = {High-entanglement regimes in the weisskopf-wigner theory for spontaneous decay}, volume = {112}, year = {2025}, }
• (2025). Synthetic-reflectionless-mode exceptional degeneracies via emergent local symmetries. PRA, 112(4), L041502. (www)

  @article{ , abstract = {We propose physically realizable exceptional point degeneracies (EPDs) corresponding to synthetic reflectionless modes (SRMs). These are solutions of an auxiliary wave operator that is defined in synthetic frequency dimensions and describe incoming reflectionless waves onto a Floquet-driven cavity. The SRM-EPD emerges as a consequence of a local symmetry imposed on the auxiliary operator via appropriate Floquet driving. Its presence signifies the possibility to design wavefronts and time-modulated schemes with up or down targeted frequency conversion and flat transmission spectra. The theory is validated via simulations with driven RF resonators.}, archive = {J_PRA}, author = {William Tuxbury and Lucas J. Fernández-Alcázar and Tsampikos Kottos}, doi = {10.1103/vtps-ksmx}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L041502}, shortjournal = {Phys. Rev. A}, title = {Synthetic-reflectionless-mode exceptional degeneracies via emergent local symmetries}, volume = {112}, year = {2025}, }
• (2025). Kelvin-wave-inspired optical vortex excitation in kerr nonlinear media. PRA, 112(4), L041501. (www)

  @article{ , abstract = {We demonstrate a direct one-to-one correspondence between nonlinear optical fields in defocusing Kerr media and wave functions in weakly interacting Bose-Einstein condensates or quantum fluids. Based on this correspondence, we propose the existence of excitations in an optical vortex beam characterized by a helical deformation of its phase singularity core. These excitations are direct analogs of Kelvin waves known in quantum and classical fluid dynamics. We further show that the excitations exhibit two distinct branches, one of which includes a stationary solution. A feasible experimental scheme for generating these excitations is also discussed.}, archive = {J_PRA}, author = {Yosuke Minowa and Nobuhiko Yokoshi and Makoto Tsubota}, doi = {10.1103/mnlm-x9ch}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L041501}, shortjournal = {Phys. Rev. A}, title = {Kelvin-wave-inspired optical vortex excitation in kerr nonlinear media}, volume = {112}, year = {2025}, }
• (2025). Two-body contact of a bose gas near the superfluid–Mott-insulator transition. PRA, 112(4), L041301. (www)

  @article{ , abstract = {The two-body contact is a fundamental quantity of a dilute Bose gas that relates the thermodynamics to the short-distance two-body correlations. For a Bose gas in an optical lattice, near the superfluid–Mott-insulator transition, we show that a “universal” contact can be defined from the singular part of the pressure ( is the pressure of the Mott insulator). Its expression coincides with that of a dilute Bose gas provided we consider the effective “scattering length” of the quasiparticles at the quantum critical point (QCP) rather than the scattering length in vacuum, and the excess density of particles (or holes) with respect to the Mott insulator. Close to the transition, we find that the singular part of the momentum distribution exhibits a high-momentum tail of the form over a broad region of the Brillouin zone, where is the quasiparticle weight of the elementary excitations at the QCP. Our results demonstrate that the notion of contact extends to strongly correlated lattice bosons, and we argue that the contact can be measured in state-of-the-art experiments on Bose gases in optical lattices and magnetic insulators.}, archive = {J_PRA}, author = {Moksh Bhateja and Nicolas Dupuis and Adam Rançon}, doi = {10.1103/35w3-7snk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L041301}, shortjournal = {Phys. Rev. A}, title = {Two-body contact of a bose gas near the superfluid–Mott-insulator transition}, volume = {112}, year = {2025}, }
• (2025). Magic-wavelength trapping of alkali-metal rydberg atoms: The role of landscape polarization modulation. PRA, 112(4), L041101. (www)

  @article{ , abstract = {We construct an optical tweezer array for Rb atoms that provides the same trapping potentials for ground and Rydberg levels. By comparing the value of the trapping field detuning from the 40 s − 6 p transition frequency required to create such an array with that previously measured in an optical lattice [J. Lampen et al. , Phys. Rev. A 98 , 033411 (2018) ], we determine the modification of the polarizability of a Rydberg state atom confined in a spatially varying optical potential, as predicted by Topcu and Derevianko [ Phys. Rev. A 88 , 043407 (2013) ]. A state-insensitive atom array should enable more complex quantum computation by allowing the tweezer potentials to remain on during Rydberg gate operations.}, archive = {J_PRA}, author = {C. Jansohn and A. Londoño and Y. Li and H. Nguyen and P. R. Berman and A. Kuzmich}, doi = {10.1103/43wm-383m}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L041101}, shortjournal = {Phys. Rev. A}, title = {Magic-wavelength trapping of alkali-metal rydberg atoms: The role of landscape polarization modulation}, volume = {112}, year = {2025}, }
• (2025). Mass of helium-4 from cyclotron frequency ratios He+4/D2+ and He+4/H2D+. PRA, 112(4), L040801. (www)

  @article{ , abstract = {An accurate atomic mass of (or the alpha particle) is required for deriving the atomic mass of the electron from proposed measurements of the ground-state factor of . However, there is a six-standard deviation discrepancy between a recent measurement [S. Sasidharan, O. Bezrodnova, S. Rau, W. Quint, S. Sturm, and K. Blaum, Phys. Rev. Lett. 131 , 093201 (2023) ] and the measurement by Van Dyck et al. [R. S. Van Dyck, Jr., D. B. Pinegar, S. Van Liew, and S. L. Zafonte, Int. J. Mass Spectrom. 251 , 231 (2006) ], on which the current values in the Atomic Mass Evaluation and CODATA tabulation of fundamental constants are based. By measuring the cyclotron frequency ratios of to , and of to , we find the mass of to be , favoring the more recent value.}, archive = {J_PRA}, author = {Moisés Medina Restrepo and Maria Fernandez Davila and Cristian A. Navarro and Edmund G. Myers}, doi = {10.1103/v7k8-8my2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L040801}, shortjournal = {Phys. Rev. A}, title = {Mass of helium-4 from cyclotron frequency ratios He+4/D2+ and He+4/H2D+}, volume = {112}, year = {2025}, }
• (2025). Quantum metrology via floquet-engineered two-axis twisting and turning dynamics. PRA, 112(4), L040602. (www)

  @article{ , abstract = {One core of quantum metrology is the utilization of entanglement to enhance measurement precision beyond the standard quantum limit. Here, we utilize the Floquet-engineered two-axis twisting (TAT) and turning dynamics to generate Greenberger-Horne-Zeilinger (GHZ)-like states for quantum metrology. Using both analytical semiclassical and quantum approaches, we find that the desired N -particle GHZ-like state can be produced in a remarkably short time, t opt ∝ ln N / N , and its quantum Fisher information F Q opt ∝ N 2 approaches the Heisenberg limit. Owing to the rapid state preparation, it shows outstanding robustness against decoherence. Moreover, using the Floquet-engineered anti-TAT-and-turn, one may implement an efficient interaction-based readout protocol to extract the signal encoded in this GHZ-like state. This Floquet-engineered anti-TAT-and-turn approach offers a viable method to achieve effective time-reversal dynamics to improve measurement precision and resilience against detection noise, all without the need to invert the sign of the nonlinear interaction. This study paves a way for achieving entanglement-enhanced quantum metrology via rapid generation of GHZ-like states at high particle numbers through continuous Floquet engineering.}, archive = {J_PRA}, author = {Jihao Ma and Yi Shen and Jiahao Huang and Chaohong Lee}, doi = {10.1103/32n5-mhk1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L040602}, shortjournal = {Phys. Rev. A}, title = {Quantum metrology via floquet-engineered two-axis twisting and turning dynamics}, volume = {112}, year = {2025}, }
• (2025). Echoes in a parametrically perturbed kerr-nonlinear oscillator. PRA, 112(4), L040601. (www)

  @article{ , abstract = {We study classical and quantum echoes in a Kerr oscillator driven by a frequency-controlling pulsed perturbation. We consider the dynamical response to the perturbation for a single coherent state and for Schrödinger cat states constructed as both balanced and imbalanced superpositions of two coherent states. For individual coherent states, we demonstrate that a weak parametric drive yields a long-lived sequence of classical echoes. Cat states are found to exhibit distinct quantum echoes that are sensitive to the initial relative phase and weights of the coherent states in superposition. We examine the effect of dissipation on quantum echoes and quantum revivals of cat states. We demonstrate that, even when dissipation suppresses quantum revivals, quantum echoes can be recovered by properly tuning the timing and strength of the perturbation. These results may be useful for characterizing and mitigating errors of cat qubits.}, archive = {J_PRA}, author = {Yun-Wen Mao and Ilia Tutunnikov and Roman V. Krems and Ilya Sh. Averbukh}, doi = {10.1103/bv4c-6q9k}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L040601}, shortjournal = {Phys. Rev. A}, title = {Echoes in a parametrically perturbed kerr-nonlinear oscillator}, volume = {112}, year = {2025}, }
• (2025). Single-shot and measurement-based quantum error correction via fault complexes. PRA, 112(4), L040401. (www)

  @article{ , abstract = {Photonics provides a viable path to a scalable fault-tolerant quantum computer. The natural framework for this platform is measurement-based quantum computation, where fault-tolerant graph states supersede traditional quantum error-correcting codes. However, the existing formalism for foliation—the construction of fault-tolerant graph states—does not reveal how certain properties, such as single-shot error correction, manifest in the measurement-based setting. We introduce the fault complex, a representation of dynamic quantum error-correction protocols particularly well suited to describe foliation. Our approach enables precise computation of fault tolerance properties of foliated codes and provides insights into circuit-based quantum computation. Analyzing the fault complex yields improved thresholds for three- and four-dimensional toric codes, a generalization of stability experiments, and the existence of single-shot lattice surgery with higher-dimensional topological codes.}, archive = {J_PRA}, author = {Timo Hillmann and Guillaume Dauphinais and Ilan Tzitrin and Michael Vasmer}, doi = {10.1103/cjb4-l57n}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {L040401}, shortjournal = {Phys. Rev. A}, title = {Single-shot and measurement-based quantum error correction via fault complexes}, volume = {112}, year = {2025}, }
• (2025). Erratum: Cavity-assisted controlled phase-flip gates [Phys. rev. a 102, 013703 (2020)]. PRA, 112(4), 049903. (www)

  @article{ , abstract = {Phys. Rev. A 112, 049903 (2025)}, archive = {J_PRA}, author = {F. Kimiaee Asadi and S. C. Wein and C. Simon}, doi = {10.1103/c8yf-kv59}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {049903}, shortjournal = {Phys. Rev. A}, title = {Erratum: Cavity-assisted controlled phase-flip gates [Phys. rev. a 102, 013703 (2020)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Precision measurement of the ionization energy of cs i [Phys. rev. a 93, 013424 (2016)]. PRA, 112(4), 049902. (www)

  @article{ , abstract = {Phys. Rev. A 112, 049902 (2025)}, archive = {J_PRA}, author = {Johannes Deiglmayr and Holger Herburger and Heiner Saßmannshausen and Paul Jansen, Hansjürg Schmutz and Frédéric Merkt}, doi = {10.1103/5v5y-8m53}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {049902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Precision measurement of the ionization energy of cs i [Phys. rev. a 93, 013424 (2016)]}, volume = {112}, year = {2025}, }
• (2025). Retraction: Exotic behavior of parity in the superradiant phase of the quantum rabi model [Phys. rev. a 111, 043710 (2025)]. PRA, 112(4), 049901. (www)

  @article{ , abstract = {Phys. Rev. A 112, 049901 (2025)}, archive = {J_PRA}, author = {Yun-Tong Yang and Junpeng Liu and Hong-Gang Luo}, doi = {10.1103/nkhg-ztz1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {049901}, shortjournal = {Phys. Rev. A}, title = {Retraction: Exotic behavior of parity in the superradiant phase of the quantum rabi model [Phys. rev. a 111, 043710 (2025)]}, volume = {112}, year = {2025}, }
• (2025). Einstein-podolsky-rosen-type entanglement properties of a nondegenerate parametric amplifier with time-delayed coherent feedback. PRA, 112(4), 043724. (www)

  @article{ , abstract = {A study of an open nondegenerate parametric oscillator is presented below threshold in the undepleted pump regime with time-delayed coherent feedback. The figure of merit is the two-mode squeezing spectrum measuring the strength of continuous-variable Einstein-Podolsky-Rosen-type entanglement between the down-converted modes in the output field as a function of frequency. Exploring different areas of the parameter space reveals the possibility of significantly enhanced entanglement with tunable characteristic frequency. This is a result of the emerging dynamical features that are only accessible due to delayed feedback. The system is very sensitive to phase matching, which can be adjusted by various parameters of the system and the feedback loop. In this way, sharp, resonancelike features are obtained that show a level of robustness against extraneous losses.}, archive = {J_PRA}, author = {Nikolett Német and Tamás Kiss and Scott Parkins}, doi = {10.1103/lg16-k4c9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043724}, shortjournal = {Phys. Rev. A}, title = {Einstein-podolsky-rosen-type entanglement properties of a nondegenerate parametric amplifier with time-delayed coherent feedback}, volume = {112}, year = {2025}, }
• (2025). Non-markovian spontaneous emission in a tunable cavity formed by atomic mirrors. PRA, 112(4), 043723. (www)

  @article{ , abstract = {We analyze the non-Markovian spontaneous-emission dynamics of a two-level test atom placed in a cavity formed by two atomic arrays in a waveguide quantum electrodynamics (QED) setup. We demonstrate a crossover from single-mode to multimode strong-coupling cavity QED as the cavity length becomes comparable to the coherence length associated with collective spontaneous emission . The resulting non-Markovian dynamics of the test atom and the emergent spectral density of the field are analyzed as a function of various tunable atomic array parameters: the number of atoms, length of the atomic cavity, and resonance frequency of the atoms forming the atomic mirrors. Our results show limitations to cooperatively enhanced light-matter coupling in the presence of time-delayed feedback. We further illustrate that the non-Markovian system dynamics can be efficiently approximated in terms of a few modes of the emergent spectral density of the field.}, archive = {J_PRA}, author = {Annyun Das and Pablo Solano and Kanu Sinha}, doi = {10.1103/29yv-12sq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043723}, shortjournal = {Phys. Rev. A}, title = {Non-markovian spontaneous emission in a tunable cavity formed by atomic mirrors}, volume = {112}, year = {2025}, }
• (2025). Enhancement of non-gaussianity and nonclassicality of pair coherent states with a postselected von neumann measurement. PRA, 112(4), 043722. (www)

  @article{ , abstract = {We investigate the effects of postselected von Neumann measurements on the nonclassical properties of pair coherent states (PCS). We calculated key quantum characteristics, such as squeezing, photon statistics, entanglement between the two modes of PCS, and teleportation fidelity. Our results demonstrate that postselected von Neumann measurements enhance both the non-Gaussianity and nonclassicality of PCS. These findings are validated by analyzing the scaled joint Wigner function across various system parameters. We also notice that in weak measurement regimes, the teleportation fidelity via a PCS-based quantum channel under postselected von Neumann measurements could maintain successful teleportation for anomalous weak values of the measured system observable. The theoretical optimization scheme offers an alternative approach for improving PCS-based quantum information efficiency and facilitates practical implementations in quantum technologies.}, archive = {J_PRA}, author = {Yi-Fang Ren and Janarbek Yuanbek and Yusuf Turek}, doi = {10.1103/xldj-cz67}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043722}, shortjournal = {Phys. Rev. A}, title = {Enhancement of non-gaussianity and nonclassicality of pair coherent states with a postselected von neumann measurement}, volume = {112}, year = {2025}, }
• (2025). Hofstadter butterfly and topological edge states in a one-dimensional cavity magnonic lattice. PRA, 112(4), 043721. (www)

  @article{ , abstract = {Fractal energy spectra arise from the interplay between two periodic parameters at different scales. Artificial lattices with nontrivial topological features in synthetic dimensions can emulate such interplay, exhibiting topological boundary correspondence and fractal structures resembling the Hofstadter butterfly. However, the realization of Hofstadter butterfly spectra in cavity magnonic lattices has received limited attention. In this work, we propose a one-dimensional cavity magnonic lattice in which each unit cell couples a cavity photon with a magnon. By tuning the system parameters to implement a synthetic magnetic flux, we demonstrate the emergence of a Hofstadter butterflylike energy spectrum and the formation of distinct edge-state modes. These edge states exhibit flipping behavior, enabling controlled storage and transmission of quantum information. We further analyze the spectral structure and compute thetopological invariants to characterize the system's phase diagram. The influence of random defects is also investigated. While small imperfections have minimal impact on topological properties, larger defects may disrupt the edge modes, highlighting the need for defect suppression to preserve topological robustness in practical implementations.}, archive = {J_PRA}, author = {Ling Li and Yi-Ping Wang and Ai-Xi Chen}, doi = {10.1103/cc91-n6b3}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043721}, shortjournal = {Phys. Rev. A}, title = {Hofstadter butterfly and topological edge states in a one-dimensional cavity magnonic lattice}, volume = {112}, year = {2025}, }
• (2025). Transient dynamics of the quantum stuart-landau oscillator. PRA, 112(4), 043720. (www)

  @article{ , abstract = {We investigate the transient dynamics of the quantum Stuart-Landau oscillator, a paradigmatic quantum system exhibiting a quantum limit cycle and synchronization. From the energy dynamics, we determine a condition for the classical regime of transient dynamics and the limit cycle. Additionally, we formulate a guess function that fits the classical-regime steady-state Wigner function. The equation of motion for the Wigner function is derived and compared to the Kramers-Moyal equation for stochastic processes. We then characterize the classical-like behavior as the system evolves from a coherent state, noting the slow decay of neighboring-level coherence. We also study the evolution of the Wigner negativity as an indicator of nonclassicality, showing its temporary increase for some specific cases. To quantify the evolution speed, we examined the system's Lindbladian spectra, particularly the Liouvillian gap. Finally, we record the time it takes to reach the steady state for some Fock, thermal, and coherent states. The parameter dependence of the steady-state time may differ from the Liouvillian gap, and the limit-cycle attraction is significantly slower for coherent states compared to Fock or thermal states. For the diagonal states, there are fast convergence regimes for which the steady-state time is locally minimized. This study provides a deeper insight into the transient behavior of self-sustained quantum systems.}, archive = {J_PRA}, author = {Hendry M. Lim and Donny Dwiputra and M. Shoufie Ukhtary and Ahmad R. T. Nugraha}, doi = {10.1103/vtt6-qr94}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043720}, shortjournal = {Phys. Rev. A}, title = {Transient dynamics of the quantum stuart-landau oscillator}, volume = {112}, year = {2025}, }
• (2025). Spin-selective coherent light scattering from ion crystals. PRA, 112(4), 043719. (www)

  @article{ , abstract = {We study coherent light scattering from linear crystals with up to twelve ions, acting as single photon emitters. Light scattering is induced by two-photon laser excitation, starting from the quadrupole transition at 729 nm followed by the dipole transition at 854 nm, from where the ions decay back to the ground state via emission of a photon near 393 nm. We realize spin-selective excitation from the Zeeman-split ground states , of the ions and observe, in the far-field, spin-dependent interference patterns displaying the spin textures of the ion crystals. We investigate their dynamics by measuring the temporal evolution of the spatial Fourier frequencies of the observed patterns.}, archive = {J_PRA}, author = {Maurizio Verde and Ansgar Schaefer and Benjamin Zenz and Zyad Shehata and Stefan Richter and Christian T. Schmiegelow and Joachim von Zanthier and Ferdinand Schmidt-Kaler}, doi = {10.1103/7bd7-4trn}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043719}, shortjournal = {Phys. Rev. A}, title = {Spin-selective coherent light scattering from ion crystals}, volume = {112}, year = {2025}, }
• (2025). Moiré superradiance in cavity quantum electrodynamics with quantum atom gas. PRA, 112(4), 043718. (www)

  @article{ , abstract = {As a novel platform for exploring exotic quantum phenomena, the moiré lattice has garnered significant interest in solid-state physics, photonics, and cold-atom physics. While moiré lattices in two- and three-dimensional systems have been proposed for neutral cold atoms, the simpler one-dimensional moiré effect remains largely unexplored. We present a scheme demonstrating moiré effects in a one-dimensional cold-atom–cavity coupling system, which resembles a generalized open Dicke model exhibiting superradiant phase transitions. We reveal a strong link between the phase transition critical point and the one-dimensional moiré parameter. Evidence of the one-dimensional moiré effect is explicitly explored, including the cavity field spectrum, phase transition dynamics, and anomalous atomic diffusion. This work provides a new route for testing one-dimensional moiré effects with cold atoms and opens new possibilities in moiré metrology.}, archive = {J_PRA}, author = {Lu Zhou and Zheng-Chun Li and Keye Zhang and Zhihao Lan and Alessio Celi and Weiping Zhang}, doi = {10.1103/6751-zclb}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043718}, shortjournal = {Phys. Rev. A}, title = {Moiré superradiance in cavity quantum electrodynamics with quantum atom gas}, volume = {112}, year = {2025}, }
• (2025). Collective emission and selective radiance in atomic clouds and arrays coupled to a microring resonator. PRA, 112(4), 043717. (www)

  @article{ , abstract = {We theoretically investigate the collective dipole-dipole interactions in atoms coupled to a nanophotonic microring resonator. The atoms can interact with each other through light-induced dipole-dipole interactions mediated by free space and through the resonator whispering-gallery modes. The differing characteristics and mismatched wave numbers of these modes give rise to complex dynamics and provide new opportunities for controlling light-matter interactions. We explore these phenomena in the context of an experimentally realized atom cloud and study the potential of the proposed subwavelength atom arrays.}, archive = {J_PRA}, author = {Deepak A. Suresh and Xinchao Zhou and Chen-Lung Hung and F. Robicheaux}, doi = {10.1103/q8rz-8g2h}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043717}, shortjournal = {Phys. Rev. A}, title = {Collective emission and selective radiance in atomic clouds and arrays coupled to a microring resonator}, volume = {112}, year = {2025}, }
• (2025). Complementary probes of gravitational radiation states. PRA, 112(4), 043716. (www)

  @article{ , abstract = {We demonstrate that statistical fluctuations in resonant radiation detectors operating in homodyne and heterodyne modes offer additional, complementary information to that obtained from their direct operation as click detectors. We use this to refine tests of the coherent-state hypothesis, which is of special interest for gravitational wave fields.}, archive = {J_PRA}, author = {Sreenath K. Manikandan and Frank Wilczek}, doi = {10.1103/83tt-tt57}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043716}, shortjournal = {Phys. Rev. A}, title = {Complementary probes of gravitational radiation states}, volume = {112}, year = {2025}, }
• (2025). Quantification of dissipation in a multilevel electromagnetically-induced-transparency system. PRA, 112(4), 043715. (www)

  @article{ , abstract = {Electromagnetically induced transparency (EIT) in multilevel atomic systems exhibits complex dependencies on optical depth (OD) and polarization configurations, yet their combined effects remain underexplored. Here, we introduce a dissipation factor which quantifies polarization-dependent absorption resulting from the emergence of dissipative channels. Starting from a semiclassical framework, we derive the transmission of a resonant probe as , where denotes the optical depth, demonstrating that and OD jointly govern the transparency. And broadly, is universally applicable across any multilevel system when its value spans a range , where corresponds to ideal transparency and represents pure absorption. Our experimental results in cold atomic ensemble across low and high OD regimes confirm the completeness of the theoretical model, with EIT line shapes showing close agreement with simulations. By elucidating the joint effects of OD and polarization-dependent dissipation in EIT, this work is conducive to systemic optimization in multilevel EIT systems such as quantum memory, optical switching, and precision metrology applications.}, archive = {J_PRA}, author = {ZeHao Shen and Enze Li and Yan Li and Wei Zhang and Hong Gao}, doi = {10.1103/qby1-jhtm}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043715}, shortjournal = {Phys. Rev. A}, title = {Quantification of dissipation in a multilevel electromagnetically-induced-transparency system}, volume = {112}, year = {2025}, }
• (2025). Quantum aberrations: Entangling photons with zernike polynomials. PRA, 112(4), 043714. (www)

  @article{ , abstract = {We introduce Zernike polynomials as a novel degree of freedom for encoding quantum information in the spatial structure of photons. Building on their orthogonality and completeness over the unit disk, we develop a framework for generating, manipulating, and detecting photons in Zernike modes, and propose methods for realizing single-photon and two-photon Zernike wave packets. We demonstrate analytically that two-photon states generated via spontaneous parametric down-conversion exhibit mode entanglement in the Zernike basis, with correlations arising from selection rules enforced by Clebsch-Gordan coefficients. Our results open a new pathway for structured spatial entanglement, complementary to schemes based on Laguerre-Gaussian or Hermite-Gaussian modes, and suggest practical experimental implementations based on holographic modulation and optical Fourier techniques.}, archive = {J_PRA}, author = {H. Avetisyan and G. Nikoghosyan}, doi = {10.1103/dbfr-f46b}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043714}, shortjournal = {Phys. Rev. A}, title = {Quantum aberrations: Entangling photons with zernike polynomials}, volume = {112}, year = {2025}, }
• (2025). Excitation transfer and many-body dark states in waveguide quantum electrodynamics. PRA, 112(4), 043713. (www)

  @article{ , abstract = {In one-dimensional waveguide quantum electrodynamics systems, quantum emitters interact through infinite-range, dispersive, and dissipative dipole-dipole interactions mediated by guided photonic modes. These long-range periodic interactions give rise to rich many-body physics absent in free space. In this work, we construct a set of symmetrized multiexcitation dark states and derive analytic expressions for their time-evolution projections. This framework captures the essential dynamics of excitation transport and storage while significantly reducing computational complexity compared to full master equation simulations. Our analysis reveals a fundamental bound on energy redistribution governed by the structure of dark states and collective dissipation and discovers that optimal excitation transfer between emitter ensembles converges toward an initial pumped fraction of N p / N ≈ 0.55 for large system sizes. We further examine the robustness of this mechanism under realistic imperfections, including positional disorder, nonradiative decay, and dephasing. These results highlight the role of many-body dark states in enabling efficient and controllable energy transfer, offering new insights into dissipative many-body dynamics in integrated quantum platforms.}, archive = {J_PRA}, author = {Wei Chen and Guin-Dar Lin and H. H. Jen}, doi = {10.1103/tgbv-x4qz}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043713}, shortjournal = {Phys. Rev. A}, title = {Excitation transfer and many-body dark states in waveguide quantum electrodynamics}, volume = {112}, year = {2025}, }
• (2025). Two-photon superradiance and subradiance. PRA, 112(4), 043712. (www)

  @article{ , abstract = {We consider the problem of two-photon cooperative emission in systems of two-level atoms. Two physically distinct regimes are analyzed. First, we investigate the case of a small number of atoms. We study the evolution of two-photon super- and subradiant states and the associated two-photon spectra. Second, we investigate the problem of atoms at constant density confined to a spherical volume. We analyze separately the cases in which the radius is small or large compared to the resonant wavelength.}, archive = {J_PRA}, author = {Wenxuan Xie and Imran M. Mirza and John C. Schotland}, doi = {10.1103/dbny-pjqc}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043712}, shortjournal = {Phys. Rev. A}, title = {Two-photon superradiance and subradiance}, volume = {112}, year = {2025}, }
• (2025). Dual-domain coherent emission: Photon-magnon laser in a hybrid quantum system. PRA, 112(4), 043711. (www)

  @article{ , abstract = {We present a quantum theoretical framework that describes the simultaneous emergence of magnon- and photon lasing in a tripartite hybrid solid-state platform. The system integrates optically pumped nitrogen-vacancy (NV) centers, a magnetic yttrium-iron-garnet (YIG) microsphere, and a microwave (MW) cavity. Through a comprehensive analysis of the system's dynamics, we reveal the cooperative interactions that drive coherent-stimulated emission in both the magnonic (spin-wave) and photonic (electromagnetic) domains. The model outlines a scalable configuration in which NV centers, excited via optical pumping, couple efficiently to the magnon modes of the YIG sphere placed inside the microwave cavity. Numerical simulations based on experimentally accessible parameters confirm the feasibility of dual-domain lasing. This work advances the integration of photonic and magnonic platforms, opening new opportunities for quantum-enhanced sensing, low-power spintronics, and on-chip quantum information processing.}, archive = {J_PRA}, author = {Sofia Ribeiro and Pardeep Kumar}, doi = {10.1103/2vkc-y6ww}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043711}, shortjournal = {Phys. Rev. A}, title = {Dual-domain coherent emission: Photon-magnon laser in a hybrid quantum system}, volume = {112}, year = {2025}, }
• (2025). Floquet engineering of light-matter strong coupling. PRA, 112(4), 043710. (www)

  @article{ , abstract = {Light-matter strong coupling has been the subject of much attention in recent decades, giving optical systems unique features. However, properties of a system with strong coupling are determined by the properties of its components and are thus difficult to control. Here, we propose Floquet engineering, a technique of controlling the energy levels of a quantum system using external fields, as a method of manipulating a hybrid system of a molecule strongly coupled to a single-mode resonator. We show that an external field can change the relative positions of levels in an open strongly coupled system, leading to a change in the rates of transitions between them. We demonstrate that if the frequency of the pumping wave is close to polariton transitions in the hybrid system, nonmonotonic dependence of fluorescence and scattering amplitudes on pump intensity with a narrow resonance-like response occurs. We show that this phenomenon occurs due to hybridization of the lower and upper polaritons with substantially different excitation numbers caused by the pumping affecting polariton states of the system. This occurs when the Rabi interaction with the coherent field is comparable to the field-matter coupling constant, which in turn needs to be sufficient for the manifestation of strong coupling. This nonmonotonic dependence of the fluorescence and scattering amplitudes on pump rate intensity paves the way for the creation of nonlinear optical devices.}, archive = {J_PRA}, author = {I. S. Pashkevich and I. V. Doronin and A. A. Zyablovsky and E. S. Andrianov}, doi = {10.1103/41fc-w2jy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043710}, shortjournal = {Phys. Rev. A}, title = {Floquet engineering of light-matter strong coupling}, volume = {112}, year = {2025}, }
• (2025). Collective dissipation of oscillator dipoles strongly coupled to one-dimensional electromagnetic reservoirs. PRA, 112(4), 043709. (www)

  @article{ , abstract = {We study the collective dissipative dynamics of dipoles modeled as harmonic oscillators coupled to one-dimensional electromagnetic reservoirs. The bosonic nature of the dipole oscillators as well as the reservoir modes allows an exact numerical simulation of the dynamics for arbitrary coupling strengths. At weak coupling, apart from essentially recovering the dynamics expected from a Markovian Lindblad master equation, we also obtain non-Markovian effects for spatially separated two-level emitters. In the so-called ultrastrong coupling regime, we find the dynamics and steady state depends on the choice of the reservoir which is chosen as either an ideal cavity with equispaced, unbounded dispersion or a cavity array with a bounded dispersion. Moreover, at even higher coupling strengths, we find a decoupling between the light and matter degrees of freedom attributable to the increased importance of the diamagnetic term in the Hamiltonian. In this regime we find that the dependence of the dynamics on the separation between the dipoles is not important and the dynamics is dominated by the occupation of the polariton mode of lowest energy.}, archive = {J_PRA}, author = {Subhasish Guha and Ipsita Bar and Bijay Kumar Agarwalla and B. Prasanna Venkatesh}, doi = {10.1103/dnnn-5b5p}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043709}, shortjournal = {Phys. Rev. A}, title = {Collective dissipation of oscillator dipoles strongly coupled to one-dimensional electromagnetic reservoirs}, volume = {112}, year = {2025}, }
• (2025). Dark-state entanglement of two atomic ensembles via cavity superradiance. PRA, 112(4), 043708. (www)

  @article{ , abstract = {We propose an effective model leveraging cavity superradiance to achieve entanglement between two spatially separated two-level atomic ensembles trapped in a standing-wave optical cavity. This model is based on permutational symmetry breaking, which leads to the emergence of entangled quantum dark states with nonzero excitations but vanishing decay rate. This steady-state entanglement is created by purely dissipative dynamics, unlike the superradiance of permutationally symmetric two-level atoms, whose steady state is the ground state. Furthermore, we show that the entanglement is significantly enhanced near critical points in the superradiance potential because of the extremely high two-mode squeezing factor between two atomic ensembles. We also discuss spin squeezing in each atomic ensemble in the vicinity of specific critical points in the potential. These findings may play an important role in the generation of correlations immune to dissipation in separated atomic modes.}, archive = {J_PRA}, author = {Kang Shen and Xiangming Hu and Fei Wang}, doi = {10.1103/8jcs-g21s}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043708}, shortjournal = {Phys. Rev. A}, title = {Dark-state entanglement of two atomic ensembles via cavity superradiance}, volume = {112}, year = {2025}, }
• (2025). Dissipatively driven non-gaussian mechanical entanglement and remote preparation of motional schrödinger cat states. PRA, 112(4), 043707. (www)

  @article{ , abstract = {In this paper, we propose a driven-dissipative scheme for generating non-Gaussian entangled mechanical states and consider the remote preparation of motional Schrödinger cat states via mechanical entanglement. The system under our study consists of a cavity optomechanical setup with two frequency-mismatched mechanical oscillators simultaneously coupled to a bichromatically driven cavity field. We show that under appropriate conditions, an effective Hamiltonian for nondegenerate parametric down-conversion involving the two mechanical oscillators and the cavity field can be engineered. We demonstrate analytically and numerically that the cavity dissipation drives the mechanical oscillators into a steady-state non-Gaussian entangled state. The properties of the mechanical state, including non-Gaussianity, Wigner negativity, entanglement, and quantum steering, are investigated in detail. We further reveal that through the non-Gaussian mechanical entanglement, the remote preparation of the Schrödinger cat states of one mechanical oscillator can be achieved by coupling the other one to an auxiliary probe cavity and homodyning the output of the probe cavity. We also discuss the robustness of the mechanical states against thermal fluctuations. Our scheme provides a feasible approach for the dissipative and remote preparation of non-Gaussian mechanical nonclassical states.}, archive = {J_PRA}, author = {Zunbo Yu and Miaomiao Wei and Huatang Tan}, doi = {10.1103/rm6d-49zs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043707}, shortjournal = {Phys. Rev. A}, title = {Dissipatively driven non-gaussian mechanical entanglement and remote preparation of motional schrödinger cat states}, volume = {112}, year = {2025}, }
• (2025). Vacuum-induced excitation of surface plasmon polaritons. PRA, 112(4), 043706. (www)

  @article{ , abstract = {We present a surface plasmon resonance scheme for the excitation of surface plasmon polaritons (SPPs) employing vacuum-induced transparency. The system under consideration consists of a metal-dielectric interface placed within an optical cavity, where the dielectric medium is composed of three-level atoms in a Λ -type configuration. These atoms interact coherently with an incident probe and quantized cavity fields. Our theoretical analysis demonstrates that SPPs can be excited even in the absence of classical control fields, i.e., when the cavity is in its vacuum state. We also show that the electric-field-enhancement factor increases with the number of cavity photons. Furthermore, we analyze the propagation length and lifetime of the SPPs and observe that both are enhanced as the cavity photon number increases.}, archive = {J_PRA}, author = {Fazal Badshah and Yuan Zhou and Muhammad Idrees and Ziauddin and Rahmatullah}, doi = {10.1103/p7k9-y1vr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043706}, shortjournal = {Phys. Rev. A}, title = {Vacuum-induced excitation of surface plasmon polaritons}, volume = {112}, year = {2025}, }
• (2025). Improving quantum-battery lifetime by the electromagnetically-induced-transparency effect and bound states. PRA, 112(4), 043705. (www)

  @article{ , abstract = {Quantum battery (QB) is an application of quantum thermodynamics which uses quantum effects to store and transfer energy, overcoming the limitations of classical batteries and potentially improving the QB's performance. However, due to the interaction with the external environment, it leads to decoherence and thus reduces both the lifetime and the charging efficiency of QB. Here, we propose suppressing the environmental dissipation in the energy-storage process of the QB by exploiting both the electromagnetically-induced-transparency (EIT) effect and bound states. By constructing a hybrid system composed of a four-level atom and a coupled-cavity array, two bound states are formed in the system when the energy of the QB is in the energy band of the cavity array. Environmental dissipation is significantly inhibited due to the bound state and EIT effects, which extends the lifetime of the QB. We show that the charging efficiency of the QB is optimal when the energy of the QB is in resonance with the cavity. In addition, there is an optimal coupling strength between the two adjacent cavities, which helps to improve the performance of the QB. Our research has achieved the realization of long-term energy storage while improving the charging efficiency of QB, which has practical implications for the realization of QB.}, archive = {J_PRA}, author = {Jin-Tian Zhang and Cheng-Ge Liu and Qing Ai}, doi = {10.1103/rzgc-h78v}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043705}, shortjournal = {Phys. Rev. A}, title = {Improving quantum-battery lifetime by the electromagnetically-induced-transparency effect and bound states}, volume = {112}, year = {2025}, }
• (2025). Vacuum rabi splitting and quantum fisher information of a non-hermitian qubit in a single-mode cavity. PRA, 112(4), 043704. (www)

  @article{ , abstract = {A natural extension of the non-Hermitian qubit is to place it in a single-mode cavity. This setup corresponds to the quantum Rabi model (QRM) with a purely imaginary bias on the qubit, exhibiting parity-time ( P T ) symmetry. In this work, we first solve the P T -symmetric QRM using the Bogoliubov operator approach. We derive the transcendental function responsible for the exact solution, which can also be used to precisely identify exceptional points. The adiabatic approximation previously used can be easily formulated within this approach by considering transitions between the same manifolds in the space of Bogoliubov operators. By further considering transitions between the nearest-neighboring manifolds, we can analytically obtain more accurate eigensolutions. Moreover, these simple corrections can capture the main features of the dynamics, where the adiabatic approximation fails. Furthermore, the rich characteristics of the vacuum Rabi splitting in the emission spectrum are predicted. The width of the peaks increases with the coupling strength and the imaginary biases, reflecting the nature of open quantum systems. Additionally, we identify a quantum-criticality-enhanced effect by calculating the quantum Fisher information. Near the exceptional points, the quantum Fisher information in the P T -symmetric QRM is significantly higher than that of the non-Hermitian qubit component. This may open a new avenue for enhancing quantum sensitivity in non-Hermitian systems by incorporating coupling with an additional degree of freedom, enabling more precise parameter estimation.}, archive = {J_PRA}, author = {Yi-Cheng Wang and Jiong Li and Li-Wei Duan and Qing-Hu Chen}, doi = {10.1103/m7kc-vc9h}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043704}, shortjournal = {Phys. Rev. A}, title = {Vacuum rabi splitting and quantum fisher information of a non-hermitian qubit in a single-mode cavity}, volume = {112}, year = {2025}, }
• (2025). Emission from driven atoms in collective strong coupling with an optical cavity. PRA, 112(4), 043703. (www)

  @article{ , abstract = {We study self-sustained cavity emission from driven atoms in collective strong coupling. The cavity emission occurs over a wide range of atom-cavity and drive-laser detunings without any external input to the cavity mode. Second-order correlation measurements g ( 2 ) ( τ ) further reveal unanticipated phenomena in the observed cavity emission such as (1) damped oscillations at two frequencies and (2) significantly distinct g ( 2 ) ( τ ) for different polarization components. The intricate relation between cavity-emission intensity, drive-laser detuning, and atom-cavity detunings is explained. A possible mechanism for the damped oscillations with two frequency components in g ( 2 ) ( τ ) is suggested. Measurements show the existence of two separate polarization-decoupled mechanisms with distinct photon statistics, through which energy is transferred from the drive field to the cavity field. The statistical properties and mechanisms underlying cavity emission present valuable insights for extending nondestructive detection techniques to the regime of collective strong coupling.}, archive = {J_PRA}, author = {V. R. Thakar and Arun Bahuleyan and V. I. Gokul and S. P. Dinesh and S. A. Rangwala}, doi = {10.1103/hbp6-72yn}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043703}, shortjournal = {Phys. Rev. A}, title = {Emission from driven atoms in collective strong coupling with an optical cavity}, volume = {112}, year = {2025}, }
• (2025). Spectral control of quantum correlations in four-wave mixing using dressing fields. PRA, 112(4), 043702. (www)

  @article{ , abstract = {We present a microscopic description of dressed four-wave mixing (4WM) demonstrating spectral control of quantum correlations. Starting from a double Λ model for a single pump 4WM, we include a dressing field coupling the excited level, which leads to a six-wave mixing process. The model describes the enhancement of amplification and amplitude modulation in situ , due to the interaction of the dressing field, according to the experimental parameters. Moreover, the model predicts that the interaction with dressing fields allows the spectral control of the quantum correlations between pairs of sidebands by simply tuning the dressing field accordingly. This work paves the way towards all-optical control of quantum correlations in the continuous variable context.}, archive = {J_PRA}, author = {R. L. Rincon Celis and A. Montaña Guerrero and H. M. Florez}, doi = {10.1103/l4tn-sbfp}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043702}, shortjournal = {Phys. Rev. A}, title = {Spectral control of quantum correlations in four-wave mixing using dressing fields}, volume = {112}, year = {2025}, }
• (2025). Two-photon resonance fluorescence in a three-level ladder-type atom. PRA, 112(4), 043701. (www)

  @article{ , abstract = {In this work, we consider a three-level ladder-type atom driven by a coherent field, inspired by the experimental work of Gasparinetti et al. [ Phys. Rev. A 100 , 033802 (2019) ]. When driven on two-photon resonance, the atom is excited into its highest energy state | f 〉 by absorbing two photons simultaneously. The atom then de-excites via a cascaded decay | f 〉 → | e 〉 → | g 〉 . Here we present a theoretical study of the atomic fluorescence spectrum where, upon strong coherent driving, the spectrum exhibits seven distinct frequencies corresponding to transitions among the atomic dressed states. We characterize the quantum statistics of the emitted photons by investigating the second-order correlation functions of the emitted field. We do so by considering the total field emitted by the atom and focusing on each of the dressed-state components, taking in particular a secular-approximation and deriving straightforward, transparent analytic expressions for the second-order auto- and cross-correlations.}, archive = {J_PRA}, author = {Jacob Ngaha and Scott Parkins and Howard J. Carmichael}, doi = {10.1103/3lrt-ygwp}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043701}, shortjournal = {Phys. Rev. A}, title = {Two-photon resonance fluorescence in a three-level ladder-type atom}, volume = {112}, year = {2025}, }
• (2025). Multigap topology engineering in non-hermitian superlattices. PRA, 112(4), 043549. (www)

  @article{ , abstract = {Non-Hermiticity incorporating gain and loss allows new symmetries, enriching the fundamental topological classification. While various non-Hermitian topological phases have been uncovered, the interplay between multigap topology and non-Hermiticity remains to be explored. Here we investigate the topological states of a multiband tetramerized superlattice by introducing three distinct gain-loss patterns: ( i g , − i g , i g , − i g ) , ( i g , i g , − i g , − i g ) , and ( i g , − i g , − i g , i g ) . We uncover the unique effects of each configuration on the multigap topological edge states. Specifically, we find that the non-Hermiticity in the first configuration does not affect the multigap topological phases. Interestingly, it leads to a multiple reemergence behavior of the midgap defect state. For the second one, the gain-loss induces a topological phase transition in the midgap from nontrivial to trivial. Additionally, it results in the emergence of trivial edge states when the nonmidgap is initially trivial. The non-Hermiticity in the third one drives a topological phase transition in the midgap from trivial to nontrivial, while simultaneously destroying the localized topological edge states in the nonmidgap. Our results show a rich synergy between non-Hermiticity and multigap topology, introducing avenues for controlling multigap topological edge modes, which may have potential applications in multifrequency topological devices.}, archive = {J_PRA}, author = {Gaoyu Zhang and Juan Kang and Chaohua Wu and D. Zheng and Y. Zhou and W. Bao and Gang Chen}, doi = {10.1103/xwb5-d933}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043549}, shortjournal = {Phys. Rev. A}, title = {Multigap topology engineering in non-hermitian superlattices}, volume = {112}, year = {2025}, }
• (2025). Enhanced asymmetric entanglement dynamics at higher-order exceptional points via optomechanical induced squeezing. PRA, 112(4), 043548. (www)

  @article{ , abstract = {The exotic entanglement dynamics associated with exceptional points (EP) have been explored in a ring mechanical system, which consists of a phase-dependent phonon-hopping interaction and two phonon-squeezing interactions. By modulating the gauge-invariant phase of the system, the spontaneous -symmetry breaking can be generated, enabling the realization of higher-order EPs, such as second- and third-order EPs. The entanglement dynamics are strongly dependent on the orders of the EP. Specifically, both bipartite and tripartite entanglements emerge near the second-order EP, while the third-order EP leads to optimal bipartite entanglement with vanishing tripartite entanglement. Moreover, the asymmetric feature of the bipartite entanglement can be controlled by tuning the parity of the third-order EP through modulation of the system's gauge-invariant phase. The work indicates that the entanglement dynamics associated with EPs may provide a useful platform for realizing non-Hermiticity-enhanced quantum information processing.}, archive = {J_PRA}, author = {Yi-Bing Qian and Lei Tang and Deng-Gao Lai and Bang-Pin Hou}, doi = {10.1103/jjq2-m5k8}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043548}, shortjournal = {Phys. Rev. A}, title = {Enhanced asymmetric entanglement dynamics at higher-order exceptional points via optomechanical induced squeezing}, volume = {112}, year = {2025}, }
• (2025). Single-layered all-dielectric chiral metasurfaces via mie resonances. PRA, 112(4), 043547. (www)

  @article{ , abstract = {This study reports the design and optimization of a single-layer, all-dielectric chiral metasurface based on Mie resonances. The metasurface comprises dielectric cylinders with varying radii and exhibits strong performance in the near-infrared region, showing pronounced circular dichroism and optical activity. Its performance is analyzed using exact Mie resonance decomposition to calculate the scattering cross section and the phase of the electric dipole mode. The metasurface achieves a transmittance difference of 0.644 between right- and left-circularly polarized light at 1520 nm and a maximum optical activity of 150 °/λ, despite a thickness of only 580 nm (about one-third of the target wavelength). These results demonstrate that a single-layer metasurface can deliver optical performance comparable to more complex chiral structures, highlighting its efficiency and potential for practical optical applications. Moreover, the design strategy can be extended to other chiral metasurfaces by varying the arrangement and spacing of the dielectric cylinders, offering advantages in fabrication simplicity and cost effectiveness. This work advances the development of next-generation chiral devices for sensing, polarization control, and nonlinear optical applications.}, archive = {J_PRA}, author = {S. H. Hong and S. Hong and Y. Kim and B. Kim and J. Lee and S.-H. Kwon}, doi = {10.1103/32kk-5w5x}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043547}, shortjournal = {Phys. Rev. A}, title = {Single-layered all-dielectric chiral metasurfaces via mie resonances}, volume = {112}, year = {2025}, }
• (2025). Incomplete chirality of exceptional points in asymmetric optical microcavity. PRA, 112(4), 043546. (www)

  @article{ , abstract = {A chiral exceptional point (EP) in an optical microcavity emerges from the coalescence of even and odd modes with identical azimuthal modal numbers under asymmetric perturbation. While the chirality of such EPs is well understood in circular disks with asymmetrically positioned Rayleigh scatterers, it becomes more intricate in asymmetric microcavities, where the contributing modes can exhibit nontrivial wave morphology according to chaotic deformation. To explore this, we consider a stand-alone microcavity composed of one half ellipse and two quarter ellipses, for which EPs exhibit incomplete chirality. Our analysis reveals that this incomplete chirality originates from prior mode coupling. After the prior mode coupling, only the quasinormal modes within each superposed mode pair that have identical azimuthal modal numbers but opposite parities contribute to the chirality at EPs. Consequently, the chirality of the EP modes remains incomplete, depending on the relative weight of the original mode pair. Finally, we analyze the formation of EPs and their chiral properties in a generic asymmetric microcavity, providing insights into the underlying mechanisms of incomplete chirality.}, archive = {J_PRA}, author = {Hyundong Kim and Youngmin Eom and Hoyeon Lee and Yanni Cho and Seungwoo Lee and Sunjae Gwak and Hyeon-Hye Yu and Chang-Hwan Yi and Chil-Min Kim}, doi = {10.1103/xqpf-t9h6}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043546}, shortjournal = {Phys. Rev. A}, title = {Incomplete chirality of exceptional points in asymmetric optical microcavity}, volume = {112}, year = {2025}, }
• (2025). Quantumness and its hierarchies in PT-symmetric down-conversion models. PRA, 112(4), 043545. (www)

  @article{ , abstract = {We investigate the hierarchy of quantum correlations in a quadratic bosonic parity-time-symmetric system (PTSS) featuring distinct dissipation and amplification channels. The hierarchy includes global nonclassicality, entanglement, asymmetric quantum steering, and Bell nonlocality. We elucidate the interplay between the system physical nonlinearity (which serves as a source of quantumness) and the specific dynamics of bosonic PTSSs, which are qualitatively influenced by their damping and amplification characteristics. Using a set of quantifiers (including local and global nonclassicality depths, negativity, steering parameters, and the Bell parameter) we demonstrate that the standard PTSS typically exhibits weaker quantumness than its counterparts affected solely by damping or solely by amplification. Both the maximum values attained by these quantifiers and the speed and duration of their generation are generally lower in the standard PTSS. A comparative analysis of three two-mode PTSSs (standard, passive, and active) with identical eigenvectors and real parts of eigenfrequencies, but differing in their damping and amplification strengths, reveals the crucial role of quantum fluctuations associated with gain and loss. Among them, the passive PTSS yields the most strongly nonclassical states. Nevertheless, under suitable conditions, the standard PTSS can also generate highly nonclassical states. The supremacy of the passive PTSS is further supported by its fundamental advantages in practical realizations.}, archive = {J_PRA}, author = {Jan Peřina, Jr and Karol Bartkiewicz and Grzegorz Chimczak and Anna Kowalewska-Kudlaszyk and Adam Miranowicz and Joanna K. Kalaga and Wiesław Leoński}, doi = {10.1103/9vty-ctf7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043545}, shortjournal = {Phys. Rev. A}, title = {Quantumness and its hierarchies in PT-symmetric down-conversion models}, volume = {112}, year = {2025}, }
• (2025). Carrier-wave self-induced transparency. PRA, 112(4), 043544. (www)

  @article{ , abstract = {The standard self-induced transparency (SIT) phenomenon represents the lossless propagation of a long multicycle stable soliton in an absorbing two-level resonant medium, if the soliton's envelope area equals ( pulse). In this case, the leading half of the pulse excites the medium, while the trailing half completely brings the medium back to the ground state. In this work, we theoretically demonstrate an analogous phenomenon for subcycle pulses propagating in an arbitrary multilevel resonant medium. The duration of the obtained solitary pulses must be smaller than the periods of resonant transitions in the medium. The obtained subcycle solitary solutions first turn an initially unexcited multi-level resonant medium to excited levels and then fully return it back to the ground state.}, archive = {J_PRA}, author = {Anton Pakhomov}, doi = {10.1103/jpnp-1tqr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043544}, shortjournal = {Phys. Rev. A}, title = {Carrier-wave self-induced transparency}, volume = {112}, year = {2025}, }
• (2025). Parametric dependence of unidirectional guided resonances in periodic structures. PRA, 112(4), 043543. (www)

  @article{ , abstract = {Unidirectional guided resonances (UGRs) in periodic structures are special resonant modes that exhibit strict one-sided radiation, even though radiation in both sides is allowed, offering significant advantages for various applications. Under a structural perturbation, a UGR typically turns to a regular resonant mode that radiates to both sides. Existing numerical results indicate that to find UGRs in any periodic structure, it is necessary to tune at least one parameter. In this work, we develop a rigorous theory on the parametric dependence of UGRs. We show that in the presence of a single radiation channel, a UGR can exist continuously with respect to a structural parameter, provided that another parameter (associated with a generic perturbation) is properly tuned. Moreover, from a periodic structure with a generic bound state in the continuum (BIC), it is always possible to obtain a continuous family of UGRs by tuning one parameter. This implies that UGRs with arbitrarily large quality factor can be easily obtained. Our work provides a theoretical basis for designing useful photonic devices based on UGRs.}, archive = {J_PRA}, author = {Lijun Yuan and Ya Yan Lu}, doi = {10.1103/jgd6-t8yp}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043543}, shortjournal = {Phys. Rev. A}, title = {Parametric dependence of unidirectional guided resonances in periodic structures}, volume = {112}, year = {2025}, }
• (2025). Nonlinear dynamics of soliton molecules in a kerr microring. PRA, 112(4), 043542. (www)

  @article{ , abstract = {The optical Kerr microring provides an ideal platform for the study of dissipative optical solitons. The dissipative solitons are local waves generated after achieving a delicate balance between dispersion and nonlinearity, gain and loss. The dissipative bright solitons are susceptible to external noise, while the dissipative dark solitons have a higher robustness against noise and losses. In this paper, the input pump light field is split into transverse electric (TE) and transverse magnetic (TM) modes. TE mode generates bright solitons. TM mode forms dark solitons via cross-phase modulation, inducing a self-focusing effect. The bright and dark solitons bind into a soliton molecule pair through mutual interactions. We scan the entire detuning interval; within the positive small detuning interval, two modes simultaneously generate light-dark soliton pair Turing roll states. Within the larger detuning interval, the excited Brillouin scattering noise induces a high suppression ratio between the dark and bright soliton pumps, which is unfavorable for the formation of the bright-dark soliton pair. The system provides a new multisoliton manipulation scheme for optical communications. The soliton molecule pairs hold significant implications for high-precision measurement and all-optical controlling fields.}, archive = {J_PRA}, author = {Zijian Zhang and Chaoying Zhao}, doi = {10.1103/6zh3-mt3p}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043542}, shortjournal = {Phys. Rev. A}, title = {Nonlinear dynamics of soliton molecules in a kerr microring}, volume = {112}, year = {2025}, }
• (2025). Tailoring spatial modes produced by stimulated parametric down-conversion. PRA, 112(4), 043541. (www)

  @article{ , abstract = {We theoretically study and experimentally demonstrate controlled generation of spatial modes of light via stimulated parametric down-conversion (StimPDC) by transferring the spatial structure of a pump beam to the stimulated idler beam. We show how the beam characteristics of the stimulated beam depend on both the pump and seed beam's characteristics, enabling experimental control over size and propagation behavior. We also show how to control and improve the fidelity of different spatial modes and demonstrate that the angular basis ensures uniform fidelity across modes generated with StimPDC.}, archive = {J_PRA}, author = {A. A. Aguilar-Cardoso and C. Li and T. J. B. Luck and M. F. Ferrer-Garcia and J. Upham and J. S. Lundeen and R. W. Boyd}, doi = {10.1103/g22l-cgr1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043541}, shortjournal = {Phys. Rev. A}, title = {Tailoring spatial modes produced by stimulated parametric down-conversion}, volume = {112}, year = {2025}, }
• (2025). Nonlinear propagation of subcycle pulses in a nonequilibrium multilevel medium. PRA, 112(4), 043540. (www)

  @article{ , abstract = {The ultrabroad spectrum of few-cycle and especially subcycle pulses requires multiple energy levels in a medium to be properly considered in order to describe the pulse propagation effects. In this paper we go beyond the standard two-level or related few-level approximations and theoretically analyze the propagation of subcycle pulses in a nonequilibrium multilevel resonant medium. We specifically address the case of pulse durations, smaller than the periods of resonant transitions in a medium, where the appropriate analytical models can be provided, and assume accordingly a slow dissipation in the medium. We demonstrate a number of nonlinear phenomena, arising under such conditions, in particular the formation of stable subcycle dissipative solitons of various profiles in a nonequilibrium medium, including superluminal ones, as well as study possible scenarios of their collision.}, archive = {J_PRA}, author = {Anton Pakhomov}, doi = {10.1103/5ch5-wvy2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043540}, shortjournal = {Phys. Rev. A}, title = {Nonlinear propagation of subcycle pulses in a nonequilibrium multilevel medium}, volume = {112}, year = {2025}, }
• (2025). Explosion dynamics of invisible pulsation solitons in an er-doped passively mode-locked fiber laser. PRA, 112(4), 043539. (www)

  @article{ , abstract = {An invisible pulsation soliton (IPS) is a novel type of soliton with an inconspicuous pulse energy fluctuation in contrast with a stable soliton. In this work, echoing previous investigations of IPS dynamics, such as the IP of soliton molecules, the IP of harmonic mode locking, and intermittent IP induced by temporal-gain dynamics, we report the experimental observation of IPS explosion dynamics in a mode-locked fiber laser. Three types of IPS explosion phenomena with different evolution characteristics are successively obtained, i.e., an ordinary IPS explosion, an IPS explosion accompanied by soliton splitting, and an IPS explosion induced by collision after soliton splitting. Our work provides complementary evidence for IPS as a metastable state, and might benefit the understanding of nonlinear soliton dynamics.}, archive = {J_PRA}, author = {Qingbo Wang and Pan Wang and Zhifeng Shi and Jiangyong He and Zhi Wang and Yan-ge Liu}, doi = {10.1103/7hzb-b98v}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043539}, shortjournal = {Phys. Rev. A}, title = {Explosion dynamics of invisible pulsation solitons in an er-doped passively mode-locked fiber laser}, volume = {112}, year = {2025}, }
• (2025). Modulation instability, solitons, and interactions in one-dimensional competing cubic-quintic nonlinear media with fourth-order diffraction. PRA, 112(4), 043538. (www)

  @article{ , abstract = {Modulation instability of one-dimensional plane waves, fundamental solitons, and interactions are investigated in competing cubic-quintic nonlinear media with fourth-order diffraction (FOD). Analytical results of the growth rate of modulation instability spectra are obtained with linear-stability analysis and confirmed numerically. Plane waves can propagate stably when modulation instability can be suppressed by FOD and competing nonlinearities. In addition, bifurcated solutions of fundamental Gaussian-type solitons are obtained by using a variational approach. Numerical simulations show that solitons are unstable (stable) in the regime of normal (anomalous) FOD. Interactions of in-phase and out-of-phase solitons are also demonstrated numerically, which show that normal (anomalous) FOD weakens (strengthens) the attractions of in-phase solitons and also weakens (strengthens) the repulsions of out-of phase solitons. It is also demonstrated that competing self-defocusing quintic nonlinearities always strengthen the attractive (repulsive) force between in-phase (out-of-phase) solitons.}, archive = {J_PRA}, author = {Wenwen Zhao and Lijuan Ge and Ming Shen}, doi = {10.1103/xmsj-ktq7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043538}, shortjournal = {Phys. Rev. A}, title = {Modulation instability, solitons, and interactions in one-dimensional competing cubic-quintic nonlinear media with fourth-order diffraction}, volume = {112}, year = {2025}, }
• (2025). Zero-index topological interface states in a distorted kekulé photonic crystal. PRA, 112(4), 043537. (www)

  @article{ , abstract = {Topological interface states (TISs) and zero-index behavior are two unique phenomena in photonic systems. TISs enable robust wave propagation along a topological interface, while zero-index behavior allows waves to travel without phase variation. However, photonic structures that simultaneously exhibit both topological properties and zero-index behavior remain largely unexplored. In this work, we present two distorted Kekulé photonic crystals capable of supporting a pair of gapless pseudospin TISs. Since this degeneracy occurs at the center of the Brillouin zone, the TISs inherently combine topological protection with a zero-index response, which we refer to as zero-index TISs. This enables unidirectional wave propagation with minimal phase variation while maintaining robustness against interface corners. Our work offers an effective approach to achieving zero-index topological mode, with potential applications in signal transmission, qubit entanglement, and beyond.}, archive = {J_PRA}, author = {Guochao Wei and Yuankai Li and Beibei Wang and Wei Zhu and Shengxiang Wang}, doi = {10.1103/p67k-qz9b}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043537}, shortjournal = {Phys. Rev. A}, title = {Zero-index topological interface states in a distorted kekulé photonic crystal}, volume = {112}, year = {2025}, }
• (2025). Topological resilience of optical skyrmions in local decoherence. PRA, 112(4), 043536. (www)

  @article{ , abstract = {The topologically protected configuration embedded in skyrmions has prompted some investigations into their fundamental properties and versatile applications, sparking interest and guiding ongoing development. The topological protection associated with skyrmions was initially observed in systems with interactions. It is widely believed that skyrmions are stable, yet relevant confirmation and empirical research remain limited. A pertinent question is whether skyrmion configurations formed by a single classical beam with two coupled degrees of freedom also exhibit topological stability. In this study, we affirm this hypothesis by investigating the effects of local decoherence. We analytically and numerically demonstrate the topological resilience of skyrmions and the occurrence of transition points of skyrmion numbers in local decoherence across three typical decoherence channels. On the other hand, we show that these qualities are independent of the initial state. From the numerical results, we find that inhomogeneous but continuous decoherence channels also have the same behaviors and maintain the topological stability of skyrmions as homogeneous decoherence channels do. These properties of skyrmions contribute to further applications in various areas, including communication and imaging.}, archive = {J_PRA}, author = {Li-Wen Wang and Sheng Liu and Cheng-Jie Zhang and Geng Chen and Yong-Sheng Zhang and Chuan-Feng Li and Guang-Can Guo}, doi = {10.1103/6z82-8r47}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043536}, shortjournal = {Phys. Rev. A}, title = {Topological resilience of optical skyrmions in local decoherence}, volume = {112}, year = {2025}, }
• (2025). Dual-polarization perfect janus dipole in near-field coupling. PRA, 112(4), 043535. (www)

  @article{ , abstract = {Janus dipoles have exotic features in near-field coupling since they have two distinct faces, namely, the so-called coupling and noncoupling faces. When the out-coupler (e.g., a waveguide) is oriented toward the noncoupling (coupling) face of Janus dipoles, the guided waves can be inefficiently (efficiently) excited. Moreover, the noncoupling face of Janus dipoles can be engineered on demand to fully suppress the excitation of guided waves with either polarization or polarization, giving rise to the single-polarization perfect Janus dipole. However, whether it is possible to achieve a dual-polarization perfect Janus dipole in near-field coupling remains elusive. Here we theoretically reveal the possibility to realize a dual-polarization perfect Janus dipole, which requires the judicious design of both the constituent dipole moments of Janus dipoles and the dispersion relation of waveguides. When placing the dual-polarization perfect Janus dipole in the middle of two parallel identical waveguides, we theoretically find that the -polarized guided waves are exclusively excited in one waveguide, while the -polarized guided waves are excited solely in the other waveguide. Our findings might provide an enticing route for the development of polarization-multiplexed photonic devices, quantum routing, and on-chip signal processing.}, archive = {J_PRA}, author = {Wenbo Ma and Xuhuinan Chen and Yuhan Zhong and Chenxu Bian and Guanqing Zhao and Chan Wang and Hongsheng Chen and Xiao Lin}, doi = {10.1103/fypp-w26t}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043535}, shortjournal = {Phys. Rev. A}, title = {Dual-polarization perfect janus dipole in near-field coupling}, volume = {112}, year = {2025}, }
• (2025). Chiral gain-induced time-reversal symmetry breaking in quantum systems. PRA, 112(4), 043534. (www)

  @article{ , abstract = {Structured light offers a powerful approach to tailor light–matter interactions in quantum systems with chiral properties. While chirality has been extensively studied in passive platforms, the role of optical gain in controlling chiral quantum dynamics remains largely unexplored. In this work, we develop a general theoretical framework to describe the dynamics of an atomic system interacting with structured gain environments, where amplification depends on the light's polarization or momentum. By quantizing the electromagnetic field in linear bianisotropic media with gain and extending the Lindblad formalism to these settings, we derive a master equation governing the atom's irreversible evolution. We show that chiral gain can break time-reversal symmetry and drive the system toward a symmetry-broken steady state with nonreciprocal properties. This effect is illustrated in detail for moving plasmonic substrates, which exhibit inherently chiral gain that selectively amplifies transitions of a given handedness. Our results establish chiral gain as a novel mechanism for engineering nonreciprocal quantum steady states.}, archive = {J_PRA}, author = {Mário G. Silveirinha and Daigo Oue}, doi = {10.1103/47fd-w495}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043534}, shortjournal = {Phys. Rev. A}, title = {Chiral gain-induced time-reversal symmetry breaking in quantum systems}, volume = {112}, year = {2025}, }
• (2025). Kerr-enhanced optomechanical entanglement generation via reservoir design. PRA, 112(4), 043533. (www)

  @article{ , abstract = {Quantum entanglement is a crucial resource in quantum technologies, enabling advancements in quantum computing, quantum communication, and quantum precision measurement. Here, we propose a method to enhance optomechanical entanglement by introducing an optical Kerr nonlinear medium and a squeezed vacuum reservoir of the optomechanical cavity. By performing the displacement and squeezing transformations, the system can be reduced to a standard linearized optomechanical system with normalized driving detuning and linearized-coupling strength, in which the optical and mechanical modes are, respectively, coupled to an optical vacuum bath and a mechanical heat bath. We focus on the entanglement generation in the single stable regime of the system. By evaluating the steady-state logarithm negativity, we find that the optomechanical entanglement can be enhanced within a wide range of the Kerr constant. In addition, the Kerr nonlinearity can extend the stable region, enabling considerable entanglement generation in the blue-sideband parameter region. We also investigate the dependence of the entanglement generation on the average thermal phonon occupation of the mechanical bath and the optical driving amplitude. It is found that the presence of the Kerr nonlinearity allows the generation of optomechanical entanglement even when the thermal phonon occupation of the mechanical bath is as high as 3000. Our findings will provide valuable insights into enhancing fragile quantum resources in quantum systems.}, archive = {J_PRA}, author = {Yan Li and Cheng Liu and Yu-Hong Liu and Yue-Hui Zhou and Jie-Qiao Liao}, doi = {10.1103/5m5v-kr6r}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043533}, shortjournal = {Phys. Rev. A}, title = {Kerr-enhanced optomechanical entanglement generation via reservoir design}, volume = {112}, year = {2025}, }
• (2025). Analytical solutions of partially coherent beams propagating in photonic lattices. PRA, 112(4), 043532. (www)

  @article{ , abstract = {The analytical solution for partially coherent beams propagating in one-dimensional (1D) uniform or binary periodic photonic environments is presented. The cross-spectral density (CSD) of a partially coherent Gaussian-Schell model (GSM) beam and a partially coherent Hermite-Gaussian correlated Schell-model (HGCSM) beam in uniform periodic photonic lattices is derived in detail. These analytical expressions demonstrate that the evolution of the spectral density is determined not only by the characteristics of the light sources, such as the coherence or correlation function structure, but also by the properties of the photonic lattices, specifically the coupling coefficient. Our findings pave the way for the analytical study of the propagation of partially coherent beams in photonic lattices.}, archive = {J_PRA}, author = {Zhuohang Zhang and Yikang Wang and Anli Xiang and Yangjian Cai and Gaofeng Wu}, doi = {10.1103/1qdp-gpvy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043532}, shortjournal = {Phys. Rev. A}, title = {Analytical solutions of partially coherent beams propagating in photonic lattices}, volume = {112}, year = {2025}, }
• (2025). All-dielectric metasurface polarization scrambler for imaging applications. PRA, 112(4), 043531. (www)

  @article{ , abstract = {The partial polarization of the earth's radiation can be the source of radiometric errors for space instruments with polarization-sensitive components. It is therefore necessary to have a device capable of depolarizing the light before it enters the instrument, i.e., a polarization scrambler. Current scramblers used in optical payloads generally comprise combinations of prisms that enable spatial depolarization. However, polarization insensitivity comes at the cost of an inevitable degradation in imaging performance. Here we present a device based on an all-dielectric metasurface using anisotropic scatterers capable of generating multiple polarization states by varying their orientation angle. Our scrambling solution allows a massive reduction in the integrated degree of polarization and thus the spatial depolarization of any incident linear polarization, while reducing the impact on its image quality and allowing easier integration into the instrument design.}, archive = {J_PRA}, author = {Edith Hartmann and Michel Lequime and Matthieu Castelnau and Hélène Krol and Myriam Zerrad}, doi = {10.1103/vphf-51q9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043531}, shortjournal = {Phys. Rev. A}, title = {All-dielectric metasurface polarization scrambler for imaging applications}, volume = {112}, year = {2025}, }
• (2025). Influence of optical self-injection on the statistical properties of laser-pulse interference. PRA, 112(4), 043530. (www)

  @article{ , abstract = {Pulsed optical self-injection markedly affects the emission characteristics of semiconductor lasers. In this work, we analyze its influence on the statistical properties of laser-pulse interference. We experimentally demonstrate that varying the arrival time of reflected optical pulses back into the laser cavity influences the phase diffusion and induces an effect that, by analogy with external optical injection, we call phase locking. A comprehensive theoretical analysis of this phenomenon is also presented.}, archive = {J_PRA}, author = {Roman Shakhovoy and Elizaveta Maksimova and Matvey Boltanskiy and Maxim Fadeev}, doi = {10.1103/3g4d-5dtq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043530}, shortjournal = {Phys. Rev. A}, title = {Influence of optical self-injection on the statistical properties of laser-pulse interference}, volume = {112}, year = {2025}, }
• (2025). Experimental evidence of a strange nonchaotic attractor in a Nd:YVO4 laser with saturable absorber. PRA, 112(4), 043529. (www)

  @article{ , abstract = {The diode-pumped Nd:vanadate laser is one of the most widely used lasers in the near-infrared range. Using passive Q -switching with a Cr:YAG saturable absorber, it generates nanosecond pulses at tens of kilohertz. It is well known to display either regular pulsing or low-dimensional deterministic chaos, depending on the absorber's position within the cavity. However, to our knowledge, a strange nonchaotic attractor (SNA) has never been reported in this system. Our experiments provide evidence that, for a specific absorber position, the laser dynamics correspond to a strange nonchaotic attractor. SNAs exhibit complex dynamical behavior that is neither periodic nor chaotic, positioning them as a valuable resource for applications requiring high spectral diversity while preserving predictable dynamics. By experimentally obtaining time series of two laser variables, we reconstruct the underlying attractor. For a certain position of the SA, we find that all Lyapunov exponents are negative and that the energy spectra exhibit a broad frequency range, indicating that the attractor is nonchaotic and lacks periodicity. Using Higuchi's method, we estimate the fractal dimension and find that of the nonchaotic time series exhibit a well-defined , confirming the presence of an SNA.}, archive = {J_PRA}, author = {Juliana N. Bourdieu and Mónica B. Agüero and Marcelo G. Kovalsky}, doi = {10.1103/sxh7-fmlj}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043529}, shortjournal = {Phys. Rev. A}, title = {Experimental evidence of a strange nonchaotic attractor in a Nd:YVO4 laser with saturable absorber}, volume = {112}, year = {2025}, }
• (2025). Asymptotic-field approach for the control of dipole emission in integrated structures. PRA, 112(4), 043527. (www)

  @article{ , abstract = {We present a general framework to model spontaneous emission in integrated photonic structures by exploiting quantization of the electromagnetic field in terms of asymptotic-in/out modes. This approach allows for an efficient and physically meaningful calculation of the emission rate into each radiative channel of an arbitrary structure, without relying on approximations such as Lorentzian lineshapes or point-like system-bath coupling. We show that with this approach one can recover well-known results for dipole emission in waveguides or ring resonators, and that such results can be easily extended to include the effect of backscattering. Finally, as an application, we design a tunable integrated single-photon source that enables full control over both the emission rate and output mode. This flexibility makes our method particularly well suited for the design and analysis of integrated single-photon sources in various material platforms.}, archive = {J_PRA}, author = {Vincenzo Macrì and Alice Viola and Marco Liscidini}, doi = {10.1103/8fbs-z1sv}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043527}, shortjournal = {Phys. Rev. A}, title = {Asymptotic-field approach for the control of dipole emission in integrated structures}, volume = {112}, year = {2025}, }
• (2025). Tunable antichiral hinge state in photonic synthetic dimensions. PRA, 112(4), 043526. (www)

  @article{ , abstract = {Recent research in two-dimensional topological matter has generalized the notion of edge states from chiral to antichiral configurations with the same propagating direction at parallel edges, revealing a rich variety of robust transport phenomena. Here we propose that antichiral hinge states can emerge in a three-dimensional higher-order topological insulator or semimetal, where two surface or bulk Dirac points are connected by the hinge states. The band dispersion can be controlled and tilted independently for each hinge using properly designed tunnelings, resulting in tunable antichiral hinge states with programmable propagation direction and velocity. Moreover, we propose experimental realization schemes based on a one-dimensional coupled cavity array with additional synthetic dimensions represented by the photonic orbital angular momentum and frequency. We introduce both longitudinal and transversal electro-optic modulators to generate the desired tunable tunnelings along the synthetic dimensions, which significantly reduce the experimental complexity by eliminating the need for beam splittings and auxiliary cavities. The tunable antichiral hinge states are confirmed by the photonic transmission spectra. Our work presents robust and tunable antichiral hinge-state transports, which pave the way for exploring novel topological matter and their device applications.}, archive = {J_PRA}, author = {Xian-Hao Wei and Xi-Wang Luo and Mu Yang and Yu-Wei Liao and Jin-Shi Xu and Guang-Can Guo and Zheng-Wei Zhou}, doi = {10.1103/w559-rdq6}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043526}, shortjournal = {Phys. Rev. A}, title = {Tunable antichiral hinge state in photonic synthetic dimensions}, volume = {112}, year = {2025}, }
• (2025). Coherent exciton pulse propagation in disordered transmission lines. PRA, 112(4), 043525. (www)

  @article{ , abstract = {Coherent exciton transport is investigated in the presence of several different forms of disorder. We consider linear dye assemblies capable of functioning as exciton transmission lines and focus on the degrading effects of static disorder on exciton coherence in several scenarios, whether introduced through lattice imperfections or in the optical response of the constituent dyes. Impurities are ascribed to sections of consecutive dyes in the line in which incident ballistic excitons can propagate in and scatter, reflecting and transmitting as conditions permit. Single- and few-site impurities are first considered, and then static disorder is introduced in the scattering sections in two ways: as random transition energies or as altered transfer couplings between dyes. These cases are compared, and some intriguing dynamics result: reflection (attenuation) is more significant with disorder in the transfer couplings, some conditions have an even-odd pattern in reflections, and midband exciton encounters with this type of disorder acquire no phase alteration. Lastly, these two cases of static disorder are compared with the dynamic noise arising from molecular vibrations, and both are found to be comparably modest. With applications in mind, several phenomenological and quantitative relations for coherent exciton transport are obtained as simple functions of the introduced disorder.}, archive = {J_PRA}, author = {Richard Elliott and Bernard Yurke and Aaron Sup}, doi = {10.1103/rm4n-76jr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043525}, shortjournal = {Phys. Rev. A}, title = {Coherent exciton pulse propagation in disordered transmission lines}, volume = {112}, year = {2025}, }
• (2025). Effect of imaginary gauge on wave transport in driven-dissipative systems. PRA, 112(4), 043524. (www)

  @article{ , abstract = {Wave transport in disordered media is a fundamental problem with direct implications in condensed matter, materials science, optics, atomic physics, and even biology. The majority of these studies focuses on disorder-induced localization in Hermitian systems. However, recent studies of non-Hermitian disordered media have revealed unique behaviors, with a universal principle emerging that links the eigenvalue spectrum of the disordered Hamiltonian and its statistics with its transport properties. In this work we show that the situation can be very different in driven-dissipative lattices of cavities, where a uniform gain applied equally to all the components of the system can act as a knob for controlling the wave transport properties without altering the eigenvalue statistics of the underlying Hamiltonian. Our results provide deeper insight into the transport properties of disordered media and will aid in the development of new devices. Our work, which is presented in the context of optics, generalizes to any physical platforms where gain can be implemented. These include acoustics, electronics, and coupled quantum oscillators such as atoms, diamond centers, and superconducting qubits.}, archive = {J_PRA}, author = {I. Komis and K. G. Makris and K. Busch and R. El-Ganainy}, doi = {10.1103/m8kz-rwsk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043524}, shortjournal = {Phys. Rev. A}, title = {Effect of imaginary gauge on wave transport in driven-dissipative systems}, volume = {112}, year = {2025}, }
• (2025). Beam dynamics inside a symmetrically chirped waveguide array mimicking graded index media. PRA, 112(4), 043523. (www)

  @article{ , abstract = {In this article, we explore the beam dynamics within symmetrically chirped nonlinear waveguide arrays, focusing on linear and quadratic chirping schemes. We propose a practical structure for these arrays that enhances control over light propagation. By employing a continuous approximation of the discrete nonlinear Schrödinger equation, we utilize a semianalytical variational method to analyze beam behavior under waveguide chirping. Our findings indicate that the symmetrically chirped waveguide arrays behave similarly to graded index systems, with varying coupling coefficients analogous to the refractive index in continuous media. We derive a steady-state solution and validate it against numerical simulations, alongside conducting a linear stability analysis to assess the robustness of these solutions. The results reveal that input Gaussian beams in such waveguide arrays follow an oscillatory trajectory akin to that in parabolic index media. Notably, under nonlinear conditions, these beams evolve as discrete solitons. Our rigorous investigation of the propagation characteristics in both linear and nonlinear regimes highlights the intricate dynamics of optical beams within the engineered chirped waveguide arrays, supported by comparisons to comprehensive numerical simulations.}, archive = {J_PRA}, author = {Anuj P. Lara and Samudra Roy}, doi = {10.1103/1f2f-lg27}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043523}, shortjournal = {Phys. Rev. A}, title = {Beam dynamics inside a symmetrically chirped waveguide array mimicking graded index media}, volume = {112}, year = {2025}, }
• (2025). Analytical exploration of the optomechanical attractor diagram and of limit cycles. PRA, 112(4), 043522. (www)

  @article{ , abstract = {We analyze the interplay between mechanical and radiation pressure in an optomechanical cavity system. Our study is based on an analytical evaluation of the infinite Bessel summations involved, which previously had led to a numerical exploration of the so-called attractor diagram. The analytical expressions are then suitable for further asymptotic analysis in opposing regimes of the amplitude, which allows for a characterization of the diagram in terms of elementary functions. Building on this framework, we investigate the emergence and properties of optomechanical limit cycles beyond the constraints of the resolved sideband approximation. By employing a Fokker-Planck formalism originally developed in the context of laser theory and then used in cavity optomechanics, we describe the quantum regime of these limit cycles, offering a more detailed and unified analytical perspective.}, archive = {J_PRA}, author = {Jorge G. Russo and Miguel Tierz}, doi = {10.1103/jbqp-3s26}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043522}, shortjournal = {Phys. Rev. A}, title = {Analytical exploration of the optomechanical attractor diagram and of limit cycles}, volume = {112}, year = {2025}, }
• (2025). Spin-dependent routing of optical beams in the bulk of twisted anisotropic media. PRA, 112(4), 043521. (www)

  @article{ , abstract = {We theoretically discuss a kind of photonic spin-Hall effect (PSHE) for optical beams propagating inside an inhomogeneously twisted anisotropic material. The rotation angle plays the role of an effective gauge field. When the twisting distribution is odd symmetric, the optical beams move along mirror-symmetric trajectories according to their helicity. Connection of this volumetric PSHE with the geometric phase and the Kapitza effect is elucidated.}, archive = {J_PRA}, author = {Chandroth P. Jisha and Lorenzo Marrucci and Stefan Nolte and Alessandro Alberucci}, doi = {10.1103/jm7q-nxy1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043521}, shortjournal = {Phys. Rev. A}, title = {Spin-dependent routing of optical beams in the bulk of twisted anisotropic media}, volume = {112}, year = {2025}, }
• (2025). Classical simulation of an all-optical toffoli gate using soliton scattering through asymmetric potential wells. PRA, 112(4), 043520. (www)

  @article{ , abstract = {We propose and numerically simulate an all-optical Toffoli (controlled-controlled- not ) gate based on the scattering of spatial solitons by asymmetric Pöschl-Teller potential wells. In our scheme, the logical state of the target bit is encoded in the relative spatial ordering of two distinguishable soliton components, while the control bits are represented by the presence or absence of external potential wells. We solve the nonlinear Schrödinger equations governing the soliton dynamics and systematically scan soliton amplitude and velocity, analyzing reflection and transmission coefficients to identify the operational conditions for Toffoli gate behavior. Our results demonstrate that introducing asymmetry in the potential wells significantly broadens the operational parameter window compared to symmetric configurations. We also investigate the impacts of varying degrees of asymmetry and soliton amplitude on gate performance. Furthermore, we examine the influence of weak intercomponent coupling and confirm that it is not essential for gate operation. These findings generalize earlier soliton-based cnot simulations and support the broader feasibility of classical analog modeling of multiqubit logic gates in nonlinear optical systems.}, archive = {J_PRA}, author = {Melih Özkurt and Özgür E. Müstecaplıoğlu}, doi = {10.1103/y6sc-bzk5}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043520}, shortjournal = {Phys. Rev. A}, title = {Classical simulation of an all-optical toffoli gate using soliton scattering through asymmetric potential wells}, volume = {112}, year = {2025}, }
• (2025). Energy and photon centroids of spatiotemporal light pulses and consequences for their intrinsic orbital angular momentum. PRA, 112(4), 043519. (www)

  @article{ , abstract = {An ongoing debate surrounding the intrinsic transverse orbital angular momentum (OAM) attributed to spatiotemporal optical vortex (STOV) light pulses has raised the energy and photon-density centroids as two alternative frameworks to define the center of a free electromagnetic wave packet. We herein derive, within a single formalism, lowest-order expressions for the positions and velocities of both centroids, directly applicable to an arbitrary scalar, near-paraxial, and quasimonochromatic pulse envelope formulated in space-time. Examining pulses with structures including temporal chirp, wavefront rotation, Gaussian-type STOVs, and tilted lobulated profiles, we illustrate general principles underlying the shifts and propagation dynamics of the two centroids and discuss how these properties underpin the value and conservation of intrinsic OAM referenced to either centroid. Finally, despite widespread use of the notion of intrinsic OAM per photon , we argue that in neither framework could individual STOV photons be said to carry a well-defined quantum of intrinsic transverse OAM, as such quantities do not read as expectation values of a single operator for which STOV states could form a basis of orthogonal eigenmodes. This contrasts with the well-established quantization scheme for the total longitudinal OAM of light in spatial vortex beams, bearing implications for the interpretation of future experiments involving STOV pulses in quantum optics, nonlinear wave-mixing, or light-matter interactions.}, archive = {J_PRA}, author = {Titouan Gadeyne and Thierry Ruchon}, doi = {10.1103/1wsz-48br}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043519}, shortjournal = {Phys. Rev. A}, title = {Energy and photon centroids of spatiotemporal light pulses and consequences for their intrinsic orbital angular momentum}, volume = {112}, year = {2025}, }
• (2025). Energy-driven multistage evolution and reversible transitions between vector dissipative solitons and noise-like pulses in a pure-quartic fiber laser. PRA, 112(4), 043518. (www)

  @article{ , abstract = {Although pure-quartic fiber lasers exhibit diverse soliton dynamics, the multistage evolution and controllability of vector dissipative pure-quartic solitons remain underexplored. We show that increasing the saturable energy enhances the spectral group delay near the frequency edges via positive fourth-order dispersion, breaking phase equilibrium and triggering a cross-phase-modulation-induced energy imbalance between polarization components. This, combined with modulation instability, leads to spectral collapse and transition into noise-like pulses. Remarkably, precise tuning of the polarization controller enables reversible switching back to the vector dissipative pure-quartic soliton state. We further employ mutual information and Pearson correlation analysis to quantify spectral coherence and verify deterministic chaos in noise-like pulses via Poincaré sections and Grassberger-Procaccia dimensions. These results offer insight into nonlinear dynamics and controllable state transitions in high-order-dispersion fiber lasers.}, archive = {J_PRA}, author = {Jia-Hao Zhang and Zhen-Tao Ju and Xue-Peng Wang and Yue-Yue Wang and Chao-Qing Dai}, doi = {10.1103/j4xs-hfky}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043518}, shortjournal = {Phys. Rev. A}, title = {Energy-driven multistage evolution and reversible transitions between vector dissipative solitons and noise-like pulses in a pure-quartic fiber laser}, volume = {112}, year = {2025}, }
• (2025). Reconfigurable polariton mode control in a liquid-crystal microcavity. PRA, 112(4), 043517. (www)

  @article{ , abstract = {We propose a reconfigurable polaritonic platform based on a liquid-crystal (LC)-filled microcavity with embedded excitonic layers, enabling selective control over multiple polariton field distributions within a single structure. In earlier work we used a similar LC geometry for polarization-encoded confinement of two polariton modes [Sedov and Kavokin, Phys. Rev. A 112 , 013504 (2025) ]. Whereas the previous scheme was limited to two polarization-selected modes, the present approach harnesses the LC's externally tunable birefringence to program spatial potentials for multiple modes. The system leverages LC-induced anisotropy to tune the photonic component and spatially structured excitonic layers to modulate light-matter interaction. Using topology optimization, we design stationary potentials that reshape the spatial profiles of distinct polariton modes depending on the orientation of the LC molecules. Our approach allows for mode-selective control and supports versatile polariton field reconfiguration in a single compact structure, highlighting a pathway toward programmable polaritonic architectures.}, archive = {J_PRA}, author = {E. Sedov and A. Kavokin}, doi = {10.1103/2spp-3lby}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043517}, shortjournal = {Phys. Rev. A}, title = {Reconfigurable polariton mode control in a liquid-crystal microcavity}, volume = {112}, year = {2025}, }
• (2025). Vortex solitons in quasi-phase-matched photonic crystals with the third harmonic generation. PRA, 112(4), 043516. (www)

  @article{ , abstract = {We report stable composite vortex solitons in the model of a three-dimensional photonic crystal with the third-harmonic (TH) generation provided by the quasi-phase-matched quadratic nonlinearity. The photonic crystal is designed with a checkerboard structure in the ( x , y ) plane, while the second-order nonlinear susceptibility, d ( z ) , is modulated along the propagation direction as a chain of rectangles with two different periods. This structure can be fabricated by means of available technologies. The composite vortex solitons are built of fundamental-frequency (FF), second-harmonic (SH), and TH components, exhibiting spatial patterns which correspond, respectively, to a vortex with topological charges s = 1 , a quadrupole emulating s = 2 , and an antivortex with s = − 1 in these components (due to the system's symmetry, the latter value is actually tantamount to s = 3 ). Soliton profiles feature rhombic or square patterns, corresponding to phase-matching conditions φ d ( x , y ) = 0 or π , respectively, the rhombic solitons possessing a broader stability region. From the perspective of the experimental feasibility, we show that both the rhombic and square-shaped composite vortex solitons may stably propagate in the photonic crystals over distances of up to 1 m. The TH component of the soliton with s = ∓ 1 is produced by cascaded nonlinear interactions, starting from the FF vortex component with s = ± 1 and proceeding through the quadrupole SH one. These findings offer a previously unexplored approach to the creation of stable vortex solitons in nonlinear optics.}, archive = {J_PRA}, author = {Xuening Wang and Yuxin Guo and Qiuyi Ning and Bin Liu and Hexiang He and Li Zhang and Boris A. Malomed and Yongyao Li}, doi = {10.1103/b4l2-47dd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043516}, shortjournal = {Phys. Rev. A}, title = {Vortex solitons in quasi-phase-matched photonic crystals with the third harmonic generation}, volume = {112}, year = {2025}, }
• (2025). Bistable quartic soliton in saturable nonlinear media. PRA, 112(4), 043515. (www)

  @article{ , abstract = {This report presents a theoretical demonstration of a bistable quartic soliton (BQS) in saturable nonlinear media, specifically within a realistic dispersion-engineered ridge waveguide made of lithium niobate ( LiNbO 3 ). The study employs the variational method to establish the amplitude-width relationship, indicating the coexistence of stable solitons with the same duration but differing amplitudes. The impact of shock on the bistable soliton is examined through perturbative variational analysis, supported by numerical results. Additionally, we examine the interaction of BQS in different regimes and analyze the formation of the bound state. The robustness of the BQS under perturbations is further investigated via linear stability analysis.}, archive = {J_PRA}, author = {Tiyas Das and Anuj Pratim Lara and Samudra Roy}, doi = {10.1103/wdy3-tzmy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043515}, shortjournal = {Phys. Rev. A}, title = {Bistable quartic soliton in saturable nonlinear media}, volume = {112}, year = {2025}, }
• (2025). Spiral-like beams from diametric drive acceleration with positive and negative effective mass in a photonic lattice. PRA, 112(4), 043514. (www)

  @article{ , abstract = {This paper predicts the spiral-like beams based on the effective mass tensor by extending the diametric drive acceleration mechanism to a two-dimensional local photonic lattice. Such spiral-like beams differ from conventional optical rotation mechanisms that rely on orbital angular momentum, spin-orbit coupling, or exotic materials. Instead, they arise from the combined effects of anisotropic effective mass properties and the optical Kerr effect, without requiring conventional angular momentum or chiral media. Numerical simulations show that the specific beam combinations, such as Γ − X and M − X , can induce spiral-like motion under both self-focusing or self-defocusing conditions. This study breaks through the physical constraints of existing optical rotation mechanisms, highlighting the crucial role of effective mass in optical field dynamics.}, archive = {J_PRA}, author = {Shuxia Mo and Yinuo Cui and Wei Hu and Daquan Lu}, doi = {10.1103/vtzf-mq3k}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043514}, shortjournal = {Phys. Rev. A}, title = {Spiral-like beams from diametric drive acceleration with positive and negative effective mass in a photonic lattice}, volume = {112}, year = {2025}, }
• (2025). Anomalous-dispersion phase matching in a hypergap crystal. PRA, 112(4), 043513. (www)

  @article{ , abstract = {While two perfect phase-matching mechanisms exist in homogeneous single crystals, birefringent phase-matching (BPM) dominates for nonlinear optical applications. The anomalous-dispersion phase matching (ADPM), though demonstrated in gases and liquids, has not been established in crystals due to the parasitic material absorption that induces the anomalous dispersion in the first place. This absorption bottleneck can be overcome by a crystal possessing an additional spectral gap in its absorption spectrum, beyond the regular band gap, which we term the “hypergap”. Here, we theoretically propose and experimentally demonstrate such a hypergap and the ADPM-enabled third harmonic generation in potassium chromate K 2 CrO 4 . Our results introduce a class of nonlinear optical materials that do not rely on lattice anisotropy or periodic poling.}, archive = {J_PRA}, author = {Kun Chen and Xiaolei Hu and Zhengran Wu and Xiang Guo and Zhilin Li and Ling Lu}, doi = {10.1103/hnf1-vj2r}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043513}, shortjournal = {Phys. Rev. A}, title = {Anomalous-dispersion phase matching in a hypergap crystal}, volume = {112}, year = {2025}, }
• (2025). Characterizing stationary optomechanical entanglement in the presence of non-markovian noise. PRA, 112(4), 043512. (www)

  @article{ , abstract = {We study an optomechanical system, where a mechanical oscillator interacts with a Gaussian input optical field. In the linearized picture, we analytically prove that if the input light field is the vacuum state, or is frequency-independently squeezed, the stationary entanglement between the oscillator and the output optical field is independent of the coherent coupling between them, which we refer to as the universality of entanglement. Furthermore, we demonstrate that entanglement cannot be generated by performing arbitrary frequency-dependent squeezing on the input optical field. Our results hold in the presence of general, Gaussian environmental noise sources, including non-Markovian noise.}, archive = {J_PRA}, author = {Su Direkci and Klemens Winkler and Corentin Gut and Markus Aspelmeyer and Yanbei Chen}, doi = {10.1103/gysx-m9p2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043512}, shortjournal = {Phys. Rev. A}, title = {Characterizing stationary optomechanical entanglement in the presence of non-markovian noise}, volume = {112}, year = {2025}, }
• (2025). Polygon-based unified fourier-modal approach for diffractive-optics simulations. PRA, 112(4), 043511. (www)

  @article{ , abstract = {In this article, we derive a theoretical formalism that unifies the rigorous coupled wave analysis and the dynamical diffraction theory. Based on this formalism, we design a computational approach for the diffraction calculation for the nanoscale lamellar gratings with an arbitrary line profile shape. In this approach, the gratings line profile is approximated as a polygon. This proves to be convenient since such an approach does not rely on the geometry model of the grating. We test the proposed approach against other computational theories and a synchrotron scattering experiment.}, archive = {J_PRA}, author = {K. V. Nikolaev and V. Soltwisch and M. A. Botchev and A. Fernández Herrero and P. Hönicke and F. Scholze and S. N. Yakunin}, doi = {10.1103/n2qj-l886}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043511}, shortjournal = {Phys. Rev. A}, title = {Polygon-based unified fourier-modal approach for diffractive-optics simulations}, volume = {112}, year = {2025}, }
• (2025). Non-abelian braiding in stampfli-type quasicrystals. PRA, 112(4), 043510. (www)

  @article{ , abstract = {Non-Abelian braiding, as a promising approach for topological quantum computation, is typically based on topologically protected quantum gates. However, existing braiding schemes have primarily focused on arrays constructed from periodic lattices, which provide limited types of quantum gates and lack flexibility in braiding path design. In this work, we propose two structurally distinct X junctions based on a one-dimensional single-particle tight-binding model, and present a braiding protocol that yields a topologically protected gate by adiabatically moving defects. The two proposed junctions are introduced into the Stampfli-type quasicrystal, and each is successfully used to demonstrate non-Abelian braiding. Our braiding scheme allows for multimode braiding and flexible path design, providing a novel approach for designing non-Abelian devices in optical and acoustic platforms.}, archive = {J_PRA}, author = {Keran Hu and Aoqian Shi and Linsheng Bao and Shilong Li and Shuangchun Wen and Jianjun Liu}, doi = {10.1103/xwx2-lbpg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043510}, shortjournal = {Phys. Rev. A}, title = {Non-abelian braiding in stampfli-type quasicrystals}, volume = {112}, year = {2025}, }
• (2025). Filamentation of chirped femtosecond radiation in compressed nitrogen: Spectral saturation effect as a universal manifestation of kerr collapse arrest in dense gas. PRA, 112(4), 043509. (www)

  @article{ , abstract = {The formation of the supercontinuum spectrum during filamentation in compressed nitrogen with chirped femtosecond optical pulses in the sharp focusing regime has been investigated experimentally and theoretically. We show that chirped pulses exhibit a decrease in the spectral broadening of the pulse with increasing gas pressure. At the same time, pulses with a negative chirp demonstrate a wider supercontinuum than pulses equal in modulation depth but positive in chirp sign. A theoretical analysis and numerical modeling of the propagation of high-power chirped femtosecond optical pulses under conditions corresponding to the experiment are carried out, and an adequate analytical model explaining the main features of the formation of spectral characteristics of chirped optical radiation in a compressed gas is elaborated.}, archive = {J_PRA}, author = {Yu. E. Geints and A. D. Bulygin and V. O. Kompanets and S. V. Chekalin}, doi = {10.1103/jncc-6z57}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043509}, shortjournal = {Phys. Rev. A}, title = {Filamentation of chirped femtosecond radiation in compressed nitrogen: Spectral saturation effect as a universal manifestation of kerr collapse arrest in dense gas}, volume = {112}, year = {2025}, }
• (2025). Autonomous quantum heat engine enabled by molecular optomechanics and hysteresis switching. PRA, 112(4), 043508. (www)

  @article{ , abstract = {By integrating molecular optomechanics with molecular switches, we propose a scheme for a molecular quantum heat engine. If the molecular switch is effectively classical, the engine operates autonomously through hysteretic feedback, without external driving or modulation. However, this description needs to be revisited and modified in the case of a fully quantum molecular switch. Through a comparative analysis conducted within both semiclassical and fully quantum frameworks, we reveal the central role of quantum tunneling and quantum correlations in the operation of this advanced molecular machine in that regime.}, archive = {J_PRA}, author = {Baiqiang Zhu and Pierre Meystre and Weiping Zhang and Keye Zhang}, doi = {10.1103/v66j-6fv4}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043508}, shortjournal = {Phys. Rev. A}, title = {Autonomous quantum heat engine enabled by molecular optomechanics and hysteresis switching}, volume = {112}, year = {2025}, }
• (2025). Partially coherent dissipative-soliton resonances in lasers. PRA, 112(4), 043507. (www)

  @article{ , abstract = {Dissipative-soliton resonance (DSR) is theoretically predicted to enable unlimited energy scaling while maintaining a constant power in dissipative systems. It has traditionally been regarded as a fully coherent structure. Here, through comprehensive simulations, we show that DSRs can exhibit partial coherence, characterized by stochastic temporal and spectral dynamics. Under appropriate saturation power of a nonmonotonic saturable absorber, the pulse develops a strong nonlinear chirp induced by self-phase modulation, which, in conjunction with normal dispersion, gives rise to wave-breaking-induced temporal fringes and the chaotic proliferation and decay of dark solitons. Concurrently, spatiotemporal intermittency emerges across the pulse plateau in the form of irregular patterns. These dynamics lead to stochastic temporal evolution and the degradation of spectral coherence, quantified by the decay of first-order spectral coherence between successive pulses. Nevertheless, the partially coherent DSR still exhibits characteristics similar to those of the coherent DSR, such as constant power and a pulse duration that increases with pump strength. Our results provide new physical insight into the coherence properties of DSRs and offer practical criteria for experimentally identifying the widely observed flat-top square pulses.}, archive = {J_PRA}, author = {Ling Yun and Yueqing Du and Chao Zeng and Zuxing Zhang and Dong Mao}, doi = {10.1103/lhkp-1lh1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043507}, shortjournal = {Phys. Rev. A}, title = {Partially coherent dissipative-soliton resonances in lasers}, volume = {112}, year = {2025}, }
• (2025). Laser-induced magnetic dichroism and birefringence in a left-handed atomic medium. PRA, 112(4), 043506. (www)

  @article{ , abstract = {Birefringence and dichroism in atomic systems are active areas of research. Circular dichroism is typically observed in chiral atoms, molecules (such as DNA), and optically asymmetric materials. These phenomena enable polarization-based selectivity and high-precision measurements with applications in optical systems, biomedical diagnostics, and advanced photonics. Meanwhile, negative-refractive-index materials offer exotic applications in optics and photonics, including superresolution imaging, invisibility cloaking, and subwavelength imaging. Here we identify a route to achieving birefringence and dichroism in a left-handed system. We investigate the optical activity of an atomic left-handed medium, analyzing the interaction of left- and right-circularly polarized light with different atomic states while incorporating local field corrections. Notably, our results demonstrate simultaneous left-handedness for both polarization states. Furthermore, we find that electric birefringence and dichroism are significantly enhanced with increasing control field strength, while magnetic birefringence and dichroism can be fully controlled via strong laser coupling. These findings have promising implications in fields at the interface of left-handedness and dichroism.}, archive = {J_PRA}, author = {Haris Waleed Abbasi and Yasir Saeed and Nadia Boutabba and Hazrat Ali}, doi = {10.1103/nx3r-f3zs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043506}, shortjournal = {Phys. Rev. A}, title = {Laser-induced magnetic dichroism and birefringence in a left-handed atomic medium}, volume = {112}, year = {2025}, }
• (2025). Spin-orbit interactions induced by light drag in moving media. PRA, 112(4), 043505. (www)

  @article{ , abstract = {Spin-orbit interactions (SOIs) of light are manifestations of coupling between components of light's angular momentum. They are at play in most basic optical processes, offering opportunities both to understand their fundamental origin and to control light in novel ways. Because SOIs become significant at subwavelength scale, they have largely been explored in the context of inhomogeneous materials exhibiting wavelength-scale structures and notably metamaterials. Here we demonstrate that spin-orbit interactions can in fact analogously emerge in moving matter through the well-known light-dragging effects. SOIs in moving media are shown to manifest through a Berry phase induced by vorticity, which then leads to a rotation of the wave's polarization. In bringing together electrodynamics of moving media and SOIs of light, our work not only paves the way for the discovery of fundamental effects but also uncovers alternative means to harness SOIs to control light.}, archive = {J_PRA}, author = {Aymeric Braud and Renaud Gueroult}, doi = {10.1103/lsgb-ylzf}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043505}, shortjournal = {Phys. Rev. A}, title = {Spin-orbit interactions induced by light drag in moving media}, volume = {112}, year = {2025}, }
• (2025). Time dilation effects in micron-size rotating optical ferris-wheel traps. PRA, 112(4), 043503. (www)

  @article{ , abstract = {Advances in lasers and atomic clock technologies have enabled delicate measurements to be made of minute relativistic effects. Here, we propose that such developments should lead to the measurement of relativistic effects involving atoms and molecules in dynamic optical traps. Specifically, we make a case for the study of time dilation in the context of atoms and molecules trapped in a rotating optical Ferris wheel. With experimentally relevant examples, we demonstrate how this would extend relativity tests down to the micron scale and would constitute a potential advance toward micron-size Mössbauer-style spectroscopy for trapped atoms and molecules.}, archive = {J_PRA}, author = {V. E. Lembessis and J. Yuan and K. Köksal and M. Babiker}, doi = {10.1103/5m6c-hfqt}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043503}, shortjournal = {Phys. Rev. A}, title = {Time dilation effects in micron-size rotating optical ferris-wheel traps}, volume = {112}, year = {2025}, }
• (2025). Nonlinear-optical realization of nonintegrable phases accompanying quantum phase transitions. PRA, 112(4), 043502. (www)

  @article{ , abstract = {In this work, we propose an experimentally feasible nonlinear optical platform to realize nonintegrable geometric phases that emerge in interacting quantum systems undergoing quantum phase transitions. Specifically, we demonstrate that an exotic nonlinear term in the dynamical equations governs the polarization evolution of the optical field propagating along an anisotropic low-birefringence fiber with tetragonal symmetry. Intriguingly, by adiabatically tuning the nonlinear susceptibilities along the fiber, the Stokes vector on the Poincaré sphere accumulates a nonintegrable phase known as the Hannay angle—the classical counterpart to the Berry phase—which exhibits the same geometric gauge structure, including conic singularities in parameter space, as those associated with quantum phase transitions in systems like Bose-Einstein condensates. We further discuss a practical experimental implementation through the adiabatic deposition of nanocrystals along the fiber to control these susceptibilities, highlighting assumptions such as negligible losses and low birefringence for realistic fiber lengths.}, archive = {J_PRA}, author = {Chon-Fai Kam}, doi = {10.1103/7xy5-cx8l}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043502}, shortjournal = {Phys. Rev. A}, title = {Nonlinear-optical realization of nonintegrable phases accompanying quantum phase transitions}, volume = {112}, year = {2025}, }
• (2025). Three-dimensional canonical quantum plasmonics for finite media: Exact solution in terms of the classical green tensor. PRA, 112(4), 043501. (www)

  @article{ , abstract = {This article presents a comprehensive three-dimensional canonical quantization to treat quantum plasmonics for finite metallic or dielectric media of arbitrary shape. We use a microscopic model for the dissipative and dispersive medium coupled with the electromagnetic field, which is justified by the fact that if one integrates the degrees of freedom of the medium, one obtains the macroscopic Maxwell equations. Its quantization features a Hamiltonian formulation having the form of two infinite harmonic oscillators characterized by a double continuum. The diagonalized Hamiltonian is quantized by the correspondence principle, introducing creation-annihilation operators in a bosonic Fock space. The diagonal quantum Hamiltonian is the sum of two terms corresponding to the two continua. The physical observables, such as the electric field, are also the sum of two terms corresponding to the two continua, one of which had been omitted in the literature geared for an infinite bulk medium. In a second step, we show that the electric field operator can by written as linear combinations of the creation-annihilation operators with coefficients that satisfy integral equations of Fredholm type. We show that the solution of these equations can be expressed in terms of the classical Green tensor of the medium satisfying the Sommerfeld radiation condition. Finally, we consider the Purcell effect for the spontaneous emission of an atom close to the medium. We show that through an exact compensation of some terms, the Purcell factor for the system with the double continuum is proportional to the imaginary part of the Green tensor, which defines the local density of states. This result has the same form as the one obtained in the literature for bulk systems that involve a single continuum and a small dissipative background extending to infinity, and can be seen as a justification of this approach.}, archive = {J_PRA}, author = {Georgii Semin and Hans-Rudolf Jauslin and Stéphane Guérin}, doi = {10.1103/73rb-yr5m}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043501}, shortjournal = {Phys. Rev. A}, title = {Three-dimensional canonical quantum plasmonics for finite media: Exact solution in terms of the classical green tensor}, volume = {112}, year = {2025}, }
• (2025). Long-wavelength optical lattices from optical beatnotes: Theory and applications. PRA, 112(4), 043323. (www)

  @article{ , abstract = {We present a theoretical analysis of BeatNote Superlattices (BNSLs), a recently demonstrated technique for generating periodic trapping potentials for ultracold atomic clouds, with arbitrarily large lattice spacings while maintaining interferometric stability. By combining two optical lattices with slightly different wavelengths, a beatnote intensity pattern is formed, generating, for low depths, an effective lattice potential with a periodicity equal to the wavelength associated to the difference between the wave vectors of the two lattices. We study the range of lattice depths and wavelengths under which this approximation is valid and investigate its robustness against perturbations. We present a few examples where the use of BNSLs could offer significant advantages in comparison to well-established techniques for the manipulation of ultracold atomic gases. Our results highlight the potential of BNSLs for quantum simulation, atom interferometry, and other applications in quantum technologies.}, archive = {J_PRA}, author = {T. Petrucciani and A. Santoni and C. Mazzinghi and D. Trypogeorgos and F. Minardi and M. Fattori and M. Modugno}, doi = {10.1103/zpxp-btt5}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043323}, shortjournal = {Phys. Rev. A}, title = {Long-wavelength optical lattices from optical beatnotes: Theory and applications}, volume = {112}, year = {2025}, }
• (2025). Expansion dynamics of strongly correlated lattice bosons: A self-consistent density-matrix approach. PRA, 112(4), 043322. (www)

  @article{ , abstract = {We study the spatiotemporal dynamics of interacting bosons on a two-dimensional Hubbard lattice in the strongly interacting regime, taking into account the dynamics of condensate amplitude as well as the direct transport of noncondensed fluctuations. To that end we develop a self-consistent density-matrix approach which goes beyond the standard Gutzwiller mean-field theory. Starting from the Liouville-von-Neumann equation we derive a quantum master equation for the time evolution of the system's local density matrix at each lattice site, with a dynamical bath that represents the rest of the system. We apply this method to the expansion dynamics of an initially prepared cloud of interacting bosons in an optical lattice. We observe a ballistic expansion of the condensate, as expected, followed by slow, diffusive transport of the normal bosons. We discuss, in particular, the robustness of the Mott insulator phase as well as its melting due to incoherent transport. The method should be applicable to various models of lattice bosons in the strongly correlated regime.}, archive = {J_PRA}, author = {Julian Schwingel and Michael Turaev and Johann Kroha and Sayak Ray}, doi = {10.1103/bzvn-sp2h}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043322}, shortjournal = {Phys. Rev. A}, title = {Expansion dynamics of strongly correlated lattice bosons: A self-consistent density-matrix approach}, volume = {112}, year = {2025}, }
• (2025). Nonequilibrium magnetic dynamics of the two-component bose-hubbard model. PRA, 112(4), 043321. (www)

  @article{ , abstract = {A central challenge in strongly interacting many-body systems is understanding the far-from-equilibrium dynamics. Here we study the many-body magnetic dynamics of the two-component Bose-Hubbard model by developing a two-component extension of nonequilibrium bosonic dynamical mean-field theory. Using this numerical method, we uncover rich quantum spin dynamics via interspecies interaction quenches. A sudden ramp up of interactions induces slow thermalization, leading to a long-lived metastable state, whereas quenching to weak interactions results in rapid thermal equilibrium, featuring a two-step relaxation behavior through distinct exponential decays. Furthermore, under periodic modulation of the interspecies interactions, emergent Floquet dynamics drives a transition from a magnetic to an unordered phase.}, archive = {J_PRA}, author = {Hui Tan and Jianmin Yuan and Yongqiang Li}, doi = {10.1103/3dng-3jhl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043321}, shortjournal = {Phys. Rev. A}, title = {Nonequilibrium magnetic dynamics of the two-component bose-hubbard model}, volume = {112}, year = {2025}, }
• (2025). Bose-hubbard model on a honeycomb superlattice: Quantum phase transitions and lattice effects. PRA, 112(4), 043320. (www)

  @article{ , abstract = {We investigate the ground-state and finite-temperature phase diagrams of the Bose-Hubbard model on a honeycomb superlattice. The interplay between the superlattice potential depth Δ / t and the on-site interaction U / t gives rise to three distinct quantum phases at zero temperature: a superfluid phase, a Mott insulator I phase with unit filling on each site, and a Mott insulator II phase characterized by density imbalance—double occupancy on one sublattice and vacancy on the other at unit filling. The SF-MI transitions are found to be continuous, consistent with second-order quantum phase transitions. We further extend our analysis to finite temperatures within the superfluid regime. Our work highlights how a honeycomb superlattice geometry enables access to interaction- and lattice-modulation-driven quantum phases, including a density-imbalanced Mott insulator and a robust superfluid regime, offering concrete theoretical predictions for cold-atom experiments.}, archive = {J_PRA}, author = {Wei-Wei Wang and Jin Yang and Jian-Ping Lv and Chao Zhang}, doi = {10.1103/pkdf-tf5r}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043320}, shortjournal = {Phys. Rev. A}, title = {Bose-hubbard model on a honeycomb superlattice: Quantum phase transitions and lattice effects}, volume = {112}, year = {2025}, }
• (2025). Dynamical generation of geometric squeezing in interacting bose-einstein condensates. PRA, 112(4), 043319. (www)

  @article{ , abstract = {When the rotating frequency of a noninteracting Bose-Einstein condensate (BEC) confined in a weak anisotropic harmonic potential is suddenly quenched to its trapping frequency, the condensate evolves from its ground state to a single-mode squeezed state with exponentially growing quantum fluctuation anisotropy. Such a squeezed state is called the geometrically squeezed state. However, for interacting BECs with two-body collisions, a similar quench only results in quantum fluctuations oscillating periodically without squeezing. In this work, we identify superfluid stability as the key factor behind this nonsqueezing phenomenon, with the periodic oscillations arising from collective excitations of a stable collective excitation mode. By strategically breaking the stability criteria, we propose a dynamical approach for generating squeezing that can exponentially suppress quantum fluctuations in a relatively short time, surpassing the efficiency of existing experimental preparation schemes.}, archive = {J_PRA}, author = {Li Chen and Fei Zhu and Zheng Tang and Liang Zeng and Jae Joon Lee and Han Pu}, doi = {10.1103/sf74-lk9d}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043319}, shortjournal = {Phys. Rev. A}, title = {Dynamical generation of geometric squeezing in interacting bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Single half-skyrmion chain in spin-orbit-coupled toroidal bose-einstein condensate with gradient magnetic field. PRA, 112(4), 043318. (www)

  @article{ , abstract = {The ground-state properties of a spin-orbit-coupled rotating Bose-Einstein condensate with a gradient magnetic field in a toroidal trap are studied. When gradient magnetic fields are taken into account, the results are quite novel in that, in the spin-orbit-coupled nonrotating Bose-Einstein condensate with small gradient magnetic field intensity, the ferromagnetic system presents a plane-wave phase and satisfies the translational symmetry, and the antiferromagnetic system presents a stripe phase. With the increase of the magnetic field intensity, the translational symmetry of the ground state of the ferromagnetic system is broken, and the phase change tends to be similar in both ferromagnetic and antiferromagnetic systems. Considering the spin-orbit-coupled rotating Bose-Einstein condensate, the system gradually transforms from the nonsingle half-skyrmion chain to the single half-skyrmion chain with the increase of the gradient magnetic field, while the single half-skyrmion chain transforms to the nonsingle half-skyrmion chain with the increase of spin-orbit coupling. In addition, we obtain the phase diagram as a function of the gradient magnetic field and the spin-orbit-coupling intensity.}, archive = {J_PRA}, author = {Li Wang and Wen-Kai Bai and Hao Zhu and Xiao-Lin Zhou and Ji Li and Xiang-Rong Chen and Wu-Ming Liu}, doi = {10.1103/z9bb-k3tg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043318}, shortjournal = {Phys. Rev. A}, title = {Single half-skyrmion chain in spin-orbit-coupled toroidal bose-einstein condensate with gradient magnetic field}, volume = {112}, year = {2025}, }
• (2025). Two-photon-assisted collisions in ultracold gases of polar molecules. PRA, 112(4), 043317. (www)

  @article{ , abstract = {We present a theoretical formalism to treat the ultracold dynamics of a pair of colliding polar molecules submitted to two laser fields. We express the dressed Hamiltonian including the dipole-dipole interaction of the colliding molecular pair, both in their ground and electronic excited states, as well as their interaction with the two laser fields. We apply adiabatic elimination of the electronic excited state to reduce the size of the dressed-state basis in which the dressed Hamiltonian is expressed. In an application, we investigate the feasibility of two-photon collisional shielding between two molecules, which could be favored by the Raman resonance condition suppressing unwanted spontaneous emission and photon scattering. We demonstrate the influence of laser Rabi frequencies on the dynamics through the computation of elastic, inelastic, and reactive collision rates, which is still insufficient to ensure noticeable shielding.}, archive = {J_PRA}, author = {Charbel Karam and Gohar Hovhannesyan and Romain Vexiau and Maxence Lepers and Nadia Bouloufa-Maafa and Olivier Dulieu}, doi = {10.1103/9q1s-pjrs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043317}, shortjournal = {Phys. Rev. A}, title = {Two-photon-assisted collisions in ultracold gases of polar molecules}, volume = {112}, year = {2025}, }
• (2025). Suppression of capillary instability in a confined quantum liquid filament. PRA, 112(4), 043316. (www)

  @article{ , abstract = {Quantum Bose-Bose mixtures with large interspecies attraction can form self-bound, liquid-like droplets stabilized by quantum fluctuations. Despite equilibrium densities much lower than those of classical liquids, these droplets exhibit finite surface tension and liquid-like behaviors. Recent experiments have demonstrated Rayleigh-Plateau instability (a paradigmatic example of capillary instability) in elongated droplets confined in an optical waveguide. Here, we consider the case of an infinite filament and extend the theoretical description to include transverse harmonic confinement. By solving the Bogoliubov–de Gennes equations within a single-component framework, benchmarked against full Gross-Pitaevskii simulations, we show that increasing confinement progressively suppresses the instability, leading to complete stabilization beyond a critical trap frequency.}, archive = {J_PRA}, author = {Francesco Ancilotto and Michele Modugno and Chiara Fort}, doi = {10.1103/f1j6-st85}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043316}, shortjournal = {Phys. Rev. A}, title = {Suppression of capillary instability in a confined quantum liquid filament}, volume = {112}, year = {2025}, }
• (2025). Theory of itinerant collisional spin dynamics in nondegenerate molecular gases. PRA, 112(4), 043315. (www)

  @article{ , abstract = {We study the fully itinerant dynamics of ultracold but nondegenerate polar molecules with a spin- 1 / 2 degree of freedom encoded into two of their electric field dressed rotational states. Center-of-mass molecular motion is constrained to two dimensions via tight confinement with a one-dimensional optical lattice, but remains mostly unconstrained within the plane. The pseudospins can become entangled through ultracold dipolar collisions, for which the locality of interactions is greatly relaxed by free molecular motion. At the level of single-molecule observables, collision-induced entanglement manifests as spin decoherence, for which our theoretical calculations serve well to describe recent Ramsey contrast measurements of quasi-two-dimensional confined KRb molecules at JILA [A. Carroll et al. , Science 388 , 6745 (2025) ]. In presenting a more detailed theoretical analysis of the KRb experiment, we highlight a key finding that molecular loss enhanced by particle exchange symmetry can lead to a suppression of collective spin decoherence, a mechanism we refer to as “loss-induced quantum autoselection.” We then show that, by utilizing bialkali species with sufficiently large dipole moments, loss can be near completely suppressed in all collision channels via electric field tunable confinement-induced collisional shielding. The afforded collisional stability permits fully coherent spin mixing dynamics, natively realizing unitary circuit dynamics with random all-to-all connectivity and U(1) charge conservation. This work establishes a bridge between the domains of ultracold molecular collisions and many-body spin physics, ultimately proposing the use of nondegenerate bulk molecular gases as a controllable platform for nonequilibrium explorations of itinerant quantum matter.}, archive = {J_PRA}, author = {Reuben R. W. Wang and John L. Bohn}, doi = {10.1103/bsfk-57cg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043315}, shortjournal = {Phys. Rev. A}, title = {Theory of itinerant collisional spin dynamics in nondegenerate molecular gases}, volume = {112}, year = {2025}, }
• (2025). Four-mode quantum sensing and fisher information in a spin-orbit-coupled bose gas. PRA, 112(4), 043314. (www)

  @article{ , abstract = {Multimode squeezing and entanglement are important resources in quantum metrology and sensing. For spin-1/2 Bose-Einstein condensates subject to spin-orbit coupling (SOC), previous studies on spin squeezing have been limited to two-mode systems. In this work, we demonstrate that such a system can naturally construct a four-mode model spanning an su ( 4 ) algebra with six SU(2) subspaces. Using spin squeezing parameters and quantum Fisher information matrices, we analyze the dynamical evolution of coherent spin states. The results show that, beyond two-mode models, the SOC-induced four-mode couplings give rise to richer entanglement-enhanced sensing approaching the Heisenberg limit across various SU(2) subspaces. Additionally, by tuning a single system parameter (the Raman Rabi frequency), one can selectively control the optimal measurement across different subspaces.}, archive = {J_PRA}, author = {Fei Zhu and Zheng Tang and Liang Zeng and Shu Wang and Li Chen}, doi = {10.1103/5z1q-4rzl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043314}, shortjournal = {Phys. Rev. A}, title = {Four-mode quantum sensing and fisher information in a spin-orbit-coupled bose gas}, volume = {112}, year = {2025}, }
• (2025). Confinement-induced resonances for the creation of quasi-one-dimensional ultracold gases of alkali–alkaline-earth dimers. PRA, 112(4), 043313. (www)

  @article{ , abstract = {We theoretically investigate the role of confinement-induced resonances (CIRs) in low-dimensional ultracold atomic mixtures in the formation of weakly bound dimers. To this end, we examine the scattering properties of a binary atomic mixture confined by a quasi-one-dimensional (quasi-1D) potential. In this regime, the interspecies two-body interaction is modeled as an effective 1D zero-range pseudopotential, with a coupling strength g 1 D derived as a function of the three-dimensional scattering length a . This framework enables the study of CIRs in harmonically confined systems, with particular attention paid to the case of mismatched transverse trapping frequencies of the two atomic species. Finally, we consider the Bose-Fermi mixture of Rb 87 and Sr 87 and identify values of the experimentally accessible parameters for which CIRs can be exploited to create weakly bound molecules.}, archive = {J_PRA}, author = {Lorenzo Oghittu and Premjith Thekkeppatt and Nirav P. Mehta and Seth T. Rittenhouse and Klaasjan van Druten and Florian Schreck and Arghavan Safavi-Naini}, doi = {10.1103/3m6z-t6pb}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043313}, shortjournal = {Phys. Rev. A}, title = {Confinement-induced resonances for the creation of quasi-one-dimensional ultracold gases of alkali–alkaline-earth dimers}, volume = {112}, year = {2025}, }
• (2025). Chiral quantum droplet in a spin-orbit-coupled bose gas. PRA, 112(4), 043312. (www)

  @article{ , abstract = {We report the formation of the chiral quantum droplet in a spin-orbit-coupled Bose gas, where the system turns to a self-bound droplet when moving towards a particular direction and remains gaseous otherwise. The chirality arises from the breaking of Galilean invariance by spin-orbit coupling, which enables the system to dynamically adjust its condensation momentum and spin polarization in response to its velocity. As a result, only towards a specific moving direction and beyond a critical velocity, the acquired spin polarization can trigger collective interactions sufficient for self-binding and drive a first-order transition from gas to droplet. We map out a phase diagram of the droplet, gas, and their coexistence for realistic spin-orbit-coupled K 39 mixtures with tunable moving velocity and magnetic detuning. Our results reveal the emergence of chirality in spin-orbit-coupled quantum gases, which shed light on general chiral phenomena in moving systems with broken Galilean invariance.}, archive = {J_PRA}, author = {Tianqi Luo and Xiaoling Cui}, doi = {10.1103/8nvh-541r}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043312}, shortjournal = {Phys. Rev. A}, title = {Chiral quantum droplet in a spin-orbit-coupled bose gas}, volume = {112}, year = {2025}, }
• (2025). From elastic to inelastic deformation of a dipolar supersolid. PRA, 112(4), 043311. (www)

  @article{ , abstract = {Due to its peculiar superfluid-crystal duality feature, the supersolid has received great research interest. Recently, researchers have paid much attention to its elastic response properties; however, the inelastic deformation has barely been explored. In this work, we study the transition from elastic to inelastic deformation of a dipolar supersolid Bose-Einstein condensate trapped in a box potential (i.e., a dipolar supersolid with finite size). We obtain the stationary supersolid states (both ground and excited) of the system and examine the relation between the supersolid size and the number of unit cells it can accommodate, which can essentially help us to understand the dynamical responses of the supersolid during a dilation or compression process. We found that within a certain dilation or compression extent, the supersolid can retain its original crystal structure, that is, it endures an elastic deformation; however, when the extent exceeds a critical threshold, the original crystal structure of the supersolid will be disrupted, which signifies an inelastic deformation. Furthermore, we both analytically and numerically determine the critical point of the transition from elastic to inelastic deformation and map out a phase diagram. These results open up new territory in the research of supersolid mechanical properties and may find applications in quantum material science and quantum-based technologies.}, archive = {J_PRA}, author = {Qiaomei Zhao and Xingdong Zhao and Jieli Qin}, doi = {10.1103/2vyl-dg7c}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043311}, shortjournal = {Phys. Rev. A}, title = {From elastic to inelastic deformation of a dipolar supersolid}, volume = {112}, year = {2025}, }
• (2025). Vortex mass in superfluid fermi gases along the BEC-BCS crossover. PRA, 112(4), 043310. (www)

  @article{ , abstract = {Vortex mass is a key concept in the study of superfluid dynamics, referring to the inertia of vortices in a superfluid, which affects their motion and behavior. Despite being an important quantity, the vortex mass has never been observed experimentally, and remains an unresolved issue in this field. As of now, a large body of research assumes that the vortex mass is a local parameter. In contrast, we present a calculation that suggests a logarithmic dependence on the system size, agreeing with some earlier predictions in the context of Bose gases. We analyze the problem using an effective field theory that describes ultracold atomic Fermi gases over the BEC-BCS crossover at both zero and nonzero temperatures. Our study reveals a strong dependence of the vortex mass on the scattering length; in particular, the vortex mass grows rapidly when moving toward the BCS side. Furthermore, we find that the system-size dependence of the vortex mass results in values an order of magnitude larger than those predicted by other models for realistic system sizes. This implies that the vortex mass could be observable in a wider parameter range than was previously expected. This is particularly relevant considering recent advances in experimental techniques that place the observation of vortex mass in superfluid Fermi gases within reach.}, archive = {J_PRA}, author = {Lucas Levrouw and Hiromitsu Takeuchi and Jacques Tempere}, doi = {10.1103/p24p-k59v}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043310}, shortjournal = {Phys. Rev. A}, title = {Vortex mass in superfluid fermi gases along the BEC-BCS crossover}, volume = {112}, year = {2025}, }
• (2025). Thermal relaxation and the complete set of second-order transport coefficients for the unitary fermi gas from kinetic theory. PRA, 112(4), 043309. (www)

  @article{ , abstract = {We compute the complete set of second-order transport coefficients of the unitary Fermi gas, a dilute gas of spin-1/2 particles interacting via an s -wave interaction tuned to infinite scattering length. The calculation is based on kinetic theory and the Chapman-Enskog method at second order in the Knudsen expansion. We take into account the exact two-body collision integral. We extend previous results on second-order coefficients related to shear stress by including terms related to heat flow and gradients of the fugacity. We confirm that the thermal relaxation time is given by the simple estimate τ κ = κ m / ( c P T ) even if the full collision kernel is taken into account. Here, κ is the thermal conductivity, m is the mass of the particles, c P is the specific heat at constant pressure, and T is the temperature.}, archive = {J_PRA}, author = {Christian Hall and Thomas Schäfer}, doi = {10.1103/wtrz-tmcd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043309}, shortjournal = {Phys. Rev. A}, title = {Thermal relaxation and the complete set of second-order transport coefficients for the unitary fermi gas from kinetic theory}, volume = {112}, year = {2025}, }
• (2025). Excitation spectrum of vortex-lattice modes in a rotating condensate with a density-dependent gauge potential. PRA, 112(4), 043308. (www)

  @article{ , abstract = {We investigate the collective excitation spectrum of a quasi-two-dimensional Bose-Einstein condensate trapped in a harmonic confinement with nonlinear rotation induced by a density-dependent gauge potential. Using a Bogoliubov–de Gennes (BdG) analysis, we show that the dipole mode frequency depends strongly on the nonlinear interaction strength, violating Kohn's theorem which is also well complemented by the analytical expression for the dipole and breathing modes obtained employing a variational analysis. We identify four different vortex displacement modes, Tkachenko, circular, quadratic, and rational, whose frequencies are rotation sensitive. An analytical Tkachenko mode frequency from a hydrodynamic approach agrees well with that computed using BdG and Fourier analysis. The excitation spectrum remains symmetric around the angular quantum number l = 0 , but energy splitting between l and − l varies with the sign and strength of the nonlinear rotation. Finally, we demonstrate that the surface mode excitation frequency increases (decreases) with an increase in the positive (negative) nonlinear rotation strength.}, archive = {J_PRA}, author = {Rony Boral and Swarup K. Sarkar and Matthew Edmonds and Paulsamy Muruganandam and Pankaj Kumar Mishra}, doi = {10.1103/99xp-w23f}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043308}, shortjournal = {Phys. Rev. A}, title = {Excitation spectrum of vortex-lattice modes in a rotating condensate with a density-dependent gauge potential}, volume = {112}, year = {2025}, }
• (2025). Antiscarring from eigenstate stacking in a chaotic spinor condensate. PRA, 112(4), 043307. (www)

  @article{ , abstract = {We reveal a feature of quantum scarring in systems with many particles: quantum scars, living densely near an unstable periodic orbit, must be compensated by corresponding antiscarred states suppressed there to establish the uniformity of the whole. The uniformity of the underlying phase space is linked to early-time dynamics—a regime beyond the predictions of random matrix theory and encapsulated in the eigenstate stacking theorem. By extending the domain of the stacking theorem, we apply our theory to a chaotic spinor Bose-Einstein condensate, whose quantum scar dynamics have recently been observed in the laboratory. Our work uncovers how scarring of some eigenstates affects the rest of the chaotic and thermal spectrum in quantum systems with many particles.}, archive = {J_PRA}, author = {Zhongling Lu and Anton M. Graf and Eric J. Heller and Joonas Keski-Rahkonen and Ceren B. Dag}, doi = {10.1103/k594-zxlj}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043307}, shortjournal = {Phys. Rev. A}, title = {Antiscarring from eigenstate stacking in a chaotic spinor condensate}, volume = {112}, year = {2025}, }
• (2025). Effective potential and scattering length of shielded polar molecules. PRA, 112(4), 043306. (www)

  @article{ , abstract = {We investigate the effective potential and scattering length of ultracold polar molecules under different shielding techniques. First, we derive the effective potential for two polar molecules in the presence of (i) an elliptical polarization field alone, (ii) combined elliptical and linear polarization fields, and (iii) combined elliptical polarization and static fields. The effective potential is then expressed as a sum of a zero-range contact interaction and a long-range dipolar interaction under the Born approximation. We find that the methods (i) and (ii) only partially suppress attractive interactions, while the method (ii) allows for the construction of bound states with different polarization shapes. The last shielding method (iii) can achieve complete cancellation of residual attractive forces [Micheli et al. , Phys. Rev. A 76 , 043604 (2007) ; Gorshkov et al. , Phys. Rev. Lett. 101 , 073201 (2008) ], which is particularly significant for maintaining quantum degeneracy in ultracold dipolar systems. Our results provide a comprehensive understanding of the effective potential and scattering length of shielding polar molecules, which is crucial for studying many-body physics in ultracold dipolar systems.}, archive = {J_PRA}, author = {Peng Xu and Gang Chen}, doi = {10.1103/dw1b-g5cs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043306}, shortjournal = {Phys. Rev. A}, title = {Effective potential and scattering length of shielded polar molecules}, volume = {112}, year = {2025}, }
• (2025). Stable high-order vortices in spin-orbit-coupled spin-1 bose-einstein condensates. PRA, 112(4), 043305. (www)

  @article{ , abstract = {The present contribution explores phase transitions that occur in the ground state (GS) of spin-1 Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) under the action of gradient magnetic fields. By solving the corresponding linearized system in an exact fashion, we identify the conditions under which the GS phase transitions occur, thus transforming excited states into GSs. The study of the full nonlinear system, including both density-density and spin-spin interactions, is numerically analyzed. For the case of repulsive spin-spin interactions, the results resemble the linear case, while attractive spin-spin interactions lead to the formation of mixed states near the GS phase-transition points. Additionally, higher-order vortex states are found to be stable even in the nonlinear regime. These findings demonstrate that arbitrary winding numbers corresponding to stable GSs can be achieved, thus contributing to the understanding of topological properties in SOC BECs.}, archive = {J_PRA}, author = {Xin-Feng Zhang and Huan-Bo Luo and Josep Batle and Bin Liu and Yongyao Li}, doi = {10.1103/kb8m-847n}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043305}, shortjournal = {Phys. Rev. A}, title = {Stable high-order vortices in spin-orbit-coupled spin-1 bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Strong-coupling random-phase-approximation theory of a bose gas near the superfluid–Mott-insulator transition: Universal thermodynamics and two-body contact. PRA, 112(4), 043304. (www)

  @article{ , abstract = {We present a strong-coupling expansion of the Bose-Hubbard model based on a mean-field treatment of the hopping term, while onsite fluctuations are taken into account exactly. This random phase approximation describes the universal features of the generic Mott-insulator–superfluid transition (induced by a density change) and the superfluid state near the phase transition. The critical quasiparticles at the quantum critical point have a quadratic dispersion with an effective mass and their mutual interaction is described by an effective -wave scattering length . The singular part of the pressure takes the same form as in a dilute Bose gas, provided we replace the boson mass and the scattering length in vacuum by and , and the density by the excess density of particles (or holes) with respect to the Mott insulator. We define a universal two-body contact that controls the high-momentum tail of the singular part of the momentum distribution. We also apply the strong-coupling RPA to a lattice model of hard-core bosons and find that the high-momentum distribution is controlled by a universal contact, in complete agreement with the Bose-Hubbard model. Finally, we discuss a continuum model of bosons in an optical lattice and define two additional two-body contacts: a short-distance universal contact which controls the high-momentum tail of at scales larger than the inverse lattice spacing, and a full contact , which controls the high-momentum tail of the full-momentum distribution .}, archive = {J_PRA}, author = {Nicolas Dupuis and Moksh Bhateja and Adam Rançon}, doi = {10.1103/zhpw-crqc}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043304}, shortjournal = {Phys. Rev. A}, title = {Strong-coupling random-phase-approximation theory of a bose gas near the superfluid–Mott-insulator transition: Universal thermodynamics and two-body contact}, volume = {112}, year = {2025}, }
• (2025). Momentum relaxation of strongly coupled impurities in quantum gases: A nonequilibrium green's function approach. PRA, 112(4), 043303. (www)

  @article{ , abstract = {Within the nonequilibrium Green's function framework, we systematically analyze the momentum relaxation dynamics of strongly coupled impurities in three-dimensional nondegenerate quantum gases. Using the Hartree-Fock approximation, we establish that the impurity velocity exhibits exponential decay asymptotically. When the impurity velocity is much lower than the thermal velocity of the gas atoms, the relaxation time τ is governed entirely by the self-energy evaluated at zero momentum and zero frequency, Σ ( p = 0 ; ω = 0 ) . Furthermore, via virial expansion theory, τ admits a systematic expansion in powers of the fugacity z ≡ e β μ . The leading-order term precisely recovers the Boltzmann semiclassical result, while higher-order corrections capture quantum many-body effects beyond the semiclassical approximation.}, archive = {J_PRA}, author = {Baihua Gong}, doi = {10.1103/frw1-nsln}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043303}, shortjournal = {Phys. Rev. A}, title = {Momentum relaxation of strongly coupled impurities in quantum gases: A nonequilibrium green's function approach}, volume = {112}, year = {2025}, }
• (2025). Rabi-induced localization and resonant delocalization of a binary condensate in a spin-asymmetric quasiperiodic potential. PRA, 112(4), 043302. (www)

  @article{ , abstract = {We theoretically investigate the ground state and dynamics of a Rabi-coupled pseudospin-1/2 Bose-Einstein condensate, where only one spin component is subjected to an external potential. We show that in the quasiperiodic potential the Rabi coupling induces localization between the components as it is raised above the threshold value. Interestingly, the localization is mutually induced by both components for the quasiperiodic confinement, whereas for a harmonic trap the localization is induced in the potential-free component by interaction with that confined in the potential. Further, we explore the condensate dynamics by implementing a periodic driving of the Rabi frequency, where various frequency-dependent delocalization patterns, such as double- (triple)-minima, treelike (parquetlike), and frozen distributions with a correlated propagation of different spin populations are observed in the condensate density. These features pave the way to control the condensate mass and spin density patterns, both in the stationary and dynamical realizations.}, archive = {J_PRA}, author = {Swarup K. Sarkar and Sh. Mardonov and E. Ya. Sherman and Pankaj K. Mishra}, doi = {10.1103/f67w-kd5j}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043302}, shortjournal = {Phys. Rev. A}, title = {Rabi-induced localization and resonant delocalization of a binary condensate in a spin-asymmetric quasiperiodic potential}, volume = {112}, year = {2025}, }
• (2025). Engineering the kondo impurity problem with alkaline-earth-atom arrays. PRA, 112(4), 043301. (www)

  @article{ , abstract = {We propose quantum simulation experiments of the Kondo impurity problem using cold alkaline-earth(-like) atoms (AEAs) in a combination of optical lattice and optical tweezer potentials. Within an ab initio model for atomic interactions in the optical potentials, we analyze hallmark signatures of the Kondo effect in a variety of observables accessible in cold-atom quantum simulators. We identify additional terms not part of the textbook Kondo problem, mostly ignored in previous works and giving rise to a direct competition between spin and charge correlations, strongly suppressing Kondo physics. We show that the Kondo effect can be restored by locally adjusting the chemical potential on the impurity site, and we identify realistic parameter regimes and preparation protocols suited to current experiments with AEA arrays. Our work paves the way for quantum simulations of the Kondo problem and offers insights into Kondo physics in unconventional regimes.}, archive = {J_PRA}, author = {A. Amaricci and A. Richaud and M. Capone and N. Darkwah Oppong and F. Scazza}, doi = {10.1103/m7l3-y2f8}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043301}, shortjournal = {Phys. Rev. A}, title = {Engineering the kondo impurity problem with alkaline-earth-atom arrays}, volume = {112}, year = {2025}, }
• (2025). Rapid passage to ordered states in rydberg-atom arrays. PRA, 112(4), 043124. (www)

  @article{ , abstract = {Given a finite lifetime, a ubiquitous challenge in quantum systems is how to prepare a target state in the shortest possible time. This issue is particularly relevant for Rydberg-atom arrays in optical tweezers, where the dephasing time is typically restricted to a few microseconds. In this work, we develop a rapid passage to ordered many-body states in a Rydberg-atomic chain, which allows the transition of the system to various ordered phases in the phase diagram, such as the -, -, and -ordered antiferromagnetic states. Our scheme ramps the parameter in a “nonadiabatic to quasi-adiabatic to nonadiabatic (NQN)” manner. The NQN configuration significantly reduces the time cost required for the state preparation using entirely adiabatic methods and is generally applicable to a sizable number of atoms. Moreover, we experimentally validate the NQN scheme on the neutral-atom quantum cloud computer Aquila.}, archive = {J_PRA}, author = {Liang Zeng and Fei Zhu and Li Chen and Heng Shen}, doi = {10.1103/ctwz-rhdv}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043124}, shortjournal = {Phys. Rev. A}, title = {Rapid passage to ordered states in rydberg-atom arrays}, volume = {112}, year = {2025}, }
• (2025). Harmonic generation in preionized liquid plasmas driven by intense midinfrared pulses. PRA, 112(4), 043123. (www)

  @article{ , abstract = {We investigated harmonic generation in preionized liquid ethanol and water driven by linearly polarized midinfrared (MIR) pulses at a center wavelength of 3100 nm. The liquid targets were preionized by a near-infrared pump pulse at 800 nm, enabling systematic control of the electron density in the liquids. At low pump intensities, the harmonic spectra remain unchanged. In contrast, at intermediate pump intensities, the spectra exhibit pronounced target- and delay-dependent modifications, reflecting changes in the optical properties of the ionized liquids. At high intensities, where the electron density exceeds the critical plasma density for MIR light, harmonic yields are strongly suppressed and spectral broadening disappears. Numerical simulations based on the nonlinear propagation model, incorporating plasma and Kerr effects, qualitatively reproduce the experimental observations above the critical plasma density and confirm the significant role of plasma shuttering in harmonic generation. The observation of narrow harmonic spectra provides clear evidence of evanescent-field-induced harmonic generation in preionized liquids. This highlights the potential of ionized liquid plasmas as a robust platform for exploring strong-field phenomena driven by intense and spatially nonuniform fields, beyond the damage thresholds of conventional materials.}, archive = {J_PRA}, author = {Tomoya Mizuno and Tianqi Yang and Takayuki Kurihara and Yimin Gu and Tomoyuki Shoji and Teruto Kanai and Jiro Itatani}, doi = {10.1103/1mtc-m2gt}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043123}, shortjournal = {Phys. Rev. A}, title = {Harmonic generation in preionized liquid plasmas driven by intense midinfrared pulses}, volume = {112}, year = {2025}, }
• (2025). Breit-wheeler pair production in circularly polarized laser pulses seeded by a noble gas: Magnetic-field effects. PRA, 112(4), 043122. (www)

  @article{ , abstract = {We investigate the phenomenon of electron-positron pair production resulting from the interaction of neutral xenon gas with a high-intensity laser field. The pairs are generated through a combination of nonlinear Compton scattering and the Breit-Wheeler mechanism. We examine the pair-production process in a single circularly polarized laser pulse and in a combination of two counterpropagating pulses with opposite circular polarizations. Special focus is placed on analyzing the role of an additional external magnetic field. It is demonstrated that one can significantly enhance the positron yield by introducing a constant magnetic field, the strength of which is of the same order as the laser amplitude. We show that the magnetic field modifies the electron dynamics and gives rise to much larger values of the corresponding nonlinearity parameters for the particles. Within the framework of quantum electrodynamics, it is well known that these quantities predominantly govern the rates of photon emission and pair production; therefore, the magnetic field can considerably stimulate the mechanism of positron creation. In this context, we also discuss experimentally relevant scenarios where such strong magnetic fields may arise and prospects for determining laser intensity by measuring the number of positrons produced.}, archive = {J_PRA}, author = {I. A. Aleksandrov and A. A. Andreev}, doi = {10.1103/b5kv-5nl4}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043122}, shortjournal = {Phys. Rev. A}, title = {Breit-wheeler pair production in circularly polarized laser pulses seeded by a noble gas: Magnetic-field effects}, volume = {112}, year = {2025}, }
• (2025). Local nonadiabatic coupling effects on rovibrationally resolved photodissociation dynamics of BeH in ultraviolet region. PRA, 112(4), 043121. (www)

  @article{ , abstract = {Accurate photodissociation cross sections of beryllium monohydride (BeH) have been calculated for photon wavelengths ranging from 82 nm to the dissociation threshold, covering transitions from the ground state to excited electronic states up to and . Particular emphasis is placed on elucidating the nonadiabatic coupling between states and , and its fundamental role in photodissociation dynamics. By explicitly incorporating these nonadiabatic effects into rovibrationally resolved cross sections calculated at various temperatures, we demonstrate how nonadiabatic couplings profoundly influence molecular fragmentation pathways. Our analysis reveals that such couplings induce numerous Feshbach resonances, significantly modifying both resonance positions and intensities in the computed cross sections. The physical origin of these resonances is interpreted in terms of coupling-induced trapping of continuum states by bound or quasibound rovibrational levels, highlighting the importance of rigorous nonadiabatic treatments for accurate predictions. This study presents the first comprehensive theoretical characterization of BeH photodissociation including nonadiabatic interactions, providing essential benchmark data for experimental verifications and astrophysical modeling, particularly relevant for understanding BeH photochemical processes in the early universe and ultraviolet-irradiated interstellar environments. The present framework provides a potentially instructive reference for future implementations of local nonadiabatic coupling in molecular photodissociation investigations.}, archive = {J_PRA}, author = {Yu Kun Yang and Xing Guang Su and Yongjun Cheng and Chao Wang and Yu Wang and Yong Wu and Jian Guo Wang and Yi Zhi Qu and Ke Dong Wang and Kun Wang and Song Bin Zhang}, doi = {10.1103/2kkp-qngs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043121}, shortjournal = {Phys. Rev. A}, title = {Local nonadiabatic coupling effects on rovibrationally resolved photodissociation dynamics of BeH in ultraviolet region}, volume = {112}, year = {2025}, }
• (2025). Floquet interpretation of dynamic interference in laser-assisted photoemission. PRA, 112(4), 043120. (www)

  @article{ , abstract = {We present a theoretical study of dynamic interference (DI) in laser-assisted photoemission (LAPE), a regime widely employed in attosecond and few-femtosecond spectroscopy. Using the strong-field approximation (SFA) and a Floquet framework, we analyze the influence of a finite infrared (IR) pulse envelope under experimentally relevant conditions. In addition to the established phase modulation mechanism—referred to as laser-assisted dynamic interference (LADI)—we identify an alternative source of DI arising from a time-dependent amplitude modulation, which we term dynamic multiphoton interference (DMPI). We attribute DMPI to quantum-path interference among competing multiphoton transitions, which, depending on the exact employed parameters, can overshadow LADI when electrons are emitted along the IR polarization axis. We further delineate the conditions necessary for the clear experimental observation of both effects and assess their robustness against variations in pump pulse intensity in a realistic experimental condition.}, archive = {J_PRA}, author = {Matteo Lucchini}, doi = {10.1103/s7zk-n6bw}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043120}, shortjournal = {Phys. Rev. A}, title = {Floquet interpretation of dynamic interference in laser-assisted photoemission}, volume = {112}, year = {2025}, }
• (2025). Quantum path control in high-order harmonic generation via squeezed light. PRA, 112(4), 043119. (www)

  @article{ , abstract = {High-order harmonic generation (HHG), a robust tabletop source for producing attosecond pulses, has been extensively utilized in attosecond metrology. Traditionally, HHG driven by classical laser fields involves two typical quantum paths (short and long quantum paths) contributing to harmonic emission. Here we demonstrate that these quantum paths in HHG can be selectively controlled using squeezed light, a form of nonclassical light. Our results indicate that the long (short) quantum path of HHG will be dramatically suppressed in the phase (amplitude)-squeezed fields. The time-frequency analysis reveals that this quantum path control stems from the quantum fluctuations in the squeezed light, which modify the phase matching of harmonic emission from different quantum states of the squeezed light. Such a quantum path selection can be achieved for the whole harmonic plateau, which has great potential to generate ultrashort isolated attosecond pulses with duration less than one atomic unit of time.}, archive = {J_PRA}, author = {Feng Wang and Chunhui Yang and Xinyi Cui and Lixin He and Tianxin Ou and Rui-Bo Jin and Qing Liao and Pengfei Lan and Peixiang Lu}, doi = {10.1103/hph3-kzb2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043119}, shortjournal = {Phys. Rev. A}, title = {Quantum path control in high-order harmonic generation via squeezed light}, volume = {112}, year = {2025}, }
• (2025). Analyzing the optical pumping on the 5s4dD21−5s8pP11 transition in a magneto-optical trap of sr atoms. PRA, 112(4), 043118. (www)

  @article{ , abstract = {We explore the efficacy of optical pumping on the transition in a magneto-optical trap (MOT) of Sr atoms. The number of trapped atoms is enhanced by a factor of relative to the case without repumping light, which is six times as large as that obtained using the pumping transition . This enhancement is limited by decay pathways that bypass the state, namely and , which account for 8% of the total loss of the trapped atoms. We determine the decay rates for the and transitions to be and , respectively. Furthermore, we experimentally demonstrate, when the trap beam diameter is small, escape of atoms in the state, which has a relatively long lifetime of , becomes a dominant loss mechanism, and that the pumping light effectively suppresses this escape. Our findings will contribute to improved laser cooling and fluorescence imaging in cold strontium atom platforms, such as quantum computers based on optical tweezer arrays.}, archive = {J_PRA}, author = {Naohiro Okamoto and Takatoshi Aoki and Yoshio Torii}, doi = {10.1103/j7s7-b7mj}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043118}, shortjournal = {Phys. Rev. A}, title = {Analyzing the optical pumping on the 5s4dD21−5s8pP11 transition in a magneto-optical trap of sr atoms}, volume = {112}, year = {2025}, }
• (2025). Reverse-engineering control of the population and phase dynamics of strongly driven open systems. PRA, 112(4), 043117. (www)

  @article{ , abstract = {We apply reverse engineering to design laser pulse shapes for controlling the time evolution of strong-field transitions under environmental effects. Our effective two-state representation of the full quantum system involves dynamic Stark shifts and multiphoton Rabi frequency. Furthermore, the environment is modeled with dephasing and dissipative terms. Solving the master equation of the two-level density matrix inversely for the field, we obtain quasianalytic laser pulse shapes that simultaneously drive the populations and relative phase according to user-defined quantum pathways. The validity of the proposed scheme is demonstrated with the example of the two-photon transition of atomic sodium by solving the master equation of the multilevel system that incorporates effects beyond the adiabatic elimination and the rotating wave approximation. Due to the open character of the system, the proposed control is not always possible. We explore these situations and point out the conditions for creating steady states with large coherence.}, archive = {J_PRA}, author = {András Csehi}, doi = {10.1103/8h2d-cblx}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043117}, shortjournal = {Phys. Rev. A}, title = {Reverse-engineering control of the population and phase dynamics of strongly driven open systems}, volume = {112}, year = {2025}, }
• (2025). Experimental determination of the angular dependence of the ionization probability of n2 in an intense laser field. PRA, 112(4), 043116. (www)

  @article{ , abstract = {We investigate the dependence of the ionization probability of N 2 in an intense laser field on the angle between the laser polarization direction and the molecular axis by recording the yield of N 2 + as a function of both the time delay between the pump and probe laser pulses and the polarization angle ( Θ ) between the pump and probe laser polarization directions when the rotational wave packet of N 2 is created by the pump pulse and N 2 is ionized by the probe pulse. The Fourier transform of the delay dependence of the N 2 + yield exhibits peaks at the energy differences of the rotational levels of N 2 with J + 2 and J , with J being the rotational quantum number of N 2 , and the polarization dependences of the amplitudes of these peaks are mainly given by the Legendre polynomial P 2 ( cos Θ ) . From the comparison with the analytical formula of the polarization dependent Fourier transform spectra, we partly determine the angular dependence of the ionization probability of N 2 without estimating the molecular axis distribution of N 2 prepared as the ensemble of the rotational wave packets. The resultant angular dependence of the ionization probability suggests the ionization induced by the photoelectron emission from the lower-lying 1 π u orbital of N 2 in addition to the highest occupied 3 σ g orbital.}, archive = {J_PRA}, author = {Shinichi Fukahori and Hirokazu Hasegawa}, doi = {10.1103/mnb2-c8gy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043116}, shortjournal = {Phys. Rev. A}, title = {Experimental determination of the angular dependence of the ionization probability of n2 in an intense laser field}, volume = {112}, year = {2025}, }
• (2025). Enhanced extreme-ultraviolet-radiation generation via controllable spontaneous emission induced by two-color orthogonally polarized laser fields. PRA, 112(4), 043115. (www)

  @article{ , abstract = {We theoretically investigate the enhancement of extreme-ultraviolet-radiation (XUV) generation by orthogonally polarized laser-controlled spontaneous emission of Ar atoms. The three-dimensional time-dependent Schrödinger equation is solved numerically using the generalized pseudospectral method. Applying an intense third-harmonic field of 1030-nm laser results in a series of spectral lines appearing in the harmonic spectrum between 13.5  and 15.8 eV. These lines correspond to field-free transitions between the ground state and 3 s 2 3 p 5 n d ( n = 3 , 4 , 5 , ... ) excited states of argon. Introducing a weak multicycle fundamental laser pulse perpendicular to the third-harmonic field leads to a narrowband XUV emission centered at 14.15 eV, corresponding to the transition from the 3 s 2 3 p 5 3 d excited state to the ground state. Combining population analysis with the synchrosqueezed transform time-frequency spectra, we attribute those emissions to free induction decay from the coherently excited states. The perpendicular fundamental field will cause the ionization of excited states, leading to the depletion of those states and the generation of excited states' high-order harmonics, which suppress the free induction decay emission. For higher excited states, the fundamental field alters the excitation pathways, significantly reducing state populations. The use of orthogonally polarized laser fields enables selective excitation of specific electronic states, enhancing the spectral purity. Our findings demonstrate the potential of orthogonal two-color laser pulses in generating bright, narrowband XUV radiation. This research provides new insights for developing XUV and soft x-ray light sources, offering promising applications in various fields requiring precise and intense XUV radiation.}, archive = {J_PRA}, author = {Zhi-Bin Wang and Hu-Bao Li and Zheng-Qian Guo and Ling-Ling Du and Xiao-Xin Zhou and Peng-Cheng Li}, doi = {10.1103/jrsk-c715}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043115}, shortjournal = {Phys. Rev. A}, title = {Enhanced extreme-ultraviolet-radiation generation via controllable spontaneous emission induced by two-color orthogonally polarized laser fields}, volume = {112}, year = {2025}, }
• (2025). Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field. III. two-component fields. PRA, 112(4), 043114. (www)

  @article{ , abstract = {The complete classification of the saddle-point solutions for high-order above-threshold ionization, presented in Phys. Rev. A 111 , 023103 (2025) and Phys. Rev. A 111 , 053110 (2025) for a linearly polarized laser field, is generalized to the case of an arbitrary bichromatic elliptically polarized field. We first present the classification of the saddle-point solutions for the case of a monochromatic elliptically polarized driving field, which is the simplest example of the field that has two components, i.e., that evolves in the plane. For a bichromatic laser field whose elliptically polarized components have the frequencies r ω and s ω ( r and s are integers, s > r , and ω is the fundamental frequency), the system of the saddle-point equations has 8 s 2 solutions per optical cycle. One-half of these solutions are the so-called backward-scattering solutions for which the direction of the electron motion is significantly affected by the rescattering. The other half are the forward-scattering solutions for which the electron is only slightly deflected during the rescattering event. For some specific field configurations, the number of saddle-point solutions can be smaller. For example, for a bicircular field, which consists of two counterrotating circularly polarized components, there are 4 s ( r + s ) solutions, while for the corotating configuration there are 4 s 2 solutions. As an application, we have shown that for a monochromatic elliptically polarized laser field, all four threshold anomalies appear in the spectra of the rescattered photoelectrons.}, archive = {J_PRA}, author = {D. Habibović and D. B. Milošević}, doi = {10.1103/gqcl-2t7s}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043114}, shortjournal = {Phys. Rev. A}, title = {Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field. III. two-component fields}, volume = {112}, year = {2025}, }
• (2025). Optical interference effect in strong-field electronic coherence spectroscopy. PRA, 112(4), 043113. (www)

  @article{ , abstract = {We investigate strong-field-induced electronic coherences in argon and molecular nitrogen ions created by high-intensity, few-cycle infrared laser pulses. This is a step toward the long-sought goal of strong-field coherent control in molecular chemistry. We employ high-intensity, few-cycle infrared laser pulses in a pump-probe setup to investigate a recent prediction that electronic coherences in nitrogen molecules change the ion yields versus pump-probe delay. [Yuen et al. , Phys. Rev. A 109 , L011101 (2024) ]. The predicted coherence signals in molecular nitrogen could not be resolved above the optical interference of the pump and probe pulses; a simultaneous measurement clearly resolved the induced cation fine-structure coherence in strong-field-ionized argon. The results of our comparison with simulations suggest that optical interference effects manifest differently in each ionic species and must be carefully accounted for when interpreting experimental data. We find that nonsequential double ionization in the low-intensity region of the focal volume can reduce the visibility of coherence generated by two-pulse sequential ionization, and we quantify the importance of pulse shape and spectral characteristics for isolating the desired coherence signals.}, archive = {J_PRA}, author = {Eleanor Weckwerth and Andrew J. Howard and Chuan Cheng and Ian Gabalski and Aaron M. Ghrist and Salma A. Mohideen and Chii-Dong Lin and Chi-Hong Yuen and Philip H. Bucksbaum}, doi = {10.1103/rkdq-5skq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043113}, shortjournal = {Phys. Rev. A}, title = {Optical interference effect in strong-field electronic coherence spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Quantum theory of a magneto-optical trap. PRA, 112(4), 043112. (www)

  @article{ , abstract = {We present a quantum theory of a magneto-optical trap (MOT) from first principles based on the quantum kinetic equation for the atomic density matrix, taking into account the recoil effects caused by the interaction of atoms with the laser field. An efficient method for solving the quantum kinetic equation is proposed. It is shown that the steady-state solution describing the atoms in the MOT has a significantly nonequilibrium nature and can be described within the framework of a two-temperature distribution. The momentum distribution of cold atoms in the MOT depends on the magnetic field gradient and, in general, significantly differs from the momentum distribution of atoms in the optical molasses, which is usually used as an approximation to describe the MOT. We have also shown that with an increase in the magnetic field gradient, a spatial two-component distribution of atoms in the trap is formed even for a single-particle approximation when interatomic interactions are neglected.}, archive = {J_PRA}, author = {O. N. Prudnikov and V. I. Yudin and A. V. Taichenachev and L. Zhou and M. S. Zhan}, doi = {10.1103/5v11-cwv2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043112}, shortjournal = {Phys. Rev. A}, title = {Quantum theory of a magneto-optical trap}, volume = {112}, year = {2025}, }
• (2025). Simulation of stimulated raman adiabatic passage from the 1S to the 2S states of the hydrogen and antihydrogen atoms. PRA, 112(4), 043111. (www)

  @article{ , abstract = {Achieving a high population of antihydrogen and hydrogen atoms in the level is essential for spectroscopy measurements testing similarities between matter and antimatter. We propose and examine the efficiency of applying the STIRAP (stimulated Raman adiabatic passage) process in achieving high population transfer from the 1 to the levels. We utilized a circularly polarized Lyman alpha pulse to couple the state to the state and a microwave pulse to couple the state and the state. We calculate the efficiency of the STIRAP process for transferring the population between the stretched states as a function of experimental parameters such as Rabi frequencies and pulse durations. We find that a pulse with an energy of a few nanojoules could produce nearly perfect transfer at zero detunings for atoms on the laser beam axis. We extended the analysis to a thermal ensemble of atoms, where Doppler detuning affects the velocity distribution of the hydrogen atoms produced in the level. We found that the width of such velocity distribution is controlled by the Rabi frequency. We show that the peak velocity of the hydrogen atoms in the level after STIRAP can be controlled by the pulse detuning. The efficiency of STIRAP in transferring population increases at low temperature . Finally, we show that a background magnetic field improves the transfer rates between the other trappable states .}, archive = {J_PRA}, author = {AbdAlGhaffar K. Amer and A. Capra and T. Friesen and M. C. Fujiwara and T. Momose and C. So and F. Robicheaux}, doi = {10.1103/wx74-xg4j}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043111}, shortjournal = {Phys. Rev. A}, title = {Simulation of stimulated raman adiabatic passage from the 1S to the 2S states of the hydrogen and antihydrogen atoms}, volume = {112}, year = {2025}, }
• (2025). Collisional frequency shifts in sr+ optical clocks. PRA, 112(4), 043110. (www)

  @article{ , abstract = {Collisions of atomic ions in optical clocks with background gas molecules result in systematic frequency shifts. We evaluate the frequency shift in Sr + clocks due to collisions with helium atoms and hydrogen molecules, using ab initio spin-orbit-coupled potential energy surfaces together with a master equation for the collisional shift. Our results lead to improved uncertainty estimates for collisional frequency shifts in Sr + optical clocks.}, archive = {J_PRA}, author = {Iosif Leibin and Inna S. Kalinina and Amar C. Vutha and Alexei A. Buchachenko}, doi = {10.1103/knhc-k4p8}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043110}, shortjournal = {Phys. Rev. A}, title = {Collisional frequency shifts in sr+ optical clocks}, volume = {112}, year = {2025}, }
• (2025). Narrow-line electric quadrupole cooling and background-free imaging of a single cs atom with spatially structured light. PRA, 112(4), 043109. (www)

  @article{ , abstract = {We demonstrate background-free imaging and sideband cooling of a single atom via the narrow-line electric quadrupole transition in a 1064 nm optical tweezer. The state decays through the state to the ground state, emitting an 852 nm wavelength photon that allows for background-free imaging. By encoding both spin and orbital angular momentum onto the 685 nm excitation light, we achieve background-free fluorescence histograms with 99.58(3)% imaging fidelity by positioning the atom at the dark center of a vortex beam. Tuning the tweezer polarization ellipticity realizes a magic trap for the stretched cycling transition. Using a Gaussian beam, we cool to in a 1.1 mK trap and outline a strategy for ground-state cooling. We compare cooling performance across different sideband regimes, while also exploring how the orbital angular momentum of structured light controls the selection rules for quadrupole transitions. These results expand the toolbox for high-fidelity quantum control and cooling in alkali-atom tweezer arrays.}, archive = {J_PRA}, author = {Karl N. Blodgett and Saumitra S. Phatak and Meng Raymond Chen and David Peana and Claire Pritts and Jonathan D. Hood}, doi = {10.1103/vr4g-h995}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043109}, shortjournal = {Phys. Rev. A}, title = {Narrow-line electric quadrupole cooling and background-free imaging of a single cs atom with spatially structured light}, volume = {112}, year = {2025}, }
• (2025). Coulomb-potential imaging of a diatomic molecule using attosecond photoelectron momentum spectroscopy. PRA, 112(4), 043108. (www)

  @article{ , abstract = {We present simulations of attosecond photoelectron momentum distributions for the molecule by numerically solving the two-dimensional time-dependent Schrödinger equation (TDSE). We employ a semiclassical two-center interference model that incorporates the influence of the Coulomb potential on photoelectron phase modulation to interpret the calculated photoelectron angular distributions derived from TDSE simulations. Building on this model, we propose a methodology to reconstruct the molecular Coulomb potential using attosecond photoelectron momentum spectroscopy. The retrieved potential exhibits good consistency with the original input potential, thereby enabling direct imaging of the transient Coulomb potential during attosecond photoionization processes.}, archive = {J_PRA}, author = {Yanhong Liu and Liang-Wen Pi and Peixiang Lu and Wei Cao}, doi = {10.1103/1pcl-tb3j}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043108}, shortjournal = {Phys. Rev. A}, title = {Coulomb-potential imaging of a diatomic molecule using attosecond photoelectron momentum spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Isolated elliptically polarized attosecond pulse generation in gapped graphene driven by linearly polarized laser fields. PRA, 112(4), 043107. (www)

  @article{ , abstract = {We investigate theoretically high-order harmonic generation (HHG) and its ellipticity in gapped graphene, driven by a femtosecond short-pulse laser at various orientation angles, employing the two-band density-matrix equations within the tight-binding approximation. The orientation-dependent harmonic spectra exhibit pronounced enhancement of specific harmonics, which we attribute to the caustic effect. Using the recombination trajectory model, we reveal that the orientation dependence of these enhanced harmonics originates from the distinct band structures encountered by electrons ionized from the two inequivalent points. Moreover, we focus on the ellipticity of the enhanced harmonics at specific angles and demonstrate that it primarily depends on the phase difference between the parallel and perpendicular components, which can be accurately predicted by our recombination trajectory model. Based on these insights, we propose a two-color (fundamental plus second-harmonic) field scheme to generate isolated elliptically polarized attosecond pulses (IEAPs) in gapped graphene and discuss the dependence of IEAPs on the laser parameters and gap energy. Our findings may provide a promising pathway for generating IEAPs in gapped graphene or transition-metal dichalcogenides.}, archive = {J_PRA}, author = {Xinru Song and Xiaoyu Bu and Xiaohui Zhao and Rongxiang Zhang and Shang Wang and Fulong Dong}, doi = {10.1103/gv5n-vwvs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043107}, shortjournal = {Phys. Rev. A}, title = {Isolated elliptically polarized attosecond pulse generation in gapped graphene driven by linearly polarized laser fields}, volume = {112}, year = {2025}, }
• (2025). Noise performance of a rydberg atomic receiver. PRA, 112(4), 043106. (www)

  @article{ , abstract = {This paper systematically analyzes the key noise sources limiting the sensitivity of Rydberg atomic receivers. First, the quantum projection noise inherent to the system is modeled, as this noise sets the theoretical limit for receiver sensitivity. Second, the paper establishes the constraints relationship between photodetector noise and system sensitivity under both direct detection and heterodyne detection methods. Subsequently, this paper establishes the constraint relationships between the laser's intensity noise and receiver sensitivity, and between the phase noise and receiver sensitivity, respectively. The research reveals that the intensity noise of the probe light significantly exceeds that of the coupling light in its effect on receiver performance, while its phase noise exerts a comparable level of influence.}, archive = {J_PRA}, author = {Yu Tang and Hanbin Zhou and Chuang Yang and Shuang Ren and Siyuan Wang and Chenxi Lu}, doi = {10.1103/3zlx-g5xl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043106}, shortjournal = {Phys. Rev. A}, title = {Noise performance of a rydberg atomic receiver}, volume = {112}, year = {2025}, }
• (2025). Long-lived CO22+ produced from carbon dioxide and formic acid by strong-field double ionization. PRA, 112(4), 043105. (www)

  @article{ , abstract = {We explore the formation of metastable CO 2 2 + from linear and “bent” carbon dioxide by intense ultrashort laser pulses. In particular, we evaluate the fraction of these dications that survive to the detector and determine the lifetime of those that dissociate in flight through our apparatus. Curiously, the fraction of those dissociating in flight changes significantly when cooling the linear CO 2 target using a He carrier gas, while the lifetimes change only slightly. To determine these lifetimes we employ an improved method that takes into account the dissociation velocity of the O + + CO + fragments in a self-consistent manner. We also determine the dissociation-in-flight lifetime of an initially bent CO 2 2 + fragment of HCOOD 2 + following rapid double hydrogen elimination.}, archive = {J_PRA}, author = {Eleanor Weckwerth and T. Severt and Bethany Jochim and Reid Erdwien and Lucy Bartee and F. Ziaee and K. Borne and S. Bhattacharyya and P. Feizollah and Kanaka Raju P and Chandan Bagdia and K. D. Carnes and D. Rolles and A. Rudenko and E. Wells and I. Ben-Itzhak}, doi = {10.1103/r6c2-jzh3}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043105}, shortjournal = {Phys. Rev. A}, title = {Long-lived CO22+ produced from carbon dioxide and formic acid by strong-field double ionization}, volume = {112}, year = {2025}, }
• (2025). Strong-field double ionization of formic acid leading to hydrogen elimination and multibody fragmentation. PRA, 112(4), 043104. (www)

  @article{ , abstract = {Investigating the behavior of polyatomic molecules in strong laser fields allows the examination of coupled nuclear and electronic dynamics. In this article we examine multibody fragmentation of formic acid dications, produced by ultrashort intense laser pulses, using coincidence momentum imaging and deuterium tagging to distinguish the hydrogen sites. Our measurements indicate that double hydrogen elimination leads to three- and four-body breakup, specifically H + D + CO 2 2 + and H + D + O + + CO + , respectively. We find that the latter breakup channel also proceeds via the CO 2 2 + metastable dication, but with shorter lifetimes than the CO 2 2 + dications detected intact. This intriguing sequential breakup is identified using native frames analysis and simulations to confirm the signature of this process in spite of the inferior momentum resolution associated with breakup channels for which not all fragments are detected. In addition to the fragmentation channel above, we found no evidence of sequential breakup for single hydrogen elimination, H + CO + + OD + . The elimination of three atoms, H + D + O + C + + O + , shows evidence of both concerted fragmentation and sequential breakup via metastable intermediate CO 2 + ions. Measuring the dissociation dynamics of these highly excited molecular ions yields information that can be used to test theoretical approaches to these challenging few-body systems.}, archive = {J_PRA}, author = {Lucy Bartee and Eleanor Weckwerth and T. Severt and F. Ziaee and K. Borne and S. Bhattacharyya and K. D. Carnes and D. Rolles and A. Rudenko and E. Wells and I. Ben-Itzhak}, doi = {10.1103/s7v8-5hmk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043104}, shortjournal = {Phys. Rev. A}, title = {Strong-field double ionization of formic acid leading to hydrogen elimination and multibody fragmentation}, volume = {112}, year = {2025}, }
• (2025). Reconstruction of the semiconductor transition dipole moment from solid-state high-harmonic generation with a machine-learning method. PRA, 112(4), 043103. (www)

  @article{ , abstract = {The transition dipole moments between different energy bands of a crystal determine the optical properties of the solid and the light-induced electron-hole dynamics. Solid-state high-harmonic generation encodes all the information about the dipole in momentum space, making it a promising approach for reconstructing the momentum-space dipole. In this work, we develop a machine-learning framework, based on a one-dimensional semiconductor Bloch equation combined with the strong-field approximation in a single-electron picture, to reconstruct semiconductor dipoles from solid-state high-harmonic spectra. As long as the assumptions of the underlying model are satisfied, the proposed approach is robust against variations in the laser parameters, band dispersion, and hidden errors in the input data. We also discuss the potential influence of the approximations employed on the reconstruction accuracy. This method provides an alternative pathway for extracting dipole information from high-harmonic spectra.}, archive = {J_PRA}, author = {Jiaqi Zhang and Jun Wang and Xi Zhao}, doi = {10.1103/3j3k-8xg8}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043103}, shortjournal = {Phys. Rev. A}, title = {Reconstruction of the semiconductor transition dipole moment from solid-state high-harmonic generation with a machine-learning method}, volume = {112}, year = {2025}, }
• (2025). Laser-induced three-body fragmentation dynamics of hydrogen-bonded (H2O)2 and (NH3)2 dimers. PRA, 112(4), 043102. (www)

  @article{ , abstract = {We investigate the three-body fragmentation dynamics of hydrogen-bonded molecular dimers ( H 2 O ) 2 and ( NH 3 ) 2 under intense femtosecond laser irradiation. Using a reaction microscope for coincident detection of all ionic fragments, we observe the fragmentation channels H 2 O + + O H + + H + and NH 3 + + NH 2 + + H + . By diagnosing the Newton diagrams, Dalitz plots, and kinetic-energy correlation maps, one concerted pathway and two sequential dissociation pathways are identified in both channels. Native frame analysis enables reconstruction of the branching ratios for these pathways. While the behaviors of the concerted pathway and the sequential pathway involving initial H + emission are comparable in both systems, the sequential pathway with H + emission in the second step exhibits distinct dynamics, with a higher relative branching ratio for ( NH 3 ) 2 . These differences arise from the stronger hydrogen bonds in ( H 2 O ) 2 promoting proton transfer and the weaker hydrogen bonds in ( NH 3 ) 2 favoring hydrogen bond breaking. Our findings underscore the critical role of hydrogen bond strength in shaping the fragmentation dynamics of hydrogen-bonded molecular dimers under laser-induced dissociation.}, archive = {J_PRA}, author = {Menghang Shi and Chenxu Lu and Zhejun Jiang and Zhengjun Ye and Jiaxuan Chen and Xinglei Long and Yue Hu and Wenxuan Zhao and Wenbin Zhang and Jian Wu}, doi = {10.1103/jjbn-vtjm}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043102}, shortjournal = {Phys. Rev. A}, title = {Laser-induced three-body fragmentation dynamics of hydrogen-bonded (H2O)2 and (NH3)2 dimers}, volume = {112}, year = {2025}, }
• (2025). Ultrafast demethylation following femtosecond-laser-induced ionization of ethanol dimers. PRA, 112(4), 043101. (www)

  @article{ , abstract = {We report the experimental observation of ultrafast demethylation in ethanol dimers following single ionization induced by a 400-nm femtosecond laser field, described by the reaction ( C 2 H 5 OH ) 2 + n ℏ ω → C H 3 + C H 2 O · ( C 2 H 5 OH ) H + + e − . This demethylation pathway is identified through the detection of the ionic fragment C H 2 O · ( C 2 H 5 OH ) H + , accompanied by the coincident measurement of emitted electron. Analysis of the electron-nuclear joint kinetic energy spectrum reveals multiple diagonal features spaced by the photon energy, showing the essential role of electron-nuclear correlation in the demethylation process. The reaction timescale is determined by introducing a time-delayed 800-nm femtosecond probe pulse, yielding a characteristic time of approximately 0.95 ps. This duration is longer than that observed for demethylation following single ionization of ethanol monomers, highlighting the pronounced influence of intermolecular interactions in the dimeric system.}, archive = {J_PRA}, author = {Junyang Ma and Zhubin Hu and Yan Yang and Zhenrong Sun}, doi = {10.1103/2zhl-4vr2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {043101}, shortjournal = {Phys. Rev. A}, title = {Ultrafast demethylation following femtosecond-laser-induced ionization of ethanol dimers}, volume = {112}, year = {2025}, }
• (2025). Multipole transition amplitudes and radiative decay rates in neutral cadmium. PRA, 112(4), 042819. (www)

  @article{ , abstract = {We present a comprehensive study of the electronic transitions in neutral cadmium (Cd i ) with a focus on forbidden transitions, motivated by recent advances in laser technology and the growing relevance of cadmium in quantum gas research, precision metrology, and atom trapping. General analytic expressions are derived for transition matrix elements of all multipolar orders, formulated to be applicable for experimental use. Using configuration interaction combined with many-body perturbation theory, we calculate not only the previously reported contributions from electric dipole ( ) transitions, but also the electric quadrupole ( ), electric octupole ( ), magnetic dipole ( ), and magnetic quadrupole transitions ( ) that have not yet been investigated for cadmium. These matrix elements are then employed to determine the lifetimes of key excited states, particularly those pertinent to laser cooling and optical frequency standards, and to evaluate the long-range dispersion coefficient . The linewidths of the strongest transitions, along with the atomic energy levels, are compared with available experimental data to validate the accuracy of the simulations. Overall, the results are in good agreement, with the calculated energy levels exhibiting an average relative deviation of from experiments. These values serve as benchmarks for both bosonic and fermionic isotopes, providing a foundation for future experimental and theoretical work in cadmium-based precision spectroscopy and cold-collision studies.}, archive = {J_PRA}, author = {P. J. Robert and S. Manzoor and M. Chiarotti and N. Poli}, doi = {10.1103/2n82-9bfr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042819}, shortjournal = {Phys. Rev. A}, title = {Multipole transition amplitudes and radiative decay rates in neutral cadmium}, volume = {112}, year = {2025}, }
• (2025). Charge-exchange processes in low-energy collisions of c3+ ions with h and d. PRA, 112(4), 042818. (www)

  @article{ , abstract = {Charge-exchange processes in collisions of ions with hydrogen and deuterium atoms are investigated employing the full quantum-mechanical molecular-orbital close-coupling method in the large energy range of –10 keV/u. The required molecular potential curves and coupling matrix elements are calculated by the ab initio multireference single- and double-excitation configuration interaction method, and large basis sets with full active electrons are employed to obtain accurate asymptotic energy differences. Total and state-selective electron capture cross sections and rate coefficients are obtained and show satisfactory agreement with the experimental data. Total cross sections are found to increase as the collision energy decreases with the dominance of and channels in the energy region below 0.1 keV/u, and then increase as the collision energy increases above 0.1 keV/u due to the contributions of higher states. Meanwhile, the total cross sections exhibit complex oscillatory behaviors in various energy regions. Below 1 eV/u, the dense oscillatory structures arise from quasibound vibrotational states in the entrance channel, and the isotope effect for hydrogen and deuterium targets is noticeable in this energy region. Around 10 eV/u, the oscillatory patterns originate from the interference between the channel and the entrance channel, while in the 0.5–3.0 keV/u energy range, the oscillatory structures primarily arise from the multichannel interference among the , and states in both the triplet and singlet states of ions. The ratios of cross sections for electron capture to the triplet- and singlet-state manifolds are found to deviate from the spin-statistics rule bacause of the significant differences in electron capture to and electronic configurations between triplet and singlet states.}, archive = {J_PRA}, author = {Yun-Yu Wu and Yu Wang and Ya-Dong Liu and Min-Xuan Ma and Xiao-He Lin and Chun-Hua Liu and Ling Liu and Yong Wu and Jian-Guo Wang}, doi = {10.1103/1893-sjqz}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042818}, shortjournal = {Phys. Rev. A}, title = {Charge-exchange processes in low-energy collisions of c3+ ions with h and d}, volume = {112}, year = {2025}, }
• (2025). Microwave spectroscopy and multichannel quantum defect analysis of ytterbium 6snp, 6snf, and 6sng rydberg states. PRA, 112(4), 042817. (www)

  @article{ , abstract = {The complex Rydberg structure of ytterbium atoms is shaped by multiple low-lying ion-core-excited states and strong channel interactions, which presents both opportunities and challenges for quantum information processing and precision metrology. In this work, we extend high-resolution microwave spectroscopy and multichannel quantum defect theory (MQDT) modeling of singly excited Rydberg states in and to include the ( ) and ( ) series. Our measurements reveal mixing in odd-parity Rydberg states of , which we incorporate by combined MQDT models for and series. Additionally, we observe that for the spin-orbit interaction dominates over the exchange interaction, such that the states are more accurately described in a -coupled basis. We validate our models by comparing the predicted Landé factors and static dipole polarizabilities with experimental measurements, finding excellent agreement. These results provide important input for designing high-fidelity entangling gates with ytterbium atoms.}, archive = {J_PRA}, author = {Rin Kuroda and Vernon M. Hughes and Martin Poitrinal and Michael Peper and Jeff D. Thompson}, doi = {10.1103/mzsv-rckx}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042817}, shortjournal = {Phys. Rev. A}, title = {Microwave spectroscopy and multichannel quantum defect analysis of ytterbium 6snp, 6snf, and 6sng rydberg states}, volume = {112}, year = {2025}, }
• (2025). Convergent close-coupling approach to ion collisions with multielectron targets: Application to p¯+C collisions. PRA, 112(4), 042816. (www)

  @article{ , abstract = {The single-center convergent close-coupling approach to ion-atom collisions is extended to model collisions involving arbitrary multielectron atoms and partially stripped ions. This is accomplished by generating a set of target pseudostates using the configuration-interaction method. The resulting pseudostates are expanded in terms of configuration state functions, constructed using a hybrid of Hartree-Fock and Coulomb-Sturmian spin orbitals. This approach is applied to study antiproton collisions with atomic carbon. We present excitation energies, oscillator strengths, and the dipole polarizability obtained using the target structure model to validate its accuracy. Furthermore, we present results for elastic-scattering, total excitation, and ionization cross sections in the incident energy range between 10 and 1000 keV. State-resolved excitation cross sections for the first few dominant transitions are also presented. Throughout the paper, we compare results obtained using the multicore target structure model with those from a frozen-core one. Generally, we find that a multicore description of the carbon atom target is needed for accurately modeling these collisions.}, archive = {J_PRA}, author = {N. W. Antonio and A. S. Kadyrov}, doi = {10.1103/xchs-rct2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042816}, shortjournal = {Phys. Rev. A}, title = {Convergent close-coupling approach to ion collisions with multielectron targets: Application to p¯+C collisions}, volume = {112}, year = {2025}, }
• (2025). Trap-induced atom-ion complexes: A time-independent approach. PRA, 112(4), 042815. (www)

  @article{ , abstract = {A trapped ion immersed in a neutral bath shows long-lived atom-ion complexes that significantly alter its chemical properties and thus the ion stability. In this work, we present a general study of trapped-ion–atom scattering with the ion modeled as a charge distribution defined by the spatial extent of its ground-state wave function. After mapping the time-dependent problem onto a time-independent framework, we investigate the conditions under which chaotic scattering arises and develops using classical trajectory simulations. In particular, we characterize the role of the trap, the atomic species, the atom-ion interaction, and the collision energy in shaping the chaotic dynamics of the system.}, archive = {J_PRA}, author = {Zhongqi Liang and Ruiren Shi and Jesús Pérez-Ríos}, doi = {10.1103/mbzh-s8jm}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042815}, shortjournal = {Phys. Rev. A}, title = {Trap-induced atom-ion complexes: A time-independent approach}, volume = {112}, year = {2025}, }
• (2025). Precision calculation of hyperfine-structure constants for extracting the nuclear quadrupole moment of ca43. PRA, 112(4), 042814. (www)

  @article{ , abstract = {There have been several reported values for the nuclear quadrupole moment of , but significant discrepancies exist among these reported values, ranging from b to b. In this work we perform an accurate calculation of the electric-field gradients of the , and states in the atom using a hybrid method. This hybrid method integrates the advantages of the configuration-interaction method and the coupled-cluster method and can simultaneously account for core-core, core-valence, and valence-valence correlations. By combining our calculated results with the experimental values of the electric quadrupole hyperfine-structure constants of these three states, an accurate and reliable nuclear quadrupole moment of is determined to be b, which could be recommended as a reference for .}, archive = {J_PRA}, author = {Yong-Bo Tang}, doi = {10.1103/l6y6-cf78}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042814}, shortjournal = {Phys. Rev. A}, title = {Precision calculation of hyperfine-structure constants for extracting the nuclear quadrupole moment of ca43}, volume = {112}, year = {2025}, }
• (2025). Magnetic shielding in the atomic hydrogen anion. PRA, 112(4), 042813. (www)

  @article{ , abstract = {The atomic hydrogen anion is the lightest stable anion and its bound states and resonances are well studied in the literature. Due to the planned comparison of the bare antiproton to in a Penning trap, we study the magnetic shielding of using the nonrelativistic quantum electrodynamics theory, by accurately calculating the nonrelativistic shielding, as well as finite nuclear mass, relativistic, and partially QED corrections. We find that the finite nuclear mass correction is quite significant in contributing about of the total shielding, which is more than twice as much as the relativistic correction. Our final result for the shielding constant has a nine-parts-per-trillion accuracy and paves the way for direct comparison of the antiproton-to-proton magnetic moments.}, archive = {J_PRA}, author = {Tymon Kilich and Krzysztof Pachucki}, doi = {10.1103/fhnl-9mk9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042813}, shortjournal = {Phys. Rev. A}, title = {Magnetic shielding in the atomic hydrogen anion}, volume = {112}, year = {2025}, }
• (2025). Atom-surface interaction induced by quenched monopolar charge disorder. PRA, 112(4), 042812. (www)

  @article{ , abstract = {We study the modification to the energy level shifts of an atom induced by the quenched monopolar charge disorder inside the bulk of neighboring dielectric slabs as well as their surfaces. By assuming that the charge disorder follows Gaussian statistics with a zero mean, we find that the disorder generally results in a downward shift of the energy levels, which corresponds to an attractive force that can compete with and overcome the nonresonant Casimir-Polder force for sufficiently large atom-surface separations z 0 . For an atom near a single semi-infinite slab with bulk (surface) charge disorder, the shift decays as z 0 − 1 ( z 0 − 2 ) . For both surface and bulk disorder, the shift is proportional to the variance of the charge disorder density. In addition, we investigate the behavior of the charge disorder-induced energy level shift for an atom confined to a vacuum gap between two coplanar and semi-infinite slabs of the same dielectric material, finding that the position of net zero disorder-induced force occurs closer to the surface of the slab with the smaller charge disorder variance.}, archive = {J_PRA}, author = {Bing-Sui Lu}, doi = {10.1103/f19n-7bdn}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042812}, shortjournal = {Phys. Rev. A}, title = {Atom-surface interaction induced by quenched monopolar charge disorder}, volume = {112}, year = {2025}, }
• (2025). Convergent close-coupling approach to excitation in proton collisions with helium at intermediate energies. PRA, 112(4), 042811. (www)

  @article{ , abstract = {We have applied a semiclassical impact-parameter close-coupling method to calculate the state-resolved excitation cross sections in proton collisions with the ground state of helium. Using both correlation-configuration and frozen-core two-electron basis functions, we construct a large number of helium pseudostates to use in the expansion of the total scattering wave function. Extensive convergence studies show that the present results are accurate to within a few percent. The present cross sections for transitions from the ground state into all states for the , and symmetries agree very well with experimental data where available. This work serves to provide a comprehensive set of excitation cross sections that were previously available only in narrow energy regions and for some channels. Furthermore, we present elastic-scattering, total excitation, and total electron-loss cross sections from 2 to . We conclude that with modern supercomputer technology, a single-center method can accurately model collisions through implicit inclusion of the electron-capture process via coupling to the large number of positive-energy pseudostates representing the continuum.}, archive = {J_PRA}, author = {C. T. Plowman and L. H. Scarlett and M. C. Zammit and I. Bray and D. V. Fursa}, doi = {10.1103/y3hw-kyc4}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042811}, shortjournal = {Phys. Rev. A}, title = {Convergent close-coupling approach to excitation in proton collisions with helium at intermediate energies}, volume = {112}, year = {2025}, }
• (2025). Electron-impact total, multiple-differential elastic, and ionization cross sections of ammonia: A joint theoretical and experimental study. PRA, 112(4), 042810. (www)

  @article{ , abstract = {Combined experimental and theoretical studies are performed on the elastic scattering and electron-impact ionization of ammonia in the energy range of to . Differential elastic scattering cross sections are measured across an angular range of to , while doubly differential ionization cross sections were measured in the angular range of to , with secondary electron energies ranging from up to about half the primary electron energy. In parallel with the measurements, theoretical calculations of differential elastic scattering and doubly differential ionization cross sections of are performed using the approach, the polydcs code, and the distorted wave Born approximation. Reasonably good agreement is observed between the present experimental results and theoretical predictions. Total ionization cross sections, derived by integrating the experimental doubly differential ionization cross sections over the emission angle and secondary electron energies, show excellent agreement with theoretical values obtained using the Binary-Encounter-Bethe model with rescaled orbital binding and mean kinetic energies, and are consistent with experimental data measured by another group using a different method. As a final validation, the sum of the total elastic and ionization cross sections is compared with the recommended total electron scattering cross sections, confirming the consistency of the present experimental results.}, archive = {J_PRA}, author = {M. Dinger and W. Y. Baek}, doi = {10.1103/4wbr-p9wk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042810}, shortjournal = {Phys. Rev. A}, title = {Electron-impact total, multiple-differential elastic, and ionization cross sections of ammonia: A joint theoretical and experimental study}, volume = {112}, year = {2025}, }
• (2025). Relativistic corrections to vibrational states of mu2 beyond the born-oppenheimer approximation. PRA, 112(4), 042809. (www)

  @article{ , abstract = {We present the ab initio calculation of leading-order relativistic corrections to the pure vibrational energies of the muonium-muonium molecule ( ), an exotic four-lepton system composed of two positive muons and two electrons. These corrections are evaluated perturbatively using variational wave functions constructed from an explicitly correlated Gaussian basis, within a fully non-Born-Oppenheimer framework. We accurately determine the rotationless vibrational spectrum, dissociation energy, and key spectroscopic constants, including the harmonic constant and the anharmonicity constant . Furthermore, we present a range of expectation values for various structural quantities that provide insight into the intrinsic properties of this system. Our results represent a meaningful step toward a more accurate theoretical description of .}, archive = {J_PRA}, author = {K. Hu and D.-X. Zhao and K.-D. Wang and L.-M. Wang and M.-S. Wu and J.-Y. Zhang and Z.-C. Yan and K. Varga}, doi = {10.1103/6k4y-vljq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042809}, shortjournal = {Phys. Rev. A}, title = {Relativistic corrections to vibrational states of mu2 beyond the born-oppenheimer approximation}, volume = {112}, year = {2025}, }
• (2025). Magnetic hyperfine structure constants of BaF137 in the Π1/22 and Π3/22 excited states. PRA, 112(4), 042808. (www)

  @article{ , abstract = {High-precision molecular experiments testing the Standard Model of particle physics require an accurate understanding of the molecular structure at the hyperfine level, both for the control of the molecules and for the interpretation of the results. In this work, we calculate the hyperfine structure constants for the excited states Π 1 / 2 2 and Π 3 / 2 2 of BaF 137 due to the Ba 137 nucleus. We use the four-component relativistic Fock-space coupled-cluster method, extrapolating our results to the complete basis set limit. We investigate the effect of the basis sets and electron correlation, and estimate the uncertainty in our final results. Our results are used in the interpretation of the experimental spectroscopy of the hyperfine and rovibrational spectra of BaF, and the planning of laser-cooling schemes for future parity-violating anapole moment measurements [Kogel et al. , Phys. Rev. A 112 , 042807 (2025) ].}, archive = {J_PRA}, author = {Yuly Chamorro and Felix Kogel and Tim Langen and Anastasia Borschevsky}, doi = {10.1103/sksm-t85m}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042808}, shortjournal = {Phys. Rev. A}, title = {Magnetic hyperfine structure constants of BaF137 in the Π1/22 and Π3/22 excited states}, volume = {112}, year = {2025}, }
• (2025). High-resolution spectroscopy of barium monofluoride: Odd isotopologues, hyperfine structure, and isotope shifts. PRA, 112(4), 042807. (www)

  @article{ , abstract = {Barium monofluoride (BaF) is a promising molecular species for precision tests of fundamental symmetries and interactions. We present a combined theoretical and experimental study of BaF spectra and isotope shifts, focusing in particular on the poorly understood odd isotopologues BaF 137 and BaF 135 . By comparing state-of-the-art ab initio calculations with high-resolution fluorescence and absorption spectroscopy data, we provide a benchmark for electronic structure theory and disentangle the hyperfine and rovibrational spectra of the five most abundant isotopologues, from BaF 138 to BaF 134 . The comprehensive knowledge gained enables a King plot analysis of the isotope shifts that reveals the odd-even staggering of the barium nuclear charge radii. It also paths the way for improved laser cooling of rare BaF isotopologues and crucially supports future measurements of nuclear anapole and Schiff moments.}, archive = {J_PRA}, author = {Felix Kogel and Yuly Chamorro and Mangesh Bhattarai and Marian Rockenhäuser and Tatsam Garg and David DeMille and Anastasia Borschevsky and Tim Langen}, doi = {10.1103/rdpt-99qy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042807}, shortjournal = {Phys. Rev. A}, title = {High-resolution spectroscopy of barium monofluoride: Odd isotopologues, hyperfine structure, and isotope shifts}, volume = {112}, year = {2025}, }
• (2025). Intensity-dependent precision two-photon doppler-free spectroscopy of xe using narrow-bandwidth long-pulse deep-UV laser radiation. PRA, 112(4), 042806. (www)

  @article{ , abstract = {We report on a precision measurement of the ( 5 p ) 5 6 p [ 1 / 2 ] 0 ← ( 5 p ) 6 S 0 1 transition wave number of Xe by Doppler-free two-photon spectroscopy using near-Fourier-transform-limited long pulses of UV-laser radiation. The measurements led to absolute uncertainties of 750 kHz in the two-photon transition wave numbers for the five dominant isotopes of Xe, e.g., 80 118.982 918(27) cm − 1 for Xe 136 . These values were combined with other precision measurements in Xe to resolve an ∼ 1 − GHz discrepancy between the ionization energy of Xe obtained in recent measurements from the ( 6 s ) [ 3 / 2 ] 2 metastable state [Herburger et al., Phys. Rev. A 109 , 032816 (2024) ] and the ionization energy listed in the NIST atomic database. The analysis indicates that the natural-abundance-weighted ionization energy of Xe should be revised by − 0.023 cm − 1 to 97 833.7641(20) cm − 1 . Large fluctuations in the UV-laser pulse intensities were exploited to characterize intensity-dependent shifts of the observed two-photon transition frequencies. Shifts of up to − 20 MHz were observed and attributed to frequency shifts arising from chirps in the amplification and up-conversion of the laser radiation rather than to the ac-Stark effect.}, archive = {J_PRA}, author = {M. H. Rayment and R. Stech and F. Merkt}, doi = {10.1103/jnww-fyt7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042806}, shortjournal = {Phys. Rev. A}, title = {Intensity-dependent precision two-photon doppler-free spectroscopy of xe using narrow-bandwidth long-pulse deep-UV laser radiation}, volume = {112}, year = {2025}, }
• (2025). Resonant optical bistability in support of enhanced rydberg-atom sensors. PRA, 112(4), 042805. (www)

  @article{ , abstract = {Radio frequency antennas based on highly excited Rydberg atom vapors can in principle reach sensitivities beyond those of any conventional wire antenna, especially at lower frequencies where very long wires are needed to accommodate the growing wavelength. Conventional Rydberg sensors are based on individual atom response, with increased signal resolution relying on the O ( 10 3 ) electric dipole moment enhancement, scaling as the square of the Rydberg-state principal quantum number N ∼ 50 . However, despite more than 30 years of steady advances, beyond-classical signal sensitivity has yet to be demonstrated. More recently, the optical bistability effect, a many-body nonequilibrium phase transition occurring at somewhat higher vapor densities, has been exploited for an order of magnitude or more increased sensitivity for some setups through tuning into the critical region. However, the results fall significantly short of those using more advanced “conventional” Rydberg sensor setups—which achieve even greater enhancement by exploiting resonant interaction between a pair of nearby Rydberg levels. This paper seeks to combine the many-body and resonant enhancement effects by extending the bistable phase analysis to include a pair of resonant Rydberg levels, supported by an exact treatment of the atom velocity thermal average. A dynamic linear response formalism is developed as well to explore the trade-off between measurement sensitivity and finite-bandwidth signals. We demonstrate regions of the phase diagram which could be exploited for record breaking, beyond-classical sensitivity. Of course, only a limited number of vapor parameters are under full experimental control, and experiments will be needed to quantitatively constrain the effective mean-field interaction parameters appearing in the theory and thereby define the accessible regions of the phase diagram.}, archive = {J_PRA}, author = {Peter B. Weichman}, doi = {10.1103/k2n6-1xm3}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042805}, shortjournal = {Phys. Rev. A}, title = {Resonant optical bistability in support of enhanced rydberg-atom sensors}, volume = {112}, year = {2025}, }
• (2025). Improved positron-molecule scattering calculations with the schwinger multichannel method. PRA, 112(4), 042803. (www)

  @article{ , abstract = {We report methodological improvements to the Schwinger multichannel method in the static plus polarization (SP) approximation for low-energy positron-molecule scattering. The enhancements include the use of -type Gaussian functions in the basis sets for both the positron and target molecules, as well as a refined placement of chargeless extra centers to better describe short-range positron-electron interactions. Annihilation parameters are calculated both directly and with enhancement factors to assess the role of correlation effects beyond the SP approximation. The improved approach is applied to positron scattering from hydrogen molecule, nitrogen molecule, methane, acetylene, and ethylene, resulting in cross sections and bound-state energies showing improved agreement with recent experimental and theoretical data.}, archive = {J_PRA}, author = {Francisco F. Frighetto and Alessandra Souza Barbosa and Sergio d'A. Sanchez}, doi = {10.1103/bh8d-drw5}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042803}, shortjournal = {Phys. Rev. A}, title = {Improved positron-molecule scattering calculations with the schwinger multichannel method}, volume = {112}, year = {2025}, }
• (2025). 5p and 4f photoabsorption in third-peak rapid-neutron-capture-process elements ir, pt, and au. PRA, 112(4), 042802. (www)

  @article{ , abstract = {Photoabsorption spectra of ions of iridium, platinum, and gold have been recorded using the dual laser plasma technique in the spectral region between 48 and 126 eV. Features due to 5 p and 4 f excitation in neutral to four times ionized species lie in this region. Evidence of the rapid decay of the 5 p hole following photoabsorption is provided by the widths of the spin-orbit split transition arrays, in contrast to the sharper and narrower features seen arising from 4 f photoabsorption. The analysis of the iridium spectra is supported by atomic structure calculations and isoelectronic series analysis. Agreement with previous analysis of the spectra of platinum and gold is seen and some new identifications are also made. The significance of these r -process elements for astrophysical research is highlighted.}, archive = {J_PRA}, author = {Eric Doyle and Padraig Dunne and Patrick Hayden}, doi = {10.1103/xk71-4n9b}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042802}, shortjournal = {Phys. Rev. A}, title = {5p and 4f photoabsorption in third-peak rapid-neutron-capture-process elements ir, pt, and au}, volume = {112}, year = {2025}, }
• (2025). QED calculations of the 2p–2s transition energies in li-like ions. PRA, 112(4), 042801. (www)

  @article{ , abstract = {Systematic QED calculations of ionization energies of the 2 s , 2 p 1 / 2 , and 2 p 3 / 2 states as well as the 2 p 1 / 2 – 2 s and 2 p 3 / 2 – 2 s transition energies are performed for Li-like ions with the nuclear charge numbers Z = 10 – 100 . The convergence of QED perturbative expansion is improved by using the extended Furry picture, which starts from the Dirac equation with a local screening potential. An ab initio treatment is accomplished for one- and two-photon electron-structure QED effects and the one-photon screening of the self-energy and vacuum-polarization corrections. This is complemented with an approximate treatment of the two-photon QED screening and higher-order (three or more photon) electron-structure effects. As a result, the obtained theoretical predictions improve upon the accuracy achieved in previous calculations. Comparison with available experimental data shows a good agreement between theory and experiment. In most cases, the theoretical values surpass the experimental results in precision with only a few exceptions. In the case of uranium and bismuth, the comparison provides one of the most stringent tests of bound-state QED in the strong-field regime. Alternatively, the obtained results can be employed for high-precision determinations of nuclear charge radii.}, archive = {J_PRA}, author = {V. A. Yerokhin and Z. Harman and C. H. Keitel}, doi = {10.1103/pwmr-r9gc}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042801}, shortjournal = {Phys. Rev. A}, title = {QED calculations of the 2p–2s transition energies in li-like ions}, volume = {112}, year = {2025}, }
• (2025). Increasing angular entanglement of spontaneous parametric down-conversion biphoton states via noncollinearity and the walk-off effect. PRA, 112(4), 042622. (www)

  @article{ , abstract = {Angular entanglement is investigated theoretically in various realizable regimes of SPDC. It is shown, in particular, that in the sufficiently well pronounced, noncollinear regime the degree of angular entanglement grows with increasing degree of noncollinearity. A rather specific dependence is found for the degree of entanglement in its dependence on the varying influence of the so-called walk-off effect of the pump in the SPDC crystal. A joint influence of the walk-off and noncollinearity is found to partly suppress the degree of angular entanglement.}, archive = {J_PRA}, author = {M. V. Fedorov}, doi = {10.1103/67h9-82sf}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042622}, shortjournal = {Phys. Rev. A}, title = {Increasing angular entanglement of spontaneous parametric down-conversion biphoton states via noncollinearity and the walk-off effect}, volume = {112}, year = {2025}, }
• (2025). Bayesian mitigation of measurement errors in multiqubit experiments. PRA, 112(4), 042621. (www)

  @article{ , abstract = {In Phys. Rev. A 108 , L060402 (2023) , we introduced a Bayesian measurement error mitigation algorithm, which leveraged complete information from the readout signal, and validated the protocol on a quantum device with five superconducting qubits. Here, we present an improved algorithm's implementation, tailored for multiqubit experiments on near-term superconducting qubit quantum devices. In particular, we provide a detailed algorithm workflow, from calibrating the detector response functions to the postprocessing of measurement outcomes, offering a computationally efficient solution for the output size typical of current quantum computing devices. We show how the numerical representation of the noise function affects the performance of the error mitigation algorithm and test the convergence criteria. We benchmark our protocol on actual quantum computers with superconducting qubits, where the readout signal encodes the measurement information as unprocessed analog data before qubit state assignment. Finally, we compare the performance of our algorithm against other measurement error mitigation methods, such as iterative Bayesian unfolding and the Mthree method, and show how our method can be integrated on top of other readout error mitigation protocols.}, archive = {J_PRA}, author = {F. Cosco and F. Plastina and N. Lo Gullo}, doi = {10.1103/d65d-x8lt}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042621}, shortjournal = {Phys. Rev. A}, title = {Bayesian mitigation of measurement errors in multiqubit experiments}, volume = {112}, year = {2025}, }
• (2025). Multiobjective optimization for robust holonomic quantum gates. PRA, 112(4), 042620. (www)

  @article{ , abstract = {The practical implementation of high-fidelity quantum gates faces significant challenges in simultaneously mitigating multiple operational errors arising from distinct physical mechanisms. These errors often span orders of magnitude in severity and their respective suppression strategies may inherently conflict. In this work we develop a universal multiobjective optimization framework for quantum gate design by integrating Pareto optimal solutions with an entropy-weight method. Using Rydberg-based nonadiabatic holonomic quantum gates (affected by amplitude errors, detuning errors, and Rydberg decoherence) as a test bed, we theoretically demonstrate the superiority of our algorithm. The optimized gates exhibit enhanced fidelity and robustness compared to those derived from one-objective optimization strategies. Furthermore, this framework is readily adaptable to other quantum gate protocols and provides a robust foundation for advancing fault-tolerant quantum computing.}, archive = {J_PRA}, author = {Min-Hua Zhang and Jing Qian}, doi = {10.1103/xhm9-g914}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042620}, shortjournal = {Phys. Rev. A}, title = {Multiobjective optimization for robust holonomic quantum gates}, volume = {112}, year = {2025}, }
• (2025). Space-time trade-off in networked virtual distillation. PRA, 112(4), 042619. (www)

  @article{ , abstract = {In contrast to monolithic devices, modular, networked quantum architectures are based on interconnecting smaller quantum hardware nodes using quantum communication links and offer a promising approach to scalability. Virtual distillation (VD) is a technique that can, under ideal conditions, suppress errors exponentially as the number of quantum state copies increases. However, additional gate operations required for VD introduce further errors, which may limit its practical effectiveness. In this work, we analyze three practical implementations of VD that correspond to edge cases that maximize space-time trade-offs. Specifically, we consider an implementation that minimizes the number of qubits but introduces significantly deeper quantum circuits and contrast it with implementations that parallelize the preparation of copies using additional qubits, including a constant-depth implementation. We rigorously characterize their circuit depth and gate count requirements and develop explicit architectures for implementing them in networked quantum systems—while also detailing implementations in early fault-tolerant quantum architectures. We numerically compare the performance of the three implementations under realistic noise characteristics of networked ion trap systems and conclude the following. First, VD effectively suppresses errors even for very noisy states. Second, the constant-depth implementation consistently outperforms the implementation that minimizes the number of qubits. Finally, the approach is highly robust to errors in remote entangling operations, with noise in local gates being the main limiting factor to its performance.}, archive = {J_PRA}, author = {Tenzan Araki and Joseph F. Goodwin and Bálint Koczor}, doi = {10.1103/t828-wvgl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042619}, shortjournal = {Phys. Rev. A}, title = {Space-time trade-off in networked virtual distillation}, volume = {112}, year = {2025}, }
• (2025). Robust iswap gates for semiconductor spin qubits with local driving. PRA, 112(4), 042618. (www)

  @article{ , abstract = {Scalable quantum computation demands high-fidelity two-qubit gates. However, decoherence and control errors are inevitable, which can decrease the quality of implemented quantum operations. We propose a robust i swap gate protocol for semiconductor spin qubits, which is a promising platform for scalable quantum computing. Our scheme uses only local microwave drives on conventional exchange-coupled spin qubits. This approach simultaneously addresses two critical challenges to semiconductor quantum computing: It suppresses low-frequency noise via continuous dynamical decoupling, and it circumvents the control difficulties associated with the ac modulation of the exchange interaction. We further develop a composite pulse sequence to remove drive-strength constraints and a dynamically corrected method to provide first-order immunity to microwave amplitude errors. Numerical simulations confirm that our scheme can achieve fidelity above the fault-tolerance threshold under current experimental conditions, offering a building block for practical quantum processors.}, archive = {J_PRA}, author = {Qi-Pei Liu and Zheng-Yuan Xue}, doi = {10.1103/68m1-mjzy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042618}, shortjournal = {Phys. Rev. A}, title = {Robust iswap gates for semiconductor spin qubits with local driving}, volume = {112}, year = {2025}, }
• (2025). Quantum oblivious transfer for quantum messages. PRA, 112(4), 042617. (www)

  @article{ , abstract = {Oblivious transfer (OT) is an essential building block for secure multiparty computation. Up to now, one- and two-server OT protocols have been investigated. It has been proven that unconditionally secure one-server OT is impossible even with the quantum system. Recently, Hayashi and Song proposed the first two-server OT protocol for quantum messages [ Adv. Quantum Technol. 7 , 2300184 (2024) ], which is the only one for two-server OT for quantum messages to our knowledge. This protocol has the assumption that two quantum servers do not communicate with each other. However, it is unrealistic to make such an assumption. In addition, an equation error occurs in the protocol description. To tackle these issues, we first point out the equation error existent in the protocol of Hayashi and Song and correct it. Then, we propose a two-server OT protocol for quantum messages by using entanglement swapping. Security analysis shows that the user privacy holds even if the two quantum servers communicate mutually.}, archive = {J_PRA}, author = {Yu-Guang Yang and Shi Qiu and Yan Chang and Guang-Bao Xu and Dong-Huan Jiang and Dan Li}, doi = {10.1103/8963-6537}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042617}, shortjournal = {Phys. Rev. A}, title = {Quantum oblivious transfer for quantum messages}, volume = {112}, year = {2025}, }
• (2025). Improving success probability in lechner-hauke-zoller parity embedding by computing with quantum walks. PRA, 112(4), 042616. (www)

  @article{ , abstract = {Lechner-Hauke-Zoller (LHZ) parity embedding is one of the front-running methods for implementing difficult-to-engineer long-range interactions in quantum optimization problems. Continuous-time quantum walks are a leading approach for solving quantum optimization problems. Because they populate excited states, quantum walks can avoid the exponential gap-closing problems seen in other continuous-time techniques such as quantum annealing and adiabatic quantum computation. An important question, therefore, is how continuous-time quantum walks perform in combination with the LHZ parity embedding. By numerically simulating continuous-time quantum walks on four-, five-, and six-logical-qubit Sherrington-Kirkpatrick Ising spin glass instances embedded onto the LHZ parity embedding, we are able to verify the continued efficacy of heuristics used to estimate the optimal hopping rate and the numerical agreement with the theory behind the location of the lower bound of the LHZ parity constraint strength. In addition, by comparing several different LHZ-based decoding methods, we identified postreadout error correction techniques which improve the success probability of the quantum walk.}, archive = {J_PRA}, author = {Jemma Bennett and Nicholas Chancellor and Viv Kendon and Wolfgang Lechner}, doi = {10.1103/my7q-8tbj}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042616}, shortjournal = {Phys. Rev. A}, title = {Improving success probability in lechner-hauke-zoller parity embedding by computing with quantum walks}, volume = {112}, year = {2025}, }
• (2025). Linear optical quantum computing with a hybrid squeezed-cat code. PRA, 112(4), 042615. (www)

  @article{ , abstract = {In recent years, squeezed-cat codes with resilience to specific types of loss have been proposed as a step toward realizing fault-tolerant optical quantum computers. However, error correction for squeezed-cat codes requires a strong nonlinearity, which makes its implementation challenging with current technology. We propose a novel hybrid code that combines the squeezed-cat code and the polarization qubit. First, we propose a generation method and a universal gate set that can be implemented with a linear optical system. Then we show the superiority of the hybrid squeezed-cat code over the hybrid cat code and the squeezed-cat code through numerical simulations. These results demonstrate that the hybrid squeezed-cat code is a promising candidate as a new resource for optical quantum information processing.}, archive = {J_PRA}, author = {Shohei Kiryu and Kosuke Fukui and Atsushi Okamoto and Akihisa Tomita}, doi = {10.1103/jxbx-75m9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042615}, shortjournal = {Phys. Rev. A}, title = {Linear optical quantum computing with a hybrid squeezed-cat code}, volume = {112}, year = {2025}, }
• (2025). Approaching the quantum speed limit in quantum gates with geometric control. PRA, 112(4), 042614. (www)

  @article{ , abstract = {We present a geometric optimization method for implementing quantum gates by optimally controlling the Hamiltonian parameters, with the goal of approaching the Mandelstam-Tamm quantum speed limit (MT-QSL). Achieving this bound requires satisfying precise geometric conditions that govern the evolution of quantum states. We extend this geometric framework to quantum unitary operators in arbitrary dimensions and analyze the conditions necessary for saturation of the bound. Additionally, we show that the quantum brachistochrone, when generalized to operators, does not, in general, saturate the MT-QSL bound. Finally, we propose a systematic optimal control strategy based on geometric principles to approach the quantum speed limit for unitary driving. We illustrate this optimization method on a set of four well-known two-qubit quantum gates. Our procedure significantly reduces the deviation from the optimal quantum speed limit while preserving high quantum fidelity.}, archive = {J_PRA}, author = {François Impens and David Guéry-Odelin}, doi = {10.1103/h747-mwwv}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042614}, shortjournal = {Phys. Rev. A}, title = {Approaching the quantum speed limit in quantum gates with geometric control}, volume = {112}, year = {2025}, }
• (2025). Robust dynamical and steady-state entanglement of phonons in the magnetic microsphere. PRA, 112(4), 042613. (www)

  @article{ , abstract = {In the field of quantum information, robust entanglement has received widespread attention. In this work, we investigate the magnon-mediated robust entanglement between the acoustic phonon and the center-of-mass motion (CMM) phonon in a yttrium iron garnet sphere. By analyzing the system's dynamic evolution, we demonstrate that phonon-phonon entanglement, which is robust with respect to the magnon mode, can be generated at a specific moment. Furthermore, we introduce a scheme for generating stable bipartite entanglement that remains robust against varying initial states by utilizing an engineered reservoir. This approach maintains effectiveness even under high dissipation rates of the magnon mode, leveraging the magnon dissipation as a beneficial resource. The approaches we present for generating robust phonon-phonon entanglement not only offer a feasible method for monitoring internal acoustic modes within magnetic systems using easily detectable CMM phonons, but also provide a viable platform for the manipulation and processing of quantum information.}, archive = {J_PRA}, author = {Xiao-Wen Huo and Shi-Ni Yang and Xin-Lei Hei and Jia-Qiang Chen and Yi-Fan Qiao and Xue-Feng Pan and Xiao-Yu Yao and Jun-Cong Zheng and Yu-Meng Ren and Guo-Yu Shu and Peng-Bo Li}, doi = {10.1103/b6kk-rd74}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042613}, shortjournal = {Phys. Rev. A}, title = {Robust dynamical and steady-state entanglement of phonons in the magnetic microsphere}, volume = {112}, year = {2025}, }
• (2025). Limitations of strong coupling in non-markovian quantum thermometry. PRA, 112(4), 042612. (www)

  @article{ , abstract = {We investigate quantum thermometry using a single-qubit probe embedded in a non-Markovian environment, employing the numerically exact hierarchical equations of motion (HEOM) to overcome the limitations of Born-Markov approximations. Through a systematic analysis of the dynamical and steady-state behavior of the quantum signal-to-noise ratio (QSNR) for temperature estimation, we identify several key findings that challenge the conventional expectation that strong coupling necessarily enhances thermometric performance. In nonequilibrium dynamical thermometry, weak system-environment coupling generally yields the optimal QSNR, whereas in the steady-state regime, strong coupling enhances sensitivity only in the ultralow-temperature limit, while weak coupling significantly improves precision at moderately low temperatures. To optimize performance across coupling regimes, we develop a hybrid computational framework that integrates HEOM with quantum-enhanced particle swarm optimization, enabling precise quantum dynamical control under varying coupling strengths. Our results reveal fundamental constraints and opportunities in quantum thermometry, offering practical strategies for the design of high-performance quantum thermometers operating in realistic open quantum systems.}, archive = {J_PRA}, author = {Qing-Shou Tan and Yang Liu and Xulin Liu and Hao Chen and Xing Xiao and Wei Wu}, doi = {10.1103/t74h-c8kw}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042612}, shortjournal = {Phys. Rev. A}, title = {Limitations of strong coupling in non-markovian quantum thermometry}, volume = {112}, year = {2025}, }
• (2025). Noise reduction of multimode gaussian-boson-sampling circuits via unitary averaging. PRA, 112(4), 042611. (www)

  @article{ , abstract = {We improve Gaussian-boson-sampling circuits by integrating the unitary-averaging (UA) protocol, previously demonstrated to protect unknown Gaussian states from phase errors [Swain et al. , Phys. Rev. A 110 , 032622 (2024) ]. Our work extends the applicability of UA to mitigate arbitrary interferometric noise, including beam-splitter and phase-shifter imperfections. Through comprehensive numerical analysis, we demonstrate that UA consistently achieves higher fidelity and success probability than unprotected circuits, establishing its robustness in noisy conditions. Remarkably, enhancement is maintained across varying numbers of modes with respect to the noise. We further derive a power-law formula predicting performance gains in large-scale systems, including 100-mode and 216-mode configurations. A detailed step-by-step algorithm for implementing the UA protocol is also provided, offering a practical road map for advancing near-term quantum technologies.}, archive = {J_PRA}, author = {S. Nibedita Swain and Ryan J. Marshman and Alexander S. Solntsev and Timothy C. Ralph}, doi = {10.1103/n9nc-xcmr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042611}, shortjournal = {Phys. Rev. A}, title = {Noise reduction of multimode gaussian-boson-sampling circuits via unitary averaging}, volume = {112}, year = {2025}, }
• (2025). Multimode NOON-state generation with ultracold atoms via geodesic counterdiabatic driving. PRA, 112(4), 042610. (www)

  @article{ , abstract = {We present a protocol for the generation of NOON states with ultracold atoms, leveraging the Bose-Hubbard model in the self-trapping regime. By means of an optimized adiabatic protocol, we achieve a significant reduction in the time required for the preparation of highly entangled NOON states, involving two or more modes. Our method saturates the quantum speed limit, ensuring both efficiency and high fidelity in state preparation. A detailed analysis of the geodesic counterdiabatic driving protocol and its application to the Bose-Hubbard system highlights its ability to expand the energy gap, facilitating faster adiabatic evolution. Through perturbation theory, we derive effective parameters that emulate the counterdiabatic Hamiltonian, enabling experimentally viable implementations with constant physical parameters. This approach is demonstrated to yield exponential time savings compared with standard geodesic driving, making it a powerful tool for creating complex entangled states for applications in quantum metrology and quantum information. Our findings pave the way for scalable and precise quantum state control in ultracold atomic systems.}, archive = {J_PRA}, author = {Simon Dengis and Sandro Wimberger and Peter Schlagheck}, doi = {10.1103/qxqg-qnnq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042610}, shortjournal = {Phys. Rev. A}, title = {Multimode NOON-state generation with ultracold atoms via geodesic counterdiabatic driving}, volume = {112}, year = {2025}, }
• (2025). Geometric gates in atomic arrays without rydberg blockade. PRA, 112(4), 042609. (www)

  @article{ , abstract = {The Rydberg blockade effect plays an important role in realizing two-qubit gates in atomic arrays. Meanwhile, such mechanics will increase the crosstalk between atoms and enhance the decoherence. In this paper, we propose a new scheme to realize the controlled-phase gate without Rydberg blockade. The scheme works effectively with large atomic spacings and is insensitive to the thermal motions of atoms. The proposal is robust against random noises due to the geometric characteristic and operates fast based on the nonadiabatic evolution. The proposed gate is actually a geometric gate that consolidates the nonadiabatic holonomic control and the unconventional geometric control simultaneously. The interference between two different types of geometric phases can be investigated in the proposal. Furthermore, we show that the actuating quantity (the product of interaction strength and the evolution time) of the proposed scheme is 90 times smaller than the present Rydberg blockade scheme. Therefore, our proposal provides a fast and robust way to realize geometric quantum control, and it may trigger the discoveries of new geometric gates in high-dimensional Hilbert space.}, archive = {J_PRA}, author = {Yue Ming and Zhao-Xin Fu and Yan-Xiong Du}, doi = {10.1103/tmr4-gtnl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042609}, shortjournal = {Phys. Rev. A}, title = {Geometric gates in atomic arrays without rydberg blockade}, volume = {112}, year = {2025}, }
• (2025). Enhanced simultaneous quantum-classical communications under composable security. PRA, 112(4), 042608. (www)

  @article{ , abstract = {Simultaneous quantum-classical communications (SQCC) protocols are a family of continuous-variable quantum key distribution (CV-QKD) protocols that allow for quantum and classical symbols to be integrated concurrently on the same optical pulse and mode. In this work, we present a revised analysis of simultaneous quantum-classical communications in Gaussian-modulated coherent-state CV-QKD protocols. We address security concerns inherently associated with SQCC schemes and provide an updated model of the coupling between the classical and quantum channels. We provide evidence for our model via Monte Carlo simulation. We compute the performance of our revised SQCC protocol in terms of the secret-key generation rate optimized over free parameters and demonstrate improved quantum efficiency for a given classical bit-error rate. Lastly, we extend our analysis into the finite-key regime, where we propose a scheme for composably secure SQCC under realistic operating conditions and demonstrate that our scheme retains the advantage in quantum performance over previous models.}, archive = {J_PRA}, author = {Nicholas Zaunders and Ziqing Wang and Robert Malaney and Ryan Aguinaldo and Timothy C. Ralph}, doi = {10.1103/p34s-5217}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042608}, shortjournal = {Phys. Rev. A}, title = {Enhanced simultaneous quantum-classical communications under composable security}, volume = {112}, year = {2025}, }
• (2025). Accelerating feedback-based quantum algorithms through time rescaling. PRA, 112(4), 042607. (www)

  @article{ , abstract = {This work investigates the impact of time rescaling on the performance of Feedback-Based Quantum Algorithms (FQAs) and their variant for optimization tasks, Feedback-Based Algorithm for Quantum Optimization (FALQON). We introduce the Time-Rescaled Feedback-Based Quantum Algorithm (TR-FQA) and Time-Rescaled Feedback-Based Algorithm for Quantum Optimization (TR-FALQON), time-rescaled versions of FQA and FALQON, respectively. The method is applied to two representative problems: the MaxCut combinatorial optimization problem and ground-state preparation in the axial next-nearest neighbor Ising (ANNNI) model. The results show that TR-FALQON accelerates convergence toward the optimal solution in the circuit's early layers and outperforms the standard version in low-depth regimes. In the context of state preparation, TR-FQA requires fewer layers than the original algorithm. These findings suggest that time rescaling can reduce the number of layers needed to reach a high-quality solution, even if the exact ground state is not obtained.}, archive = {J_PRA}, author = {L. A. M. Rattighieri and G. E. L. Pexe and B. L. Bernardo and F. F. Fanchini}, doi = {10.1103/qc91-5mj2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042607}, shortjournal = {Phys. Rev. A}, title = {Accelerating feedback-based quantum algorithms through time rescaling}, volume = {112}, year = {2025}, }
• (2025). Entanglement between surface-plasmon-polariton modes and its application to long-distance quantum communication. PRA, 112(4), 042606. (www)

  @article{ , abstract = {We propose a scheme for achieving quantum entanglement between surface-plasmon-polariton (SPP) modes in a hybrid plasmonic-graphene waveguide system. We then demonstrate that the entanglement of two SPP modes can serve as a useful resource for quantum communication of continuous-variable light signals over a long distance, mediated by concatenated swap operations. The teleportation fidelity of an unknown coherent state has strong robustness to loss and imperfect detection at relatively strong effective optical-microwave coupling. Our study opens the way for continuous-variable quantum communication and quantum information based on hybrid plasmonic-graphene systems.}, archive = {J_PRA}, author = {Jia-Xin Peng and Baiqiang Zhu and Muhammad Asjad}, doi = {10.1103/5dv2-jh25}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042606}, shortjournal = {Phys. Rev. A}, title = {Entanglement between surface-plasmon-polariton modes and its application to long-distance quantum communication}, volume = {112}, year = {2025}, }
• (2025). Strong-driving toolkit for topological floquet energy pumps with superconducting circuits. PRA, 112(4), 042605. (www)

  @article{ , abstract = {Topological Floquet energy pumps, which use periodic driving to create a topologically protected quantized energy current, have been proposed and studied theoretically, but have never been observed directly. Previous work [D. M. Long et al. , Phys. Rev. Lett. 128 , 183602 (2022) ] proposed that such a pump could be realized with a strongly driven superconducting qubit coupled to a cavity. Here, we experimentally demonstrate that the proposed hierarchy of energy scales and drive frequencies can be realized using a transmon qubit. We develop an experimental toolkit to realize the adiabatic driving field required for energy pumping using coordinated frequency modulation of the transmon and amplitude modulation of an applied resonant microwave drive. With this toolkit, we measure adiabatic evolution of the qubit under the applied field for times comparable to T 1 , which far exceed the bare qubit dephasing time. This result paves the way for direct experimental observation of topological energy pumping.}, archive = {J_PRA}, author = {Martin Ritter and David M. Long and Qianao Yue and Maya Amouzegar and Anushya Chandran and Alicia J. Kollár}, doi = {10.1103/syst-93sh}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042605}, shortjournal = {Phys. Rev. A}, title = {Strong-driving toolkit for topological floquet energy pumps with superconducting circuits}, volume = {112}, year = {2025}, }
• (2025). Measurement compatibility in multiparameter quantum interferometry. PRA, 112(4), 042604. (www)

  @article{ , abstract = {The Cramér-Rao bound captures completely the performance of single-parameter quantum sensors. On the other hand, its extension to multiple parameters demands more caution. Different aspects need to be captured at once, including, critically, compatibility. In this article we consider compatibility in quantum interferometry for an important class of probe states, measured by double homodyne or photon counters, standard benchmarks for these applications. We include the presence of loss and phase diffusion in the estimation of a phase. Our results illustrate how different weighting of the precision on individual parameters affects their compatibility, adding to the list of considerations for quantum multiparameter estimation.}, archive = {J_PRA}, author = {Jayanth Jayakumar and Marco Barbieri and Magdalena Stobińska}, doi = {10.1103/m8l6-8nct}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042604}, shortjournal = {Phys. Rev. A}, title = {Measurement compatibility in multiparameter quantum interferometry}, volume = {112}, year = {2025}, }
• (2025). Efficient quantum algorithm for simulating a time-dependent hamiltonian that commutes at different times. PRA, 112(4), 042603. (www)

  @article{ , abstract = {We describe a quantum algorithm to simulate the time-dependent Hamiltonian, extending the methodology of quantum signal processing. The framework achieves optimal scaling up to some factor with respect to other parameters, and is nearly optimal in inverse of error tolerance, which could be improved to optimal scaling under certain input models. As applications, we discuss the problem of simulating tje generalized lattice system and time-periodic, or Floquet system, showing that our framework provides a neater yet highly efficient solution, achieving nearly optimal scaling in all parameters. In particular, our method also paves a new way for studying phase transition on quantum computer, extending the reach of quantum simulation.}, archive = {J_PRA}, author = {Nhat A. Nghiem}, doi = {10.1103/98x7-9z98}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042603}, shortjournal = {Phys. Rev. A}, title = {Efficient quantum algorithm for simulating a time-dependent hamiltonian that commutes at different times}, volume = {112}, year = {2025}, }
• (2025). Simulation of quantum computation with magic states via jordan-wigner transformations. PRA, 112(4), 042602. (www)

  @article{ , abstract = {Negativity in certain quasiprobability representations is a necessary condition for a quantum computational advantage. Here we define a quasiprobability representation exhibiting this property with respect to quantum computations in the magic state model. It is based on generalized Jordan-Wigner transformations, and it has a close connection to the probability representation of universal quantum computation based on the Λ polytopes. For each number of qubits, it defines a polytope contained in the Λ polytope with some shared vertices. It leads to an efficient classical simulation algorithm for magic state quantum circuits for which the input state is positively represented, and it outperforms previous representations in terms of the states that can be positively represented.}, archive = {J_PRA}, author = {Michael Zurel and Lawrence Z. Cohen and Robert Raussendorf}, doi = {10.1103/ng4l-96kd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042602}, shortjournal = {Phys. Rev. A}, title = {Simulation of quantum computation with magic states via jordan-wigner transformations}, volume = {112}, year = {2025}, }
• (2025). Dynamical decoupling of interacting spins through group factorization. PRA, 112(4), 042601. (www)

  @article{ , abstract = {Dynamical decoupling (DD) is a well-known open-loop protocol for suppressing unwanted interactions in a quantum system, thereby drastically extending the coherence time of useful quantum states. In the original framework of evolution symmetrization, a DD sequence was shown to enforce a symmetry on the unwanted Hamiltonian, thereby suppressing it if the symmetry was inaccessible. In this work, we show how symmetries already present in the undesired Hamiltonian can be harnessed to reduce the complexity of decoupling sequences and to construct nested protocols that correct dominant errors at shorter timescales using the factorization of DD symmetry groups into a product of its subgroups. We provide many relevant examples in various spin systems, using the Majorana constellation and point-group factorization to identify and exploit symmetries in the interaction Hamiltonian. Our framework recovers tailored pulse sequences developed in the context of NMR, including the classical Lee-Goldburg protocol, and further produces novel short and robust sequences capable of suppressing on-site disorder, dipole-dipole interactions, and more exotic many-body interactions in spin ensembles.}, archive = {J_PRA}, author = {Colin Read and Eduardo Serrano-Ensástiga and John Martin}, doi = {10.1103/w5f7-4z5l}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042601}, shortjournal = {Phys. Rev. A}, title = {Dynamical decoupling of interacting spins through group factorization}, volume = {112}, year = {2025}, }
• (2025). Approximate combinatorial optimization with rydberg atoms: The barrier of interpretability. PRA, 112(4), 042441. (www)

  @article{ , abstract = {Analog quantum computing with Rydberg atoms is seen as an avenue to solve hard graph optimization problems, because they naturally encode the maximum independent set (MIS) problem on unit disk (UD) graphs, a problem that admits rather efficient approximation schemes on classical computers. Going beyond UD-MIS to address generic graphs requires embedding schemes, typically with chains of ancilla atoms, and an interpretation algorithm to map results back to the original problem. However, interpreting approximate solutions obtained with realistic quantum computers proves to be a difficult problem. As a case study, we evaluate the ability of two interpretation strategies to correct errors in the recently introduced crossing lattice embedding. We find that one strategy, based on finding the closest embedding solution, leads to very high qualities, albeit at an exponential cost. The second strategy, based on ignoring defective regions of the embedding graph, is polynomial in the graph size, but it leads to a degradation of the solution quality which is prohibitive under realistic assumptions on the defect generation. Moreover, more favorable defect scalings lead to a contradiction with well-known approximability conjectures. Therefore, it is unlikely that a scalable and generic improvement in solution quality can be achieved with Rydberg platforms—thus moving the focus to heuristic algorithms.}, archive = {J_PRA}, author = {Christian de Correc and Thomas Ayral and Corentin Bertrand}, doi = {10.1103/ss3t-j4y5}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042441}, shortjournal = {Phys. Rev. A}, title = {Approximate combinatorial optimization with rydberg atoms: The barrier of interpretability}, volume = {112}, year = {2025}, }
• (2025). Universal entanglement revival of topological origin. PRA, 112(4), 042440. (www)

  @article{ , abstract = {We investigate the dynamics of entanglement in dissipative fermionic and bosonic Su-Schrieffer-Heeger (SSH) models and discover that they exhibit a revival dynamics of entanglement when the decoherence channel preserves the chiral symmetry. This behavior is only observable in the topological phase, and the visibility of the revival diminishes to zero at the phase boundary. Furthermore, the revival acquires a universal character, meaning that the entire time-evolution profile remains independent of system size, provided that the size exceeds the localization length of the edge modes associated with the topological phase. Our findings suggest that the universal entanglement revival originates from the topological properties of the SSH model. These dynamical properties may be experimentally accessible, for instance, by utilizing photonic quantum computers.}, archive = {J_PRA}, author = {Dongni Chen and Stefano Chesi and Mahn-Soo Choi}, doi = {10.1103/qsc2-rcy7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042440}, shortjournal = {Phys. Rev. A}, title = {Universal entanglement revival of topological origin}, volume = {112}, year = {2025}, }
• (2025). Enhancing quantum teleportation with continuous-variable cluster states via photon subtraction. PRA, 112(4), 042439. (www)

  @article{ , abstract = {Quantum teleportation using continuous-variable cluster states is a promising method for quantum state transmission. Experiments show photon subtraction improves the fidelity of two-mode-entangled state-based teleportation, but its effect on universal quantum teleportation with cluster states is unclear. This study clarifies this issue. We create a characteristic function-based representation for universal teleportation, combining it with the Hermite polynomial representation to analyze the impact of photon subtraction. Our analysis finds that the enhancement depends on the photon subtraction modes and the initial squeezing parameter of cluster states. Contrary to the two-mode case, subtracting photons from all cluster state modes does not improve fidelity. By analyzing the equivalent squeezing of initial states after photon subtraction, we determine that squeezing improvement decides teleportation quality. A remarkable finding reveals that performing photon subtraction on two modes of a multirail cluster state can enhance equivalent squeezing of all modes, offering new possibilities for quantum information processing tasks.}, archive = {J_PRA}, author = {Mingjian He and Shouyin Liu}, doi = {10.1103/1jvj-r27q}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042439}, shortjournal = {Phys. Rev. A}, title = {Enhancing quantum teleportation with continuous-variable cluster states via photon subtraction}, volume = {112}, year = {2025}, }
• (2025). Quantum search with a generalized laplacian. PRA, 112(4), 042438. (www)

  @article{ , abstract = {A single excitation in a quantum spin network described by the Heisenberg model can affect a variety of continuous-time quantum walks on unweighted graphs, including those governed by the discrete Laplacian, adjacency matrix, and signless Laplacian. In this paper, we show that the Heisenberg model can affect these three quantum walks on signed weighted graphs, as well as a generalized Laplacian equal to the discrete Laplacian plus a real-valued multiple of the degree matrix, for which the standard Laplacian, adjacency matrix, and signless Laplacian are special cases. We explore the algorithmic consequence of this generalized Laplacian quantum walk when searching a weighted barbell graph consisting of two equal-sized, unweighted cliques connected by a single signed weighted edge or bridge, with the search oracle constituting an external magnetic field in the spin network. We prove that there are two weights for the bridge (which could both be positive, both negative, or one of each, depending on the multiple of the degree matrix) that allow amplitude to cross from one clique to the other—except for the standard and signless Laplacians that respectively only have one negative or positive weight bridge—boosting the success probability from 0.5 to 0.820 or 0.843 for each weight. Moreover, one of the weights leads to a two-stage algorithm that further boosts the success probability to 0.996.}, archive = {J_PRA}, author = {Jonas Duda and Molly E. McLaughlin and Thomas G. Wong}, doi = {10.1103/fsxq-tyxl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042438}, shortjournal = {Phys. Rev. A}, title = {Quantum search with a generalized laplacian}, volume = {112}, year = {2025}, }
• (2025). Efficient implementation of quantum signal processing via the adiabatic-impulse model. PRA, 112(4), 042437. (www)

  @article{ , abstract = {We investigate an analogy between quantum signal processing (QSP) and the adiabatic-impulse model (AIM) in order to implement the QSP algorithm with fast quantum logic gates. QSP is an algorithmic technique that uses single-qubit dynamics to perform a polynomial function transformation. The adiabatic-impulse model effectively describes the evolution of a two-level quantum system under a strong external driving field. We can map parameters from QSP to the AIM to implement a QSP-like evolution with nonadiabatic, high-amplitude external drives. By choosing the AIM driving parameters that control the nonadiabatic transition parameters (such as driving amplitude , frequency , and signal timing), one can achieve polynomial approximations and increase robustness in quantum circuits. The analogy between QSP and AIM presented here can be useful as a way to directly implement the QSP algorithmic technique on quantum systems and show the benefits from fast Landau-Zener-Stückelberg-Majorana (LZSM) quantum logic gates in comparison with usual resonance driving gates in IBM-Q quantum processors.}, archive = {J_PRA}, author = {D. O. Shendryk and O. V. Ivakhnenko and S. N. Shevchenko and Franco Nori}, doi = {10.1103/gnr5-583s}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042437}, shortjournal = {Phys. Rev. A}, title = {Efficient implementation of quantum signal processing via the adiabatic-impulse model}, volume = {112}, year = {2025}, }
• (2025). Approximate maximum-likelihood decoding with k minimum weight matchings. PRA, 112(4), 042436. (www)

  @article{ , abstract = {Minimum weight matching (MWM) and maximum likelihood decoding (MLD) are two widely used and distinct decoding strategies for quantum error correction. For a given syndrome, the MWM decoder finds the most probable physical error corresponding to the MWM of the decoding graph, whereas MLD aims to find the most probable logical error. Although MLD is the optimal error correction strategy, it is typically more computationally expensive compared to the MWM decoder. In this work, we introduce an algorithm that approximates MLD with K MWMs from the decoding graph. Taking the surface code subject to graphlike errors as an example, we show that it is possible to efficiently find the first K MWMs by systematically modifying the original decoding graph followed by finding the MWMs of the modified graphs. For the case where the X and Z errors are correlated, despite the fact that the MWM of the decoding hypergraph cannot be found efficiently, we present a heuristic approach to approximate the MLD by finding the K MWMs in the X and Z subgraphs. We benchmark the efficacy of our algorithm for the surface code subject to graphlike errors as well as the surface-square Gottesman-Kitaev-Preskill (GKP) code and surface-hexagonal GKP code subject to the Gaussian random displacement errors, showing that the fidelity approaches that of the exact MLD (for the first two cases) or the tensor-network decoder (for the last case) as K increases.}, archive = {J_PRA}, author = {Mao Lin (林茂}, doi = {10.1103/vf9r-z5qg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042436}, shortjournal = {Phys. Rev. A}, title = {Approximate maximum-likelihood decoding with k minimum weight matchings}, volume = {112}, year = {2025}, }
• (2025). Multipartite steering verification with imprecise measurements. PRA, 112(4), 042435. (www)

  @article{ , abstract = {Quantum steering is a fundamental quantum correlation that plays a pivotal role in quantum technologies, but its verification crucially relies on precise measurements—an assumption often undermined by practical imperfections. Here, we investigate multipartite steering verification under imprecise measurements and develop a quantitative method that effectively eliminates false positives induced by measurement imprecision. A comparison with a device-independent approach demonstrates that our method accurately delineates the scope of valid verification. In a special case, our method also enables the verification of multipartite entanglement under nonideal conditions. These results substantially enhance the robustness of multipartite steering and entanglement verification against measurement imprecision, thereby promoting their applicability in realistic quantum technologies.}, archive = {J_PRA}, author = {Zeyang Lu and Chan Li and Gang Wang and Zhu Cao}, doi = {10.1103/v4yv-zvsc}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042435}, shortjournal = {Phys. Rev. A}, title = {Multipartite steering verification with imprecise measurements}, volume = {112}, year = {2025}, }
• (2025). Estimating bell diagonal states with separable measurements. PRA, 112(4), 042434. (www)

  @article{ , abstract = {Quantum network protocols depend on the availability of shared entanglement. Given that entanglement generation and distribution are affected by noise, characterization of the shared entangled states is essential to bound the errors of the protocols. This work analyzes the estimation of Bell diagonal states within quantum networks, where operations are limited to local actions and classical communication. We demonstrate the advantages of Bayesian mean estimation over direct inversion and maximum-likelihood estimation, providing analytical expressions for estimation risk and supporting our findings with numerical simulations.}, archive = {J_PRA}, author = {Noah Kaufmann and Maria Quadeer and David Elkouss}, doi = {10.1103/5f1m-p865}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042434}, shortjournal = {Phys. Rev. A}, title = {Estimating bell diagonal states with separable measurements}, volume = {112}, year = {2025}, }
• (2025). Local distinguishability of four multipartite orthogonal product states. PRA, 112(4), 042433. (www)

  @article{ , abstract = {In this paper, we give the local distinguishability of four orthogonal product states (OPSs) on multipartite and high-dimension systems. To characterize the different orthogonal relationships between four multipartite OPSs, a new concept, i.e., the vector of the numbers of pairwise orthogonal relations, is proposed. We classify four tripartite OPSs, any two of which are orthogonal only on one subsystem, into three categories by using the vectors of the numbers of pairwise orthogonal relations. We prove that any four tripartite OPSs belonging to two of the three categories can be perfectly distinguished by local operations and classical communication (LOCC). Meanwhile, we find an interesting phenomenon that two sets of four tripartite OPSs belonging to the remaining one of the three categories have different local distinguishability even if they have the same orthogonal graph. This means that the orthogonal graph is not a sufficient condition for determining the local distinguishability of a set of OPSs. Additionally, for the remaining category, we specify the conditions under which four tripartite OPSs can be locally distinguished and the conditions under which four tripartite OPSs cannot be perfectly distinguished by LOCC. On the other hand, we prove that any four tripartite OPSs with seven or more pairwise orthogonal relations can be perfectly distinguished by LOCC. Furthermore, we prove that any four OPSs with six or more pairwise orthogonal relations can be perfectly distinguished by LOCC on four-, five-, and six-partite systems.}, archive = {J_PRA}, author = {Guang-Bao Xu and Zi-Yan Hao and Hua-Kun Wang and Yu-Guang Yang and Dong-Huan Jiang}, doi = {10.1103/ht8g-43kp}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042433}, shortjournal = {Phys. Rev. A}, title = {Local distinguishability of four multipartite orthogonal product states}, volume = {112}, year = {2025}, }
• (2025). Partitewise entanglement. PRA, 112(4), 042432. (www)

  @article{ , abstract = {It is known that as a bipartite reduced state of the three-qubit Greenberger-Horne-Zeilinger (GHZ) state is separable, but part and part indeed “share tripartite entanglement” in the GHZ state. Namely, whether a state can “share” more entanglement is dependent on the global system it lives in. Here We explore such kind of entanglement in any -partite system with arbitrary dimensions, and call it partitewise entanglement, which includes pairwise entanglement proposed by Dong et al. [ Phys. Rev. A 110 , 032420 (2024) ] as a special case. We propose three classes of the partitewise entanglement measures, which are based on the genuine entanglement measure, the minimal bipartition, and the minimal distance from the partitewise separable states, respectively. The former two methods are far ranging since all of them are defined by the reduced function. [Note: If a positive function satisfies for some bipartite entanglement measure is called the reduced function (of ).] Consequently, we establish the framework of the resource theory of the partitewise entanglement. In addition, we investigate the partitewise entanglement extensibility and give a measure of such extensibility, from which we find that the maximal partitewise entanglement extension is its purification. Lastly, the relation between this extensibility and the partitewise entanglement is discussed.}, archive = {J_PRA}, author = {Yu Guo and Ning Yang}, doi = {10.1103/nj88-wns1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042432}, shortjournal = {Phys. Rev. A}, title = {Partitewise entanglement}, volume = {112}, year = {2025}, }
• (2025). Optimal adaptation of surface-code decoders to local noise. PRA, 112(4), 042431. (www)

  @article{ , abstract = {Information obtained from noise characterization of a quantum device can be used in classical decoding algorithms to improve the performance of quantum error-correcting codes. Focusing on the surface code under local (i.e., single-qubit) noise, we present a versatile, numerical method to quantify the performance improvement gained by adapting an optimal surface-code decoder to specific, user-defined features of the physical noise model. Our method is based on a tensor-network decoding algorithm, which uses the syndrome information as well as a process matrix description of the noise to compute a near-optimal correction. By selectively mischaracterizing the noise model input to the decoder and measuring the resulting loss in fidelity of the logical qubit, we can determine the relative importance of individual noise parameters for decoding. We apply this method to several physically relevant uncorrelated noise models with features such as coherence, spatial inhomogeneity, and bias. While noise generally requires many parameters to describe completely, we find that to achieve near-optimal decoding it appears only necessary to adapt the decoder to a small number of critical parameters.}, archive = {J_PRA}, author = {Andrew S. Darmawan}, doi = {10.1103/r2dc-qcrx}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042431}, shortjournal = {Phys. Rev. A}, title = {Optimal adaptation of surface-code decoders to local noise}, volume = {112}, year = {2025}, }
• (2025). Symmetric vs asymmetric magnon pairing: Comparative study of quantum entanglement and synchronization in the cavity-magnon system. PRA, 112(4), 042430. (www)

  @article{ , abstract = {We investigate magnon-magnon entanglement and synchronization in a cavity-magnon system comprising two yttrium iron garnet spheres, focusing on the role of symmetric and asymmetric magnon pairs under varying physical parameters, including cavity detuning, photon-magnon coupling, dissipation rates, and thermal noise. Our results demonstrate that symmetric magnon pairs generally favor the generation of both quantum entanglement and synchronization, with enhanced resilience to thermal fluctuations compared to asymmetric configurations. Particularly, the quantum entanglement and synchronization obtained in both scenarios (symmetric and asymmetric magnon pairs) can exhibit vastly different behaviors with changes in some physical factors. Further, we explore the interplay between magnon-magnon quantum entanglement and synchronization. We identify a competitive relationship between entanglement and synchronization in certain situations, manifesting as parameter-dependent complementarity where enhancement of one effect correlates with suppression of the other. This study underscores the critical influence of symmetry configuration on quantum correlations in hybrid cavity-magnon systems, offering theoretical guidance for optimizing entanglement and synchronization in quantum information platforms.}, archive = {J_PRA}, author = {Jia-Xin Peng and S. K. Singh and Naeem Akhtar and Zhidong Gu and Chunfeng Wu and Jian-Feng Li}, doi = {10.1103/7hhn-zypy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042430}, shortjournal = {Phys. Rev. A}, title = {Symmetric vs asymmetric magnon pairing: Comparative study of quantum entanglement and synchronization in the cavity-magnon system}, volume = {112}, year = {2025}, }
• (2025). Quantum interferometric protocol using spin-dependent displacements. PRA, 112(4), 042429. (www)

  @article{ , abstract = {We propose a quantum interferometric protocol that leverages spin-dependent spatial displacements to enable high-precision parameter estimation beyond classical limits. By inducing a unitary coupling between a particle's spin degree of freedom and its momentum, the protocol generates entanglement between spin states and spatial positions, resulting in coherent spatial superpositions. Interferometric reconstruction of the resulting phase differences enables Heisenberg-limited sensitivity for parameters encoded in the spin Hamiltonian. As a concrete application, we demonstrate the protocol's effectiveness in magnetic field sensing, where the field is transduced into spatial interference fringes. Quantum Fisher information analysis confirms sub-shot-noise scaling, and the protocol's feasibility is discussed for physical platforms including ultracold atoms and nitrogen-vacancy centers. Our framework provides a versatile approach to quantum metrology with potential extensions to multiparameter sensing and gravitational wave detection.}, archive = {J_PRA}, author = {Necati Çelik and Songül Akbulut Özen and Burhan Engin}, doi = {10.1103/hw3x-1lrm}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042429}, shortjournal = {Phys. Rev. A}, title = {Quantum interferometric protocol using spin-dependent displacements}, volume = {112}, year = {2025}, }
• (2025). Investigating layer-selective transfer learning of quantum approximate optimization algorithm parameters for the max-cut problem. PRA, 112(4), 042428. (www)

  @article{ , abstract = {The quantum approximate optimization algorithm (QAOA) is a variational quantum algorithm (VQA) ideal for noisy intermediate-scale quantum (NISQ) processors, and is highly successful in solving combinatorial optimization problems (COPs). It has been observed that the optimal parameters obtained from one instance of a COP can be transferred to another instance, resulting in generally good solutions for the latter. In this work, we propose a refinement scheme in which only a subset of QAOA layers is optimized following parameter transfer, with a focus on the Max-Cut problem. Our motivation is to reduce the complexity of the loss landscape when optimizing all the layers of high-depth QAOA circuits, as well as to reduce the optimization time. We investigate the potential hierarchical roles of different layers and analyze how the approximation ratio scales with increasing problem size. Our findings indicate that the selective layer optimization scheme offers a favorable trade-off between solution quality and computational time, and can be more beneficial than full optimization at a lower optimization time.}, archive = {J_PRA}, author = {Francesco Aldo Venturelli and Sreetama Das and Filippo Caruso}, doi = {10.1103/cjjm-87gl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042428}, shortjournal = {Phys. Rev. A}, title = {Investigating layer-selective transfer learning of quantum approximate optimization algorithm parameters for the max-cut problem}, volume = {112}, year = {2025}, }
• (2025). Nonlocality under jaynes-cummings evolution: Beyond pseudospin operators. PRA, 112(4), 042427. (www)

  @article{ , abstract = {We revisit the generation and evolution of Bell nonlocality in hybrid scenarios of which the dynamics is determined by the Jaynes-Cummings Hamiltonian, a relevant example of which is the atom-cavity system. Previous approaches evaluate the nonlocality through the well-known qubit-qubit Clauser-Horne-Shimony-Holt (CHSH) formulas, using combinations of pseudospin operators for the electromagnetic (EM) field observables. While such an approach is sensible, it is far from optimal. In the present work we have used recent results on optimal Bell violation in qubit-qudit systems, showing that the nonlocality is much greater than previously estimated, both with and without noise. In addition, we provide an optimal treatment of noise, ensuring that our results are the best possible within this framework. We illustrate the results using different initial states for the EM field, including squeezed and coherent states. In addition, we study the asymptotic behavior of the entanglement. Remarkably, starting with a generic separable pure coherent state, the asymptotic mixed state is entangled, though it does not violate CHSH inequalities.}, archive = {J_PRA}, author = {Alexander Bernal and J. Alberto Casas and Jesús M. Moreno}, doi = {10.1103/m248-tz9x}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042427}, shortjournal = {Phys. Rev. A}, title = {Nonlocality under jaynes-cummings evolution: Beyond pseudospin operators}, volume = {112}, year = {2025}, }
• (2025). Active learning with variational quantum circuits for quantum process tomography. PRA, 112(4), 042426. (www)

  @article{ , abstract = {Quantum process tomography (QPT) is a fundamental tool for fully characterizing quantum systems. It relies on querying a set of quantum states as input to the quantum process. Previous QPT methods typically employ a straightforward strategy for randomly selecting quantum states, overlooking differences in informativeness among them. In this work we propose a general active learning (AL) framework that adaptively selects the most informative subset of quantum states for reconstruction. We design and evaluate various AL algorithms and provide practical guidelines for selecting suitable methods in different scenarios. In particular, we introduce a learning framework that leverages the widely used variational quantum circuits to perform the QPT task and integrate our AL algorithms into the query step. We demonstrate our algorithms by reconstructing the unitary quantum processes resulting from random quantum circuits with up to seven qubits. Numerical results show that our AL algorithms achieve significantly improved reconstruction and the improvement increases with the size of the underlying quantum system. Our work opens new avenues for further advancing existing QPT methods.}, archive = {J_PRA}, author = {Jiaqi Yang and Xiaohua Xu and Wei Xie}, doi = {10.1103/wr3n-v85k}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042426}, shortjournal = {Phys. Rev. A}, title = {Active learning with variational quantum circuits for quantum process tomography}, volume = {112}, year = {2025}, }
• (2025). Entangling two exciton modes placed in two separate exciton-optomechanical cavities. PRA, 112(4), 042425. (www)

  @article{ , abstract = {Distributing robust and long-distance entanglement between repeater nodes is a critical task for both foundational tests of quantum physics and the development of scalable quantum networks. In this paper, we propose a scheme for entangling two spatially separated exciton modes located in two exciton-optomechanical cavities. Each cavity, consisting of a semiconductor optomechanical cavity integrated with a quantum well, is simultaneously driven by a red-detuned laser and a squeezed vacuum light. Under realistic experimental conditions, we show that steady-state entanglement can be established between the two exciton modes by transferring quantum correlations from the squeezed light to them. Maximum entanglement is achieved when the exciton modes are tuned to resonance with the anti-Stokes sidebands of the driving lasers. With a high mechanical quality factor, the resulting entanglement exhibits robust behavior against thermal noise and remains significantly nonzero even at room temperature. Furthermore, we discuss a method to access and detect the excitonic entanglement. Our scheme provides a promising platform for practical long-distance entanglement distribution, which is of fundamental importance for quantum information processing and network architectures.}, archive = {J_PRA}, author = {Jamal El Qars and Moussa Kibbou and Ismail Essaoudi and Abdelmajid Ainane}, doi = {10.1103/vbzm-fggh}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042425}, shortjournal = {Phys. Rev. A}, title = {Entangling two exciton modes placed in two separate exciton-optomechanical cavities}, volume = {112}, year = {2025}, }
• (2025). Temperature and non-markovian parameter estimation in quantum brownian motion. PRA, 112(4), 042424. (www)

  @article{ , abstract = {We investigate a quantum metrological protocol operating in a non-Markovian environment by employing the quantum Brownian motion model, in which the system is linearly coupled to a reservoir of harmonic oscillators. Specifically, we use a position-momentum (PM) correlated Gaussian state as a probe to examine how memory effects influence the evolution of the system's covariance matrix in the weak-coupling regime under both high- and low-temperature conditions. To confirm the presence of non-Markovian behavior, we apply two well-established non-Markovianity quantifiers. Furthermore, we estimate both the channel's sample temperature and its non-Markovianity witness parameter. Our results demonstrate that non-Markovianity and PM correlations can jointly be valuable resources to enhance metrological performance.}, archive = {J_PRA}, author = {João C. P. Porto and Carlos H. S. Vieira and Irismar G. da Paz and Pedro R. Dieguez and Lucas S. Marinho}, doi = {10.1103/c87r-22mn}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042424}, shortjournal = {Phys. Rev. A}, title = {Temperature and non-markovian parameter estimation in quantum brownian motion}, volume = {112}, year = {2025}, }
• (2025). Tripartite entanglement in multimode cavity quantum electrodynamics. PRA, 112(4), 042423. (www)

  @article{ , abstract = {We numerically investigate the generation and dynamics of tripartite entanglement among qubits (quantum emitters or atoms) in multimode cavity quantum electrodynamics (cQED). Our cQED architecture features three initially unentangled excited two-level quantum emitters confined within a triangle-shaped multimode optical cavity, which later become entangled due to a Jaynes-Cummings-like interaction. Using the tripartite negativity measure of entanglement and fidelity with respect to the genuine tripartite entangled state (Greenberger-Horne-Zeilinger state, to be precise), we analyze the impact of the number of cavity modes, qubit locations, and losses (spontaneous emission from qubits and photon leakage from the cavity mirrors) on the generated entanglement. Our key results include the presence of two kinds of retardation effects: one resulting from the time it takes for photons to propagate from one qubit to another, and the other to complete one round trip in the cavity. We observed these retardation effects only in multimode cavities, with the exciting possibility of controlling the collapse and revival patterns of tripartite entanglement by altering the qubit locations in the cavity. Furthermore, the impact of losses on the generated entanglement and the dependence of maximum entanglement on the total number of modes yield results that surpass those reported for single and two excitations. With recent advances in circuit quantum electrodynamics, these findings hold promise for the development of entanglement-based quantum networking protocols and quantum memories.}, archive = {J_PRA}, author = {Nishan Amgain and Mahir Rahman and Umar Arshad and Fernando R. Consuegra and Emil Sayahi and Imran M. Mirza}, doi = {10.1103/d6d5-cc1d}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042423}, shortjournal = {Phys. Rev. A}, title = {Tripartite entanglement in multimode cavity quantum electrodynamics}, volume = {112}, year = {2025}, }
• (2025). Improved sampling bounds and scalable partitioning for quantum circuit cutting beyond bipartitions. PRA, 112(4), 042422. (www)

  @article{ , abstract = {We propose a new method for identifying cutting locations for quantum circuit cutting, with a primary focus on partitioning circuits into three or more parts. Under the assumption that the classical postprocessing function is decomposable, we derive a new upper bound on the sampling overhead resulting from both timelike and spacelike cuts. We show that this bound improves upon the previously known bound by orders of magnitude in cases of three or more partitions. Based on this bound, we formulate an objective function L Q and present a method to determine cutting locations that minimize it. Our method is shown to outperform a previous approach in terms of computation time. Moreover, the quality of the obtained partitioning is found to be comparable to or better than that of the baseline in all but a few cases, as measured by L Q . These results are obtained by identifying cutting locations in a number of benchmark circuits of the size and type expected in quantum computations that outperform classical computers.}, archive = {J_PRA}, author = {Junya Nakamura and Takahiko Satoh and Shinichiro Sanji}, doi = {10.1103/xnw7-mtbd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042422}, shortjournal = {Phys. Rev. A}, title = {Improved sampling bounds and scalable partitioning for quantum circuit cutting beyond bipartitions}, volume = {112}, year = {2025}, }
• (2025). Elementary characterization of bargmann invariants. PRA, 112(4), 042421. (www)

  @article{ , abstract = {Bargmann invariants, also known as multivariate traces of quantum states , are unitary invariant quantities used to characterize weak values, Kirkwood-Dirac quasiprobabilities, out-of-time-order correlators, and geometric phases. Here we give a complete characterization of the set of complex values that -order invariants can take, resolving some recently proposed conjectures. We show that is equal to the range of invariants arising from pure states described by Gram matrices of circulant form. We show that both ranges are equal to the power of the complex unit -gon and are therefore convex, which provides a simple geometric intuition. Finally, we show that any Bargmann invariant of order is realizable using either qubit states or circulant qutrit states.}, archive = {J_PRA}, author = {Sagar Silva Pratapsi and João Gouveia and Leonardo Novo and Ernesto F. Galvão}, doi = {10.1103/hsnv-wpt3}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042421}, shortjournal = {Phys. Rev. A}, title = {Elementary characterization of bargmann invariants}, volume = {112}, year = {2025}, }
• (2025). Classical optimization with imaginary-time block encoding on quantum computers: The MaxCut problem. PRA, 112(4), 042420. (www)

  @article{ , abstract = {Optimization problems in finance, physics, and computer science are typically very hard to tackle in classical computing; quantum computing could help speed up computations and provide efficient methods for tackling large problems. Typically, to treat a problem with a quantum computer, the optimal solution is cast as the ground state of a diagonal Hamiltonian. We develop a method, called imaginary-time evolution block encoding (ITE-BE), based on a recent imaginary-time algorithm, which requires no variational parameter optimization, as all parameters can be derived analytically from the target Hamiltonian. We also demonstrate that our method can be successfully combined with other quantum algorithms such as the quantum approximate optimization algorithm (QAOA). For illustration, here we study the MaxCut problem. We find that the QAOA ansatz increases the postselection success of ITE-BE, and shallow QAOA circuits, when boosted with ITE-BE, achieve better performance than deeper QAOA circuits. For the special case of the transverse initial state, we adapt our block-encoding scheme to allow for a deterministic application of the first layer of the circuit.}, archive = {J_PRA}, author = {Dawei Zhong and Akhil Francis and Ermal Rrapaj}, doi = {10.1103/gtq3-j37b}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042420}, shortjournal = {Phys. Rev. A}, title = {Classical optimization with imaginary-time block encoding on quantum computers: The MaxCut problem}, volume = {112}, year = {2025}, }
• (2025). Quantum algorithms for solving a drift-diffusion equation: A complexity analysis. PRA, 112(4), 042419. (www)

  @article{ , abstract = {We present four quantum algorithms for solving a multidimensional drift-diffusion equation. They rely on a quantum linear system solver, a quantum Hamiltonian simulation, a quantum random walk, and the quantum Fourier transform. We compare the complexities of these methods to their classical counterparts, finding that diagonalization via the quantum Fourier transform offers a quantum computational advantage for solving linear partial differential equations at a fixed final time. We employ a multidimensional amplitude estimation process to extract the full probability distribution from the quantum computer.}, archive = {J_PRA}, author = {Ellen Devereux and Animesh Datta}, doi = {10.1103/1fw9-h14w}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042419}, shortjournal = {Phys. Rev. A}, title = {Quantum algorithms for solving a drift-diffusion equation: A complexity analysis}, volume = {112}, year = {2025}, }
• (2025). Optimal and robust error filtration for quantum information processing. PRA, 112(4), 042418. (www)

  @article{ , abstract = {Error filtration is a hardware scheme that mitigates noise by exploiting auxiliary qubits and entangling gates. Although both the signal and ancillae are subject to local noise, constructive interference and postselection allow us to reduce the noise level in the signal qubit. Here we highlight the relation between error filtration and error detection codes and determine the optimal codes that make the qubits interfere most effectively. We examine our optimized scheme under imperfect implementation, where ancillary qubits may be noisy or subject to crosstalk. Even with these imperfections, we find that adding more ancillary qubits helps to protect quantum information. We benchmark our approach against figures of merit that correspond to different applications, including entanglement fidelity, quantum Fisher information (for applications in quantum sensing), and the Clauser-Horne-Shimony-Holt value (for cryptographic applications), with one, two, and three ancillary qubits. By using the entanglement fidelity as a figure of merit, we suggest a general condition for error filtration, and for one and two ancillae, we obtain some explicit expressions for the optimal codes. We also compare our method with the recently introduced superposed quantum error mitigation (SQEM) scheme based on superposition of causal orders and show that, for a wide range of noise strengths, our approach may outperform SQEM in terms of effectiveness and robustness.}, archive = {J_PRA}, author = {Aaqib Ali and Giovanni Scala and Cosmo Lupo}, doi = {10.1103/534r-kp3z}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042418}, shortjournal = {Phys. Rev. A}, title = {Optimal and robust error filtration for quantum information processing}, volume = {112}, year = {2025}, }
• (2025). Logical channel for heralded and pure loss with the gottesman-kitaev-preskill code. PRA, 112(4), 042417. (www)

  @article{ , abstract = {Photon loss is the dominant source of noise in optical quantum systems. The Gottesman-Kitaev-Preskill (GKP) bosonic code provides significant protection; however, even low levels of loss can generate uncorrectable errors that another concatenated code must handle. In this work, we characterize these errors by deriving analytic expressions for the logical channel that arises from pure loss acting on approximate GKP qubits. Unlike random displacement noise, we find that the loss-induced logical channel is not a stochastic Pauli channel. We also provide analytic expressions for the logical channel for “heralded loss,” when the light scattered out of the signal mode is measured either by photon number counting, i.e., photon subtraction, or heterodyne detection. These expressions offer a pathway to intentionally inducing non-Pauli channels for, e.g., magic-state production.}, archive = {J_PRA}, author = {Tom B. Harris and Takaya Matsuura and Ben Q. Baragiola and Nicolas C. Menicucci}, doi = {10.1103/rmlm-vbfd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042417}, shortjournal = {Phys. Rev. A}, title = {Logical channel for heralded and pure loss with the gottesman-kitaev-preskill code}, volume = {112}, year = {2025}, }
• (2025). Flexible manipulation of bipartite and multipartite einstein-podolsky-rosen steering. PRA, 112(4), 042416. (www)

  @article{ , abstract = {Bipartite and multipartite quantum steerings are significant resources for various quantum tasks such as ultrasecure multiuser quantum networks, one-site-trusted quantum communication, and high-fidelity quantum computation. A flexible steering manipulation scheme of five down-converted Hermitian Gaussian modes generated from an optical parametric oscillator using a spatial structured pump is presented. In our scheme, not only the direction and types of the bipartite steering, but also different situations of multipartite steering can be manipulated effectively, by adjusting the pump proportions with a spatial light modulator. In addition, stricter genuine pentapartite steering (only one site is trusted) can also be achieved by making the pump proportions as balanced as possible. Our scheme is versatile and experimentally feasible and offers new insights into the manipulation of steering, especially multipartite steering, which is valuable in many special quantum tasks.}, archive = {J_PRA}, author = {Yunyun Liang and Jing Zhang and Rongguo Yang and Tiancai Zhang and Jiangrui Gao}, doi = {10.1103/wb5p-jfnk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042416}, shortjournal = {Phys. Rev. A}, title = {Flexible manipulation of bipartite and multipartite einstein-podolsky-rosen steering}, volume = {112}, year = {2025}, }
• (2025). Saturation of the cramér-rao bound for atomic resonance frequency measurements with a phased array of hyperbolic secant pulses. PRA, 112(4), 042415. (www)

  @article{ , abstract = {Precise estimation of the atomic resonance frequency is fundamental for the characterization and control of quantum systems. The resonance experiment is a standard method for this measurement, wherein the drive field frequency is swept to invert the system population. We analyze the classical and quantum Fisher information for the resonance experiment driven by hyperbolic-secant-shaped pulses, setting a fundamental limit on the precision obtainable using the resonance method. We show that measurements using sequences of pulses with alternating phases nearly saturate the quantum Cramér-Rao bound, improving the precision of atomic resonance frequency measurements.}, archive = {J_PRA}, author = {Tharon Holdsworth and Jacob Adamczyk and Girish S. Agarwal}, doi = {10.1103/2y17-j6fv}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042415}, shortjournal = {Phys. Rev. A}, title = {Saturation of the cramér-rao bound for atomic resonance frequency measurements with a phased array of hyperbolic secant pulses}, volume = {112}, year = {2025}, }
• (2025). Machine learning for detecting steering in qutrit-pair states. PRA, 112(4), 042414. (www)

  @article{ , abstract = {Only a few states in high-dimensional systems can be identified as (un)steerable using existing theoretical or experimental methods. We utilize semidefinite programming (SDP) to construct a dataset for steerability detection in qutrit-qutrit systems. For the full-information feature F 1 , artificial neural networks achieve high classification accuracy and generalization, and perform better than the support vector machine. As feature engineering plays a pivotal role, we introduce a steering ellipsoidlike feature, F 2 , which significantly enhances the performance of each of our models. To address quantum steering detection in isotropic states, partially entangled states, and random states, we explore, respectively, the most tailored feature and classifier. Given that the SDP method provides only a sufficient condition for steerability detection, we establish the first rigorously constructed, accurately labeled dataset based on theoretical foundations. This dataset enables models to exhibit outstanding accuracy and generalization capabilities, independent of the choice of features. As applications, we investigate the steerability boundaries of isotropic states and partially entangled states, discover new steerable states, and determine their parameter ranges. This work not only advances the application of machine learning for probing quantum steerability in high-dimensional systems but also deepens the theoretical understanding of quantum steerability itself.}, archive = {J_PRA}, author = {Pu Wang and Zhongyan Li and Huixian Meng}, doi = {10.1103/h7qp-63dg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042414}, shortjournal = {Phys. Rev. A}, title = {Machine learning for detecting steering in qutrit-pair states}, volume = {112}, year = {2025}, }
• (2025). Fault-tolerant pairwise measurement-based code on eight qubits. PRA, 112(4), 042413. (www)

  @article{ , abstract = {We construct a pairwise measurement-based code on eight qubits that is error-correcting for circuit noise, with fault distance 3. The code can be implemented on a subset of a rectangular array of qubits with nearest-neighbor connectivity of pairwise Pauli measurements, with a syndrome extraction circuit of depth 28. We describe fault-tolerant logical operations on patches of this eight-qubit code that generate the full Clifford group. We estimate the performance under circuit noise both during logical idle and during a logical two-qubit measurement. We estimate the pseudothreshold to be between 10 − 5 and 2 × 10 − 4 , depending on the amount of noise on idle physical qubits. The use of postselection in addition to error correction (correcting all degree-one faults and rejecting a subset of the higher degree faults) can improve the pseudothreshold by up to an order of magnitude.}, archive = {J_PRA}, author = {Linnea Grans-Samuelsson and David Aasen and Parsa Bonderson}, doi = {10.1103/c54n-y9vw}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042413}, shortjournal = {Phys. Rev. A}, title = {Fault-tolerant pairwise measurement-based code on eight qubits}, volume = {112}, year = {2025}, }
• (2025). Digital-analog simulations of schrödinger cat states in the dicke-ising model. PRA, 112(4), 042412. (www)

  @article{ , abstract = {The Dicke-Ising model, one of the few paradigmatic models of matter-light interaction, exhibits a superradiant quantum phase transition above a critical coupling strength. However, in natural optical systems, its experimental validation is hindered by a “no-go theorem.” Here, we propose a digital-analog quantum simulator for this model based on an ensemble of interacting qubits coupled to a single-mode photonic resonator. We analyze the system's free-energy landscape using field-theoretical methods and develop a digital-analog quantum algorithm that disentangles qubit and photon degrees of freedom through a parity-measurement protocol. This disentangling enables the emulation of a photonic Schrödinger cat state, which is a hallmark of the superradiant ground state in finite-size systems and can be unambiguously probed through the Wigner tomography of the resonator's field.}, archive = {J_PRA}, author = {Dmitriy S. Shapiro and Yannik Weber and Tim Bode and Frank K. Wilhelm and Dmitry Bagrets}, doi = {10.1103/wbp6-y3vd}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042412}, shortjournal = {Phys. Rev. A}, title = {Digital-analog simulations of schrödinger cat states in the dicke-ising model}, volume = {112}, year = {2025}, }
• (2025). Correlated dynamics as a resource in molecular switches. PRA, 112(4), 042411. (www)

  @article{ , abstract = {Photoisomerization, a photochemical process underlying many biological mechanisms, has been modeled recently within the quantum resource theory of thermodynamics. This approach has emerged as a promising tool for studying fundamental limitations to nanoscale processes independently of the microscopic details governing their dynamics. On the other hand, correlations between physical systems have been shown to play a crucial role in quantum thermodynamics by lowering the work cost of certain operations. Here we explore quantitatively how correlations between multiple photoswitches can enhance the efficiency of photoisomerization beyond that attainable for single molecules. Furthermore, our analysis provides insights into the interplay between quantum and classical correlations in these transformations.}, archive = {J_PRA}, author = {Daniel Siciliano and Rudi B. P. Pietsch and Giovanni Spaventa and Susana F. Huelga and Martin B. Plenio}, doi = {10.1103/khj7-3clh}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042411}, shortjournal = {Phys. Rev. A}, title = {Correlated dynamics as a resource in molecular switches}, volume = {112}, year = {2025}, }
• (2025). Semi-device-independent nonstabilizerness certification in the prepare-and-measure scenario. PRA, 112(4), 042410. (www)

  @article{ , abstract = {Nonstabilizerness is an essential resource for quantum computational advantage as stabilizer states admit efficient classical simulation. We develop a semi-device-independent framework for certifying nonstabilizer states in prepare-and-measure (PAM) scenarios, relying only on assumptions about the system's dimension. Within this framework, we introduce PAM witnesses that can distinguish stabilizer from nonstabilizer states, and we provide analytical proofs that threshold violations of these witnesses certify nonstabilizerness. In the simplest setting—three preparations, two measurements, and qubit systems—surpassing a specific threshold guarantees that at least one prepared state lies outside the stabilizer polytope, while a stronger violation can certify at least two. We extend this approach by linking it to quantum random access codes, also generalizing our results to qutrit systems and introducing a necessary condition for certifying nonstabilizerness based on state overlaps (Gram matrices). These results offer a set of semi-device-independent tools for practically and systematically verifying nonstabilizer states using PAM inequalities.}, archive = {J_PRA}, author = {Santiago Zamora and Rafael A. Macêdo and Tailan S. Sarubi and Moisés Alves and Davide Poderini and Rafael Chaves}, doi = {10.1103/wm7m-xnfq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042410}, shortjournal = {Phys. Rev. A}, title = {Semi-device-independent nonstabilizerness certification in the prepare-and-measure scenario}, volume = {112}, year = {2025}, }
• (2025). Scalable and fault-tolerant preparation of encoded k-uniform states. PRA, 112(4), 042409. (www)

  @article{ , abstract = {k -uniform states are valuable resources in quantum information, enabling tasks such as teleportation, error correction, and accelerated quantum simulations. However, the practical realization of k -uniform states, at scale, faces major obstacles: Verifying k uniformity is as difficult as measuring code distances, and devising fault-tolerant logical preparation protocols further adds to the complexity. To address these challenges, we present a scalable fault-tolerant method for preparing encoded k -uniform states and we illustrate our approach using surface and color codes. We first present a technique to determine k uniformity of stabilizer states directly from their stabilizer tableau. We then identify a family of Clifford circuits that ensures both fault tolerance and scalability in preparing these states. Building on the encoded k -uniform states, we introduce a hybrid physical-logical strategy that retains some of the error-protection benefits of logical qubits while lowering the overhead for implementing arbitrary gates compared to fully logical algorithms. We show that this hybrid approach can outperform fully physical implementations for resource-state preparation, as demonstrated by explicit constructions of k -uniform states.}, archive = {J_PRA}, author = {Shayan Majidy and Dominik Hangleiter and Michael J. Gullans}, doi = {10.1103/cl23-c3jg}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042409}, shortjournal = {Phys. Rev. A}, title = {Scalable and fault-tolerant preparation of encoded k-uniform states}, volume = {112}, year = {2025}, }
• (2025). Quantum kernel method for learning graph data via quantum walk. PRA, 112(4), 042408. (www)

  @article{ , abstract = {Graph kernels are essential for learning the properties of graph data, a fundamental task in the analysis of such data. However, a major limitation of current graph kernel methods is their high computational cost, which becomes prohibitive when dealing with large-scale graphs. In order to address this bottleneck, we propose a quantum algorithm designed to analyze the intrinsic structural information within graph data through an efficient quantum kernel method. The core idea of our kernel method involves encoding pertinent information from graphs into quantum states, utilizing quantum kernel functions to represent the similarities among various graphs. This process is facilitated through the application of quantum walks and quantum signal processing techniques. Building upon this framework, we propose a quantum kernel ridge regression algorithm that consists of two key steps. First, we employ our quantum kernel method to prepare a quantum state, in which the amplitudes encode the kernel functions. Second, we implement quantum feature mapping in parallel to encode the corresponding kernel matrix into the quantum circuit. Crucially, we demonstrate that the computational complexity of our regression algorithm scales primarily as O ( M 3 / 2 ) with respect to the size of the graph set M . This suggests that our quantum kernel method could process graph data with resource requirements scaling approximately as O ( poly log ( N ) ) , where N denotes the number of nodes in the graph. Accordingly, this underscores the advantage of our approach over classical methods in the context of large-scale graph analysis. To validate our approach, we conduct numerical experiments on chemical molecular datasets, demonstrating the method's effectiveness and advantages. In summary, this work represents a significant advancement in quantum graph learning, enhancing its potential for analyzing large-scale graph data.}, archive = {J_PRA}, author = {Linyun Cao and Youle Wang}, doi = {10.1103/k2nx-d649}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042408}, shortjournal = {Phys. Rev. A}, title = {Quantum kernel method for learning graph data via quantum walk}, volume = {112}, year = {2025}, }
• (2025). Quantum teleportation in nonequilibrium environments and fixed-point fidelity. PRA, 112(4), 042407. (www)

  @article{ , abstract = {Quantum teleportation, a fundamental protocol in quantum information science, enables the transfer of quantum states through entangled particle pairs and classical communication channels. While ideal quantum teleportation requires maximally entangled states as resources, real-world implementations inevitably face environmental noise and decoherence effects. In this work, we investigate quantum teleportation in nonequilibrium environments with different temperatures or chemical potentials. We employ the Bloch-Redfield equation to characterize the nonequilibrium dynamics in both bosonic and fermionic reservoirs. Our analysis reveals that nonequilibrium conditions, namely, the temperature difference and chemical potential difference, can significantly enhance the teleportation fidelity beyond what is achievable in equilibrium scenarios. Notably, under certain nonequilibrium conditions, the fidelities for all input states converge to the same value. We term this behavior the teleportation with a fixed-point fidelity. Importantly, at this fixed point, fidelity can be further enhanced by tuning the nonequilibrium parameters. These findings offer crucial insights for the implementation of quantum communication protocols in realistic environments, demonstrating that nonequilibrium conditions not only improve the fidelity but also present a promising avenue for simplifying practical quantum teleportation schemes.}, archive = {J_PRA}, author = {Xiaokun Yan and Zhihai Wang and Kun Zhang and Jin Wang}, doi = {10.1103/mfn6-bndl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042407}, shortjournal = {Phys. Rev. A}, title = {Quantum teleportation in nonequilibrium environments and fixed-point fidelity}, volume = {112}, year = {2025}, }
• (2025). Continuous-variable quantum key distribution with a single quadrature measurement at an arbitrary reference frame. PRA, 112(4), 042406. (www)

  @article{ , abstract = {We propose a simplified measurement scheme for a Gaussian modulated coherent state (GMCS) protocol for continuous variable quantum key distribution (CV-QKD), utilizing homodyne detection without quadrature switching. The reference frame of measurement is taken to be at an arbitrary angle, however, reconciliation converges the proposed scheme to GMCS with switching quadrature protocol. The arbitrary frame of measurement could also include the unknown random thermal drift within Bob's optical measurement setup. We found this scheme is advantageous for practical free-space and fiber-based GMCS protocol-based CV-QKD systems as it does not require a phase modulator for random measurement selection quadrature at Bob.}, archive = {J_PRA}, author = {Vinod N. Rao and Emma Tien Hwai Medlock and Timothy Spiller and Rupesh Kumar}, doi = {10.1103/g465-pm47}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042406}, shortjournal = {Phys. Rev. A}, title = {Continuous-variable quantum key distribution with a single quadrature measurement at an arbitrary reference frame}, volume = {112}, year = {2025}, }
• (2025). Quantum correlations versus spin magnitude: Transition to the classical limit. PRA, 112(4), 042405. (www)

  @article{ , abstract = {Quantum-classical transitions have long attracted much attention. We study such transitions in quantum spin-( j ,1/2) systems at thermal equilibrium. Unlike previous work [ Phys. Rev. A 73 , 064302 (2006) ], we find that the threshold temperature of quantum entanglement decreases with increasing spin j and completely disappears in the limit j → ∞ . In the ground state of systems with highly symmetric interactions, the discord-type quantum correlations can exist even for arbitrarily large spin. Such correlations turn out to be unstable and are destroyed by small perturbations that violate the symmetry of the Hamiltonian. The stable quantum correlations gradually degrade as the spin j grows and eventually vanish when the classical limit is reached.}, archive = {J_PRA}, author = {M. A. Yurischev and E. I. Kuznetsova and Saeed Haddadi}, doi = {10.1103/qxtm-gysy}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042405}, shortjournal = {Phys. Rev. A}, title = {Quantum correlations versus spin magnitude: Transition to the classical limit}, volume = {112}, year = {2025}, }
• (2025). Maximal clauser-horne-shimony-holt violation for qubit-qudit states. PRA, 112(4), 042404. (www)

  @article{ , abstract = {We evaluate the maximal Clauser-Horne-Shimony-Holt (CHSH) violation for a generic (typically mixed) qubit-qudit state, obtaining easily computable expressions in arbitrary qudit dimension. This represents the optimal (2-2-2) Bell nonlocality for this kind of systems. The work generalizes the well-known Horodeckis result for a qubit-qubit setup. We also give simple lower and upper bounds on that violation. We apply our general results to address a number of issues, namely, we obtain a bound on the degree of purity required in a system to exhibit nonlocality and study the statistics of nonlocality in random density matrices. In addition, we show the impossibility of improving the amount of CHSH violation by embedding the qudit in a Hilbert space of larger dimension. Finally, the general result is illustrated with a family of density matrices in the context of a qubit-qutrit system.}, archive = {J_PRA}, author = {Alexander Bernal and J. Alberto Casas and Jesús M. Moreno}, doi = {10.1103/g3mw-6rl1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042404}, shortjournal = {Phys. Rev. A}, title = {Maximal clauser-horne-shimony-holt violation for qubit-qudit states}, volume = {112}, year = {2025}, }
• (2025). Qudit-based quantum error-correcting codes from irreducible representations of SU(d). PRA, 112(4), 042402. (www)

  @article{ , abstract = {Qudits naturally correspond to multilevel quantum systems, which have the potential to enable more efficient quantum information processing, but their reliability is contingent upon quantum error-correction capabilities. In this paper, we present a general procedure for constructing error-correcting qudit codes through the irreducible representations of SU ( d ) for any odd integer d ≥ 3 . Using the Weyl character formula and inner product of characters, we deduce the relevant branching rules, through which we identify the physical Hilbert spaces that contain valid code spaces. We then discuss how two forms of permutation invariance and the Heisenberg-Weyl symmetry of su ( d ) can be exploited to simplify the construction of error-correcting codes. Finally, we use our procedure to construct an infinite class of error-correcting codes encoding a logical qudit into ( d − 1 ) 2 physical qudits.}, archive = {J_PRA}, author = {Robert Frederik Uy and Dorian A. Gangloff}, doi = {10.1103/6z3t-96t9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042402}, shortjournal = {Phys. Rev. A}, title = {Qudit-based quantum error-correcting codes from irreducible representations of SU(d)}, volume = {112}, year = {2025}, }
• (2025). Barium-based rydberg-atom quantum technologies with long rydberg coherence. PRA, 112(4), 042401. (www)

  @article{ , abstract = {The short Doppler-limited coherence time of the laser-excited Rydberg state, usually orders of magnitude shorter than the lifetime of the Rydberg state, hinders the Rydberg-mediated quantum technologies. Here, we show that a 649–658-nm two-photon excitation of the 6 s n g G 4 1 Rydberg state from a long-lived d -orbital clock state of barium can be achieved with a two-photon wave vector that is tiny, which effectively removes the Doppler-limited decoherence. Moreover, the 6 s n g G 4 1 Rydberg state has strong dipole-dipole interaction due to small Förster defect with nearby Rydberg states and possesses long radiative lifetime. These can benefit quantum computing based on individually trapped neutral atoms and can enable long-lived Rydberg polaritons in atomic media, which brings fresh opportunities in all-optical quantum information.}, archive = {J_PRA}, author = {Xiao-Feng Shi}, doi = {10.1103/bbv3-d4ch}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042401}, shortjournal = {Phys. Rev. A}, title = {Barium-based rydberg-atom quantum technologies with long rydberg coherence}, volume = {112}, year = {2025}, }
• (2025). Topological phase transitions and edge-state transfer in time-multiplexed quantum walks. PRA, 112(4), 042230. (www)

  @article{ , abstract = {We investigate the topological phase transitions and edge-state properties of a time-multiplexed nonunitary quantum walk with sublattice symmetry. By constructing a Floquet operator incorporating tunable gain and loss, we systematically analyze both unitary and nonunitary regimes. In the unitary case, the conventional bulk-boundary correspondence (BBC) is preserved, with edge modes localized at opposite boundaries as predicted by topological invariants. In contrast, the nonunitary regime exhibits non-Hermitian skin effects, leading to a breakdown of the conventional BBC. By applying non-Bloch band theory and generalized Brillouin zones, we restore a generalized BBC and reveal a transfer phenomenon, where edge modes with different sublattice symmetries can become localized at the same boundary. Furthermore, we demonstrate that the structure of the spectral loops in the complex quasienergy plane provides a clear signature for these transfer behaviors. Our findings deepen the understanding of nonunitary topological phases and offer valuable insights for the experimental realization and control of edge states in non-Hermitian quantum systems.}, archive = {J_PRA}, author = {Huimin Wang and Zhihao Xu and Zhijian Li}, doi = {10.1103/sb89-p5rl}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042230}, shortjournal = {Phys. Rev. A}, title = {Topological phase transitions and edge-state transfer in time-multiplexed quantum walks}, volume = {112}, year = {2025}, }
• (2025). Enhancing ergotropy of a quantum battery with coherent chargers: The catalystlike role of indefinite causal order. PRA, 112(4), 042229. (www)

  @article{ , abstract = {In recent years, quantum battery (QB) models have emerged as crucial platforms for exploring the connections between quantum effects and energy within the framework of quantum thermodynamics. Inspired by the physical implementation of quantum switch (QS), we, in this work, present a simple QB model in which a two-level system as battery, under a series of coherent chargers, performs the indefinite causal order (ICO) charging by introducing a control qubit as QS. Within the energy-preserving collision interaction framework, we analyze the charging ICO and conventional definite causal order (DCO) dynamics, respectively, and discover the underlying connection between the final charged states of battery in ICO and DCO charging modes. That is, the ICO charged state can be understood as a split of the DCO charged state, accompanied by an offset caused by the interference component characterizing the ICO effect. That provides direct theoretical evidence that the ICO effect positively influences the ergotropy (i.e., the maximum extractable work) of QB only when quantum coherence is present in the charging process, and it is independent of the average stored energy of the QB. By combining numerical simulations, we examine that quantum coherence in our model is a strong quantum resource contributing to the ergotropy of QB, while the ICO effect plays a catalyst-like role, assisting quantum coherence in further enhancing the ergotropy of the battery. In addition, we also demonstrate that increasing the number of chargers also benefits the optimal ergotropy of QB. Finally, we reveal that, when the coherent chargers are subject to the dephasing channel, the ICO charging mode is more robust against dephasing noise than the DCO charging mode. This investigation deepens our understanding of quantum coherence and the ICO effect in the context of quantum thermodynamics.}, archive = {J_PRA}, author = {Hai Li and Haoyuan Ma and Yaming Hao and Wenli Yu}, doi = {10.1103/s6dl-zgkx}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042229}, shortjournal = {Phys. Rev. A}, title = {Enhancing ergotropy of a quantum battery with coherent chargers: The catalystlike role of indefinite causal order}, volume = {112}, year = {2025}, }
• (2025). Physical relevance of time-independent scattering calculations in non-hermitian systems: The role of time-growing bound states. PRA, 112(4), 042228. (www)

  @article{ , abstract = {Time-independent scattering methods are widely employed to analyze transport in non-Hermitian systems. Their application, however, rests on a critical yet often overlooked assumption: that an incident wave is a pure superposition of scattering states. In practice, any physically realistic, spatially localized wave packet will generally have a nonzero overlap with the system's bound states, thereby violating this premise. While this violation is inconsequential in Hermitian systems, it can invalidate the conventional scattering picture in their non-Hermitian counterparts. The underlying cause is the emergence of time-growing bound states, which manifest as poles of the scattering matrix ( matrix) in the first quadrant of the complex wave-number plane. Any initial overlap with these states becomes exponentially amplified, eventually dominating the long-time dynamics. Consequently, the actual evolution of a wave packet diverges dramatically from the conventional scattering picture, rendering the transmission and reflection coefficients derived from time-independent scattering methods unphysical. Using tight-binding models with non-Hermiticity introduced via imaginary on-site potentials or asymmetric hopping, we demonstrate that parameter regimes supporting such growing states are common. We therefore conclude that an analysis of -matrix poles is an indispensable step to confirm the physical relevance of time-independent scattering calculations in non-Hermitian systems.}, archive = {J_PRA}, author = {Chao Zheng}, doi = {10.1103/gzyf-77hr}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042228}, shortjournal = {Phys. Rev. A}, title = {Physical relevance of time-independent scattering calculations in non-hermitian systems: The role of time-growing bound states}, volume = {112}, year = {2025}, }
• (2025). Unraveling quantum environments: Transformer-assisted learning in lindblad dynamics. PRA, 112(4), 042227. (www)

  @article{ , abstract = {Understanding dissipation in open quantum systems is crucial for the development of robust quantum technologies. In this work, we introduce a transformer-based machine learning framework to infer time-dependent dissipation rates in systems governed by the Lindblad master equation. Our method requires only time series of observable quantities, such as , and , and does not require prior knowledge of the initial quantum state or the system Hamiltonian during inference. We demonstrate the effectiveness of our approach across a hierarchy of open quantum models, including single-qubit systems with time-independent and time-dependent jump rates, two-qubit interacting systems (e.g., Heisenberg and transverse Ising models), and the Jaynes-Cummings model with cavity loss and time-dependent decay. Our method accurately reconstructs both fixed and time-varying dissipation profiles from observable trajectories. We further show that under reasonable assumptions, the jump rates in these models are uniquely determined by a small set of measurable observables. The results suggest that transformer-based learning provides a scalable and data-driven route for identifying environmental effects in open quantum systems.}, archive = {J_PRA}, author = {Chi-Sheng Chen and En-Jui Kuo}, doi = {10.1103/gsxk-45mk}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042227}, shortjournal = {Phys. Rev. A}, title = {Unraveling quantum environments: Transformer-assisted learning in lindblad dynamics}, volume = {112}, year = {2025}, }
• (2025). Notions of adiabatic drift in the quantized harper model. PRA, 112(4), 042226. (www)

  @article{ , abstract = {We study a quantized, discrete, and drifting version of the Harper Hamiltonian, also called the finite almost Mathieu operator, which resembles the pendulum Hamiltonian but, in phase space, is confined to a torus. Spacing between pairs of eigenvalues of the operator spans many orders of magnitude, with nearly degenerate pairs of states at energies that are associated with circulating orbits in the associated classical system. When parameters of the system slowly vary, both adiabatic and diabatic transitions can take place at drift rates that span many orders of magnitude. Only under an extremely negligible drift rate would all transitions into superposition states be suppressed. The wide range of energy-level spacings could be a common property of quantum systems with nonlocal potentials that are related to resonant classical dynamical systems. Notions for adiabatic drift are discussed for quantum systems that are associated with classical ones with a divided phase space.}, archive = {J_PRA}, author = {Alice C. Quillen and Nathan Skerrett and Damian R. Sowinski and Abobakar Sediq Miakhel}, doi = {10.1103/gfvf-7xwq}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042226}, shortjournal = {Phys. Rev. A}, title = {Notions of adiabatic drift in the quantized harper model}, volume = {112}, year = {2025}, }
• (2025). Decoherence and brownian motion of a polarizable particle near a medium. PRA, 112(4), 042225. (www)

  @article{ , abstract = {Optically levitated nanoparticles are ideal experimental testbeds for investigating macroscopic superpositions and microscopic thermodynamics. Integrating such levitated nanoparticles with photonic structures can enable strong coupling between their center-of-mass motion and guided photonic modes, facilitating enhanced control and probing of their motion. When coupling a particle to a photonic structure, such as a waveguide, the effects of fluctuations become prominent at nanoscales. In this work, we analyze the classical and quantized center-of-mass motion of a polarizable particle interacting with the fluctuations of the electromagnetic field in the presence of a medium. We derive a position localization master equation for the particle's quantized center of mass, and examine its classical center-of-mass momentum diffusion, elucidating correspondences between classical and quantum Brownian motion of polarizable particles near media. We study the decoherence rate of the particle in the presence of a planar surface as a function of temperature and distance from the surface, comparing it to common sources of decoherence. Our results are pertinent to experiments aimed at preparing levitated nanospheres in macroscopic quantum states and investigating their Brownian dynamics.}, archive = {J_PRA}, author = {Clemens Jakubec and Christopher Jarzynski and Kanu Sinha}, doi = {10.1103/6m4t-jm4x}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042225}, shortjournal = {Phys. Rev. A}, title = {Decoherence and brownian motion of a polarizable particle near a medium}, volume = {112}, year = {2025}, }
• (2025). Anti-PT symmetry transition and scale-free localization in a non-hermitian su-schrieffer-heeger model with defects. PRA, 112(4), 042224. (www)

  @article{ , abstract = {We investigate the influence of on-site defects on topological properties, anti- symmetry, and scale-free localization in the non-Hermitian Su-Schrieffer-Heeger model. In the topologically nontrivial phase region, defects give rise to conventional localized states at the defect sites. Remarkably, in the topologically trivial phase region, defects generate a number of scale-free localized states, starkly contrasting with the absence of such states typically associated with the topologically nontrivial phase. Furthermore, we establish a numerical indicator to predict the emergence of scale-free localized states. This indicator relies on the convergence behavior of the eigenvalues. In addition, we prove the feasibility of constructing a non-Hermitian Su-Schrieffer-Heeger model utilizing cavity fields weakly coupled to engineered resonators. Our work deepens the understanding of anti- symmetry and provides insights into scale-free localization in dimerized non-Hermitian systems.}, archive = {J_PRA}, author = {Xin-Yue Zhang and Yu Yan and Zhi-Xu Zhang and Rui Hou and Li-Nan Zhong and Ji Cao and Hong-Fu Wang}, doi = {10.1103/1dsl-z45b}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042224}, shortjournal = {Phys. Rev. A}, title = {Anti-PT symmetry transition and scale-free localization in a non-hermitian su-schrieffer-heeger model with defects}, volume = {112}, year = {2025}, }
• (2025). Mitigating source and detection noises in autocorrelative weak-value amplification. PRA, 112(4), 042223. (www)

  @article{ , abstract = {Weak-value amplification (WVA), a postselection-based technique that amplifies weak physical signals by preparing nearly orthogonal pre- and postselected quantum states, is intrinsically limited by various kinds of technical noise, which distorts amplified weak values, especially when discarding photons in postselection. While prior work established the efficacy of autocorrelative weak-value amplification (AWVA) under Gaussian noise, practical implementations face challenges from band-limited laser-source noise and detection noise (including shot noise and electrical noise). Here, we demonstrate that the AWVA protocol robustly suppresses both laser-power fluctuations and detection noise. Numerical experiments in Simulink further reveal AWVA's dual advantage: under high-power conditions, the noise-reduction superiority of AWVA over WVA becomes in- creasingly pronounced as input laser power increases, whereas in detection-limited regimes AWVA achieves an order-of-magnitude lower uncertainty, closely approaching the Cramér-Rao bound. Crucially, this work demonstrates that AWVA improves precision in both high-power (laser-noise-dominated) and photon-starved (detector-noise-dominated) regimes, thereby bridging these operating extremes and advancing precision in applications from gravitational-wave detection to hybrid quantum systems.}, archive = {J_PRA}, author = {Xiang-Yun Hu and Jing-Hui Huang and Fei-Fan He and Guang-Jun Wang and Adetunmise C. Dada}, doi = {10.1103/vr7v-lwtb}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042223}, shortjournal = {Phys. Rev. A}, title = {Mitigating source and detection noises in autocorrelative weak-value amplification}, volume = {112}, year = {2025}, }
• (2025). Unraveling the non-markovian spin-boson model and quantum quasi-otto cycle. PRA, 112(4), 042222. (www)

  @article{ , abstract = {We use the spin-boson model to describe the dynamics of a two-level atom interacting with Fabry-Pérot cavity modes. We solve the Schrödinger equation for the system-bath model without the Born-Markov approximation to derive the non-Markovian reduced dynamics of the qubit. We further construct an exact Lindblad-type master equation for it. Similar to the quantum Otto cycle, we construct a non-Markovian quasicyclic process based on the atom-cavity interactions, which we call the quasi-Otto cycle. For judicious choices of input state and parameters, the quasicycle can be more efficient as a quantum engine than the Otto cycle. We also show that if the quasicycle is repeated multiple times, the efficiency of the quasi-Otto engine asymptotically approaches that of the Otto engine.}, archive = {J_PRA}, author = {Shreyas Harshal Pradhan and Hadi Mohammed Soufy and Vishal Anand and Rik Chattopadhyay and Subhadip Mitra and Samyadeb Bhattacharya}, doi = {10.1103/mp8n-xnt2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042222}, shortjournal = {Phys. Rev. A}, title = {Unraveling the non-markovian spin-boson model and quantum quasi-otto cycle}, volume = {112}, year = {2025}, }
• (2025). Confinement to deterministic manifolds and low-dimensional solution formulas for continuously measured quantum systems. PRA, 112(4), 042221. (www)

  @article{ , abstract = {Quantum systems subjected to a continuous weak measurement process evolve according to stochastic differential equations. Depending on the outcomes of these stochastic measurements, the quantum state may diffuse in various directions across the state space. This note points out that, in many scenarios relevant to quantum engineering, this diffusion is effectively constrained to a low-dimensional space. Specifically, the quantum state remains confined to a low-dimensional, nonlinear manifold—often time-dependent, yet independent of the specific measurement outcomes. This note derives the corresponding low-dimensional formulations for expressing the stochastically evolving state in several prototypical cases: quantum nondemolition measurements in arbitrary dimensions; quadrature measurements of a harmonic oscillator (linear quantum system); and measurements of subsystems within multipartite quantum systems. Additionally, it introduces an algebraic criterion to determine whether such low-dimensional manifolds exist or persist when additional dynamics are present.}, archive = {J_PRA}, author = {Alain Sarlette and Cyril Elourard and Pierre Rouchon}, doi = {10.1103/gdt7-2md2}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042221}, shortjournal = {Phys. Rev. A}, title = {Confinement to deterministic manifolds and low-dimensional solution formulas for continuously measured quantum systems}, volume = {112}, year = {2025}, }
• (2025). Lindblad evolution as gradient flow. PRA, 112(4), 042220. (www)

  @article{ , abstract = {We give a simple argument that, for a large class of jump operators, the Lindblad evolution can be written as a gradient flow in the space of density operators acting on a Hilbert space of dimension . We give explicit expressions for the (matrix-valued) eigenvectors and eigenvalues of the Lindblad evolution using this formalism. We argue that in many cases the interpretation of the evolution is simplified by passing from the complex -dimensional space of density operators to the real -dimensional space of Bloch vectors. When jump operators are non-Hermitian the evolution is not in general gradient flow, but we show that it nevertheless resembles gradient flow in two particular ways. Importantly, the steady states of Lindbladian evolution are still determined by the potential in all cases.}, archive = {J_PRA}, author = {Greg Kaplanek and Alexander Maloney and Jason Pollack and Dylan VanAllen}, doi = {10.1103/fcjk-qbwh}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042220}, shortjournal = {Phys. Rev. A}, title = {Lindblad evolution as gradient flow}, volume = {112}, year = {2025}, }
• (2025). Hidden negative differential thermal conductance. PRA, 112(4), 042219. (www)

  @article{ , abstract = {Negative differential thermal conductance (NDTC), a hallmark of nonlinear quantum thermal transport, plays a critical role in the design of quantum thermal devices, such as thermal diodes and transistors. The Lindblad dynamics predicts that the heat current through two coupled atoms increases with the increasing temperature difference of two bosonic reservoirs. However, in this paper, we uncover the suppressive effect on the heat current in this nonequilibrium system using the Bloch-Redfield master equations, which indicate the emergence of NDTC. Our findings underscore the crucial role of beyond-Lindblad dynamics in accurately capturing nonlinear features in quantum thermodynamic systems.}, archive = {J_PRA}, author = {Zi-chen Zhang and Zheng Liu and Chang-shui Yu}, doi = {10.1103/jybm-5vs7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042219}, shortjournal = {Phys. Rev. A}, title = {Hidden negative differential thermal conductance}, volume = {112}, year = {2025}, }
• (2025). Relativistic collapse model with quantized time variables. PRA, 112(4), 042218. (www)

  @article{ , abstract = {A relativistic collapse model for distinguishable particles is presented. Position and time, for each particle, are the fundamental operators of the theory. The Schrödinger equation is of the continuous spontaneous localization form, with a Hermitian Hamiltonian and an anti-Hermitian, white-noise dependent, Hamiltonian. It generates state vector evolution parametrized by an “evolution parameter.” It is shown how this can be interpreted as an evolving state in spacetime with collapses satisfying Born rule probabilities, and how certain choices of collapse generating operators lead to states of definite mass and definite configuration in spacetime. The model is Poincaré covariant and conserves energy in expectation.}, archive = {J_PRA}, author = {Daniel J. Bedingham and Philip Pearle}, doi = {10.1103/j4lc-s4pw}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042218}, shortjournal = {Phys. Rev. A}, title = {Relativistic collapse model with quantized time variables}, volume = {112}, year = {2025}, }
• (2025). Exploring dynamical quantum phase transitions from pure states to mixed states through extended su-schrieffer-heeger models. PRA, 112(4), 042217. (www)

  @article{ , abstract = {We investigate dynamical quantum phase transitions (DQPTs) in both pure and mixed states within the extended Su-Schrieffer-Heeger (SSH) model framework, focusing on the SSH-3 and SSH-4 models, which differ in symmetry properties. The SSH-3 model, characterized by a chiral-like point symmetry rather than true chiral symmetry, supports robust localized edge states tied to its topological nature. Our results show that for pure states, DQPTs occur after quenches crossing the topological transition, even when the energy band gap remains open. For mixed states, DQPT behavior aligns with pure states at low temperatures but undergoes significant changes at higher temperatures, including the emergence of multiple critical times. In contrast, the SSH-4 model, which possesses chiral symmetry, features four distinct energy-spectrum configurations. We find that pure-state DQPTs arise only when the quench starts from the initial state, chosen from a band that becomes gapless with another band at a certain critical point, and crosses the critical point. At finite temperature, mixed-state DQPTs persist at low temperatures only if the corresponding pure-state quench induces DQPTs, but they disappear at elevated temperatures. These findings elucidate the interplay between symmetry, band structures, and temperature in governing DQPTs within generalized SSH models.}, archive = {J_PRA}, author = {Kaiyuan Cao and Tianren Zhang and Xiang-Ping Jiang and Jian Wang}, doi = {10.1103/5289-8kz5}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042217}, shortjournal = {Phys. Rev. A}, title = {Exploring dynamical quantum phase transitions from pure states to mixed states through extended su-schrieffer-heeger models}, volume = {112}, year = {2025}, }
• (2025). Limitation of maximally entangled probes for single-shot distinguishability of unitaries. PRA, 112(4), 042215. (www)

  @article{ , abstract = {There have been many instances where the maximally entangled state as a probe acts better than the product and the nonmaximally entangled states in the task of distinguishing quantum channels. We provide a proof that for the single-shot discrimination of two unitary channels, entangled and product states are operationally equivalent. However, we identify pairs of unitaries that are perfectly distinguishable using a nonmaximally entangled state, but not with a maximally entangled one. This contrast becomes more pronounced when the number of unitaries exceeds two. In every dimension ⩾ 3 , we show that there exists a class of unitaries that is indistinguishable under maximally entangled probes, yet perfectly distinguishable using product or nonmaximally entangled inputs. Another interesting set of unitaries in every dimension ⩾ 3 has been presented where only a nonmaximally entangled state acts as a successful probe, while product states and maximally entangled states cannot.}, archive = {J_PRA}, author = {Satyaki Manna and Anandamay Das Bhowmik and Debashis Saha}, doi = {10.1103/bsxv-q9x7}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042215}, shortjournal = {Phys. Rev. A}, title = {Limitation of maximally entangled probes for single-shot distinguishability of unitaries}, volume = {112}, year = {2025}, }
• (2025). Dressed-state-mediated synchronization in coupled quantum oscillators. PRA, 112(4), 042214. (www)

  @article{ , abstract = {We investigate quantum synchronization in coupled self-sustained oscillators interacting via bosonic exchange. Using a phase-distribution-based synchronization measure, we identify bistable phase locking between 0 and π and uncover an expanded Arnold-tongue structure under finite detuning, indicative of enhanced quantum phase locking. Power spectral analysis reveals dual-frequency locking associated with dressed-state formation, a uniquely quantum effect. This spectral splitting persists even without detuning and increases with coupling strength, signaling coherent hybridization of oscillator modes. A comparison with a classical approximation highlights key differences, including the absence of spectral doublets in the classical regime. Finally, we show that increasing nonlinear damping induces a sharp transition in the preferred phase difference and leads to decoherence through spectral peak broadening, underscoring the critical role of dissipation in shaping quantum synchronization dynamics.}, archive = {J_PRA}, author = {B. Vigneshwar and V. K. Chandrasekar and D. V. Senthilkumar}, doi = {10.1103/k5ry-bj1g}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042214}, shortjournal = {Phys. Rev. A}, title = {Dressed-state-mediated synchronization in coupled quantum oscillators}, volume = {112}, year = {2025}, }
• (2025). Higher-order exceptional lines in a non-hermitian jaynes-cummings triangle. PRA, 112(4), 042213. (www)

  @article{ , abstract = {Higher-order exceptional points (EPs) in non-Hermitian systems showcase diverse physical phenomena but require more parameter space freedom or symmetries. We report the observation of a third-order exceptional surface and line in a Jaynes-Cummings triangle. A fine-tuning artificial magnetic field enriches the emergence of the third-order exceptional lines (ELs), which require only three tuning parameters when protected by parity-time (PT) symmetry. Third-order ELs maintain robust enhanced sensitivity through a cube-root response mechanism, displaying a greater sensitivity than second-order EPs. We develop a nontrivial fidelity metric based on the biorthogonal associated-state approach that reliably detects EPs while eliminating the unphysical fidelity values in previous approaches. Furthermore, our method captures quench dynamics across EPs, revealing distinct behavior in both PT-symmetric and PT-broken regimes. Our work establishes a platform for studying higher-order geometry in light-matter interactions using circuit QED.}, archive = {J_PRA}, author = {Hao Chen and Xiao Qin and Jian-Jun Dong and Yu-Yu Zhang and Zi-Xiang Hu}, doi = {10.1103/t49b-s4fs}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042213}, shortjournal = {Phys. Rev. A}, title = {Higher-order exceptional lines in a non-hermitian jaynes-cummings triangle}, volume = {112}, year = {2025}, }
• (2025). Non-markovian ensemble propagation. PRA, 112(4), 042212. (www)

  @article{ , abstract = {Open quantum systems are ubiquitous in nature and central to quantum technologies. A common description of their dynamics is given by the celebrated Lindblad master equation, which can be generalized to the non-Markovian scenario. In this work, we introduce the non-Markovian ensemble propagation (NMEP) method, which extends the Monte Carlo wave-function (MCWF) method to the non-Markovian case in a simple and general manner. We demonstrate its accuracy and effectiveness in a selection of examples, and compare the results with either analytic expressions or direct numerical integration of the master equation.}, archive = {J_PRA}, author = {Miralem Sinanović and Alessandro Ciani and Shai Machnes and Frank K. Wilhelm}, doi = {10.1103/zh52-bc4k}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042212}, shortjournal = {Phys. Rev. A}, title = {Non-markovian ensemble propagation}, volume = {112}, year = {2025}, }
• (2025). Mutually unbiased bases as a commuting polynomial optimization problem. PRA, 112(4), 042211. (www)

  @article{ , abstract = {We consider the problem of mutually unbiased bases as a polynomial optimization problem over the reals. After greatly reducing it by using known symmetries, we then explore it using two methods, combining a number of optimization techniques. The first of these is a search for bases using Lagrange multipliers that converges rapidly in case of mutually unbiased bases' (MUB) existence, while the second combines a hierarchy of semidefinite programs with branch-and-bound techniques to perform a global search. We demonstrate that such an algorithm would eventually solve the open question in dimension six with finite memory, although it still remains intractable. We then investigate the idea that, to show the inexistence of bases, it often suffices to search for orthonormal vector sets of smaller sizes, rather than full bases (an idea sometimes referred to as “constellations” in the literature). We use our two methods to conjecture the minimum set sizes required to show infeasibility, as well as proving it via global search for dimension three . The fact that such subproblems seem to also be infeasible heavily reduces the number of variables, by 66% in the case of the open problem, potentially providing a significant speedup for other algorithms and bringing them into the realm of tractability.}, archive = {J_PRA}, author = {Luke Mortimer}, doi = {10.1103/m8qd-x1js}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042211}, shortjournal = {Phys. Rev. A}, title = {Mutually unbiased bases as a commuting polynomial optimization problem}, volume = {112}, year = {2025}, }
• (2025). Expedited thermalization dynamics in incommensurate systems. PRA, 112(4), 042210. (www)

  @article{ , abstract = {We study the thermalization dynamics of a quantum system embedded in an incommensurate potential and coupled to a Markovian thermal reservoir. The dephasing induced by the bath drives the system toward an infinite-temperature steady state, erasing all initial information-including signatures of localization. We find that initially localized states can relax to the homogeneous steady state faster than delocalized states. Moreover, low-temperature initial states thermalize to infinite temperature more rapidly than high-temperature states—a phenomenon reminiscent of the Mpemba effect, in which hotter liquids freeze faster than colder ones. The slowest relaxation mode in the Liouvillian spectrum plays a critical role in the expedited thermalization for localized or cold initial states. Our results reveal that the combination of disordered structure and environmental dissipation may lead to nontrivial thermalization behavior, which advances both the conceptual framework of the Mpemba effect and the theoretical understanding of nonequilibrium processes in dissipative disordered systems.}, archive = {J_PRA}, author = {Mingdi Xu and Zijun Wei and Xiang-Ping Jiang and Lei Pan}, doi = {10.1103/9qkm-35y1}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042210}, shortjournal = {Phys. Rev. A}, title = {Expedited thermalization dynamics in incommensurate systems}, volume = {112}, year = {2025}, }
• (2025). Thermalization of finite complexity and its application to heat-bath algorithmic cooling. PRA, 112(4), 042209. (www)

  @article{ , abstract = {We introduce a class of thermal operations based on the collision model, where the system sequentially interacts with uncorrelated bath molecules via energy-preserving unitaries. To ensure finite complexity, each molecule is constrained to be no larger than the system. We identify a necessary condition for cooling below the bath temperature via a single collision: The system must initially lack a well-defined effective temperature, even a negative one. By constructing an iterative protocol, we demonstrate that sub-bath cooling is achievable without a machine under these restricted thermal operations. Moreover, introducing a qubit machine further enhances both the cooling limit and energy efficiency. These findings contribute to the broader study of cooling with finite resources.}, archive = {J_PRA}, author = {Xueyuan Hu and Valerio Scarani}, doi = {10.1103/r3jn-1z54}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042209}, shortjournal = {Phys. Rev. A}, title = {Thermalization of finite complexity and its application to heat-bath algorithmic cooling}, volume = {112}, year = {2025}, }
• (2025). Larmor time of a wave packet tunneling through a barrier with an infinitesimal magnetic field. PRA, 112(4), 042208. (www)

  @article{ , abstract = {Recently, experimental measurements of the Larmor time of incident wave packets have been conducted, once again drawing attention to such a time. These experiments measured the tunneling time of Bose-condensed Rb 87 atoms, with theoretical analyses employing free particles. In this paper, we investigate the tunneling process of wave packets, which, unlike free particles with a definite incident energy, have a continuous distribution of energies. We show how the Larmor time τ z ( y ) for a wave packet tunneling through a barrier depends on the barrier width d , the barrier's characteristic wave vector k 0 , the incident wave packet's central wave vector k c , and its width σ in wave-number space. When the barrier width d is small, we find that τ z ( y ) varies monotonically. For wide barriers ( d > 2.0 π ), we find an anomaly where wave packets with lower incident energy or higher barriers have shorter tunneling times, which is consistent with recent experimental results. Additionally, for narrow wave packets in wave-number space ( σ < γ ), where γ is the width of the fitted Fano peak, the results are generally consistent with those for plane waves. However, as the wave packet widens in wave-number space, the maximum points of τ z ( y ) will undergo a nonlinear decrease and σ significantly affects the maximum Larmor time.}, archive = {J_PRA}, author = {Duo Wang and Libin Fu}, doi = {10.1103/bm9q-r6j9}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042208}, shortjournal = {Phys. Rev. A}, title = {Larmor time of a wave packet tunneling through a barrier with an infinitesimal magnetic field}, volume = {112}, year = {2025}, }
• (2025). Thermodynamic constraints on information transmission in quantum ensembles. PRA, 112(4), 042207. (www)

  @article{ , abstract = {The processing of quantum information is limited by fundamental physical constraints on how information can be encoded, transmitted, and extracted. In particular, the nonorthogonality of quantum states limits their distinguishability, and thermodynamic constraints, including the energetic cost of state preparation and quantum operations, further restrict the viability of realistic information protocols. This work explores the impact of such constraints on the preparation, evolution, and readout of quantum information. We demonstrate that preparing the system for encoding and measurement affects the distinguishability and purity of the resulting ensemble of states. Furthermore, we analyze a noisy communication channel and propose an optimal protocol for encoding and decoding the transmitted information. For this realistic protocol, we show that the maximum probability of successfully retrieving the information is equal to the maximum correlation that can be achieved between the system and the register. The protocol uses only Gibbs states as free resources, ensuring minimal thermodynamic cost. Based on this, we provide a thermodynamic interpretation of the Holevo information, which quantifies the capacity of the transmitted information and establishes a fundamental limit on its retrieval in thermodynamically constrained scenarios.}, archive = {J_PRA}, author = {André T. Cesário and Tiago Debarba}, doi = {10.1103/vjvj-sz12}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042207}, shortjournal = {Phys. Rev. A}, title = {Thermodynamic constraints on information transmission in quantum ensembles}, volume = {112}, year = {2025}, }
• (2025). Distinguishing quantum causal scenarios with indistinguishable classical analogs: The significance of intermediate latents. PRA, 112(4), 042206. (www)

  @article{ , abstract = {The use of graphical models to represent causal hypotheses has enabled revolutionary progress in the study of the foundations of quantum theory. Here we consider directed acyclic graphs each of which contains both nodes representing observed variables as well as nodes representing latent or hidden variables. When comparing distinct causal structures, a natural question to ask is if they can explain distinct sets of observable distributions or not. Statisticians have developed a great variety of tools for resolving such questions under the assumption that latent nodes are interpreted classically. Here we highlight how the change to a quantum interpretation of the latent nodes induces distinctions between causal scenarios that would be classically indistinguishable. We especially concentrate on quantum scenarios containing latent nodes with at least one latent parent, a.k.a. possessing intermediate latents . This initial survey demonstrates that many such quantum processes can be operationally distinguished by considerations related to monogamy of nonlocality, especially when computationally aided by a hierarchy of semidefinite relaxations which we tailor for the study of such scenarios. We conclude by clarifying the challenges that prevent the generalization of this work, calling attention to open problems regarding observational (in)equivalence of quantum causal structures with intermediate latents.}, archive = {J_PRA}, author = {Daniel Centeno and Elie Wolfe}, doi = {10.1103/f7dh-5xht}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042206}, shortjournal = {Phys. Rev. A}, title = {Distinguishing quantum causal scenarios with indistinguishable classical analogs: The significance of intermediate latents}, volume = {112}, year = {2025}, }
• (2025). Wireless energy transfer in a non-hermitian quantum battery. PRA, 112(4), 042205. (www)

  @article{ , abstract = {Energy extraction is one of the fundamental challenges in realizing quantum batteries (QBs). Here we propose a wireless transfer scheme with parity-time symmetry to efficiently extract the energy stored in non-Hermitian QBs to consumption hubs. For linear cases, the transfer energy oscillates periodically in the unbroken symmetry region and grows hyperbolically in the broken region. For nonlinear cases, the transfer energy eventually reaches and remains steady-state values arising from the feedback mechanism of the nonlinear saturable gain. The non-Hermitian QBs with gains can persistently absorb energy and store it in batteries while transfering it to consumption hubs, thus exhibiting more considerable robustness in the large detuning regime and significant enhancement in the weak coupling regime than those in partial deep-strong coupling regime. Furthermore, we also introduce a classical simulator and demonstrate some counterintuitive advantages of the non-Hermitian QBs. Our work overcomes energy bottlenecks of wireless transfer schemes in QBs and may provide inspirations for practical applications of QBs.}, archive = {J_PRA}, author = {Fang-Mei Yang and Fu-Quan Dou}, doi = {10.1103/8xsm-5mb6}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042205}, shortjournal = {Phys. Rev. A}, title = {Wireless energy transfer in a non-hermitian quantum battery}, volume = {112}, year = {2025}, }
• (2025). Dynamics of open quantum systems with initial system-environment correlations via stochastic unravelings. PRA, 112(4), 042204. (www)

  @article{ , abstract = {In standard treatments of open quantum systems, the reduced dynamics is described starting from the assumption that the system and the environment are initially uncorrelated. This assumption, however, is not always guaranteed in realistic scenarios and several theoretical approaches to characterize initially correlated dynamics have been introduced. For the uncorrelated scenario, stochastic unravelings are a powerful tool to simulate the dynamics. So far they have not been used in the most general case in which correlations are initially present since they cannot be applied to nonpositive operators or noncompletely positive maps. In our work, we employ the bath positive or one-sided positive decomposition (OPD) formalism as a starting point to generalize stochastic unraveling in the presence of initial correlations. Noticeably, our approach does not depend on the particular unraveling technique, but holds for both piecewise deterministic and diffusive unravelings. This generalization allows not only for more powerful simulations for the reduced dynamics, but also for a deeper theoretical understanding of open system dynamics.}, archive = {J_PRA}, author = {Federico Settimo and Kimmo Luoma and Dariusz Chruściński and Andrea Smirne and Bassano Vacchini and Jyrki Piilo}, doi = {10.1103/q353-4232}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042204}, shortjournal = {Phys. Rev. A}, title = {Dynamics of open quantum systems with initial system-environment correlations via stochastic unravelings}, volume = {112}, year = {2025}, }
• (2025). Theory of finite-size scaling in dynamical quantum phase transitions. PRA, 112(4), 042203. (www)

  @article{ , abstract = {Dynamical quantum phase transitions (DQPTs) appear as nonanalyticities during the coherent evolution of closed systems. However, understanding the scaling behaviors in realistic finite-size systems is intricate and requires a framework beyond thermalized equilibrium analogies. We propose a general dynamical quantum finite-size scaling theory and demonstrate its validity using numerical and analytical approaches in a spin chain. Combining fidelity and renormalization group, we identify the scaling behavior of the transverse magnetization that simultaneously exhibits quantum coherence and statistical properties. In addition, we adapt generalized correlation functions in quantum chemistry protocols to visualize the effective light cone of quantum mutual information, demonstrating the importance of the coherence propagation to DQPTs. Our work provides a phenomenological insight and a quantitative analysis to the underlying microscopic entanglement evolution, offering an alternative interpretation of DQPTs and advancing the understanding of many-body physics.}, archive = {J_PRA}, author = {Gui-Zhong Yao and Liang-You Peng and Qihuang Gong}, doi = {10.1103/9zwv-s4bn}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042203}, shortjournal = {Phys. Rev. A}, title = {Theory of finite-size scaling in dynamical quantum phase transitions}, volume = {112}, year = {2025}, }
• (2025). Unraveling the switching dynamics in a quantum double-well potential. PRA, 112(4), 042202. (www)

  @article{ , abstract = {The spontaneous switching of a quantum particle between the wells of a double-well potential is a phenomenon of general interest to physics and chemistry. It was broadly believed that the switching rate decreases steadily as a function of the size of the energy barrier. This view was challenged by a recent experiment on a driven superconducting Kerr nonlinear oscillator (often called the Kerr-cat qubit or the Kerr parametric oscillator ), whose energy barrier can be continuously increased by ramping up the drive. Remarkably, as the drive amplitude increases, the switching rate exhibits a steplike decrease termed the “staircase.” The view challenged by the experimental staircase demands a deep review of our understanding of the role of quantum effects in double wells. In this work, we use a Lindbladian model of dissipation to derive a semianalytical formula for the switching rate, resolving a continuous transition between tunneling-dominated dynamics and dissipation-dominated dynamics. These two dynamics are observed respectively in the flat part and the steep part of each step in the staircase. Our formula exposes two distinct dissipative processes that limit tunneling: the dephasing of interwell superpositions freezes tunneling via the quantum Zeno effect, and the decay from one excited state to another limits the time during which tunneling can be attempted. This physical understanding allows us to pinpoint the critical drive amplitude that separates the flat and steep part of each step using an equation involving the rates of the two dissipative processes and the tunnel splitting. In addition, analyzing the transition matrix elements in the formula shows that in the regime of a few ( ≲ 10 ) states in the well and under moderate to low temperatures, highly excited states are populated predominantly via cascaded and direct thermal heating rather than quantum heating. At very low temperatures, we find that the perturbation induced by the non-Hermitian Hamiltonian part of the Lindbladian model becomes increasingly important and facilitates a form of quantum heating that has not been identified before. We numerically map the activation mechanism as a function of drive amplitude, damping rate, and temperature. Our theory deepens the understanding of switching dynamics between metastable quantum states, highlights the importance of a general interplay between tunneling and dissipation, and identifies a novel quantum regime in activated transitions.}, archive = {J_PRA}, author = {Qile Su and Rodrigo G. Cortiñas and Jayameenakshi Venkatraman and Shruti Puri}, doi = {10.1103/dqv5-bvd4}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042202}, shortjournal = {Phys. Rev. A}, title = {Unraveling the switching dynamics in a quantum double-well potential}, volume = {112}, year = {2025}, }
• (2025). Security of device-independent quantum key distribution via monogamy relations from multipartite information causality. PRA, 112(4), 042201. (www)

  @article{ , abstract = {The information causality principle ( IC ) was originally proposed as a promising means to understand the extent of quantum nonlocality without invoking the full mathematical formalism of quantum theory. Beyond the foundational significance, the problem of bounding nonlocal correlations by reasonable physical principles has meaningful practical consequences, particularly for device-independent (DI) cryptographic security. In this work, we advance in this direction, demonstrating that the IC is enough to ensure DI security on quantum key distribution (QKD) protocols. Security is proven for a range of theoretically quantum-attainable parameters against individual attacks by a potentially postquantum eavesdropper. This result follows as a consequence of a strong form of monogamy of Bell's inequality violations, which we prove to be implied by the recently proposed multipartite formulation for IC . Additionally, we demonstrate that the original bipartite formulation of IC fails to imply monogamy relations, and hence, ensure security of DIQKD, thus stressing the necessity of the multipartite framework.}, archive = {J_PRA}, author = {Lucas Pollyceno and Anubhav Chaturvedi and Chithra Raj and Pedro R. Dieguez and Marcin Pawłowski}, doi = {10.1103/jnng-m87v}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {042201}, shortjournal = {Phys. Rev. A}, title = {Security of device-independent quantum key distribution via monogamy relations from multipartite information causality}, volume = {112}, year = {2025}, }
• (2025). Perspective: Practical atom-based quantum sensors. PRA, 112(4), 040102. (www)

  @article{ , abstract = {Atomic vapors, manipulated and probed by light and other electromagnetic fields, constitute versatile and powerful quantum systems for sensing applications. Atoms are identical, isolatable, interfaceable, and intelligible. These features, coupled with the relative simplicity with which quantum properties can be exploited in state preparation and detection using modern laser and electro-optic tools, make atoms very attractive for sensing applications. This Perspective discusses the potential and process for realizing practical quantum sensors using atoms.}, archive = {J_PRA}, author = {Justin M. Brown and Thad G. Walker}, doi = {10.1103/q6d1-594v}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {040102}, shortjournal = {Phys. Rev. A}, title = {Perspective: Practical atom-based quantum sensors}, volume = {112}, year = {2025}, }
• (2025). Towards the time-resolved spectroscopy of photoinduced electron dynamics in nuclear transitions. PRA, 112(4), 040101. (www)

  @article{ , abstract = {The interaction between nuclear and electronic states plays a fundamental role in many nuclear processes. While such nucleus-electron couplings have been extensively studied using nuclear physics methodologies, recent advancements in light sources have introduced novel schemes for nuclear photoexcitation. This breakthrough enables a new class of experiments that could revolutionize our understanding and control of nuclear states. In this work, we review the research on electron processes associated with nuclear transitions, and the light sources that have been used for nuclear photoexcitation. Furthermore, we explore the potential for establishing time-resolved spectroscopy of electron-nucleus couplings, drawing connections to state-of-the-art light sources and time-resolved studies in atomic and molecular physics. By addressing both challenges and opportunities, we aim to provide a roadmap for future research in this interdisciplinary field. This emerging platform, linking nuclear science, atomic physics, and photonics, holds great promise for driving groundbreaking scientific and technological advancements.}, archive = {J_PRA}, author = {Marc Seitz and Francesca Calegari and Peter G. Thirolf and Andrea Trabattoni}, doi = {10.1103/31qf-pfvj}, journal = {Physical Review a}, month = {10}, number = {4}, pages = {040101}, shortjournal = {Phys. Rev. A}, title = {Towards the time-resolved spectroscopy of photoinduced electron dynamics in nuclear transitions}, volume = {112}, year = {2025}, }
• (2025). Robust exceptional point chains and chirality switch in a vast optical parameter space. PRA, 112(3), L031501. (www)

  @article{ , abstract = {While the special properties of exceptional points (EPs) may improve application relevant features such as hypersensing, often their realization requires a precise fine-tuning of parameters. Here we report the robust formation of EP chains in coupled optical microcavities over intercavity distances on the order of the cavity size. We find that coupling, or more generally, the availability of an outer (coupling) channel, is sufficient to induce EPs in the parameter space spanned by the refractive index along with . This occurs even at of several wavelengths, yielding a network of EPs in parameter space with a periodicity of the order of the wavelength in the direction. Upon the increase of , we observe a sharp transition in the sign of the chirality measured in one of the cavities that further structures the system properties. While the details of the Riemannian surfaces associated with the formation of exceptional points are mode dependent and allow for a variety of single-cavity chiralities, we find the underlying mechanism to be universal, robust, applicable to other and more general coupled systems, and promising for potential applications such as optical measurements of pressure, voltages, or distances.}, archive = {J_PRA}, author = {Chang-Hwan Yi and Jung-Wan Ryu and Tom Simon Rodemund and Martina Hentschel}, doi = {10.1103/6dgz-hzlm}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L031501}, shortjournal = {Phys. Rev. A}, title = {Robust exceptional point chains and chirality switch in a vast optical parameter space}, volume = {112}, year = {2025}, }
• (2025). Multimode feedback cooling of the collective modes of a bose-einstein condensate. PRA, 112(3), L031302. (www)

  @article{ , abstract = {We experimentally demonstrate cavity-free feedback cooling of the three lowest-lying collective modes of a Bose-Einstein condensate in a prolate harmonic trap. Using shadowgraph imaging as an in situ probe of the atomic density, we measure the time-dependent centers of mass and widths of the condensate in two dimensions and use these measurements to damp oscillations in the two visible dipole modes and the low-frequency quadrupole mode. By inducing oscillations in the condensate, we show that we can efficiently damp the dipole modes to a final mean phonon occupancy per atom of .}, archive = {J_PRA}, author = {Ryan J. Thomas and Jordan A. McMahon and Zain Mehdi and Stuart S. Szigeti and Simon A. Haine and Samuel Legge and John D. Close and Joseph J. Hope}, doi = {10.1103/jzw6-dn5h}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L031302}, shortjournal = {Phys. Rev. A}, title = {Multimode feedback cooling of the collective modes of a bose-einstein condensate}, volume = {112}, year = {2025}, }
• (2025). Observation of self-oscillating supersonic flow across an acoustic horizon in two dimensions. PRA, 112(3), L031301. (www)

  @article{ , abstract = {We report observation of self-oscillating supersonic flows in a two-dimensional atomic superfluid. By imposing a local particle sink with strong loss, we induce a convergent radial flow with a spatially bounded supersonic region, forming an acoustic analog of a black-hole horizon and an inner horizon around the sink. The observed superflow appears to be modulated by quasiperiodic bursts of superluminal signals. We measure their frequencies and find agreement with numerical simulations of the frequencies of ring soliton oscillations within the black-hole horizon. The solitons seen in the simulations are emitted from the region between the two horizons in a process that we attribute to the Landau instability. The presented experiment demonstrates a new method for creating supersonic flows in atomic superfluids, which may find applications in quantum simulations of curved spacetime, supersonic turbulence, and self-oscillating dynamics in dissipative many-body systems.}, archive = {J_PRA}, author = {Hikaru Tamura and Sergei Khlebnikov and Cheng-An Chen and Chen-Lung Hung}, doi = {10.1103/t2sn-kx99}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L031301}, shortjournal = {Phys. Rev. A}, title = {Observation of self-oscillating supersonic flow across an acoustic horizon in two dimensions}, volume = {112}, year = {2025}, }
• (2025). Modeling the dissociative sequential triple ionization of nitrogen molecules by ultrashort intense infrared laser pulses. PRA, 112(3), L031101. (www)

  @article{ , abstract = {A density matrix (DM) approach has been successfully developed for modeling the dissociative sequential double ionization of molecules driven by ultrashort intense infrared laser pulses. Here, we extend the DM method to theoretically study the dissociative sequential triple ionization of nitrogen molecules. We first calculate potential-energy curves of the states and the transition dipole moments between these states using the complete active state self-consistent field method. Using the DM method, we calculate the kinetic-energy release (KER) spectra for the dissociating through the channel. We find that our simulated KER spectra agree well with the experimental data by Wu et al. [ Phys. Chem. Chem. Phys. 13 , 18398 (2011) ]. This Letter provides a simple model for theoretically investigating the molecular dissociative sequential triple ionization.}, archive = {J_PRA}, author = {Yan-Wen Jia and Hui-Hui Wang and C. H. Yuen and C. D. Lin and Song-Feng Zhao}, doi = {10.1103/jfqj-c19k}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L031101}, shortjournal = {Phys. Rev. A}, title = {Modeling the dissociative sequential triple ionization of nitrogen molecules by ultrashort intense infrared laser pulses}, volume = {112}, year = {2025}, }
• (2025). Hyperfine structure and k doubling in the RaOCH3 molecule. PRA, 112(3), L030802. (www)

  @article{ , abstract = {The molecule is one of the most sensitive systems for electron electric dipole moment ( ) searches. Its hyperfine and structure in the external electric field is of key importance for preparing and interpreting the experiment. We proposed the method for calculation of the symmetric top molecules and applied it for . Hyperfine structure, doubling, and sensitivity of the molecule to in the external electric field were calculated.}, archive = {J_PRA}, author = {Alexander Petrov}, doi = {10.1103/59xq-73bs}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030802}, shortjournal = {Phys. Rev. A}, title = {Hyperfine structure and k doubling in the RaOCH3 molecule}, volume = {112}, year = {2025}, }
• (2025). Precision comagnetometry for T-violation searches in crystals. PRA, 112(3), L030801. (www)

  @article{ , abstract = {Searches for time-reversal symmetry ( ) violations using spin sensors are susceptible to spurious frequency shifts and noise from magnetic fields, which can mask signals originating from beyond-standard-model new physics. Therefore, a comagnetometer—an auxiliary sensor that allows mundane magnetic-field effects to be differentiated from new physics—is an essential feature of many precision measurements. We characterize an intrinsic comagnetometer that is available in crystals, which can be used to suppress spurious magnetic-field effects through comparing sets of ions related by spatial reflection symmetry. We find that the new-physics measurement channel can be effectively shielded to better than , without the need for active or passive magnetic shields. Our measurements demonstrate precise and accurate control over magnetic systematic errors, laying the groundwork for improved searches of violation using solid-state systems.}, archive = {J_PRA}, author = {Bassam Nima and Mingyu Fan and Aleksandar Radak and Andrew M. Jayich and Amar Vutha}, doi = {10.1103/jykv-rsd1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030801}, shortjournal = {Phys. Rev. A}, title = {Precision comagnetometry for T-violation searches in crystals}, volume = {112}, year = {2025}, }
• (2025). Quantum sensing of even- versus odd-body interactions. PRA, 112(3), L030603. (www)

  @article{ , abstract = {We analyze the scaling of quantum Fisher information with the number of system particles in the limit of large number of particles, as a function of the number of parties interacting with each other, for encoding Hamiltonians having -body interactions, where is arbitrary. We find that estimation of coupling strength of such arbitrary-body encoding Hamiltonians provides a super-Heisenberg scaling that increases monotonically with an increase in the number of interacting particles, in the limit of large number of system particles. Moreover, we ask if genuine multiparty entanglement is indispensable in attaining the best metrological precision if we employ nonlocal terms in the Hamiltonian. We identify a dichotomy in the answer. Specifically, we find that Hamiltonians having odd-body interactions necessarily require genuine multipartite entanglement in probes to attain the best metrological precision, but the situation is opposite in the case of Hamiltonians with even-body interactions. The optimal probes corresponding to Hamiltonians that contain even-body interaction terms may be entangled, but certainly not so in all bipartitions, and particularly it is possible to attain optimal precision using asymmetric probes. Asymmetry, which therefore is a resource in this scenario rather than genuine multiparty entanglement, refers to the disparity between states of local parts of the global system. Thereby we find a complementarity in the requirement of asymmetry and genuine entanglement in optimal probes for estimating strength of odd- and even-body interactions respectively. Additionally, we provide an upper bound on the number of parties up to which one can always obtain an asymmetric product state that gives the best metrological precision for even-body interactions. En route, we find the quantum Fisher information in closed form for two- and three-body interactions for arbitrary number of parties. Additionally, we analyze the finite-size scaling of the QFI and examine the impact of local dephasing noise during the encoding process. We also provide an analysis of the case when the Hamiltonian contains local fields and up to -body interaction terms, where the strength of interaction gradually decreases with an increase in the number of parties interacting with each other. Interestingly, we find a similar dichotomy in the nature of the optimal probe in this case as well, i.e., for encoding Hamiltonians with up to even- and odd-body interactions. Further, we identify conditions on the local component of the Hamiltonian for which this dichotomy is still shown to exist for two- and three-body encoding Hamiltonians with arbitrary local dimensions.}, archive = {J_PRA}, author = {Aparajita Bhattacharyya and Debarupa Saha and Ujjwal Sen}, doi = {10.1103/3f8n-b1kp}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030603}, shortjournal = {Phys. Rev. A}, title = {Quantum sensing of even- versus odd-body interactions}, volume = {112}, year = {2025}, }
• (2025). Toward error-free quantum target finding: When sequential detection meets high-dimensional entanglement. PRA, 112(3), L030602. (www)

  @article{ , abstract = {We present a method for target finding in LIDAR applications using high-dimensional Bell states. Combined with a sequential decision rule, this scheme asymptotically achieves zero error probability with finite average energy expenditure. This result stems from the synergy of high-dimensional entanglement suppressing false positives and the sequential decision rule optimizing energy usage. This analysis provides a theoretical foundation to further explore quantum sensing protocols that may significantly outperform classical methods in noisy environments.}, archive = {J_PRA}, author = {Armanpreet Pannu and Amr S. Helmy and Hesham El Gamal}, doi = {10.1103/jqx6-5hcc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030602}, shortjournal = {Phys. Rev. A}, title = {Toward error-free quantum target finding: When sequential detection meets high-dimensional entanglement}, volume = {112}, year = {2025}, }
• (2025). Generation of entanglement and nonstationary states via competing coherent and incoherent bosonic hopping. PRA, 112(3), L030601. (www)

  @article{ , abstract = {Incoherent stochastic processes added to unitary dynamics are typically deemed detrimental since they are expected to diminish quantum features such as superposition and entanglement. Instead of exhibiting energy-conserving persistent coherent motion, the dynamics of such open systems feature, in most cases, a steady state, which is approached in the long-time limit from all initial conditions. This can, in fact, be advantageous as it offers a mechanism for the creation of robust quantum correlations on demand without the need for fine-tuning. Here, we show this for a system consisting of two coherently coupled bosonic modes, which is a paradigmatic scenario for the realization of quantum resources such as squeezed entangled states. Rather counterintuitively, the mere addition of incoherent hopping, which results in a statistical coupling between the bosonic modes, leads to steady states with robust quantum entanglement and enables the emergence of persistent coherent nonstationary behavior.}, archive = {J_PRA}, author = {Parvinder Solanki and Albert Cabot and Matteo Brunelli and Federico Carollo and Christoph Bruder and Igor Lesanovsky}, doi = {10.1103/vnt1-m777}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030601}, shortjournal = {Phys. Rev. A}, title = {Generation of entanglement and nonstationary states via competing coherent and incoherent bosonic hopping}, volume = {112}, year = {2025}, }
• (2025). Local models and bell inequalities for the minimal triangle network. PRA, 112(3), L030403. (www)

  @article{ , abstract = {Nonlocal correlations created in networks with multiple independent sources enable surprising phenomena in quantum information and quantum foundations. The presence of independent sources, however, makes the analysis of network nonlocality challenging, and even in the simplest nontrivial scenarios a complete characterization is lacking. In this Letter we study one of the simplest of these scenarios, namely that of distributions invariant under permutations of parties in the minimal triangle network, which features no inputs and binary outcomes. We perform an exhaustive search for triangle-local models, and from it we infer analytic expressions for the boundaries of the set of distributions that admit such models, which we conjecture to be all the tight Bell inequalities for the scenario. Armed with them and with improved outer approximations of the set, we provide insights on the existence of a classical-quantum gap in the triangle network with binary outcomes.}, archive = {J_PRA}, author = {José Mário da Silva and Alejandro Pozas-Kerstjens and Fernando Parisio}, doi = {10.1103/cg9v-wv2t}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030403}, shortjournal = {Phys. Rev. A}, title = {Local models and bell inequalities for the minimal triangle network}, volume = {112}, year = {2025}, }
• (2025). Quantum assemblage tomography. PRA, 112(3), L030402. (www)

  @article{ , abstract = {A central requirement in asymmetric quantum nonlocality protocols, such as quantum steering, is the precise reconstruction of state assemblages—statistical ensembles of quantum states correlated with remote classical signals. Existing steering works often rely on simplifying assumptions about detection efficiency and photon loss. Here we introduce a generalized loss model for assemblage tomography that uses conical optimization techniques combined with maximum-likelihood estimation. This approach allows us to accurately estimate assemblages without assuming uniform detection efficiency on the untrusted party's side. Using an evidence-based framework grounded in the Akaike information criterion, we demonstrate faithful reconstructions while balancing model complexity. We validate our results through numerical simulations and an experimental setup, showing robust performance in assemblage estimation when applied to experimentally relevant data.}, archive = {J_PRA}, author = {Luis Villegas-Aguilar and Yuanlong Wang and Alex Pepper and Travis J. Baker and Dominick J. Joch and Sven Rogge and Geoff J. Pryde and Sergei Slussarenko and Nora Tischler and Howard M. Wiseman}, doi = {10.1103/k686-kvdy}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030402}, shortjournal = {Phys. Rev. A}, title = {Quantum assemblage tomography}, volume = {112}, year = {2025}, }
• (2025). Recovering optimal precision in quantum sensing with time domain imperfections. PRA, 112(3), L030401. (www)

  @article{ , abstract = {Quantum control plays a crucial role in enhancing precision scaling for quantum sensing. However, most existing protocols require perfect control, even though real-world devices inevitably have control imperfections. Here, we consider a fundamental setting of quantum sensing with time domain imperfections, where the duration of control pulses and the interrogation time are all subject to uncertainty. Under this scenario, we investigate the task of frequency estimation in the presence of a non-Markovian environment. We design a control strategy and prove that it outperforms any control-free strategies, recovering the optimal Heisenberg limit up to a small error term that is intrinsic to this model. We further demonstrate the advantage of our control strategy via experiments on a nuclear magnetic resonance platform. Our findings confirm that the advantage of quantum control in quantum sensing persists even in the presence of imperfections.}, archive = {J_PRA}, author = {Zi-Shen Li and Xinyue Long and Xiaodong Yang and Dawei Lu and Yuxiang Yang}, doi = {10.1103/xbrk-357g}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030401}, shortjournal = {Phys. Rev. A}, title = {Recovering optimal precision in quantum sensing with time domain imperfections}, volume = {112}, year = {2025}, }
• (2025). Retrodictive approach to quantum state smoothing. PRA, 112(3), L030203. (www)

  @article{ , abstract = {Smoothing is a technique for estimating the state of an imperfectly monitored open system by combining both prior and posterior measurement information. In the quantum regime, current approaches to smoothing either give unphysical outcomes, due to the noncommutativity of the measurements at different times, or require assumptions about how the environment is measuring the system, which with current technology is unverifiable. We propose a novel definition of the smoothed quantum state based on quantum Bayesian retrodiction, which mirrors the classical retrodictive approach to smoothing. This approach always yields physical results and does not require any assumption on the environment. We show that this smoothed state has, on average, greater purity than the state reconstructed using just the prior information. Finally, we make a connection with the smoothing theory of Guevara and Wiseman in a well-studied regime, and describe from a purely quantum perspective how it conditions on the posterior information.}, archive = {J_PRA}, author = {Mingxuan Liu and Valerio Scarani and Alexia Auffèves and Kiarn T. Laverick}, doi = {10.1103/8pc3-7pg5}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030203}, shortjournal = {Phys. Rev. A}, title = {Retrodictive approach to quantum state smoothing}, volume = {112}, year = {2025}, }
• (2025). Symmetry-induced failures of tomographic locality: Constructing foil theories by twirling. PRA, 112(3), L030202. (www)

  @article{ , abstract = {Tomographic locality is a principle commonly used in the program of finding axioms that pick out quantum theory within the landscape of possible theories. The principle asserts the sufficiency of local measurements for achieving a tomographic characterization of any bipartite state. In this work, we explore the meaning of the principle of tomographic locality by developing a simple scheme for generating a wide variety of theories that violate the principle. In this scheme, one starts with a tomographically local theory—which can be classical, quantum, or postquantum—and a physical symmetry, and one restricts the processes in the theory to all and only those that are covariant with respect to the collective action of that symmetry. We refer to the resulting theories as twirled worlds . We show that failures of tomographic locality are ubiquitous in twirled worlds. From the possibility of such failures in classical twirled worlds, we argue that the failure of tomographic locality (i.e., tomographic non locality) does not imply ontological holism. Our results also demonstrate the need for researchers seeking to axiomatize quantum theory to take a stand on the question of whether there are superselection rules that have a fundamental status.}, archive = {J_PRA}, author = {Daniel Centeno and Marco Erba and Thomas D. Galley and David Schmid and John H. Selby and Robert W. Spekkens and Sina Soltani and Jacopo Surace and Alex Wilce and Yìlè Yīng}, doi = {10.1103/hpmv-15sf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030202}, shortjournal = {Phys. Rev. A}, title = {Symmetry-induced failures of tomographic locality: Constructing foil theories by twirling}, volume = {112}, year = {2025}, }
• (2025). Metastability-induced solid-state quantum batteries for powering microwave quantum electronics. PRA, 112(3), L030201. (www)

  @article{ , abstract = {Metastability is ubiquitous in diverse complex systems. In open quantum systems, metastability offers protection against dissipation and decoherence, yet its application in quantum batteries remains unexplored. We propose a solid-state open quantum battery where metastable states enable stable superextensive charging without complicated protocols and energy storage with extended lifetime. Using a realistic organic maser platform, we show the controllable manner of the work extraction from the quantum battery, which can be exploited for on-demand coherent microwave emission at room temperature. These results not only demonstrate the usefulness of metastability for developing the quantum batteries robust against energy losses, but also provide a paradigm of the practical quantum device powered up by quantum batteries.}, archive = {J_PRA}, author = {Yuanjin Wang and Hao Wu and Qing Zhao}, doi = {10.1103/73rk-6cp6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {L030201}, shortjournal = {Phys. Rev. A}, title = {Metastability-induced solid-state quantum batteries for powering microwave quantum electronics}, volume = {112}, year = {2025}, }
• (2025). Erratum: Solid-state th229 nuclear laser with two-photon pumping [Phys. rev. a 108, l021502 (2023)]. PRA, 112(3), 039905. (www)

  @article{ , abstract = {Phys. Rev. A 112, 039905 (2025)}, archive = {J_PRA}, author = {Haowei Xu and Hao Tang and Guoqing Wang and Changhao Li and Boning Li and Paola Cappellaro and Ju Li}, doi = {10.1103/vmb6-z954}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {039905}, shortjournal = {Phys. Rev. A}, title = {Erratum: Solid-state th229 nuclear laser with two-photon pumping [Phys. rev. a 108, l021502 (2023)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Gauge-invariant theory of truncated quantum light-matter interactions in arbitrary media [Phys. rev. a 107, 013722 (2023)]. PRA, 112(3), 039904. (www)

  @article{ , abstract = {Phys. Rev. A 112, 039904 (2025)}, archive = {J_PRA}, author = {Chris Gustin and Sebastian Franke and Stephen Hughes}, doi = {10.1103/zwzq-4k6z}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {039904}, shortjournal = {Phys. Rev. A}, title = {Erratum: Gauge-invariant theory of truncated quantum light-matter interactions in arbitrary media [Phys. rev. a 107, 013722 (2023)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Tunable negative permeability in a quantum plasmonic metamaterial [Phys. rev. a 89, 013822 (2014)]. PRA, 112(3), 039903. (www)

  @article{ , abstract = {Phys. Rev. A 112, 039903 (2025)}, archive = {J_PRA}, author = {K. R. McEnery and M. S. Tame and S. A. Maier and M. S. Kim}, doi = {10.1103/s4g9-sydn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {039903}, shortjournal = {Phys. Rev. A}, title = {Erratum: Tunable negative permeability in a quantum plasmonic metamaterial [Phys. rev. a 89, 013822 (2014)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Non-markovian frequency conversion between optical and microwave photons with magnetomechanical transduction [Phys. rev. a 110, 043706 (2024)]. PRA, 112(3), 039902. (www)

  @article{ , abstract = {Phys. Rev. A 112, 039902 (2025)}, archive = {J_PRA}, author = {Jia Tang and Hong-Zhi Shen}, doi = {10.1103/9vs5-jdvn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {039902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Non-markovian frequency conversion between optical and microwave photons with magnetomechanical transduction [Phys. rev. a 110, 043706 (2024)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Linear gaussian quantum state smoothing: Understanding the optimal unravelings for alice to estimate bob's state [Phys. rev. a 103, 012213 (2021)]. PRA, 112(3), 039901. (www)

  @article{ , abstract = {Phys. Rev. A 112, 039901 (2025)}, archive = {J_PRA}, author = {Kiarn T. Laverick and Areeya Chantasri and Howard M. Wiseman}, doi = {10.1103/5hlk-mhf3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {039901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Linear gaussian quantum state smoothing: Understanding the optimal unravelings for alice to estimate bob's state [Phys. rev. a 103, 012213 (2021)]}, volume = {112}, year = {2025}, }
• (2025). Single-photon routing induced by giant atoms in a synthetic frequency dimension. PRA, 112(3), 033724. (www)

  @article{ , abstract = {We propose a hardware-efficient single-photon routing scheme in a synthetic frequency dimension based on a dynamically modulated multimode ring resonator and a driven cyclic three-level superconducting circuit, which effectively models a two-level giant atom coupled to a pair of one-dimensional lattices in the synthetic frequency dimension. The routing dynamics of single-photon wave packets in the frequency dimension are investigated numerically and analytically. Our results show that by tuning the phase of the external field, the photon transmission between the two frequency lattices can be well controlled, thereby determining the propagation direction of photons within the ring resonator. This work presents a feasible scheme for implementing a controllable node in quantum networks, and the predictions of this scheme are well within reach of state-of-the-art experiments.}, archive = {J_PRA}, author = {Ruolin Chai and Guoqing Cai and Qiongtao Xie and Huaizhi Wu and Yong Li}, doi = {10.1103/9ym6-xw81}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033724}, shortjournal = {Phys. Rev. A}, title = {Single-photon routing induced by giant atoms in a synthetic frequency dimension}, volume = {112}, year = {2025}, }
• (2025). Controllable single-photon scattering in a rydberg-atom–waveguide system via van der waals interactions. PRA, 112(3), 033723. (www)

  @article{ , abstract = {We investigate single-photon scattering in a system comprising a waveguide coupled to a pair of Rydberg atoms, illuminated by a coherent field. By adjusting the interatomic distance, we can transition between the Rydberg blockade and Rydberg antiblockade regimes, as the van der Waals interaction strength varies with distance. These distinct regimes, manifesting in single-photon scattering, allow flexible reflection control due to their analogy to those of small- and giant-atom interactions with the waveguide. We also derive scattering criteria for Rydberg blockade and Rydberg antiblockade, corresponding to specific features in the single-photon reflection spectrum. Based on these criteria, the blockade and antiblockade distances can be estimated.}, archive = {J_PRA}, author = {Peng-Fei Wang and Lei Huang and Yi-Long-Yue Guo and Jing Wang and Han-Xiao Zhang and Hong Yang and Dong Yan}, doi = {10.1103/cc46-f919}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033723}, shortjournal = {Phys. Rev. A}, title = {Controllable single-photon scattering in a rydberg-atom–waveguide system via van der waals interactions}, volume = {112}, year = {2025}, }
• (2025). Entanglement, loss, and quantumness: When balanced beam splitters are best. PRA, 112(3), 033722. (www)

  @article{ , abstract = {Quantum optics routinely uses beam splitters to generate entanglement, including in pioneering experiments conducted by Hanbury-Brown and Twiss and Hong, Ou, and Mandel. The quantum interference at beam splitters lies at the heart of what makes boson sampling hard to emulate by classical computers and is a vital component of quantum computation with light. Yet, despite overwhelming positive evidence, the conjecture that beam splitters with equal reflection and transmission probabilities generate the most entanglement for any state interfered with the vacuum has remained unproven for almost two decades [Asbóth et al. , Phys. Rev. Lett. 94 , 173602 (2005) ]. We prove this conjecture for ubiquitous entanglement monotones including mixed-state generalizations of entanglement entropy and purity by uncovering monotonicity and convexity with respect to photon loss for these monotones. At the same time, we highlight an infinite class of lesser-used monotones for which the conjecture fails. Because beam splitters are so fundamental, our results yield numerous corollaries for quantum optics, including proof of a recent conjecture for the evolution of a measure of quantumness through loss and a more efficient computational strategy for optimizing entanglement generation over linear optics. These results justify the value of seeking mathematical rigor behind commonly accepted facts and the danger of trusting them unconditionally.}, archive = {J_PRA}, author = {Noah Lupu-Gladstein and Anaelle Hertz and Khabat Heshami and Aaron Z. Goldberg}, doi = {10.1103/lhxk-v564}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033722}, shortjournal = {Phys. Rev. A}, title = {Entanglement, loss, and quantumness: When balanced beam splitters are best}, volume = {112}, year = {2025}, }
• (2025). Zitterbewegung, momentum, and spin dynamics of electromagnetic waves in a linear dielectric medium. PRA, 112(3), 033721. (www)

  @article{ , abstract = {The momentum of light in dielectric media has been a century-long controversy that continues to attract significant interest. In a linear dielectric medium with refractive index n , the momentum is predicted to be smaller by a factor of n according to Abraham and larger by the same factor according to Minkowski. By studying the coupled dynamics of electromagnetic waves and dipoles in a dielectric medium, we show that the change in momentum of the dipole, expressed by the Lorentz force, corresponds to the Abraham momentum and is given by the expectation value of the spin-projected momentum vector. On the other hand, the Minkowski momentum is obtained as the magnitude of the spin-projected momentum vector from the energy-momentum dispersion relation derived by diagonalizing the coupled Hamiltonian and determines the direction of refraction in accordance with Snell's law. Our model also predicts a zitterbewegung -like oscillation due to helicity mixing between left- and right-handed wave components, mediated by dipole oscillation. These internal wave dynamics may be observable via wave-packet motion or polarization-sensitive measurements.}, archive = {J_PRA}, author = {Adam B. Cahaya}, doi = {10.1103/sxh8-q8tq}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033721}, shortjournal = {Phys. Rev. A}, title = {Zitterbewegung, momentum, and spin dynamics of electromagnetic waves in a linear dielectric medium}, volume = {112}, year = {2025}, }
• (2025). Two-qubit entanglement dynamics under strong light-matter coupling near a graphene nanodisk. PRA, 112(3), 033720. (www)

  @article{ , abstract = {In this work, we theoretically analyze the population and entanglement dynamics for two identical qubits interacting with a graphene nanodisk. We consider qubits with various free-space decay rates in order to study how the coupling strength influences the dynamics of our composite system, as well as their entanglement evolution as quantified by concurrence. We find that for relatively large free-space decay rates, the population dynamics of each qubit features Rabi oscillations, while for smaller decay rates it exhibits a complex behavior, which nevertheless can be understood by semianalytical expressions using the sub- and superradiant states of the system. Additionally, we observe phenomena, such as population and entanglement trapping, induced by the strong interaction of the qubits with the graphene nanodisk, with trapping values depending solely on the initial conditions of the two qubits. Lastly, we compare our results with those obtained in the case of the two qubits interacting independently with a graphene nanodisk.}, archive = {J_PRA}, author = {Nikos Iliopoulos and Ioannis Thanopulos and Emmanuel Paspalakis and Vasilios Karanikolas}, doi = {10.1103/62cd-c8nj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033720}, shortjournal = {Phys. Rev. A}, title = {Two-qubit entanglement dynamics under strong light-matter coupling near a graphene nanodisk}, volume = {112}, year = {2025}, }
• (2025). Quantum trajectory method for highly excited environments in non-markovian open quantum dynamics. PRA, 112(3), 033719. (www)

  @article{ , abstract = {Systems in contact with an environment provide a ubiquitous challenge in quantum dynamics. Many fascinating phenomena can arise if the coupling is strong, leading to non-Markovian dynamics of the system, or collective, where the environment can become highly excited. We introduce a significant improvement of the hierarchy of pure states (HOPS) approach, which is able to efficiently deal with such highly excited, non-Markovian environments in a nearly unitary way. As our method relies on quantum trajectories, we can obtain dynamics efficiently, also for large system sizes, by (1) avoiding the quadratic scaling of a density matrix and (2) exploiting the localization properties of the trajectories with an adaptive basis. We provide the derivation of the nuHOPS (nearly unitary hierarchy of pure states) method, compare it to the original HOPS, and discuss numerical subtleties based on an illustrative dephasing model. Finally, we show its true power using the Dicke model as the paradigmatic example of many emitters decaying superradiantly inside a cavity. We reach numerically exact solutions for up to 1000 emitters. We apply our method to study emerging higher-order correlations in the emitter system or the cavity mode environment and their scaling with the number of emitters.}, archive = {J_PRA}, author = {Kai Müller and Walter T. Strunz}, doi = {10.1103/xhff-x24s}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033719}, shortjournal = {Phys. Rev. A}, title = {Quantum trajectory method for highly excited environments in non-markovian open quantum dynamics}, volume = {112}, year = {2025}, }
• (2025). Superradiant quantum beats driven by ground-state–Rydberg-state coherences. PRA, 112(3), 033717. (www)

  @article{ , abstract = {Quantum beats in superradiance arise from coherent interference between collective emission from independent transitions, fundamentally distinct from single-atom quantum beats. In this work, we report the observation of quantum beats generated from ground-state–Rydberg-state atomic coherences in a cold atomic ensemble. Using phase-matched emission, we observe various time-resolved and time-integrated beating patterns that depend on the storage time between excitation and readout pulses. We develop a detailed model of the readout and emission processes, which quantitatively reproduces all observed beating signatures.}, archive = {J_PRA}, author = {Z. Wang and B. Yang and P. R. Berman and A. Kuzmich}, doi = {10.1103/qtdb-shjx}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033717}, shortjournal = {Phys. Rev. A}, title = {Superradiant quantum beats driven by ground-state–Rydberg-state coherences}, volume = {112}, year = {2025}, }
• (2025). Photonic spin hall effect using bilayer graphene in nano-optomechanical cavities. PRA, 112(3), 033716. (www)

  @article{ , abstract = {We propose a theoretical model to obtain the photonic spin Hall effect (SHE) in an optomechanical nanocavity using a graphene bilayer as the intracavity medium. In our model, the pump and probe fields coherently drive the first mirror, whereas the second mirror has mechanical oscillation due to the radiation pressure. We show that the right- and left-circular polarization components of the Gaussian probe field striking at an arbitrary incident angle become spatially separate along a direction orthogonal to the plane of incidence. Photonic SHE can be coherently controlled by adjusting the optomechanical interaction, cavity field, and G-mode phonon coupling, as well as G-mode phonon and electronic state interaction. The findings of photonic SHE are equally valid for standard optomechanical systems in the absence of cavity field and G-mode phonon coupling and electronic state interaction. The cavity field and G-mode phonon coupling broadened the detuning range of the probe field to observe the dominant photonic SHE. Adding G-mode phonon and electronic state interaction generates enhanced photonic SHE at three different probe field detunings due to optomechanical-induced transparency being split into three windows. We show that asymmetric photonic SHE can be controlled through cavity field and G-mode phonon coupling and G-mode phonon and electronic state interaction when probe field detuning is nonzero. The photonic SHE in bilayer graphene integrated with an optomechanical cavity may enable further studies of spin-dependent photonic effects and quantum sensing applications.}, archive = {J_PRA}, author = {Muqaddar Abbas and Muhammad Awais Altaf and Pei Zhang and Muhammad Waseem}, doi = {10.1103/6tzm-36ly}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033716}, shortjournal = {Phys. Rev. A}, title = {Photonic spin hall effect using bilayer graphene in nano-optomechanical cavities}, volume = {112}, year = {2025}, }
• (2025). Path-unbalanced fourth-order interference with the aid of a weak coherent reference. PRA, 112(3), 033715. (www)

  @article{ , abstract = {Traditionally, observation of optical interference in intensity requires the balance of the paths of the two interfering fields within the coherence length of the optical fields. With intensity correlation fourth-order measurement between two detectors, such a requirement can be relaxed. Here, we report the observation of interference in a path-unbalanced Mach-Zehnder interferometer by mixing the output field with a weak coherence reference field before making a fourth-order intensity correlation measurement. Detailed theoretical analysis is made and is consistent with the experimental observation. As a side product of the study, when the coherent reference field is not present, the path-unbalanced interferometer realizes a Hong-Ou-Mandel interference effect that can be used to measure the coherence time of the input field with . Such a technique of recovering interference, which is otherwise absent with the traditional observation method, should find wide applications in optical sensing by extending the applicable range.}, archive = {J_PRA}, author = {Xuan Tang and Z. Y. Ou}, doi = {10.1103/46jb-lzk2}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033715}, shortjournal = {Phys. Rev. A}, title = {Path-unbalanced fourth-order interference with the aid of a weak coherent reference}, volume = {112}, year = {2025}, }
• (2025). Two-dimensional platforms for entanglement engineering via nonreciprocal dipole interactions. PRA, 112(3), 033714. (www)

  @article{ , abstract = {We propose a genuine two-dimensional chiral waveguide platform based on the hyperbolic surfaces to engineer nonreciprocal interactions and entanglement between quantum emitters. Tuning the dipole polarization allows for maximally chiral coupling between each emitter and the surface plasmon field, resulting in highly directional energy transfer. By employing a master equation approach, we show that the chiral environment not only enables nonreciprocal dipole interactions but also significantly enhances both transient and steady-state entanglement compared with reciprocal systems. The degree of steady-state entanglement is further tunable through dipole polarization, emitter separation, and external driving. Unlike prior implementations constrained by one-dimensional geometries, our fully planar and highly reconfigurable platform provides a scalable route toward integrated quantum photonic networks and on-chip multipartite entanglement.}, archive = {J_PRA}, author = {Wei Fang and Peng-tao Du and Gao-xiang Li and Yaping Yang}, doi = {10.1103/pd3d-h2j9}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033714}, shortjournal = {Phys. Rev. A}, title = {Two-dimensional platforms for entanglement engineering via nonreciprocal dipole interactions}, volume = {112}, year = {2025}, }
• (2025). Controlling chiral atom-photon bound states and spatial adiabatic passage in a photonic topological cold-atom system. PRA, 112(3), 033713. (www)

  @article{ , abstract = {Controlling light-matter interactions has been a long-standing goal in quantum optics, particularly through engineering the dispersion relation of the (structured) baths and tailoring the couplings between fields and emitters. We propose a topological cold-atom system with dynamical modulations to realize chiral atom-photon bound states (APBSs) and controllable spatial adiabatic passage (SAP). The system, modeled as a Rice-Mele chain using a double-well lattice and facilitating giant-atom-like nonlocal interaction, exhibits intriguing phenomena such as subradiance and superradiance. We demonstrate that APBSs with tunable chirality can be realized in the bound states in the continuum (BICs) and quasi-BICs and support the decoherence-free interaction via two distinct schemes. We also reveal the dynamical mechanisms for the topologically protected SAP, where the chiral-APBS fidelity during the adiabatic transfer is highly sensitive to the topology. These findings open possibilities for quantum simulation and information processing with cold atoms, particularly through the integration of topologically protected controllable mechanisms.}, archive = {J_PRA}, author = {Yi-Xin Wang and Yan Zhang and Xiao Liu and Jin-Hui Wu}, doi = {10.1103/z8yz-rq26}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033713}, shortjournal = {Phys. Rev. A}, title = {Controlling chiral atom-photon bound states and spatial adiabatic passage in a photonic topological cold-atom system}, volume = {112}, year = {2025}, }
• (2025). Spectral densities of a dispersive dielectric sphere in the modified langevin noise formalism. PRA, 112(3), 033712. (www)

  @article{ , abstract = {This paper deals with the spectral densities of a dispersive dielectric object in the framework of macroscopic quantum electrodynamics based on the modified Langevin noise formalism. In this formalism, the electromagnetic field in the presence of a dielectric object has two contributions, one taking into account the polarization current fluctuations of the object and the other taking into account the vacuum field fluctuations scattered by the object. The combined effect of these fields on the dynamics of a quantum emitter is described via two independent continuous bosonic reservoirs, a medium-assisted reservoir and a scattering-assisted reservoir, each characterized by its own spectral density and initial quantum state. For initial thermal states of the two reservoirs at different temperatures, the standard approach based on the knowledge of the dyadic Green's function of the dielectric object at the quantum emitter position cannot be employed. We map the two reservoirs to a single equivalent reservoir with a temperature-dependent effective spectral density and initially in its vacuum state, focusing on the case of a homogeneous dielectric sphere. We derive analytical expressions for the medium-assisted, scattering-assisted, and effective spectral densities in this setting. We then study the dynamics of the quantum emitter for initial thermal states of the two reservoirs, adopting a nonperturbative approach.}, archive = {J_PRA}, author = {Giovanni Miano and Loris Maria Cangemi and Carlo Forestiere}, doi = {10.1103/g71y-hglg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033712}, shortjournal = {Phys. Rev. A}, title = {Spectral densities of a dispersive dielectric sphere in the modified langevin noise formalism}, volume = {112}, year = {2025}, }
• (2025). Enhancement of single-photon purity and brightness via bound states in the continuum. PRA, 112(3), 033711. (www)

  @article{ , abstract = {The photon blockade is a promising mechanism for single-photon sources. However, in most systems with photon blockade, the brightness of the quantum source (being proportional to the average photon number in cavities) is limited. A recent experiment [Lei et al. , Phys. Rev. Lett. 130 , 093801 (2023) ] proves that Friedrich-Wintgen bound states in the continuum (BICs) arise when a microresonator containing a pair of near-resonant modes is side-coupled to an adjacent bus waveguide where the gap between them is narrow. To our knowledge, the impacts of BICs on the single-photon purity and brightness in the blockade process remain less explored. Here, we put forward a scheme to simultaneously enhance both the purity and brightness of single-photon emission in one cavity mode of such an integrated microresonator-waveguide system, while the other cavity mode is considered to be an active mode, modeled as incoherent-pumping (gain)-like laser production. Physically, this enhancement is achieved through BICs produced by quantum destructive interference between different dissipative pathways. We demonstrate that BICs enable the improvement of emission brightness by 1 to 2 orders of magnitude, accompanied by high single-photon purity of 0.98 (or strong photon blockade of 0.02) compared with the BIC-free configuration. As a check, the full numerical results for the second-order correlation function and the average photon number of the emission cavity mode, which respectively determine the purity and brightness of single-photon emission, are in excellent agreement with the semianalytical solutions. Our BICs-based work offers a promising avenue for constructing single-photon sources with high purity and high brightness.}, archive = {J_PRA}, author = {Yating Deng and Yaqi Fan and Jiahua Li}, doi = {10.1103/wd7y-8n4s}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033711}, shortjournal = {Phys. Rev. A}, title = {Enhancement of single-photon purity and brightness via bound states in the continuum}, volume = {112}, year = {2025}, }
• (2025). Dynamical transition of the generalized jaynes-cummings model: Multiparticle and interparticle interaction effects. PRA, 112(3), 033710. (www)

  @article{ , abstract = {How environments affect the dynamics of quantum systems remains a central question in understanding transitions between quantum and classical phenomena and optimizing quantum technologies. A paradigm model to address the above question is the generalized Jaynes-Cummings model, in which a two-level particle is coupled to its environment modeled by a continuum of boson modes. Previous analytic solutions show that, starting from the initial condition that the particle is in its excited state and the boson modes are in their vacuum state, the time evolution of the probability that the particle occupies the excited state exhibits a dynamical transition as the system-environment coupling varies; when the coupling is weak, the probability decays to zero monotonically, while a finite weight of the particle is localized in the excited state when the coupling is sufficiently strong. Here we study the dynamical transition for the case that particles are initially excited with the boson modes in their vacuum state. The boson modes are assumed to follow a spectral function up to a cutoff frequency with . In particular, we access the effects of an all-to-all Ising type interaction we introduce between the particles. Our calculation is carried out by the nonperturbative numerical renormalization group method. We find that the value of the critical coupling for the transition exhibits a maximum at a finite and decreases with sufficiently large , and is suppressed (enlarged) by a ferromagnetic (antiferromagnetic) Ising interaction. Our results enrich understanding of environmental effects on interacting quantum systems.}, archive = {J_PRA}, author = {Wen Liang and Zhenhua Yu}, doi = {10.1103/9smt-lgth}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033710}, shortjournal = {Phys. Rev. A}, title = {Dynamical transition of the generalized jaynes-cummings model: Multiparticle and interparticle interaction effects}, volume = {112}, year = {2025}, }
• (2025). Quantum phase transitions in the multiphoton jaynes-cummings-hubbard model. PRA, 112(3), 033709. (www)

  @article{ , abstract = {We explore quantum phase transitions in the multiphoton Jaynes-Cummings-Hubbard model (JCHM). Using the mean-field approximation, we demonstrate that the multiphoton JCHM exhibits quantum phase transitions between the Mott insulator (MI) phase, the superfluid phase, and an additional phase we refer to as the forbidden phase. The multiphoton JCHM MI phases are classified according to a conserved quantity associated with the total number of excited atoms and photons. When this conserved quantity diverges toward positive infinity, this system enters the forbidden phase. By analyzing the system, we observe MI, superfluid, and forbidden phases in both the single- and two-photon JCHMs, although the MI phases in the two-photon case are confined to subspaces with small values of the conserved quantity. In contrast, only the superfluid and forbidden phases appear in the three- and four-photon JCHMs, with no MI phase observed.}, archive = {J_PRA}, author = {Hiroo Azuma and William J. Munro and Kae Nemoto}, doi = {10.1103/ypts-6z4p}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033709}, shortjournal = {Phys. Rev. A}, title = {Quantum phase transitions in the multiphoton jaynes-cummings-hubbard model}, volume = {112}, year = {2025}, }
• (2025). Time crystals and nonequilibrium dissipative phase transitions mediated by squeezed bath. PRA, 112(3), 033708. (www)

  @article{ , abstract = {The nonequilibrium dissipative phase transition, arising from the competition of cooperative behavior and coherent field driving, discovered in the 1970s by Narducci et al . [ Phys. Rev. A 18 , 1571 (1978) ] and Walls et al . [ Prog. Theor. Phys. Suppl. 64 , 307 (1978) ], has been found to exhibit time-crystal behavior when the driving field exceeds the cooperative decay rate. This was seen through the study of the eigenvalues of the Liouvillian superoperator that describes the joint effect of drive and cooperativity. The cooperative decay depends on the nature of the reservoir correlations. If the reservoir correlations have phase-sensitive behavior, then the eigenvalues of the Liouvillian will be different. We investigate the time-crystal behavior of the nonequilibrium dissipative phase transitions under the influence of a squeezed vacuum reservoir. We analyze the steady-state phase diagram as a function of the control parameter and demonstrate that increasing the squeezing strength sharpens the dissipative phase transition. Spectral analysis of the Liouvillian reveals gap closings and the emergence of purely imaginary eigenvalues in the thermodynamic limit, indicating the time-crystal phase. We find that the real parts of subleading eigenvalues exhibit nonmonotonic behavior with increasing squeezing, reflecting the sensitivity of relaxation dynamics to the reservoir properties. Time-domain simulations confirm that the oscillation frequencies correspond to the imaginary parts of the Liouvillian eigenvalues. We also present results on quantum fluctuations in the time-crystal phase. Our results call attention to the study of time crystals in models of cooperativity based on engineered environments.}, archive = {J_PRA}, author = {Zhenghao Zhang and Qingtian Miao and G. S. Agarwal}, doi = {10.1103/nhdh-nvmz}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033708}, shortjournal = {Phys. Rev. A}, title = {Time crystals and nonequilibrium dissipative phase transitions mediated by squeezed bath}, volume = {112}, year = {2025}, }
• (2025). Enantiomer selectivity and energy transfer in imperfect chiral cavities. PRA, 112(3), 033707. (www)

  @article{ , abstract = {Chiral polaritonics offers promising opportunities to selectively manipulate molecular species based on their handedness by harnessing unique interaction pathways offered by strong coupling in cavity QED. While significant progress has been made in understanding the fundamental mechanisms of enantiomer selectivity, many existing studies focus on perfectly chiral cavities that contain only one type of enantiomer. Here, we investigate a scenario of imperfect cavities containing varying mixtures of enantiomers. Using a generalized Hopfield-type model, we systematically explore how the degree of enantiomeric mixing and cavity imperfections affect chiral selectivity. Our analysis includes both an examination of the cavity's eigenmode structure and a quantitative assessment of differential energy transfer into specific enantiomeric species. We demonstrate that both cavity imperfections and the presence of enantiomer mixtures profoundly modify the polaritonic dispersion. We also highlight that pushing the system into the deep strong coupling regime—by increasing molecular concentration—can decrease the efficiency of energy transfer to matter modes. These findings emphasize that precise cavity design and detailed consideration of enantiomeric composition are essential for achieving optimal chiral selectivity in practical cavity QED systems.}, archive = {J_PRA}, author = {David Dams and Carsten Rockstuhl}, doi = {10.1103/p4dp-byb8}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033707}, shortjournal = {Phys. Rev. A}, title = {Enantiomer selectivity and energy transfer in imperfect chiral cavities}, volume = {112}, year = {2025}, }
• (2025). Isoenergetic model for optical down-conversion and error-specific limits of the parametric approximation. PRA, 112(3), 033706. (www)

  @article{ , abstract = {Optical down-conversion is widely used for generating photon pairs, squeezed and entangled states of light, making it an indispensable tool in quantum optics and quantum information. In the regime where the pump is much stronger than the generated field, the standard parametric approximation treats the pump amplitude as a fixed parameter of the model. This approximation has a limited domain of validity since it assumes a nondepleted and nonentangled pump. By finding an approximate solution to the Schrödinger equation of the down-conversion process, we obtain an improved analytical model beyond the parametric one, which accounts for pump depletion and pump-signal entanglement. Our model is advantageous, first, because it allows one to compute averages of field operators far beyond the domain of validity of the parametric approximation, and second, because it allows one to establish error-specific limits of the latter domain. For a given pump amplitude, we find a maximum squeezing parameter, up to which the approximation remains valid within a specified acceptable error. Our results confirm that recent experiments on Gaussian boson sampling, with a squeezing parameter of and a coherent pump amplitude of , can still be accurately described by the standard parametric approximation. However, we observe a sharp decline in validity as the squeezing parameter increases. For pump amplitudes of , the parametric approximation breaks down when the squeezing parameter exceeds , whereas the new approximation remains valid up to with an acceptable error of 1%.}, archive = {J_PRA}, author = {D. B. Horoshko and V. S. Shchesnovich}, doi = {10.1103/wtcf-5pkh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033706}, shortjournal = {Phys. Rev. A}, title = {Isoenergetic model for optical down-conversion and error-specific limits of the parametric approximation}, volume = {112}, year = {2025}, }
• (2025). Nonlinear-linear duality for multipath quantum interference. PRA, 112(3), 033705. (www)

  @article{ , abstract = {In quantum optics, the postselection amplitude of a nondegenerate parametric down-conversion (PDC) process is linked to a beamsplitter (BS) via partial time reversal, up to a normalization coefficient which is related to the parametric gain [ Proc. Natl. Acad. Sci. USA 117 , 33107 (2020) ]. A special example where the gain is low is reminiscent of Klyshko's advanced-wave picture in quantum imaging. Here we propose and prove a generalized duality for multiple spatial paths connecting a quantum nonlinear interference setup consisting of nondegenerate PDCs and linear optical systems to a linear one, where the PDCs are directly replaced by hypothetical wavelength-shifting BSs. This replacement preserves the geometry of the original setup, and cascaded PDCs become optical cavities whose calculation involves the Redheffer star product. Additional terms in the normalization coefficient are related to the contribution of looping photons inside the cavities. Then we discuss the case of coherent state input and postselection for -function calculation. This theorem will be helpful in the development of quantum photonic devices beyond the low-gain limit.}, archive = {J_PRA}, author = {Yi Zheng and Jin-Shi Xu and Chuan-Feng Li and Guang-Can Guo}, doi = {10.1103/6zhj-5t26}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033705}, shortjournal = {Phys. Rev. A}, title = {Nonlinear-linear duality for multipath quantum interference}, volume = {112}, year = {2025}, }
• (2025). Interferometric detection of continuous-variable entanglement using two states. PRA, 112(3), 033704. (www)

  @article{ , abstract = {The efficient witnessing and certification of entanglement is necessitated by its ubiquitous use in various aspects of quantum technologies. In the case of continuous-variable bipartite systems, the Shchukin-Vogel hierarchy gives necessary conditions for separability in terms of moments of the mode operators. In this work we derive mode-operator-based witnesses for continuous-variable bipartite entanglement relying on the interference of two states. Specifically, we show how one can access higher moments of the mode operators, crucial for detecting entanglement of non-Gaussian states, using a single beamsplitter with variable phase and photon-number-resolving detectors. We demonstrate that the use of an entangled state paired with a suitable reference state is sufficient to detect entanglement in, e.g., two-mode squeezed vacuum, NOON states, and mixed entangled cat states. We also take into account experimental noise, including photon loss and detection inefficiency, as well as finite measurement statistics.}, archive = {J_PRA}, author = {Elena Callus and Martin Gärttner and Tobias Haas}, doi = {10.1103/4wzg-fc7b}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033704}, shortjournal = {Phys. Rev. A}, title = {Interferometric detection of continuous-variable entanglement using two states}, volume = {112}, year = {2025}, }
• (2025). Phase-controlled single-photon scattering in a giant-molecule waveguide-QED system. PRA, 112(3), 033703. (www)

  @article{ , abstract = {We investigate the single-photon scattering spectra in a giant-molecule waveguide quantum electrodynamics system, where a giant molecule consisting of two coupled giant atoms is connected to two waveguides via two separate sites, respectively. The phases of coupling strengths between the giant molecule and waveguides are considered. Using a real-space method, we obtain the exact analytical expressions for the single-photon scattering coefficients, which are valid both in the Markovian and non-Markovian regimes. It is shown that the transmission spectra strongly depend on phases, including the phases accumulated by photons traveling between coupling points and the phase difference between two coupled channels of the giant-molecule upper (lower) waveguide. Under the Markovian limit, we find that by selecting appropriate accumulated phases and local phase difference, targeted routing and asymmetrical scattering of photons can be achieved without breaking the symmetry in the coupling configuration between the giant molecule and waveguides. Moreover, all the optimal phase combinations for implementing single-photon routing have been summarized. In the non-Markovian regime, the scattering spectra show more complicated line shapes with multiple staggered peaks and dips. More interestingly, the scattering spectrum exhibits periodic changes during the transition from the Markovian to the non-Markovian regime, which makes one obtain a means to control photon routing in addition to phases. Our results may be useful in controlling and manipulating light-matter interactions involving giant atoms at the single-photon level.}, archive = {J_PRA}, author = {Jia-Ao Sun and Yong Wang and Wen-An Li}, doi = {10.1103/nnmt-8492}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033703}, shortjournal = {Phys. Rev. A}, title = {Phase-controlled single-photon scattering in a giant-molecule waveguide-QED system}, volume = {112}, year = {2025}, }
• (2025). Emergent broadband polarization entanglement from electronic and phononic stokes–anti-stokes indistinguishability. PRA, 112(3), 033702. (www)

  @article{ , abstract = {Recently [T. A. Freitas et al. , Phys. Rev. A 108 , L051501 (2023) ], it was shown that, in a centrosymmetric cubic system, two photons from a broadband intense laser field can be converted into a pair of Stokes and anti-Stokes (SaS) entangled photons. While the previous work was based on symmetry arguments, here we present a fully quantum theory for the SaS scattering that properly explains, quantitatively describes, and provides a means to predict its spectral and polarization properties (for diamond). We also explore the possibilities offered by such a system, designing an entanglement map based on changes in the light-matter system. In particular, we show how the broadband polarization entanglement that emerges from the interference between electronic and phononic degrees of freedom in the SaS scattering depends on parameters such as the Stokes–anti-Stokes Raman shift, scattering geometry, and laser bandwidth, opening the avenue of exploration of such phenomenon in information processing.}, archive = {J_PRA}, author = {Diego Sier and Lucas Valente and Tiago A. Freitas and Marcelo F. Santos and Carlos H. Monken and Raul Corrêa and Ado Jorio}, doi = {10.1103/c8nj-chfn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033702}, shortjournal = {Phys. Rev. A}, title = {Emergent broadband polarization entanglement from electronic and phononic stokes–anti-stokes indistinguishability}, volume = {112}, year = {2025}, }
• (2025). Four types of non-gaussian squeezed states and their entanglement properties. PRA, 112(3), 033701. (www)

  @article{ , abstract = {We investigate the coupling of the fully degenerate triple-photon state generated by three-mode spontaneous parametric down-conversion with the vacuum at a beam splitter via numerical modeling. By using fully degenerate triple-photon states with distinct pump phases as input states, four different squeezed states are extracted at the output, which can be referred to as zero-phase, -phase, -phase, and -phase positive Wigner squeezed states. The non-Gaussianity evolution during the coupling process is quantitatively analyzed via quantum relative entropy, and the entanglement between the two output modes is confirmed from an entropic perspective. Furthermore, the entanglement properties of the zero-phase and -phase positive Wigner squeezed states at the third- and sixth-order moments are revealed by applying the partial transpose positive criterion based on the higher-order covariance matrix. In particular, it is found that the steerability of the two output modes at the third- and sixth-order moments can be dynamically controlled by adjusting the intensity of the input light and the transmission of the beam splitter. These results enrich the repertoire of squeezed states in quantum optics and offer a feasible approach for the deterministic preparation of non-Gaussian entanglement via coupling fully degenerate triple-photon states with vacuum.}, archive = {J_PRA}, author = {Da Zhang and Yu Zhang and Juan Gao}, doi = {10.1103/1j44-q3bw}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033701}, shortjournal = {Phys. Rev. A}, title = {Four types of non-gaussian squeezed states and their entanglement properties}, volume = {112}, year = {2025}, }
• (2025). Localized floquet modes in arrays of out-of-phase curved waveguides with a quasiperiodic modulation. PRA, 112(3), 033538. (www)

  @article{ , abstract = {We study light propagation in an array of periodically curved waveguides consisting of pairs of waveguides with out-of-phase oscillations of waveguide centers. We compute the corresponding Floquet propagation constants and find pseudocollapses where the Floquet bands shrink and, respectively, light diffraction is significantly inhibited. When, in addition, the refractive index of the waveguides in the array has quasiperiodic modulation in the transverse direction, we establish the existence of Floquet modes localized in the transverse direction and periodic in the longitudinal direction. With increase of the depth of quasiperiodic modulation of the refractive index in the array, the localized Floquet modes emerge near the pseudocollapse points of the periodic array. In an array with sufficiently high frequencies of waveguide oscillations, the localized Floquet modes can exist even for weak quasiperiodic modulation which is situated below the localization transition in the array of straight waveguides.}, archive = {J_PRA}, author = {Yaroslav V. Kartashov and Dmitry A. Zezyulin}, doi = {10.1103/p9dw-wvpm}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033538}, shortjournal = {Phys. Rev. A}, title = {Localized floquet modes in arrays of out-of-phase curved waveguides with a quasiperiodic modulation}, volume = {112}, year = {2025}, }
• (2025). Optical microcavity characterization via resonance spectra and modes. PRA, 112(3), 033537. (www)

  @article{ , abstract = {This paper describes how resonance spectra and mode profiles can be used to characterize and quantify the mode-shaping effects in open-access plano-concave optical microcavities. The presented semi-analytic theory is based on the application of perturbation theory to the round-trip evolution of the optical field. It includes various mirror-shape and nonparaxial effects and extends the nonparaxial theory presented in [Exter et al. , Phys. Rev. A 106 , 013501 (2022) ] and verified in [Koks et al. , Phys. Rev. A 105 , 063502 (2022) ] to the common case of an anisotropic Gaussian mirror. The presented measurements and analyses of resonance spectra and mode profiles demonstrate how the different mode-shaping effects can be individually distinguished and quantified. Spin-orbit coupling, which is one of the nonparaxial effects, is prominently visible in the intriguing polarization patterns of the resonant modes, while polarization tomography yields the shape-induced birefringence and associated polarization splitting of the fundamental modes.}, archive = {J_PRA}, author = {Jonah Post and Chunjiang He and Corné Koks and Rudi van Velzen and Andrea Corazza and Yannik L. Fontana and Marcel Erbe and Richard J. Warburton and Martin P. van Exter}, doi = {10.1103/y63l-zwr5}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033537}, shortjournal = {Phys. Rev. A}, title = {Optical microcavity characterization via resonance spectra and modes}, volume = {112}, year = {2025}, }
• (2025). Controllable temporal dynamics of partially coherent pulses in nonlinear dispersive media. PRA, 112(3), 033536. (www)

  @article{ , abstract = {In this paper we employ the complex screen method to investigate the dynamic evolution of partially coherent pulses with specified properties as they propagate through a nonlinear Kerr medium. Our results reveal that partially coherent pulses can retain stable pulse characteristics and exhibit enhanced robustness when the source coherence is reduced. Importantly, by adjusting the source pulse properties, the far-zone pulse properties can be effectively predicted and shaped, even in highly nonlinear environments. These findings are of significant importance for applications such as pulse shaping, free-space optical communication, information encryption in nonlinear media. Notably, the results offer valuable insights for mitigating nonlinear effects in light beams within the spatial domain.}, archive = {J_PRA}, author = {Qian Chen and Yanlin Bai and Xiaohan Wang and Peipei Peng and Jingsong Liu and Yangjian Cai and Chunhao Liang}, doi = {10.1103/4jmj-38f6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033536}, shortjournal = {Phys. Rev. A}, title = {Controllable temporal dynamics of partially coherent pulses in nonlinear dispersive media}, volume = {112}, year = {2025}, }
• (2025). Experimental observation of self-frequency-shifting raman quasisolitons in fiber fabry-perot resonators. PRA, 112(3), 033535. (www)

  @article{ , abstract = {We report the generation of self-frequency-shifting Raman quasisolitons in a pulse-pumped high- Q fiber Fabry-Perot resonator in the weak normal dispersion regime. They are induced by modulation instability mediated by fourth-order dispersion in a regime where the Raman gain overwhelms the cavity losses. The resulting spectrum, spanning over 50 THz, is reminiscent of the supercontinuum generated in single-pass waveguides. We clearly identify this process using a dispersive Fourier transform experiment. Additionally, we demonstrate the suppression of modulation instability by tuning the synchronization mismatch between the pump repetition rate and the cavity round-trip time, enabling the generation of a standard dissipative Kerr soliton in this system. These observations align remarkably well with numerical simulations based on a generalized Lugiato-Lefever equation, incorporating the Raman response of the optical fiber.}, archive = {J_PRA}, author = {Thomas Bunel and Matteo Conforti and Arnaud Mussot}, doi = {10.1103/xpk7-n3sv}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033535}, shortjournal = {Phys. Rev. A}, title = {Experimental observation of self-frequency-shifting raman quasisolitons in fiber fabry-perot resonators}, volume = {112}, year = {2025}, }
• (2025). Impact of excitation mechanism on ellipticity and orientation dependence of solid harmonic yield. PRA, 112(3), 033534. (www)

  @article{ , abstract = {At present, the ellipticity and orientation dependence of solid harmonic yield have been widely studied, but the influence of excitation mechanism on them remains relatively unexplored. Here, taking graphene as an example, we investigate the ellipticity and orientation dependence of harmonic yield at different laser frequencies by solving the semiconductor Bloch equations. Our results reveal a transition from anomalous to normal in the ellipticity dependence as the laser frequency increases. Simultaneously, the structure of the orientation dependence undergoes a transformation. By analyzing the conduction-band electron populations, we attribute these changes to the transformation of the dominant excitation mechanism. At low frequencies, tunneling ionization dominates, whereas at high frequencies, multiphoton ionization prevails. Furthermore, the limitation of the solid Keldysh parameter is discussed. These findings underscore the crucial role of the dominant excitation mechanism in solid high-order harmonic generation.}, archive = {J_PRA}, author = {Mingying Zhang and Yupeng Zhang and Jinbin Li and Lingyue Hu and Ruofeng Zhong and Shengjun Yue and Hongchuan Du}, doi = {10.1103/lvp4-w3kb}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033534}, shortjournal = {Phys. Rev. A}, title = {Impact of excitation mechanism on ellipticity and orientation dependence of solid harmonic yield}, volume = {112}, year = {2025}, }
• (2025). Quantum heat engine in an optomechanical system with mechanical parametric drive. PRA, 112(3), 033533. (www)

  @article{ , abstract = {We consider a quantum Otto-type heat engine constructed in an optomechanical system with which the cavity is chosen as the working substance. The cavity can effectively be coupled with hot thermal baths in nonequilibrium steady states via optomechanical interaction. The mechanical mode with parametric drive fuels the cavity, and the utilization efficiency of energy is discussed. To obtain higher efficiency in finite time evolution, we use the shortcuts-to-adiabaticity method in work generation processes. The modified thermal efficiencies are obtained by numerical simulation. Such a system provides potential applications in quantum heat transfer and energy utilization in quantum devices.}, archive = {J_PRA}, author = {Zhen-Yang Peng and Ying-Dan Wang}, doi = {10.1103/hg9b-zmyv}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033533}, shortjournal = {Phys. Rev. A}, title = {Quantum heat engine in an optomechanical system with mechanical parametric drive}, volume = {112}, year = {2025}, }
• (2025). Singularity with indeterminate ellipticity and its application in manipulating spin angular momentum. PRA, 112(3), 033532. (www)

  @article{ , abstract = {Singular optics is an important and meaningful subject that has attracted widespread attention. The famous vortex beam and vector beam carrying different singularities have found broad applications, and there are four kinds of optical singularities including one kind of phase singularity and three kinds of polarization singularities. However, the classification of optical singularities remains incomplete, as the polarization singularity with indeterminate ellipticity and determinate orientation has not been defined. Here, we propose a kind of E -point singularity, where the ellipticity of polarization is indeterminate and the orientation is determinate. The amount, positions, and topological charges of the E -point singularities can be theoretically and experimentally manipulated on the wave front of the beam. It is found that the E -point singularity has a function of polarization purification in propagation, and the E -point singularity acts like catalyst when achieving pure transverse spin angular momentum (SAM) in tight focusing process. The proposed E -point singularity not only supplements the theoretical framework of singular optics, but also enables SAM manipulation during propagation and focusing processes, demonstrating broad application potential across various regions.}, archive = {J_PRA}, author = {Xu-Zhen Gao and Guo-Dong Tan and Shi-Tong Xu and Mingsheng Niu and Hongzhong Cao and Rende Ma and Yue Pan}, doi = {10.1103/z6sq-6h4x}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033532}, shortjournal = {Phys. Rev. A}, title = {Singularity with indeterminate ellipticity and its application in manipulating spin angular momentum}, volume = {112}, year = {2025}, }
• (2025). Broadband optical nonreciprocity based on gain saturation in an er-doped fiber. PRA, 112(3), 033531. (www)

  @article{ , abstract = {Nonreciprocal optical devices, allowing transmission of light with different efficiencies in opposite directions, are key elements for modern optical communication and even quantum information technologies, but elusive to be integrated on a chip to date. Such devices exploring nonlinearity can tackle this integration issue without using a magnetic field. However, they are constrained by narrow bandwidth or large signal power because of the weak nonlinear strength of materials. Here, by combining the strong gain-saturation nonlinearity of an Er-doped optical fiber and the asymmetric inputs, we experimentally demonstrate a broadband resonator-free nonreciprocal optical device. This nonmagnetic device operating at telecom wavelength shows nonreciprocal transmission with contrast of over a bandwidth of and reaches a maximum contrast of . With the potential of extending to on-chip Er-doped optical waveguides with currently existing experimental techniques, this simple design paves the way for integrated broadband nonreciprocity devices and can boost the functions of photonic chips.}, archive = {J_PRA}, author = {Yuhong Zou and Fan Lv and Haodong Wu and Jiangshan Tang and Han Zhang and Hui Jing and Keyu Xia}, doi = {10.1103/w94c-xk6j}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033531}, shortjournal = {Phys. Rev. A}, title = {Broadband optical nonreciprocity based on gain saturation in an er-doped fiber}, volume = {112}, year = {2025}, }
• (2025). Direct space-time modeling of mechanically dressed dipole-dipole interactions with electromagnetically coupled oscillating dipoles. PRA, 112(3), 033530. (www)

  @article{ , abstract = {We study the radiative dynamics of coupled electric dipoles, modelled as Lorentz oscillators, in the presence of real-time mechanical oscillations. The dipoles are treated in a self-consistent way through a direct electromagnetic simulation approach that fully includes the dynamical movement of the charges, accounting for radiation reaction, emission and absorption. This allows for a powerful numerical solution of optomechanical resonances without any perturbative approximations for the mechanical motion. The scaled population (excitation) dynamics of the Lorentz oscillators are investigated as well as the emitted radiation and electromagnetic spectra, which demonstrates how the usual dipole-dipole resonances couple to the underlying Floquet states, yielding multiple spectral peaks that are separated from the superradiant and subradiant states by an integer number of the mechanical oscillation frequency. Moreover, we observe that when the mechanical amplitude and frequency are sufficiently large, these additional spectral peaks undergo further modification, including spectral splitting, spectral squeezing, or shifting. These observations are fully corroborated by a theoretical Floquet analysis conducted on two coupled harmonic oscillators.}, archive = {J_PRA}, author = {Yi-Ming Chang and Kamran Akbari and Matthew Filipovich and Stephen Hughes}, doi = {10.1103/bmm8-9pn6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033530}, shortjournal = {Phys. Rev. A}, title = {Direct space-time modeling of mechanically dressed dipole-dipole interactions with electromagnetically coupled oscillating dipoles}, volume = {112}, year = {2025}, }
• (2025). Nonlocal nonlinear edge states in photonic floquet lattices with pseudo-spin-orbit coupling. PRA, 112(3), 033529. (www)

  @article{ , abstract = {We propose a theoretical framework for engineering wave-vector angles in nonlocal nonlinear Floquet lattices to modulate photonic spin-orbit coupling (SOC). By controlling polar and azimuthal angles of transverse wave vectors in orthogonally polarized beams, we achieve tunable SOC strength, which governs the formation and propagation dynamics of topological edge states. The nonlocal nonlinearity introduces a distinct threshold for edge state emergence while enhancing their scattering robustness. The helical lattice geometry enables dual-parameter control, linking edge state velocity and topological band-gap adjustment through a single structural parameter. This system provides a platform for investigating nonlinear topological phenomena, with potential applications in on-chip photonic devices and quantum information processing.}, archive = {J_PRA}, author = {Zhiwei Shi and Yijie Wu and Maowu Zuo and Huanggang Li and Huan Jiang and Xuekai Ma and Yaohua Deng}, doi = {10.1103/rjdz-dcqg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033529}, shortjournal = {Phys. Rev. A}, title = {Nonlocal nonlinear edge states in photonic floquet lattices with pseudo-spin-orbit coupling}, volume = {112}, year = {2025}, }
• (2025). Exceptional-point-controlled mode interaction in three-dimensional microcavities represented by generalized husimi functions. PRA, 112(3), 033528. (www)

  @article{ , abstract = {Non-Hermitian photonics has attracted significant interest and influences several key areas such as optical metamaterials, laser physics, and nonlinear optics. While non-Hermitian effects have been widely addressed in two-dimensional (2D) systems, we focus on realistic three-dimensional devices. To this end we generalize established phase-space methods from mesoscopic optics and introduce Husimi functions for three-dimensional systems that deepen the insight and access to the mode morphology and their dynamics. We illustrate that four-dimensional Husimi functions can be represented using a specific projection on two dimensions and illustrate it for (conical) cylindrical cavities. The non-Hermitian character of the intrinsically open photonic systems is in particular revealed when examining the transverse electric and transverse magnetic polarization character of the resonance modes. Unlike the 2D case, polarization is not conserved in three-dimensional cavities, and we use generalized Husimi function to represent the interaction of polarization modes. We find their dynamics to be ruled by a network of exceptional points in the parameter space spanned by the refractive index and the cavity geometry tilt angle. This approach not only enhances our understanding of cavity modes but also aids in the design of more efficient photonic devices and systems.}, archive = {J_PRA}, author = {Tom Simon Rodemund and Shilong Li and Síle Nic Chormaic and Martina Hentschel}, doi = {10.1103/2wrn-z5fg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033528}, shortjournal = {Phys. Rev. A}, title = {Exceptional-point-controlled mode interaction in three-dimensional microcavities represented by generalized husimi functions}, volume = {112}, year = {2025}, }
• (2025). Long-range optical pulling enabled by longitudinal chirality gradients. PRA, 112(3), 033527. (www)

  @article{ , abstract = {Long-range optical pulling is highly desired for nanoscale manipulation, including biomolecules and functional particles. However, its realization in a homogeneous medium remains challenging due to the absence of strong scattering asymmetry. Here, we introduce an ingenious mechanism to obtain optical pulling and pushing forces using a metasurface-engineered optical field with a tailored longitudinal chirality gradient. This approach exploits parity-asymmetric interactions between chiral particles and the metasurface-engineered needle-like optical field, eliminating the need for complex background structures. Leveraging the field manipulation versatility of spin-decoupled metasurfaces, we demonstrate enantiomer separation across thousands of particle diameters—exceeding previous works by an order of magnitude in terms of particle-scale displacement. Furthermore, by tuning the chirality density of the field, directional control of particle motion can be achieved, underscoring its potential for large-scale chiral sorting and enantioselective drug purification.}, archive = {J_PRA}, author = {Wenhao Miao and Li Long and Fei Zhang and Mingbo Pu and Anbin Du and Tongtong Kang and Ruoqin Zhang and Mingfeng Xu and Yinghui Guo and Din Ping Tsai and Xiangang Luo}, doi = {10.1103/6y69-4452}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033527}, shortjournal = {Phys. Rev. A}, title = {Long-range optical pulling enabled by longitudinal chirality gradients}, volume = {112}, year = {2025}, }
• (2025). Fast and accurate modeling of kerr-brillouin combs in fabry-perot resonators. PRA, 112(3), 033526. (www)

  @article{ , abstract = {We introduce a new mean-field equation for modeling Fabry-Perot resonators filled with a dispersive medium exhibiting both Brillouin and Kerr nonlinearities, e.g., an optical fiber. This model is derived from a unified framework that accounts for Brillouin scattering and four-wave mixing. It involves two coupled nonlinear Schrödinger equations for the forward and backward propagating fields, alongside a single equation governing the acoustic oscillation. Under the standard assumptions for the mean-field approach (high finesse, weak nonlinearity, and weak dispersion) we demonstrate that our model closely matches the original system. The simplified and elegant mathematical structure of our equation provides valuable physical insights. As a key example, we derive an expression for the growth rate of harmonic perturbations to the steady states. Additionally, our model facilitates fast and accurate numerical simulations using standard Fourier split-step methods. We highlight the effectiveness of this approach by simulating frequency comb generation in state-of-the-art high-Q fiber Fabry-Perot resonators.}, archive = {J_PRA}, author = {Matteo Conforti and Thomas Bunel and Auro M. Perego and Arnaud Mussot}, doi = {10.1103/1cfh-8c16}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033526}, shortjournal = {Phys. Rev. A}, title = {Fast and accurate modeling of kerr-brillouin combs in fabry-perot resonators}, volume = {112}, year = {2025}, }
• (2025). Superdirectional scattering enabled by degenerate ε-near-zero electric resonances. PRA, 112(3), 033525. (www)

  @article{ , abstract = {Controlling both the magnitude and directionality of light scattering by subwavelength objects plays a crucial role in enhancing light-matter interactions and has great potential in antenna design, sensing, and optical displays. Superscattering, induced by degenerate resonances, allows the scattering cross section of subwavelength structures to surpass the fundamental single-channel limit. However, most existing superscattering techniques depend on complex multilayered structures and primarily aim to enhance scattering magnitudes. In this work, we propose a single-layer plasmonic core-shell nanoparticle that achieves superdirectional scattering without relying on high-permittivity materials and magnetic resonances. We demonstrate that for nanoparticles with a thin plasmonic nanoshell, both dielectric dipolar and quadrupolar resonances occur at nearly the same frequency, where the permittivity of the plasmonic shell approaches zero (degenerate epsilon-near-zero (ENZ) resonances), enabling superscattering in this simple nanoparticle. Furthermore, by tuning the amplitudes of these ENZ resonances, we show that both zero-backward and super-forward scattering can be realized. This approach, relying solely on pure electric ENZ modes in a simple core-shell nanoparticle, offers a new pathway for achieving superdirectional scattering and holds significant potential for applications in photovoltaic devices, biosensors, and nanoantennas.}, archive = {J_PRA}, author = {Yan Li and Tian Yang and Shuaifu Zhao and Facheng Zhong and Qi Liu and Meng Li and Li Shao and Zhanjun Yu and Yinxiao Du}, doi = {10.1103/lq78-xr44}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033525}, shortjournal = {Phys. Rev. A}, title = {Superdirectional scattering enabled by degenerate ε-near-zero electric resonances}, volume = {112}, year = {2025}, }
• (2025). Conservation of optical chirality in nanoscale light-matter interactions: A study of the born-kuhn model system. PRA, 112(3), 033524. (www)

  @article{ , abstract = {Optical chirality density is a measure of the local handedness of electromagnetic fields. Like energy density, it may be absorbed or scattered through the interaction between light and matter. Here we utilize the conservation of optical chirality to connect the parity and time-reversal symmetries of the intrinsic excitational eigenmodes of a material to those of their associated electromagnetic eigenfields as dictated by Maxwell's equations. To make this connection explicit, we theoretically examine the Born-Kuhn (BK) system, composed of a pair of plasmonic nanorods of variable separation, as a prototypical material model that is both geometrically chiral in its static structure and truly excitationally chiral in its eigenexcitations and eigenfields. By relaying optical chirality metrics of the BK eigenfields back to their underlying sourcing material degrees of freedom, we derive a unique mechanical chirality measure that is related to, but distinct from, other pseudoscalar metrics recently discussed in the literature. Beyond analysis in the absence of sources, we further derive optical chiral extinction, scattering, and absorption cross sections under external drive and discuss their rigorous connection to more common circular dichroism measurements as well as their limitations in comparison to eigenfield chirality metrics. Finally, we investigate the conversion of achiral linearly polarized light into chiral elliptically polarized light through interaction with the BK system, illustrating the conservation of optical chirality in the interaction between light and matter through an analytically tractable example.}, archive = {J_PRA}, author = {Kevin N. Moser and Marc R. Bourgeois and Elliot K. Beutler and David J. Masiello}, doi = {10.1103/8f2s-rjgy}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033524}, shortjournal = {Phys. Rev. A}, title = {Conservation of optical chirality in nanoscale light-matter interactions: A study of the born-kuhn model system}, volume = {112}, year = {2025}, }
• (2025). Multiple-order differential imaging based on two types of topological singularity in one-dimensional photonic crystals. PRA, 112(3), 033523. (www)

  @article{ , abstract = {Differential imaging has garnered significant attention owing to its boundary detection capabilities in image processing. However, to date, there has been scant research investigating the relationship between the differential imaging effect and the topological properties of a one-dimensional (1D) system. In this work, we systematically investigate the multiple-order differential imaging based on two types of topological singularity in 1D photonic crystals (PhCs). For both oblique and normal incidences, we conduct a detailed investigation of differential imaging effect. For the oblique incident cases, the first type of topological singularities support first-order differential imaging in both x and y directions. Meanwhile, based on the second type of topological singularities, ∂ 2 / ∂ x ∂ y -type differential imaging can be achieved. For the normal incident cases, the first type of topological singularities can support radial second-order and fourth-order differential imaging and the second type of topological singularities can support radial fourth-order differential imaging without the need for fine-tuning of the structural parameters. We further demonstrate the realization of these differential imaging effects in the deep-subwavelength region by shifting the first type of topological singularities into this region. This research connects the topological properties of PhCs with optical differential imaging, paving the way for the development of multiple-order differential imaging devices with improved robustness and functionality.}, archive = {J_PRA}, author = {Haoran Zhang and Yufu Liu and Yunlin Li and Xunya Jiang}, doi = {10.1103/j4kb-7rkm}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033523}, shortjournal = {Phys. Rev. A}, title = {Multiple-order differential imaging based on two types of topological singularity in one-dimensional photonic crystals}, volume = {112}, year = {2025}, }
• (2025). Spatially modulated atomic ensemble for real-space band braiding. PRA, 112(3), 033522. (www)

  @article{ , abstract = {We propose a non-Hermitian momentum-lattice model based on an atomic ensemble coupled with spatially modulated optical fields. By introducing modulation to the optical fields, we realize a momentum lattice featuring nonreciprocal couplings, long-range interactions, and highly tunable parameters. In this platform, the Brillouin zone emerges in real space, enabling band braiding in the E − x space, leading to band structures such as unlinks, unknots, Hopf links, and trefoil knots. The resulting band topology is characterized by the discriminant number in one dimension and homotopy classes in two dimensions. Based on the theory called non-Hermitian absorption spectroscopy, we establish a direct correlation between complex band topological structures and spatially resolved absorption spectra. Interestingly, one can take a photo of the band braiding using an optical camera. Moreover, we propose a protocol to implement a three-band non-Hermitian lattice for exploring non-Abelian topology in a synthetic two-dimensional Brillouin torus and discuss its extension to three dimensions.}, archive = {J_PRA}, author = {Ying Zhang and Lifeng Liu and Tianze Sheng and Yueping Niu and Shangqing Gong}, doi = {10.1103/qmh6-bzc4}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033522}, shortjournal = {Phys. Rev. A}, title = {Spatially modulated atomic ensemble for real-space band braiding}, volume = {112}, year = {2025}, }
• (2025). SU(2) symmetry of spatiotemporal gaussian modes propagating in isotropic dispersive media. PRA, 112(3), 033521. (www)

  @article{ , abstract = {The far-field intensity distribution of spatiotemporal Laguerre-Gaussian (STLG) modes propagating in free space exhibits a multipetal pattern analogous to that observed in tilted Hermite-Gaussian modes. Here, we show that this phenomenon can be explained by the SU(2) symmetry of spatiotemporal Gaussian modes, which can support the irreducible representation of the SU(2) group and enable the construction of the spatiotemporal model Poincaré sphere. We have also derived analytical expressions for the STLG mode with an arbitrary radial and angular indices propagating in the isotropic media. The propagation dynamics can be understood as a unitary transformation generated by a conserved quantity, where the rotation angle is exactly the intermodal Gouy phase of the spatiotemporal modes in the same order subspace. This spatiotemporal Gouy phase depends on the ellipticity of the wave packets and the group velocity dispersion of the media. The phase, as a function of propagation distance, is categorized into three distinct regimes: normal dispersion, anomalous dispersion, and zero dispersion. Interestingly, in the regime of anomalous dispersion, the nonmonotonic behavior induces both distortion and revival of the intensity distribution, thereby establishing a phase-locked mechanism that is analogous to the Talbot effect.}, archive = {J_PRA}, author = {Fangqing Tang and Xing Xiao and Lixiang Chen}, doi = {10.1103/2jxt-d8pg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033521}, shortjournal = {Phys. Rev. A}, title = {SU(2) symmetry of spatiotemporal gaussian modes propagating in isotropic dispersive media}, volume = {112}, year = {2025}, }
• (2025). Goos-hänchen shift and slow-light enhancement in a fixed cavity: Bose-einstein condensate bogoliubov modes as mechanical oscillators. PRA, 112(3), 033520. (www)

  @article{ , abstract = {We theoretically investigate light-matter interference phenomena in a hybrid optical cavity–Bose-Einstein condensate (BEC) system incorporating both an intracavity optical parametric amplifier (OPA) and atom-atom collisions. Starting from the linearized quantum Langevin equations, we derive the drift matrix and confirm system stability by verifying that all eigenvalue real parts remain negative. We then analyze the probe transmission spectrum under two complementary control mechanisms. First, with collisional interactions suppressed, increasing the OPA gain within the stability region transforms the standard Lorentzian cavity response into a tunable Fano-like profile, accompanied by asymmetric dispersive line shapes and pronounced group delays. Second, with the OPA turned off, including atomic collisions yields an intrinsically narrow Bogoliubov excitation that interferes with the cavity continuum, reproducing Fano resonances, “S-shaped” phase dispersion, slow- and fast-light windows, and positive Goos-Hänchen shifts. By examining both absorptive (real) and dispersive (imaginary) components of the transmitted field, we establish direct links between destructive interference pathways, steep phase slopes, and enhanced optical delays. Our results demonstrate that parametric amplification and collisional nonlinearities are equally versatile tools for engineering quantum interference in cavity QED with ultracold atoms, opening prospects for reconfigurable slow-light buffers, Fano-switchable photonic routers, and atom-integrated delay lines.}, archive = {J_PRA}, author = {Ghaisud Din and Muqaddar Abbas and Fazal Badshah and Yunlong Wang and Feiran Wang and Pei Zhang}, doi = {10.1103/n6l2-c2rj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033520}, shortjournal = {Phys. Rev. A}, title = {Goos-hänchen shift and slow-light enhancement in a fixed cavity: Bose-einstein condensate bogoliubov modes as mechanical oscillators}, volume = {112}, year = {2025}, }
• (2025). Comparative study of focusing with scalar and vector beams in an active raman gain system. PRA, 112(3), 033519. (www)

  @article{ , abstract = {We investigate the focusing characteristics of scalar and vector beams within an atomic medium. An active-Raman-gain configuration is employed to achieve significant Kerr nonlinearity in a four-state atomic system. The probe beams can attain focusing within the medium through careful selection of input beam intensities and the spatial profile of the control field. We analytically derive the linear and third-order nonlinear susceptibilities for both scalar and vector probe beams. Our observations indicate that, in addition to the energy transfer from the control beam to the probe beam, the giant cross-Kerr nonlinearity facilitates the focusing of the scalar probe beam into a significantly smaller spot size. Conversely, the vector probe beams exhibit gain-induced narrowing. Furthermore, we evaluate the state of polarization for the vector beam at the minimum beam waist, observing a polarization rotation and a change in ellipticity during propagation. Through the mechanism of focusing, we achieve a reduced spot size for the probe beam, which may have substantial implications for resolution enhancement in microscopy applications.}, archive = {J_PRA}, author = {Partha Das and Tarak Nath Dey}, doi = {10.1103/8j1w-dvc1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033519}, shortjournal = {Phys. Rev. A}, title = {Comparative study of focusing with scalar and vector beams in an active raman gain system}, volume = {112}, year = {2025}, }
• (2025). Enhanced high-sensitivity mass sensor in a gain-cavity-assisted optomechanical system. PRA, 112(3), 033518. (www)

  @article{ , abstract = {In this study, we propose and analyze a highly efficient scheme for realizing sensitive mass sensors in a quadratically coupled optomechanical system, assisted by a gain cavity via a nonlinear second-order sideband process. Moving beyond conventional linearized approximations, we derive analytical expressions for both the second-order sideband efficiency and mass-sensing sensitivity using a perturbation approach. Our scheme enables mass detection by monitoring shifts in the second-order sideband generation efficiency when a target mass is deposited on the dielectric membrane. Using experimentally feasible parameters, we identify the maximum achievable efficiency of the second-order upper sideband and its corresponding optimal sensitivity. Remarkably, with the aid of a gain cavity, both the sideband efficiency and mass sensitivity are significantly enhanced—particularly near the exceptional point, where improvements exceeding three orders of magnitude are demonstrated. This work provides a promising approach to high-precision mass measurement, advancing and complementing existing methodologies.}, archive = {J_PRA}, author = {Zhong Ding and Lu-Lu Wang and Yong Zhang}, doi = {10.1103/q38z-g16c}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033518}, shortjournal = {Phys. Rev. A}, title = {Enhanced high-sensitivity mass sensor in a gain-cavity-assisted optomechanical system}, volume = {112}, year = {2025}, }
• (2025). Splitting and merging of bound states in the continuum through defect engineering. PRA, 112(3), 033517. (www)

  @article{ , abstract = {Bound states in the continuum (BICs) are electromagnetic eigenstates that theoretically exhibit infinite quality factors. However, scattering losses induced by manufacturing defects inevitably affect the confinement performance of BICs. Studies have shown that combining multiple BICs can enhance their robustness against such defects. Currently, approaches to merging BICs at off- points typically rely on altering the geometry of the central structure, which not only increases the complexity of device design but also potentially raises costs. Based on this, we propose a scheme that maintains the central structure while introducing specific defect holes to break the in-plane symmetry of the system, thereby inducing the splitting of the higher-order BIC and forming multiple off- BICs. Subsequently, these split BICs, along with the accidental BICs, will merge at the off- point as the structural parameters are varied. The proposed concept not only enhances optical confinement but also enables flexible control over the splitting direction of the higher-order BIC by manipulating the spatial positions of the defect apertures. More importantly, by rationally designing the positions of defects, we can construct merging BICs at arbitrary wave vectors through manipulations of split BICs and accidental BICs. Furthermore, even in the presence of manufacturing defects, the merging BICs demonstrate exceptional robustness. This provides new insights for the flexible control of BICs in diversified applications while also expanding their potential in a broader momentum space.}, archive = {J_PRA}, author = {Ke Xu and Miao Liu and Hao Ren and Xuesong Deng and Jian Feng and Ming Fang and Zhixiang Huang}, doi = {10.1103/2w92-47q1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033517}, shortjournal = {Phys. Rev. A}, title = {Splitting and merging of bound states in the continuum through defect engineering}, volume = {112}, year = {2025}, }
• (2025). Tunable rotation dynamics in bilayer optical matter motors via distance-modulated interlayer coupling. PRA, 112(3), 033516. (www)

  @article{ , abstract = {Optical micromotors, key components in microrobotics and biomedical applications, have attracted widespread attention for their ability to manipulate and rotate microscopic particles using light. In this study, we present a tunable bilayer optical matter motor controlled by distance-modulated electromagnetic interlayer coupling. Using the generalized Lorentz-Mie scattering theory for multispheres and the Langevin dynamics method, we investigate the dynamics of the bilayer motor during light-driven self-organization and rotation. Through the modulation of the interlayer distance to tune coupling effects, we demonstrate the capacity to selectively manipulate the rotation modes of the motor—both layers can rotate clockwise (receiving negative optical torque), rotate anticlockwise, or counterrotate. These modes arise from changes in the relative contributions of excited electric and magnetic multipoles, offering an intuitive understanding of interlayer coupling from the perspective of multipoles. The bilayer motor exhibits stable rotation across a wide range of coupling distances due to strong long-range electromagnetic coupling, and demonstrates excellent robustness to both the polarization of the incident light and structural offset from the beam center, facilitating experimental implementation. Our structural stability analysis indicates that bilayer optical matter motors constructed from equilateral triangular units maintain remarkable stability during light-driven self-organization and rotation, even with varying interlayer coupling. This research enhances our understanding of light-matter interactions in the dynamics of bilayer optical matter systems while providing theoretical foundations for novel micromotor design.}, archive = {J_PRA}, author = {Zhenyu Han and Xiao Li and Yaxin Li and Xiaoxuan Shi and Tiantao Qu and Lei Zhang and Jun Chen}, doi = {10.1103/x9xf-k6lh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033516}, shortjournal = {Phys. Rev. A}, title = {Tunable rotation dynamics in bilayer optical matter motors via distance-modulated interlayer coupling}, volume = {112}, year = {2025}, }
• (2025). Non-abelian braiding of coupled modes in photonic waveguides. PRA, 112(3), 033515. (www)

  @article{ , abstract = {Non-Abelian braiding plays a crucial role in topological quantum computing for protecting the evolution of non-Abelian anyons. Recently, the concept of non-Abelian braiding has been introduced to classical systems for applications such as quantum logic, but the working mode was restricted to the fundamental mode. Here, we propose a scheme for realizing the classical non-Abelian braiding of coupled modes in photonic waveguides system. The Hamiltonian of the designed system is built via the interplay between two sub-Hamiltonians, where one of them enables the non-Abelian braiding, while the other one generates the coupled modes. In this way, the non-Abelian braiding of coupled modes of arbitrarily high order can be realized. We carry out numerical simulations to verify the concept for coupled modes with an order of four, including the mode switching behavior as well as the non-Abelian geometric phase. The proposed concept may lead to on-chip applications including mode division multiplexing non-Abelian braiding.}, archive = {J_PRA}, author = {Zhong-Lei Shan and Xu-Lin Zhang}, doi = {10.1103/83l2-nzr1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033515}, shortjournal = {Phys. Rev. A}, title = {Non-abelian braiding of coupled modes in photonic waveguides}, volume = {112}, year = {2025}, }
• (2025). Transformation of topological optical states via spiral modulation in fractional-diffraction systems. PRA, 112(3), 033514. (www)

  @article{ , abstract = {We propose a scheme for manipulations of a variety of topological states in fractional optical systems through spiral modulation of the local refraction index. An analytical approximation, based on a truncated finite-mode system, and direct simulations reveal that the spiral modulation supports direct mutual conversion between eigenmodes with topological-charge difference , driven by the resonant coupling between the modes and the underlying spiral modulation. The conversion between eigenmodes with requires involvement of an intermediary mode and precise tuning of the resonance condition. We further explore the conversion of degenerate modes under the action of azimuthal modulation. Modulated degenerate modes exhibit incomplete conversion, evolving into intermediate states with odd parity symmetry. Finally, we examine nonlinear effects on the spiral-modulation-induced mode conversion, identifying an essential nonlinearity-induced resonance-frequency shift that critically affects the conversion efficiency.}, archive = {J_PRA}, author = {Dongdong Wang and Xueqing He and Rujiang Li and Dumitru Mihalache and Boris A. Malomed and Pengfei Li}, doi = {10.1103/srcz-2wc2}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033514}, shortjournal = {Phys. Rev. A}, title = {Transformation of topological optical states via spiral modulation in fractional-diffraction systems}, volume = {112}, year = {2025}, }
• (2025). Self-reconstruction properties of partially coherent pulses in nonlinear kerr media. PRA, 112(3), 033513. (www)

  @article{ , abstract = {Light fields with partial spatial coherence are renowned for their remarkable self-reconstruction properties, which have enabled a wide range of applications, including optical imaging and particle trapping. In this paper, we extend the self-reconstruction concept to temporal-domain partially coherent pulses and investigate their reconstruction characteristics in nonlinear Kerr media. As an illustrative example, we employ a cosine-Gaussian correlated Schell-model pulse to conduct in-depth analyses. Our numerical results reveal that the obstructed pulses, with the help of the source degree of coherence, exhibit outstanding self-reconstruction properties in the nonlinear Kerr media. Although the nonlinearity can to some extent impair the self-reconstruction ability of pulses, ultrastrong self-reconstruction of the pulses can be achieved by reducing the optical coherence. Our research findings may have potential applications in image transmission and optical information processing.}, archive = {J_PRA}, author = {Yanlin Bai and Qian Chen and Tianyu Cao and Jingsong Liu and Xin Liu and Chunhao Liang and Yangjian Cai and Xiaofeng Peng}, doi = {10.1103/fsc3-vl69}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033513}, shortjournal = {Phys. Rev. A}, title = {Self-reconstruction properties of partially coherent pulses in nonlinear kerr media}, volume = {112}, year = {2025}, }
• (2025). Integrated and tunable microwave-to-optical transduction via magno-optomechanics. PRA, 112(3), 033512. (www)

  @article{ , abstract = {Microwave-to-optical transducers facilitate the distributed quantum network by combining the high-speed information-processing abilities of superconducting circuits with the long-distance, low-loss transmitting capabilities of optical photons. Besides core metrics such as high efficiency, low noise, and wide bandwidth, practical and scalable transducers also demand a compact footprint and frequency tunability. In this work, we propose an integrated and tunable transducer that combines a coplanar waveguide microwave resonator with a magno-optomechanical microcavity via flip-chip bonding. Benefiting from the broad frequency tunability of the magnon mode, the working frequency range can be tuned over several gigahertz. Through optimization of the geometry and pump powers, our design achieves a theoretical microwave-to-optical photon conversion efficiency exceeding 50% using experimentally achievable parameters, alongside a bandwidth greater than 10 kHz. An added noise near the quantum limit is achievable at 10 mK using lower pump powers at the cost of conversion efficiency or a pulsed-pump protocol. By merging compact integration with wide frequency tunability, this platform offers a promising pathway toward scalable quantum networks.}, archive = {J_PRA}, author = {Jian-Fei Liu and Zhi-Gang Hu and Yu-Xiang Zhang and Bei-Bei Li}, doi = {10.1103/fwpw-f81y}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033512}, shortjournal = {Phys. Rev. A}, title = {Integrated and tunable microwave-to-optical transduction via magno-optomechanics}, volume = {112}, year = {2025}, }
• (2025). Photonic spin splitting with orbital angular momentum pointer states via modified weak measurement. PRA, 112(3), 033511. (www)

  @article{ , abstract = {We report an experimental demonstration of generalized photonic spin splitting (PSS) using arbitrary linearly polarized higher-order orbital angular momentum (OAM) pointer states supported by a modified weak measurement model. The experimental findings show the dependence of longitudinal and transverse PSS on linear polarization angle, postselection angle, and azimuthal index ( ) of OAM states. PSS rises as increases, reaching a maximum of roughly 300 and 120 for the transverse and longitudinal shift values, respectively. Considering , 1, and 2, the polarization-controlled variation of both shifts at three distinct angles of incidence is investigated for a fixed postselection angle. All the experimental results agree well with the developed theoretical model, proving the model's accuracy. This model is valid for both external and internal reflection of arbitrary linearly polarized incident light reflecting from absorbing as well as nonabsorbing mediums, considering arbitrary coupling strength and a very small postselection angle. The manipulation of PSS using higher-order OAM light beams shown in this study will have a wide range of applications in wavefront manipulation, optical sensors, and nanophotonics.}, archive = {J_PRA}, author = {Soumen Mandal and Dinesh Chandra Dey and Anuradha Sett and Manik Pradhan}, doi = {10.1103/y8r5-pkqy}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033511}, shortjournal = {Phys. Rev. A}, title = {Photonic spin splitting with orbital angular momentum pointer states via modified weak measurement}, volume = {112}, year = {2025}, }
• (2025). Spectral splitting of vector solitons in a birefringence-managed fiber laser. PRA, 112(3), 033510. (www)

  @article{ , abstract = {Pulse splitting, which results from the excessive accumulation of nonlinear phase shifts, enables multipulse emission with an identical spectrum in mode-locked fiber lasers. However, spectral splitting was rarely observed owing to the limited gain bandwidth and gain competition effect. We demonstrate the spectral splitting of mode-locked pulses ubiquitously existed in birefringence-managed normal-dispersion fiber lasers, where a single-spectrum pulse evolves into multispectrum pulses with different group velocities by increasing the pump intensity. Theoretical analysis and numerical simulations fully reproduce the experimental observations, confirming that the periodic linear and nonlinear coupling of vector modes split the pulse in the frequency domain. This study presents a simple yet efficient method for generating controllable multispectrum mode-locked pulses without the use of spectral filters, which has significant implications for exploring multicolor pulse interactions and facilitating practical applications such as absolute distance measurement.}, archive = {J_PRA}, author = {Jia Xue and Yufeng Zhang and Yueqing Du and Chao Zeng and Dong Li and Guanghua Cheng and Jianlin Zhao and Dong Mao}, doi = {10.1103/gdht-6b51}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033510}, shortjournal = {Phys. Rev. A}, title = {Spectral splitting of vector solitons in a birefringence-managed fiber laser}, volume = {112}, year = {2025}, }
• (2025). Chiral metasurfaces using a metamolecular pancharatnam-berry phase. PRA, 112(3), 033509. (www)

  @article{ , abstract = {The Pancharatnam-Berry (PB) phase is characterized by the simple application method and comprehensive theoretical framework, offering significant advantages in designing metasurfaces for hologram and nanoprinting. However, the PB phase relies heavily on an analyzer to enable nanoprinting. Additionally, designing a chiral metasurface by the PB phase poses significant challenges, limiting the application in multifunctional metasurfaces. This paper introduces a metamolecular Pancharatnam-Berry phase based on metamolecules to enable the design of chiral metasurfaces. Metamolecules can independently and arbitrarily adjust intensity and phase without the need for an analyzer. By introducing the chiral factor to metamolecules, the proposed chiral metasurface achieves polarization-sensitive nanoprinting and hologram without the use of an analyzer. This approach addresses the limitations of the traditional PB phase in near-field modulation and chiral research while providing a theoretical foundation for the miniaturization and advancement of intelligent metasurfaces.}, archive = {J_PRA}, author = {Yizhou Zhuo and Yingqiu Zhang and Mengshuang Peng and Linjun Yi and Guohua Qin and Zhongchao Wei}, doi = {10.1103/zbmt-b43k}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033509}, shortjournal = {Phys. Rev. A}, title = {Chiral metasurfaces using a metamolecular pancharatnam-berry phase}, volume = {112}, year = {2025}, }
• (2025). Complex networks for random lasers and photonic computing. PRA, 112(3), 033508. (www)

  @article{ , abstract = {We present a theoretical study of a random laser (RL) formed by a scale-free photonic network (PN) with dissipative photon tunneling between microcavities (MCs) hosting two-level quantum systems (TLSs). Using the Gorini-Kossakowski-Sudarshan-Lindblad framework, we identify two distinct lasing regimes. The first is independent of the tunneling parameter and emerges when the steady-state frequency of the mode is resonant with the TLS transition. This resembles lasing in uncoupled MCs and relies on population inversion. The second scenario arises from the nonreciprocal nature of dissipative tunneling and enables lasing of nonresonant modes even at vanishingly small population inversion, owing to energy redistribution across the network. In the latter case, interference effects along graph paths induce node-dependent frequency shifts and nonreciprocal photon transmission. We further propose a renormalization-group hypothesis for the PN to explain the observed spectral features. We analyze the phase structure of photonic modes in the scale-free RL and discuss its relevance for photonic Ising machines operating under the minimum power dissipation principle.}, archive = {J_PRA}, author = {Dmitriy V. Tsarev and Petr V. Zakharenko and Alexander P. Alodjants}, doi = {10.1103/1mqj-61yh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033508}, shortjournal = {Phys. Rev. A}, title = {Complex networks for random lasers and photonic computing}, volume = {112}, year = {2025}, }
• (2025). Quantum-optical signatures of solid-state high-harmonic generation driven by squeezed coherent states. PRA, 112(3), 033507. (www)

  @article{ , abstract = {Recently, the intersection of quantum optics and attosecond physics has attracted growing interest. Here, we study the quantum optical signatures of high-harmonic generation (HHG) from solid-state material driven by squeezed coherent states. We find that squeezed coherent states can either enhance or suppress the HHG yields compared to that driven by coherent light, depending on the photon bunching or antibunching characteristics of driving light. The analysis on semiclassical trajectories indicates that the amplitude fluctuation alters the recombination energy, while the phase fluctuation affects the birth and recombination time of electron-hole pairs. By calculating the Husimi Q distributions of HHG, we demonstrate that the squeezing of the two conjugate quadratures of driving light asymmetrically influence the squeezing phase of harmonics. Surprisingly, we find that even under coherent driving, the harmonics still exhibit squeezing due to the highly nonlinear response of solid-state HHG, which was overlooked previously. Numerical calculations of the Mandel parameter are performed to characterize the photon statistics of emitted HHG arising from different microscopic mechanisms. The results indicate that intraband radiation can exhibit a super-Poissonian distribution, while interband emission exhibits sub-Poissonian distribution under coherent driving.}, archive = {J_PRA}, author = {Jingze Li and Zijian Lyu and Haodong Liu and Yunquan Liu}, doi = {10.1103/vmk1-qjpj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033507}, shortjournal = {Phys. Rev. A}, title = {Quantum-optical signatures of solid-state high-harmonic generation driven by squeezed coherent states}, volume = {112}, year = {2025}, }
• (2025). Synthetic-lattice bloch wave dynamics in a single-mode microwave resonator. PRA, 112(3), 033506. (www)

  @article{ , abstract = {Frequency-based synthetic dimensions are a promising avenue for expanding the dimensionality of photonic systems. In this work, we show how a tilted synthetic lattice is naturally realized by periodically modulating a single-mode resonator under a coherent monochromatic drive. We theoretically study the Bloch wave dynamics in the tilted synthetic lattice, which gives rise to peculiar features in the spectral distribution of the cavity field. Our predictions are experimentally confirmed using a tunable superconducting microwave resonator.}, archive = {J_PRA}, author = {F. Ahrens and N. Crescini and A. Irace and G. Rastelli and P. Falferi and A. Giachero and B. Margesin and R. Mezzena and A. Vinante and I. Carusotto and F. Mantegazzini}, doi = {10.1103/x4w1-tmw8}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033506}, shortjournal = {Phys. Rev. A}, title = {Synthetic-lattice bloch wave dynamics in a single-mode microwave resonator}, volume = {112}, year = {2025}, }
• (2025). Extreme events in detuned semiconductor lasers under delayed mutual injection. PRA, 112(3), 033505. (www)

  @article{ , abstract = {Single-mode semiconductor lasers support fast nonlinear dynamics for investigating extreme events. Although one laser subject to perturbation is sufficient for yielding extreme events, multiple lasers with mutual interactions have yet to be considered. Here, extreme events are found experimentally using two detuned lasers under delayed mutual injection. The mutually injected lasers each emit an intensity that exhibits locking to a constant, except for interruptions by intermittent pulses, including very strong ones as extreme events. Such extreme eruptions from a constant background under mutual injection are different from the continual chaotic oscillations usually obtained under unidirectional injections. By varying the detuning frequency between the lasers, the intermittent pulsations with extreme events are found in a route that involves regular switching between constant and periodic oscillatory intensities. By adopting space-time representation, the extreme events are observed to emerge stochastically, together with some partial repetitions of pulses corresponding to a slightly lengthened round trip. By optimizing the detuning, the maximal normalized occurrence of extreme events reaches 0.8%, which is relatively high among approaches on lasers without external modulations for excitations. On average, about six extreme events are yielded within one round trip of 130 ns, while their short pulse widths are of the order of 0.1 ns. Applicable to generating strong random electrical pulses, the experiments point to the importance of mutual interactions in single-mode lasers for extreme events.}, archive = {J_PRA}, author = {Shi-Ya Wang and Sze-Chun Chan}, doi = {10.1103/8rrz-5kdf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033505}, shortjournal = {Phys. Rev. A}, title = {Extreme events in detuned semiconductor lasers under delayed mutual injection}, volume = {112}, year = {2025}, }
• (2025). Light amplification by active metamirrors. PRA, 112(3), 033504. (www)

  @article{ , abstract = {We consider a scheme of a thin film deposited on periodically modulated amplifying materials. We demonstrate that the reflection from such a metainterface can undergo amplification due to Fano resonances in the film. The amplification increases when the film waveguiding modes approach the edge of the continuum and degenerate into the leaky surface modes, guided by a thin film. Such modes possess a strong evanescent tail that extends into the active substrate and are therefore amplified. The study is performed by simplified analytical models, as well as by rigorous coupled wave analysis.}, archive = {J_PRA}, author = {Ignas Lukosiunas and Kestutis Staliunas}, doi = {10.1103/wg62-zt6d}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033504}, shortjournal = {Phys. Rev. A}, title = {Light amplification by active metamirrors}, volume = {112}, year = {2025}, }
• (2025). Spatial extra-bunching effect in classical light. PRA, 112(3), 033503. (www)

  @article{ , abstract = {Thermal light by nature exhibits the well-known photon bunching effect with the zero-delay second-order correlation coefficient ideally equal to 2. The Photon extra-bunching effect, as a special class of the superbunching effect ( ), describes the enhanced photon correlation ( ) through the interference of bright twin beams produced in the spontaneous parametric down-conversion. In this work, we report that this effect can exist in classical beams and that can approach 4 in some extended extreme models. We experimentally demonstrate the nontrivial extra-bunching correlation ( gain) in pairwise-generated holographic thermal light beams with a Dove prism-embedded balanced Mach-Zehnder interferometer. The interaction of such a pair of conjugated thermal light beams can generate a pair of uncorrelated superthermal light beams, enabling ghost imaging and Young's intensity interference with enhanced visibility. The quantum-inspired interference-induced spatial extra-bunching effect provides novel insights into inducing superbunching correlation in classical light and holds the potential for application in the coherent two-photon Lidar system to enhance sensitivity.}, archive = {J_PRA}, author = {Chen-Xin Ding and Run-Jie He and Zhiyuan Ye and Xue-Jiao Men and Wanting Hou and Yi Cui and Hong-Chao Liu and Hai-Bo Wang and Jun Xiong}, doi = {10.1103/2r44-md7c}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033503}, shortjournal = {Phys. Rev. A}, title = {Spatial extra-bunching effect in classical light}, volume = {112}, year = {2025}, }
• (2025). Propagation and stability of laser pulses in the atmosphere. PRA, 112(3), 033502. (www)

  @article{ , abstract = {Long-range propagation of laser pulses in the atmosphere is of interest in free-space communication, remote detection, and directed energy, among others. We analyze and numerically simulate the propagation and stability of laser pulses propagating in the vertical direction. Stability of the dynamic equilibrium of the laser pulse is analyzed and numerically simulated, taking into account the variation of the air density, linear and nonlinear dispersion, and turbulence level, as a function of altitude. In the dynamic equilibrium, the spot size, pulse duration, wave-front curvature, phase, and chirp evolve self-consistently along the propagation path. Significant intensity enhancement at remote distances is achieved by tailoring the laser parameters in such a way that the transverse and longitudinal focal points nearly coincide. In addition, the hybrid filamentation-modulation instability is analyzed and simulated, indicating that the beam breaks up transversely and longitudinally. Our model enables laser pulse propagation studies over distances that ordinarily would be computationally challenging.}, archive = {J_PRA}, author = {Gavin Blair and Bahman Hafizi and Phillip Sprangle}, doi = {10.1103/21bg-wmvz}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033502}, shortjournal = {Phys. Rev. A}, title = {Propagation and stability of laser pulses in the atmosphere}, volume = {112}, year = {2025}, }
• (2025). Phase transition between linear and nonlinear motion in a quadrupole-trap-based levitodynamic system with massive particles. PRA, 112(3), 033501. (www)

  @article{ , abstract = {We have experimentally investigated the nonlinear nature of massive particle dynamics in a quadrupole trap under atmospheric pressure. We have studied our levitated system over a wide range of trapping parameters and determined four distinct dynamical states of the trapped particle motion, which are associated with the retaining force and drag force nonlinearities. Like any other nonlinear system, the considered one possesses a phase transition in its behavior that demarcates linear and nonlinear regimes of motion. The nonlinear regime manifests itself as the formation of a specific limit cycle of the trapped particle motion also known as an extended orbit . We have shown that the birth of the extended orbits is foretold by the appearance of half-integer trapping frequency multiples in the particle motion oscillation. These half-integer multiples are highly sensitive to trapping parameters and external perturbation. We have demonstrated that the phase transition is a continuous process over a range of system parameters and can be exploited to detect small influences on the levitated system. We have tested the system response in the transient state to the external optical perturbation. The strong sensitivity to perturbation laser power has been shown for both the spectral composition of the trapped particle translational oscillations and extended orbit formation point. We believe in the potential to apply the nonlinear state of the levitodynamic system with massive particles to the field of precision measurements and nonequilibrium physics investigation.}, archive = {J_PRA}, author = {Vadim Rybin and Maxim Semynin and Semyon Rudyi and Andrei Ivanov and Dmitrii Shcherbinin}, doi = {10.1103/wh14-rd9k}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033501}, shortjournal = {Phys. Rev. A}, title = {Phase transition between linear and nonlinear motion in a quadrupole-trap-based levitodynamic system with massive particles}, volume = {112}, year = {2025}, }
• (2025). Interaction-induced reentrance of bose glass and quench dynamics of bose gases in twisted bilayer and quasicrystal optical lattices. PRA, 112(3), 033322. (www)

  @article{ , abstract = {We investigate the ground state and dynamical properties of ultracold gases in optical lattices with a quasicrystal structure—a scenario inspired by recent experiments on twisted bilayer optical lattices and optical quasicrystals. Our study reveals that the interplay between on-site repulsive interactions and a quasiperiodic potential gives rise to rich physics. At low filling factors, increasing the interaction strength induces a delocalization effect that transforms a Bose-glass (BG) phase, characterized by disconnected superfluid (SF) regions, into a robust SF phase with a percolated network of SF clusters. This transition is quantitatively characterized by monitoring the percolation probability. At higher filling factors, we uncover a striking reentrant behavior: As the on-site interaction increases, the system initially transitions from BG to SF, but a further increase reverses this trend, returning the system to the BG phase. This reentrance is ascribed to an interaction-driven rearrangement of particles, where a once-percolated SF network fragments into isolated SF islands as repulsive interactions dominate. Furthermore, our analysis of quench dynamics demonstrates distinct transient behaviors. Intraphase quenches yield minimal variations in both the percolation probability and the inverse participation ratio (IPR) of the particle-density distribution. In contrast, interphase quenches produce pronounced effects; for instance, a quench from the SF to BG phase is marked by an abrupt loss of global SF connectivity, while a BG-to-SF quench features oscillatory changes in the percolation probability and a gradual decrease in the IPR, eventually stabilizing the SF phase. Our findings unveil the complex interplay between quasiperiodic optical lattice potential and interaction in ultracold Bose gases, offering valuable insights that are highly pertinent to current experimental efforts employing state-of-the-art twisted bilayer and quasicrystalline optical lattice platforms.}, archive = {J_PRA}, author = {Shi-Hao Ding and Li-Jun Lang and Qizhong Zhu and Liang He}, doi = {10.1103/fvny-58kf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033322}, shortjournal = {Phys. Rev. A}, title = {Interaction-induced reentrance of bose glass and quench dynamics of bose gases in twisted bilayer and quasicrystal optical lattices}, volume = {112}, year = {2025}, }
• (2025). Vortices in D-dimensional anisotropic bose-einstein condensates: Dimensional perturbation theory with hypercylindrical symmetry. PRA, 112(3), 033321. (www)

  @article{ , abstract = {We investigate D -dimensional atomic Bose-Einstein condensates in a hypercylindrical trap with a vortex core along the z axis and quantized circulation ℏ m . We analytically approximate the hypercylindrical Gross-Pitaevskii equation using dimensional perturbation theory with perturbation parameter δ = 1 / ( D + 2 | m | − d ) , where d controls the contribution of kinetic energy at zeroth order. We derive the zeroth-order ( δ → 0 ) semiclassical approximations for the condensate energy, density, chemical potential, and critical vortex rotation speed in arbitrary dimensions. We investigate the effect of trap anisotropy on lower effective dimensionality and compute properties of vortices in higher dimensions motivated by the study of synthetic dimensions and holographic duality, where a higher-dimensional gravitational model corresponds to a lower-dimensional quantum model. In the zeroth-order approximation, we observe crossings between energy levels for different dimensions as a function of interaction strength and anisotropy parameters.}, archive = {J_PRA}, author = {Maria Isabelle Fite and B. A. McKinney}, doi = {10.1103/yg7l-ggnf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033321}, shortjournal = {Phys. Rev. A}, title = {Vortices in D-dimensional anisotropic bose-einstein condensates: Dimensional perturbation theory with hypercylindrical symmetry}, volume = {112}, year = {2025}, }
• (2025). Quench spectroscopy for dissipative and non-hermitian quantum lattice models. PRA, 112(3), 033320. (www)

  @article{ , abstract = {We extend the quench spectroscopy method to dissipative and isolated non-Hermitian quantum lattice models via the case study of the open Bose-Hubbard chain and the non-Hermitian transverse-field Ising chain, respectively. We first investigate theoretically the dynamics of the open Bose-Hubbard chain confined in the superfluid phase induced by a sudden global quench on the dissipations and the repulsive interactions using the equation-of-motion approach. Using the same analytical approach, we then discuss the applicability of the quench spectroscopy to non-Hermitian quantum lattice models by considering the sudden global quench dynamics of the non-Hermitian transverse-field Ising chain confined in the paramagnetic phase. We finally generalize this spectroscopy method to isolated Hermitian quantum lattice models characterized by a quadratic fermionic or bosonic Hamiltonian. For this purpose, we consider the case study of the Hermitian version of the latter one-dimensional lattice model. The investigation is performed analytically for the bosonic and fermionic reformulations while considering for each case the equation-of-motion and quasiparticle theoretical approaches.}, archive = {J_PRA}, author = {Julien Despres}, doi = {10.1103/x1jy-b9tf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033320}, shortjournal = {Phys. Rev. A}, title = {Quench spectroscopy for dissipative and non-hermitian quantum lattice models}, volume = {112}, year = {2025}, }
• (2025). Exact renormalization relation and binding energies for three identical bosons. PRA, 112(3), 033319. (www)

  @article{ , abstract = {In the low-energy limit, nonrelativistic particles with short-range interactions exhibit universal behavior that is largely independent of microscopic details. This universality is typically described by effective field theory, in which the two-body interaction is renormalized to a single parameter—the scattering length. For systems of identical bosons, the three-body problem reveals the Efimov effect, a novel phenomenon proposed that necessitates the introduction of an additional three-body parameter. However, the exact relation between this three-body parameter, the coupling constants in the effective field theory, and the binding energies of Efimov states remains unresolved. In this work, we address this question through a comprehensive analysis of the Skorniakov–Ter-Martirosian equation with a finite cutoff. We establish an exact renormalization relation for the three-body parameter and determine its connection to the energies of Efimov bound states. These results are validated through high-precision numerical simulations. We expect our findings to be of fundamental interest across various fields, including atomic, nuclear, condensed matter, and particle physics, and to have broad applications in both few-body and many-body physics.}, archive = {J_PRA}, author = {Langxuan Chen and Pengfei Zhang}, doi = {10.1103/9p77-tmzz}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033319}, shortjournal = {Phys. Rev. A}, title = {Exact renormalization relation and binding energies for three identical bosons}, volume = {112}, year = {2025}, }
• (2025). Supersonic flow past an obstacle in a quasi-two-dimensional lee-huang-yang quantum fluid. PRA, 112(3), 033318. (www)

  @article{ , abstract = {A supersonic flow past an obstacle can generate a rich variety of wave excitations. This paper investigates, both analytically and numerically, two types of excitations generated by the flow of a Lee-Huang-Yang quantum fluid past an obstacle: linear radiation and oblique dark solitons. We show that wave crests of linear radiation can be accurately described by the proper modification of the Kelvin original theory, while the oblique dark soliton solution is obtained analytically by transformation of the one-dimensional soliton solution to the obstacle's reference frame. A comparison between analytical predictions and numerical simulations demonstrates good agreement, validating our theoretical approach.}, archive = {J_PRA}, author = {G. H. dos Santos and L. F. Calazans de Brito and A. Gammal and A. M. Kamchatnov}, doi = {10.1103/mxyb-6jh1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033318}, shortjournal = {Phys. Rev. A}, title = {Supersonic flow past an obstacle in a quasi-two-dimensional lee-huang-yang quantum fluid}, volume = {112}, year = {2025}, }
• (2025). Operator-valued-flow-equation approach to the bosonic lattice polaron: Dispersion renormalization beyond the fröhlich paradigm. PRA, 112(3), 033317. (www)

  @article{ , abstract = {We consider the ground-state properties of a lattice Bose polaron, a quasiparticle arising from the interaction between an impurity confined to an optical lattice and a surrounding homogeneous Bose-Einstein condensate hosting phononic modes. We present an extension of Wegner's and Wilson's flow equation approach, the operator-valued-flow-equation approach, which allows us to calculate the renormalized dispersion of the polaron and assess the role of two-phonon scattering processes on the dispersion. The results obtained in this way are compared to a variational mean-field approach, which will allow us to demonstrate that the flow equations behave correctly at weak coupling. We find that in certain impurity phonon interaction regimes the shape of the dispersion is significantly altered by the inclusion of two-phonon scattering events as opposed to only single-phonon scattering events. Moreover, our results predict that a polaronic bound state may emerge, which is not present in Fröhlich-type models that only consider single-phonon scattering events.}, archive = {J_PRA}, author = {Jan-Philipp Christ and Pit Bermes and Fabian Grusdt}, doi = {10.1103/pcsy-czjp}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033317}, shortjournal = {Phys. Rev. A}, title = {Operator-valued-flow-equation approach to the bosonic lattice polaron: Dispersion renormalization beyond the fröhlich paradigm}, volume = {112}, year = {2025}, }
• (2025). Velocity correlations of vortices and rarefaction pulses in compressible planar quantum fluids. PRA, 112(3), 033316. (www)

  @article{ , abstract = {We present a quantitative analytical framework for calculating two-point velocity correlations in compressible quantum fluids, focusing on two key classes of superfluid excitations: vortices and rarefaction pulses. We employ two complementary approaches. First, we introduce a new Ansatz for vortex cores in planar quantum fluids that enhances analytic integrability. This Ansatz yields closed-form expressions for power spectra and velocity correlations for general vortex distributions. Using it, we identify distinct signatures of short- and long-range velocity correlations corresponding to vortex dipoles and vortex pairs, respectively. Second, we analyze the fast rarefaction pulse regime of the Jones-Roberts soliton. By applying the asymptotic high-velocity wave function, we derive analytic expressions for the velocity power spectrum and correlation function, capturing the soliton characteristic length scale. We validate our analytical results for the homogeneous system against numerical treatment of a large trapped system, finding close quantitative agreement. Our findings provide the first analytic treatment of velocity correlations for Jones-Roberts solitons in quantum fluids of light [M. Baker-Rasooli et al. , Phys. Rev. Lett. 134 , 233401 (2025) ] and establish a foundation for characterizing vortices and solitons in compressible quantum fluids.}, archive = {J_PRA}, author = {Ashton S. Bradley and Nils A. Krause}, doi = {10.1103/qmrs-x19w}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033316}, shortjournal = {Phys. Rev. A}, title = {Velocity correlations of vortices and rarefaction pulses in compressible planar quantum fluids}, volume = {112}, year = {2025}, }
• (2025). Confinement-induced unatomic trimer states in mass-imbalanced systems. PRA, 112(3), 033315. (www)

  @article{ , abstract = {As resonantly interacting trimers of the type AAB are progressively squeezed from to , unatomic states emerge. We calculated the contacts from the high-momentum tail of the single-particle densities. The sharp increase in the contacts serves as a signature of the transition between the Efimov and unatomic regimes, characterized by the emergence of continuous scale invariance when the system reaches a critical dimension . This continuous scale invariance starts to dominate the behavior of the system at the dimension , below which the trimers' momentum-distribution tails exhibit a power-law behavior signaling the unatomic regime. To illustrate our findings, we studied compounds with the forms , and . The increase in the trimers' mass imbalance reduces the interval between and . The emergence of unatomic states can be experimentally verified by observing the two-body contact parameter, which is a quantity directly related to the thermodynamic properties of the gas.}, archive = {J_PRA}, author = {R. M. Francisco and D. S. Rosa and T. Frederico and G. Krein and M. T. Yamashita}, doi = {10.1103/h9d1-bvs4}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033315}, shortjournal = {Phys. Rev. A}, title = {Confinement-induced unatomic trimer states in mass-imbalanced systems}, volume = {112}, year = {2025}, }
• (2025). Determination of the tilt of raman lasers using the tilt-scanned fringe for atom gravimeters. PRA, 112(3), 033314. (www)

  @article{ , abstract = {The sensitive axis of an atom gravimeter is defined by the direction of the Raman lasers. Any tilt of the Raman lasers with respect to the vertical direction introduces systematic errors in gravity measurements. In this work, we report a determination of the tilt of Raman lasers, where the fringe of the atom interferometer is scanned by varying the tilt, rather than the phase, of the Raman lasers. Unlike the periodic cosine fringes typically used in atom interferometers, the fringe obtained by changing the tilt, referred to as the tilt-scanned fringe, is aperiodic in tilt and exhibits a shift due to the presence of a nonzero tilt. The tilt-scanned fringe is highly sensitive to the tilt-caused shift, enabling convenient and precise determination of the Raman laser tilt in atom gravimeters. We demonstrate that one tilt-scanned fringe, corresponding to a tilt measurement sampling time of 13 s, can determine the tilt with a typical precision of about in our developed atom gravimeter. The short-term sensitivity and measurement accuracy of the tilt-scanned fringe method were evaluated, demonstrating performance comparable to conventional tilt determination techniques. We expect this method to offer a convenient solution for Raman laser alignment in atom gravimeters and enhance the efficiency of absolute gravity surveys.}, archive = {J_PRA}, author = {Xiaochun Duan and Wenxin Geng and Huaqing Luo and Yaoyao Xu and Zhongkun Hu}, doi = {10.1103/tqyc-kmf3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033314}, shortjournal = {Phys. Rev. A}, title = {Determination of the tilt of raman lasers using the tilt-scanned fringe for atom gravimeters}, volume = {112}, year = {2025}, }
• (2025). Unit-density SU(3) fermi-hubbard model with spin-flavor imbalance. PRA, 112(3), 033313. (www)

  @article{ , abstract = {The advent of ultracold alkaline-earth atoms in optical lattices has established a platform for investigating correlated quantum matter with symmetry, offering highly tunable model parameters that allow experiments to access phenomena that are unavailable in conventional materials. Understanding the ground-state physics of Fermi-Hubbard models away from the Heisenberg limit and from the spin-flavor balanced setting is important, as examining the flavor imbalance reveals new physics in Fermi-Hubbard models and shows how phases react to practical experimental imperfections in optical lattices. In this study, mean-field phase diagrams are presented for the unit-density SU(3) Fermi-Hubbard model at two sets of flavor densities, and , with the flavor imbalance introduced as . Novel phases are identified at moderate interaction strengths for both densities, and their robustness is investigated in the presence of flavor imbalance. Furthermore, we provide microscopic explanations of the phases found and their stability. Analysis of thermal ensembles of random mean-field solutions indicate that, at temperatures accessible in state-of-the-art cold atom experiments, some spin orders are hard for conventional scattering or local observable measurements to detect, but can be more accessible with quantum gas microscopy in optical lattice experiments. This work also shows that nesting and Mottness, intertwined in the usual SU(2) Hubbard model in stark contrast to generic materials, can be tuned in the SU(3) model and play distinct roles. The resulting phase diagrams not only deepen our understanding of Fermi-Hubbard models but also inform future experimental search for new phases.}, archive = {J_PRA}, author = {Zewen Zhang and Qinyuan Zheng and Eduardo Ibarra-García-Padilla and Richard T. Scalettar and Kaden R. A. Hazzard}, doi = {10.1103/7yvm-fsf5}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033313}, shortjournal = {Phys. Rev. A}, title = {Unit-density SU(3) fermi-hubbard model with spin-flavor imbalance}, volume = {112}, year = {2025}, }
• (2025). Rayleigh-taylor, kelvin-helmholtz, and immiscible-to-miscible quenching instabilities in binary bose-einstein condensates. PRA, 112(3), 033312. (www)

  @article{ , abstract = {We investigate three kinds of instabilities in binary immiscible homogeneous Bose-Einstein condensate, considering rubidium isotopes and confined in two-dimensional circular box. Rayleigh-Taylor and Kelvin-Helmholtz (KH) instability types are studied under strong perturbations. Without external perturbation, instabilities are also probed by immiscible-to-miscible quenching transition, under two different initial configurations. Our numerical simulations show that all such instability dynamics are dominated by large vortex production and sound-wave (phonon) propagation. For long-term propagation, vortex dynamics become dominant over sound waves in the KH instability, while sound-wave excitations predominate in the other cases. For all the dynamical simulations, the emergence of possible scaling laws are investigated for the compressible and incompressible parts of the kinetic energy spectra, in terms of the wave number . The corresponding results are compared with the classical Kolmogorov scalings, and , for turbulence, which are observed in the kinetic energy spectra at some specific time intervals.}, archive = {J_PRA}, author = {R. Kishor Kumar and S. Sabari and Arnaldo Gammal and Lauro Tomio}, doi = {10.1103/y226-17w9}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033312}, shortjournal = {Phys. Rev. A}, title = {Rayleigh-taylor, kelvin-helmholtz, and immiscible-to-miscible quenching instabilities in binary bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Dynamics of magnetic evaporative beamline cooling for the preparation of cold atomic beams. PRA, 112(3), 033311. (www)

  @article{ , abstract = {The most sensitive direct neutrino mass searches today are based on measurement of the end point of the spectrum of tritium to infer limits on the mass of the unobserved neutrino. To avoid the smearing associated with the distribution of molecular final states in the T-He molecule, the next generation of these experiments will need to employ atomic (T) rather than molecular tritium sources, at currents of at least atoms per second. Following production, atomic T can be trapped in gravitational and/or magnetic bottles for spectrum experiments, if and only if it can first be cooled to millikelvin temperatures. Accomplishing this cooling presents substantial technological challenges. The Project 8 collaboration is developing a technique based on magnetic evaporative cooling along a beamline (MECB) for the purpose of cooling T to feed a magnetogravitational trap that also serves as a cyclotron radiation emission spectroscope. Initial tests of the approach are planned in a pathfinder apparatus using atomic Li. This paper presents a method for analyzing the dynamics of the MECB technique and applies these calculations to the design of systems for cooling and slowing of atomic Li and T. A scheme is outlined that could provide a current of T at the millikelvin temperatures required for the Project 8 neutrino mass search.}, archive = {J_PRA}, author = {Project 8 Collaboration and A. Ashtari Esfahani and S. Bhagvati and S. Böser and M. J. Brandsema and R. Cabral and V. A. Chirayath and C. Claessens and N. Coward and L. de Viveiros and P. J. Doe and M. G. Elliott and S. Enomoto and M. Fertl and J. A. Formaggio and B. T. Foust and J. K. Gaison and P. Harmston and K. M. Heeger and B. J. P. Jones and E. Karim and K. Kazkaz and P. T. Kolbeck and M. Li and A. Lindman and C.-Y. Liu and C. Matthé and R. Mohiuddin and B. Monreal and B. Mucogllava and R. Mueller and A. Negi and J. A. Nikkel and E. Novitski and N. S. Oblath and M. Oueslati and J. I. Peña and W. Pettus and V. S. Ranatunga and R. Reimann and A. L. Reine and R. G. H. Robertson and L. Saldaña and P. L. Slocum and F. Spanier and J. Stachurska and K. Stogsdill and Y.-H. Sun and P. T. Surukuchi and L. Taylor and A. B. Telles and F. Thomas and L. A. Thorne and T. Thümmler and W. Van De Pontseele and B. A. VanDevender and T. E. Weiss and M. Wynne and A. Ziegler}, doi = {10.1103/7dkb-pc56}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033311}, shortjournal = {Phys. Rev. A}, title = {Dynamics of magnetic evaporative beamline cooling for the preparation of cold atomic beams}, volume = {112}, year = {2025}, }
• (2025). Bridging the classical and quantum regimes in a dissipative ising chain. PRA, 112(3), 033310. (www)

  @article{ , abstract = {We study the long-time dynamics of a dissipative Ising chain with varying quantum correlation. Invoking an ensemble-average formalism and assuming spatial translation symmetry, we show that the dynamics can be described by a Lindblad master equation with an interpolated coherent Hamiltonian. In the classical limit, the interpolation Hamiltonian leads to a set of nonlinear equations of motion, where limit cycles can emerge in the long-time dynamics. In the quantum limit, by contrast, the system approaches a ferromagnetic steady state at long times. In between the two extremes, the discrete spatial translation symmetry can be spontaneously broken, as an antiferromagnetic steady state emerges, bridging the classical and quantum regimes. In particular, we illustrate how the classical limit-cycle behavior gradually disappears with the increase of quantum correlation. Since our model in the two extremes respectively applies to a dissipative Rydberg gas in the high- and zero-temperature limits, we expect it to provide a qualitatively correct description of dissipative Rydberg gases at interim temperatures and shed light on the fate of limit cycles in a quantum open system.}, archive = {J_PRA}, author = {Zhenming Zhang and Haowei Li and Wei Yi}, doi = {10.1103/3jd9-5lzs}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033310}, shortjournal = {Phys. Rev. A}, title = {Bridging the classical and quantum regimes in a dissipative ising chain}, volume = {112}, year = {2025}, }
• (2025). Bose-einstein condensates in a synthetic magnetic field with tunable orientation. PRA, 112(3), 033309. (www)

  @article{ , abstract = {We systematically investigate the ground state and dynamics of spinor Bose-Einstein condensates subject to a position-dependent detuning. This detuning induces three related quantities (a synthetic magnetic field, an angular velocity, and an angular momentum), which, due to trap anisotropy, may point in different directions. When the dipole frequencies along the three symmetric axes of the harmonic trap are degenerate, the dipole motion can decompose into two coupled transverse modes in the plane perpendicular to the synthetic magnetic field, and another decoupled longitudinal mode, enabling controllable Foucault-like precession or biconical trajectories depending on the excitation protocol. Furthermore, quenching the orientation of the synthetic magnetic field excites multiple coupled quadrupole modes. We develop a hydrodynamic theory whose predictions match well with Gross-Pitaevskii simulations. This study contributes to a deeper understanding of the effects of the synthetic magnetic field and the excitations of the collective mode in quantum fluids, providing a foundation for future developments in quantum simulation and high-precision sensing technologies.}, archive = {J_PRA}, author = {Fengtao Pang and Huaxin He and Yongping Zhang and Chunlei Qu}, doi = {10.1103/1pmq-3sxg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033309}, shortjournal = {Phys. Rev. A}, title = {Bose-einstein condensates in a synthetic magnetic field with tunable orientation}, volume = {112}, year = {2025}, }
• (2025). Equilibrium, relaxation, and fluctuations in homogeneous bose-einstein condensates: Linearized classical field analysis. PRA, 112(3), 033308. (www)

  @article{ , abstract = {The theory of open quantum systems is central to describing the dynamics and equilibration of dilute-gas Bose-Einstein condensates (BECs). We present an analysis of the linearized stochastic projected Gross-Pitaevskii equation (SPGPE) describing finite-temperature BECs. Our treatment provides an optimal choice for the cutoff that divides the Bose gas into the low-energy coherent region forming a classical wave and the high-energy thermal cloud treated as a reservoir. Moreover, it highlights the relevance of energy damping, the number-conserving scattering between thermal and coherent atoms. We analyze the equilibrium properties and near-equilibrium relaxation of a homogeneous BEC in one, two, and three dimensions at high phase-space density and calculate the autocorrelation function and power spectrum of the density and phase fluctuations. Simulations of the full nonlinear SPGPE are in close agreement and extend our arguments beyond the linear regime. Our work suggests the need for a reexamination of decay processes in BECs studied under the neglect of energy damping.}, archive = {J_PRA}, author = {Nils A. Krause and Ashton S. Bradley}, doi = {10.1103/2c78-wtqp}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033308}, shortjournal = {Phys. Rev. A}, title = {Equilibrium, relaxation, and fluctuations in homogeneous bose-einstein condensates: Linearized classical field analysis}, volume = {112}, year = {2025}, }
• (2025). Composite-boson-superposition ansatz approach to one-dimensional trapped few-fermion systems. PRA, 112(3), 033307. (www)

  @article{ , abstract = {Ultracold atomic systems provide a versatile platform for exploring quantum phenomena, offering tunable interactions and diverse trapping geometries. In this study, we investigate a one-dimensional system of trapped fermionic atoms using the composite boson formalism, which describes pairs of opposite-spin fermions as cobosons (short for composite bosons). We solve the Schrödinger equation for a fermionic system across a broad range of attractive and repulsive interactions by constructing the system's wave function as a superposition of two-coboson states. We determine key observables such as particle density profiles and two-body correlations. The density profiles calculated agree with both the Tonks-Girardeau and Lieb-Liniger limits and provide a portrait of the transition between those regimes. In the strong repulsive regime, the ansatz captures the Fridel-Wigner transition characterized by a doubling of the peaks in the density profiles. Additionally, we compute the low-lying energy spectrum and estimate the pairing gap. Our results highlight the usefulness of the coboson superposition ansatz for exploring quantum phenomena in strongly correlated few-body systems.}, archive = {J_PRA}, author = {Francisco Figueiredo and Itzhak Roditi}, doi = {10.1103/t6gr-vt18}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033307}, shortjournal = {Phys. Rev. A}, title = {Composite-boson-superposition ansatz approach to one-dimensional trapped few-fermion systems}, volume = {112}, year = {2025}, }
• (2025). Self-adapted josephson oscillation of dark-bright solitons under constant forces. PRA, 112(3), 033306. (www)

  @article{ , abstract = {We study the propagation of dark-bright solitons in two-component nonlinear systems with general nonlinear parameters, and explore how nonlinear interactions enrich the soliton dynamics giving rise to nonsinusoidal oscillations under constant forces. Treating the bright soliton as an effective barrier, we reveal that such oscillations are characterized by the Josephson equations with self-adapted critical current and bias voltage, whose explicit analytic expressions are derived using the Lagrangian variational method. The dynamical phase diagram in nonlinear parameter space is presented, identifying oscillation regions with different skewed sinusoidal dependence, and diffusion regions with irreversible soliton spreading due to instability of the barrier. Furthermore, we obtain periodic dispersion relations of the solitons, indicating a switch between positive and negative inertial masses, consistent with the oscillation behaviors. Our results provide a general and comprehensive theoretical framework for soliton oscillation dynamics and pave the way for investigating various nonlinear transports and their potential applications.}, archive = {J_PRA}, author = {Ling-Zheng Meng and Xi-Wang Luo and Li-Chen Zhao}, doi = {10.1103/8l2y-d7cd}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033306}, shortjournal = {Phys. Rev. A}, title = {Self-adapted josephson oscillation of dark-bright solitons under constant forces}, volume = {112}, year = {2025}, }
• (2025). Dynamical crossover of vortex-pair annihilation in two-dimensional quantum turbulence. PRA, 112(3), 033305. (www)

  @article{ , abstract = {Understanding the elementary mechanism for the dissipation of vortex energy in quantum liquids is one central issue in quantum hydrodynamics, such as quantum turbulence in systems ranging from neutron stars to atomic condensates. In a two-dimensional (2D) Bose-Einstein condensate (BEC) at zero temperature, in addition to the vortex drift-out process from the boundary, a vortex-antivortex pair can annihilate in bulk, but controversy remains on the number of vortices involved in the annihilation process. We find that a dynamic crossover exists from four-body to three-body vortex annihilation processes with time evolution in decaying 2D quantum turbulence of a boundary-less uniform quasi-2D BEC. Such a dynamical crossover depends on the initial vortex pair density and occurs when the sound waves generated in the vortex annihilation process surpass a threshold energy. As the confinement along the third direction is relaxed in a quasi-2D BEC, the threshold sound wave energy decreases due to the three-dimensional (3D) vortex line curve and reconnection, shifting the dynamical crossover to the early time. Our work reveals an elementary mechanism for the dissipation of vortex energy that may help understand exotic matter and dynamics in quantum liquids.}, archive = {J_PRA}, author = {Toshiaki Kanai and Chuanwei Zhang}, doi = {10.1103/6zfl-dc7r}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033305}, shortjournal = {Phys. Rev. A}, title = {Dynamical crossover of vortex-pair annihilation in two-dimensional quantum turbulence}, volume = {112}, year = {2025}, }
• (2025). Dynamics of topological defects in a rashba spin-orbit-coupled bose-einstein condensate. PRA, 112(3), 033304. (www)

  @article{ , abstract = {We investigate the quench dynamics of a two-dimensional Rashba spin-orbit-coupled Bose-Einstein condensate. Our study focuses on quenching the system from a zero-momentum phase to a stripe phase. During this quench, topological defects emerge in the form of vortices. These vortices and antivortices exhibit a random spatial distribution with equal numbers. In a uniform system, we observe an exponential scaling of both the vortex production time and the vortex number with the quench rate, consistent with the conventional Kibble-Zurek mechanism, the decay of which adheres to a logarithmic law, aligning with experimental observations.}, archive = {J_PRA}, author = {Sheng Liu and Yong-Sheng Zhang}, doi = {10.1103/qlx5-dqr3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033304}, shortjournal = {Phys. Rev. A}, title = {Dynamics of topological defects in a rashba spin-orbit-coupled bose-einstein condensate}, volume = {112}, year = {2025}, }
• (2025). Dynamics of supersolid state: Normal fluid, superfluid, and supersolid velocities. PRA, 112(3), 033303. (www)

  @article{ , abstract = {We consider the dynamics of a supersolid state that is based on Leggett's idea of local phase flow around the atomic sites of the solid. This leads to a local microscopic superfluid velocity that is not Galilean and is defined only relative to the solid and a superfluid fraction (with being the macroscopic mass density). Landau's excitation-based argument for superfluids—that at temperature the normal fluid mass density is zero—should apply to supersolids. Together these two arguments imply that at low there is a missing mass density. We attribute this to a supersolid density , with and a momentum-bearing supersolid velocity . We derive the macroscopic dynamical equations for this system with three momentum-bearing macroscopic velocities using Onsager's irreversible thermodynamics. For slow spatial variations, accelerates along the negative gradient of the chemical potential or mass, like for an ordinary superfluid, and is subject to drag against with a characteristic drag time . There are three contributions to the acceleration of : drag against , along the negative gradient of the chemical potential or mass, and due to the forces of lattice elasticity. For high-frequency motion relative to the drag time , moves independently of . The normal modes for such a system have a crossover frequency below which the normal fluid velocity is dragged into motion with (so the theory reduces to the theory of Andreev and Lifshitz) and above which the normal fluid velocity is an independent variable. For an isotropic lattice we study the transverse and longitudinal responses. A frequency-dependent rotational inertia experiment is predicted to show, at frequencies that are low relative to , that and move together but that at high frequencies moves much more than .}, archive = {J_PRA}, author = {Wayne M. Saslow}, doi = {10.1103/yyjt-1tth}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033303}, shortjournal = {Phys. Rev. A}, title = {Dynamics of supersolid state: Normal fluid, superfluid, and supersolid velocities}, volume = {112}, year = {2025}, }
• (2025). Phase transitions and dynamics of one-dimensional solitons in spin-orbit-coupled bose-bose mixtures. PRA, 112(3), 033302. (www)

  @article{ , abstract = {We investigate the formation, stability, and dynamics of solitons in a one-dimensional binary Bose-Einstein condensate under the action of the spin-orbit-coupling and Lee-Huang-Yang (LHY) correction to the underlying system of the Gross-Pitaevskii equations. We identify the semi-dipole (SD) family of solitons and thoroughly analyze its properties. The numerical analysis reveals intricate bifurcations, including transitions from real to complex-valued stationary wave functions of the SD solitons and norm-dependent dynamical instabilities. Stability maps in the plane of the solitons' norm and interaction strength exhibit areas of monostability, oscillatory behavior, and soliton splitting. Solitons with complex stationary wave functions emerge as ground states in broad parameter areas due to the effects of the LHY terms. The other soliton species, in the form of mixed modes (MMs), do not feature the compexification bifurcation. In the LHY-dominated regime, the SD and MM solitons exhibit identical values of the energy for the same norm. The results deepen the understanding of nonlinear matter-wave states and reveal multistable ones in quantum gases.}, archive = {J_PRA}, author = {Gui-hua Chen and Hongcheng Wang and Boris A. Malomed and Haiming Deng and Yongyao Li}, doi = {10.1103/by2l-653h}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033302}, shortjournal = {Phys. Rev. A}, title = {Phase transitions and dynamics of one-dimensional solitons in spin-orbit-coupled bose-bose mixtures}, volume = {112}, year = {2025}, }
• (2025). Light-induced localized vortices in multicomponent bose-einstein condensates. PRA, 112(3), 033301. (www)

  @article{ , abstract = {We study continuous interaction of a trapped two-component Bose-Einstein condensate with light fields in a Λ -type configuration. Using light beams with orbital angular momentum, we theoretically show how to create a stable, pinned vortex configuration, where the rotating component is confined to the region surrounded by the second, nonrotating component. The atoms constituting this vortex can be localized in volumes much smaller than the volume occupied by the second component. We also show that the vortex position can be changed dynamically by moving the laser beams, provided the beams' movement speed remains below the speed of sound. This allows us to use the localized vortex to stir the second component, and to determine the superfluid flow's critical velocity.}, archive = {J_PRA}, author = {Y. Braver and D. Burba and S. S. Nair and G. Žlabys and E. Anisimovas and Th. Busch and G. Juzeliūnas}, doi = {10.1103/qlbm-9sps}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033301}, shortjournal = {Phys. Rev. A}, title = {Light-induced localized vortices in multicomponent bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Lateral diffusion in coated vapor cells under light-induced atomic desorption. PRA, 112(3), 033119. (www)

  @article{ , abstract = {This study investigates the atomic diffusion process within antirelaxation coated vapor cells using a partially illuminated light-induced atomic desorption (LIAD) scheme. We conducted a comprehensive theoretical analysis to model variation in vapor density during the process and predict the variation in vapor density due to lateral diffusion from the unilluminated region. This implies that under partial illumination, the number density changes follow a triexponential behavior, rather than the biexponential behavior observed under full illumination. In addition, repeated illumination confirmed the existence of lateral diffusion inside the antirelaxation coatings. Additionally, we demonstrated the impact of LIAD on the spin-relaxation time to obtain the intrinsic coating performance variation induced by atomic diffusion. Our study provides deeper insights into the atomic transport phenomena in coated vapor cells, as well as the potential of employing all-optical techniques to manipulate the vapor density and coating properties of coated vapor cells, which are beneficial for applications in quantum sensing and precision measurements.}, archive = {J_PRA}, author = {Xingqing Jin and Shuyuan Chen and Wentian Xiang and Wenlong Lyu and Changping Du and Xiang Peng and Hong Guo}, doi = {10.1103/s7vl-1dmg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033119}, shortjournal = {Phys. Rev. A}, title = {Lateral diffusion in coated vapor cells under light-induced atomic desorption}, volume = {112}, year = {2025}, }
• (2025). Carrier-envelope-phase effects in one- and two-photon directional photoionization of nonisotropic atomic states. PRA, 112(3), 033118. (www)

  @article{ , abstract = {We study the impact of two-color ( ω and 2 ω ) co- and counterrotating ultrashort attosecond laser pulses on nonisotropic atomic targets through the one- and two-photon interference pattern of the photoelectron spectrum. Specifically, we take the ground state of atomic carbon, i.e., ( 1 s 2 2 s 2 2 p 2 , 3 P e ) as a prototype. We observe and quantify the strong dependence on the relative carrier-envelope phase (CEP) of the two-color pulses and on the spatial orientation of the electronic target states. Notably, we observe that the photoelectron momentum distributions (PMDs) vary as a function of the CEP due to the interfering two-color one- and two-photon ionization paths. In addition, the PMD region corresponding to one-photon photoionization remains unaffected with varying CEP, depending only on the ellipticity of the pulse, the central photon frequency, and the magnetic quantum number of the initial state. Therefore, comparing the one-photon ionization electron ejection direction following the absorption of a single ( 2 ω ) photon with that of the two-photon ionization channel following the absorption of two photons, each with energy ω , we may extract information on the CEP difference between the two pulses.}, archive = {J_PRA}, author = {Juan J. Omiste and Lars Bojer Madsen}, doi = {10.1103/pmjn-blvf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033118}, shortjournal = {Phys. Rev. A}, title = {Carrier-envelope-phase effects in one- and two-photon directional photoionization of nonisotropic atomic states}, volume = {112}, year = {2025}, }
• (2025). Enhancement of superconducting pairing via quantum lyapunov control. PRA, 112(3), 033117. (www)

  @article{ , abstract = {We demonstrate that quantum Lyapunov control provides an effective strategy for enhancing superconducting correlations in the Fermi-Hubbard model without requiring careful parameter tuning. While photoinduced superconductivity is sensitive to the frequency and amplitude of a monochromatic laser pulse, our approach employs a simple feedback-based protocol that prevents the decrease of superconducting correlations once they begin to form. This method enables robust enhancement of pairing across a broad range of initial pumping conditions, eliminating the need for intricate frequency and amplitude optimization. We also show that an alternative implementation, asymptotic quantum control, achieves comparable results. Furthermore, our approach can be adapted to suppress previously induced superconducting correlations, providing bidirectional control over quantum pairing states. These findings suggest practical pathways for manipulating quantum correlations in strongly interacting systems with minimal experimental complexity.}, archive = {J_PRA}, author = {Oleksandr Povitchan and Denys I. Bondar and Andrii G. Sotnikov}, doi = {10.1103/7dz3-2wlk}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033117}, shortjournal = {Phys. Rev. A}, title = {Enhancement of superconducting pairing via quantum lyapunov control}, volume = {112}, year = {2025}, }
• (2025). Spin squeezing via one-axis twisting in a quadrupolar NMR system under relaxation effects. PRA, 112(3), 033116. (www)

  @article{ , abstract = {This study investigates spin-squeezed states in nuclear magnetic resonance quadrupolar systems with spins I = 3 / 2 and 7/2 at room temperature, taking into account the effects of relaxation on the dynamics. The origin of spin squeezing is attributed to the interaction between the nuclear quadrupole moment and the electric-field gradients in the molecular environment. The formal description of the nonlinear operators responsible for spin squeezing is achieved using the spin angular momentum representation via the one-axis twisting mechanism. This approach provides a framework for quantum control and metrology over the spin squeezing process while accounting for the influence of relaxation phenomena. Non-Cartesian angular momentum operators are proposed, with their variance products catching the quantum effects during the dynamics. An upper bound for the squeezing parameter and the Heisenberg uncertainty at steady state are also predicted for any spin quantum number.}, archive = {J_PRA}, author = {Adriane Consuelo Leal Auccaise and Antonio Sérgio Magalhães de Castro}, doi = {10.1103/ryvz-fksg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033116}, shortjournal = {Phys. Rev. A}, title = {Spin squeezing via one-axis twisting in a quadrupolar NMR system under relaxation effects}, volume = {112}, year = {2025}, }
• (2025). Fast and robust detection of single rydberg excitations in mesoscopic ensembles. PRA, 112(3), 033114. (www)

  @article{ , abstract = {We propose a novel nondestructive method for the detection of single Rydberg excitations in a mesoscopic ensemble. The protocol achieves high fidelities on a microsecond timescale and is robust against changes in the probe laser frequency. The technique relies on optical pumping in Autler Townes configuration, whose efficiency is controlled by the presence or absence of a Rydberg excitation. Taking rubidium atoms as an example, we give realistic estimates for the achievable fidelities and parameters. However, our protocol can be transferred to any other atomic species that features multiple stable states. Our protocol is applicable in quantum simulation and quantum information processing with mesoscopic ensembles requiring fast and high-fidelity Rydberg state detection.}, archive = {J_PRA}, author = {Sven Schmidt and Aaron Thielmann and Thomas Niederprüm and Herwig Ott}, doi = {10.1103/964l-npcf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033114}, shortjournal = {Phys. Rev. A}, title = {Fast and robust detection of single rydberg excitations in mesoscopic ensembles}, volume = {112}, year = {2025}, }
• (2025). Efficiency of double ionization of a three-electron atom in moderate laser-field intensities. PRA, 112(3), 033113. (www)

  @article{ , abstract = {We study double ionization in a one-dimensional model of a three-electron atom exposed to strong short laser fields. The corresponding ab initio simulations reveal a characteristic “knee” in the ionization yield at lower field intensities than in comparable two-electron systems. To understand the origin of this shift, a quantitative semianalytic model for double ionization of a three-electron atom has been created. In this model, ionization is treated as a combination of different scenarios and channels. Each channel is simulated with either quantitative rescattering theory (QRS) or a two-electron ab initio model. Analysis of the semianalytical results indicates that the shifted part of the “knee” is dominated by a recollision-excitation channel in which the rescattering electron initially escapes the parent atom from an inner orbital. This counterintuitive phenomenon is then discussed and explained.}, archive = {J_PRA}, author = {Dmitry K. Efimov}, doi = {10.1103/1dn8-4f6h}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033113}, shortjournal = {Phys. Rev. A}, title = {Efficiency of double ionization of a three-electron atom in moderate laser-field intensities}, volume = {112}, year = {2025}, }
• (2025). Incorporating dephasing effects into simulations of harmonic generation from finite-size topological insulators. PRA, 112(3), 033112. (www)

  @article{ , abstract = {In recent years, high harmonic generation (HHG) from topological matter has attracted considerable interest, emerging as a promising tool for detecting the topological phase. This work incorporates dephasing effects in the theoretical simulations of HHG from topological insulators described by finite-size tight-binding models. This is done by formulating a density-matrix approach in both length and velocity gauges within dipole approximation, with a gauge-invariant treatment of dephasing properly introduced such that the HHG response of a sufficiently large solidlike system is consistent with the periodic limit obtained using semiconductor Bloch equations. Applying the approach to Su-Schrieffer-Heeger chains reveals how dephasing affects the impact of topological edge states on the HHG spectra. It is found that dephasing can either weaken or strengthen the spectral contrast between the topological and trivial phases, depending on which of the intra- and interband mechanisms is dominant for a specific harmonic in the trivial phase.}, archive = {J_PRA}, author = {Chuan Yu}, doi = {10.1103/zggs-4v8m}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033112}, shortjournal = {Phys. Rev. A}, title = {Incorporating dephasing effects into simulations of harmonic generation from finite-size topological insulators}, volume = {112}, year = {2025}, }
• (2025). Theory of the photoeffect with vortex photoelectrons. PRA, 112(3), 033111. (www)

  @article{ , abstract = {The process of photoionization of an atom or molecule in the perturbative regime is described by the dipole matrix element between the initial bound and final continuum states of the active electron. In usual treatments of the photoeffect, the final state is represented by a plane-wave scattering state in which the ejected photoelectron is characterized by a definite linear momentum. We consider the photoeffect in which the ejected photoelectron is described by a vortex scattering state and characterized by a definite projection of its angular momentum on a given vortex axis. Although the plane-wave and vortex transition matrix elements can be expressed in terms of each other, the corresponding cross sections cannot. We develop a theory of the molecular photoeffect with vortex photoelectrons, which includes the introduction and analysis of various vortex photoionization observables and their averaging over molecular orientations. The averaging is essential for treating photoionization of randomly oriented molecules in the gas phase. We show that the averaged vortex differential cross sections reveal new chiral asymmetries caused by the chirality of the vortex photoelectron, which generalize the phenomenon of photoelectron circular dichroism. The theory is illustrated by calculations for the glyceraldehyde molecule described within the molecular zero-range potential model. We also propose and validate by calculations a scheme based on a ring-shaped forked grating which allows, at least in principle, to verify our predictions experimentally.}, archive = {J_PRA}, author = {Kirill V. Bazarov and Oleg I. Tolstikhin}, doi = {10.1103/9t4d-xj5v}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033111}, shortjournal = {Phys. Rev. A}, title = {Theory of the photoeffect with vortex photoelectrons}, volume = {112}, year = {2025}, }
• (2025). Generation of isolated elliptically polarized sub-100-as pulses from ne atoms in combined chirped fields. PRA, 112(3), 033110. (www)

  @article{ , abstract = {We present a method to generate an isolated elliptically polarized short attosecond pulse from the ring-current state of the Ne atom in a chirped infrared (IR) field combined with an ultraviolet (UV) field. We find that the cutoff position of the harmonic spectrum emitted from the ring-current state is extended, but the harmonic efficiency is reduced in a chirped IR field compared with a chirp-free IR field. This harmonic broadening can be well understood by the semiclassical three-step model and the quantum time-frequency analysis. By introducing a UV field into the chirped IR field with a proper chirp parameter, both the efficiency and chirality of harmonic spectrum can be improved. Our analysis indicates that the generation of the elliptically polarized harmonics can be attributed to the asymmetric emission of ionized electrons in the y direction. By optimizing the laser parameters, an isolated 98-as pulse with an ellipticity up to 0.94 is obtained by the broadband elliptically polarized supercontinuum. Our approach provides an effective way to generate and control the sub-100-as isolated elliptically polarized pulses.}, archive = {J_PRA}, author = {Si-Qi Zhang and Bing Zhang and Bo Yan and Xiang-Qian Jiang and Jing Guo and Xiu-Dong Sun}, doi = {10.1103/sjy5-q3nh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033110}, shortjournal = {Phys. Rev. A}, title = {Generation of isolated elliptically polarized sub-100-as pulses from ne atoms in combined chirped fields}, volume = {112}, year = {2025}, }
• (2025). Autocorrelation measurement of attosecond pulses based on two-photon double ionization. PRA, 112(3), 033109. (www)

  @article{ , abstract = {Autocorrelation measurement is theoretically demonstrated to characterize attosecond pulses by studying the two-photon double ionization (TPDI) process. An interferometric autocorrelation curve is presented in the change of TPDI probability with the time delay between two identical attosecond pulses, and its full width at half maximum (FWHM) has a relationship with the FWHM of the attosecond pulse. The curve is also decoded to obtain the center frequency and FWHM of the attosecond pulse by fitting.}, archive = {J_PRA}, author = {Fei Li and Kun Zhao and Bingbing Wang and Xin-Kui He and Zhi-Yi Wei}, doi = {10.1103/dshd-4j15}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033109}, shortjournal = {Phys. Rev. A}, title = {Autocorrelation measurement of attosecond pulses based on two-photon double ionization}, volume = {112}, year = {2025}, }
• (2025). Generation of ultrarelativistic longitudinally spin-polarized electrons via nonlinear compton scattering. PRA, 112(3), 033108. (www)

  @article{ , abstract = {The spin polarization of electrons in strong laser fields, an important phenomenon predicted by strong-field quantum electrodynamics, has garnered considerable attention in recent years due to its broad potential applications. In the present work we investigate the collision dynamics between multi-GeV electrons and circularly polarized laser pulses with relativistic intensity and duration of tens of femtoseconds by employing a density-matrix method. Numerical results demonstrate that the energy of outgoing electrons significantly influences their longitudinal spin polarization (LSP). Notably, for an incident electron energy of 80 GeV and a laser intensity parameter of 0.4, the LSP exceeds around the energy corresponding to the peak of the scattering energy spectrum. Our findings provide a promising avenue for experimentally generating ultrarelativistic longitudinally spin-polarized electron beams.}, archive = {J_PRA}, author = {Dejia Dai and Xiaofei Shen and Bin Qiao}, doi = {10.1103/kymn-wsyv}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033108}, shortjournal = {Phys. Rev. A}, title = {Generation of ultrarelativistic longitudinally spin-polarized electrons via nonlinear compton scattering}, volume = {112}, year = {2025}, }
• (2025). Spontaneous raman scattering from metastable states of ba+. PRA, 112(3), 033107. (www)

  @article{ , abstract = {Quantum logic gates performed via two-photon stimulated Raman transitions in ions and atoms are fundamentally limited by spontaneous scattering errors. Recent theoretical treatment of these processes has predicted no lower bound on the scattering-induced error rate of such gates when implemented with far-detuned lasers, while also providing an extension to metastable qubits. To validate this theoretical model, we provide experimental measurements of Raman scattering rates due to near- and far-detuned lasers for initial states in the metastable level of . The measured spontaneous Raman scattering rate is consistent with the theoretical prediction and suggests that metastable-level two-qubit gates with an error rate approximately equal to are possible with laser excitation detuned by tens of terahertz or more.}, archive = {J_PRA}, author = {Timothy J. Burke and Xiaoyang Shi and Jasmine Sinanan-Singh and Isaac L. Chuang and John Chiaverini}, doi = {10.1103/59jw-vycq}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033107}, shortjournal = {Phys. Rev. A}, title = {Spontaneous raman scattering from metastable states of ba+}, volume = {112}, year = {2025}, }
• (2025). Spontaneous raman scattering out of a metastable atomic qubit. PRA, 112(3), 033106. (www)

  @article{ , abstract = {Metastable qubits in atomic systems can enable large-scale quantum computing by simplifying hardware requirements and adding efficient erasure conversion to the preexisting toolbox of high-fidelity laser-based control. For trapped atomic ions, the fundamental error floor of this control is given by spontaneous Raman and Rayleigh scattering from short-lived excited states. We measure spontaneous Raman scattering rates out of a metastable qubit manifold of a single trapped ion illuminated by 976 nm light that is THz detuned from the dipole-allowed transition to the manifold. This supports the calculation of error rates from both types of scattering during one- and two-qubit gates on this platform, thus demonstrating that infidelities less than are possible.}, archive = {J_PRA}, author = {I. D. Moore and A. Quinn and J. O'Reilly and J. Metzner and S. Brudney and G. J. Gregory and D. J. Wineland and D. T. C. Allcock}, doi = {10.1103/vlz1-s6zl}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033106}, shortjournal = {Phys. Rev. A}, title = {Spontaneous raman scattering out of a metastable atomic qubit}, volume = {112}, year = {2025}, }
• (2025). Determining ion coulomb crystal temperatures with ConvNeXt and a vision transformer. PRA, 112(3), 033105. (www)

  @article{ , abstract = {Accurate determination of the temperature of trapped ion Coulomb crystals (ICCs) is critical for advancing quantum technologies. We present a deep learning approach to classify ICC temperature states from fluorescence images. A high-fidelity dataset was generated using the (py)LIon molecular dynamics toolkit, simulating ICCs containing 100–268 ions over a temperature range of 5–20 mK. In the initial 16-class problem (each class a 1-mK interval), a ConvNeXt convolutional network achieved a peak accuracy of 57%, demonstrating its ability to capture fine-grained structural features. To overcome low distinguishability among similar temperature classes, we redefined the task into four broader temperature intervals and applied a vision transformer (ViT). The ViT model achieved a test accuracy of 84%, indicating substantially improved generalization. These results highlight the complementarity of convolutional neural network and transformer architectures for noninvasive temperature diagnostics. We discuss limitations due to dataset diversity and outline future work on larger-scale simulations and physics-guided network designs to further improve ICC temperature estimation in quantum applications.}, archive = {J_PRA}, author = {Chu Zhang and Dawei Liu and Mingqing Song and Ying Jiang and Dongdong Zhang and Dajun Ding}, doi = {10.1103/qc6t-trxj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033105}, shortjournal = {Phys. Rev. A}, title = {Determining ion coulomb crystal temperatures with ConvNeXt and a vision transformer}, volume = {112}, year = {2025}, }
• (2025). Robust strong-field theory model for ultrafast electron transport through metal-insulator-metal tunneling nanojunctions. PRA, 112(3), 033104. (www)

  @article{ , abstract = {Ultrafast science studies the dynamics of electrons in matter with extreme temporal precision, typically in the attosecond and femtosecond time domain. Recent experimental and theoretical progress has put metal-insulator-metal (MIM) tunneling nanojunctions in the spotlight of ultrafast science. Waveform-controlled laser fields can induce ultrafast currents in these junctions, opening the door to petahertz electronic operation and attosecond-scale scanning tunneling microscopy. Inspired by our strong-field model for attosecond tunneling microscopy [B. Ma and M. Krüger, Phys. Rev. Lett. 133 , 236901 (2024) ], here we generalize our model to MIM nanojunctions. We introduce several refinements and corrections, accounting for the image potential inside the gap and boundary effects. Moreover, we also find that the Keldysh parameter, which is a hallmark parameter for ultrafast light-matter interactions, alone is insufficient for describing the physics in thin MIM nanojunctions. We introduce a new parameter that accounts for the effects of the limited size of the junction and provide several interpretations of the parameter that shed new light on the complex physics in the light-driven junction. Most strikingly, we find that for photon-assisted tunneling is dominating the ultrafast electron transport across the junction, regardless of the value of the Keldysh parameter. Here one or more photons are absorbed and the electron undergoes static tunneling through the barrier. is required for a regime in which the laser field and the Keldysh parameter dominate the transport. We also discuss the three-step model of electron transport across the nanojunction in the adiabatic regime, the energy cutoff of the transported electrons, and the carrier-envelope phase control of the net current. Our theory model provides a rich toolbox for understanding and predicting the physics of ultrafast MIM nanojunctions.}, archive = {J_PRA}, author = {Boyang Ma and Michael Krüger}, doi = {10.1103/h2zq-7l2n}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033104}, shortjournal = {Phys. Rev. A}, title = {Robust strong-field theory model for ultrafast electron transport through metal-insulator-metal tunneling nanojunctions}, volume = {112}, year = {2025}, }
• (2025). Orbital distortion and parabolic channel effects transforming minima in molecular ionization probabilities into maxima. PRA, 112(3), 033103. (www)

  @article{ , abstract = {In the tunneling regime and at sufficiently low field amplitudes, the shape of orientation-dependent molecular ionization rate curves usually resembles the shape of the ionized orbital. As the ionizing field strength increases, the shape of the ionization rate can deviate from this pattern. The oft-cited explanation is that the increasing contribution of excited states relative to the ground state modifies the distribution. In this paper we show that orbital distortion and parabolic channel effects, which are independent of excited-state effects, can also significantly modify the angular dependence of the yields of widely studied molecules where excited state effects are negligible. For example, as the ionizing field increases we find that (1) in CO, orbital distortion is responsible for the switch of the position of the global maximum in the orientation-dependent ionization rate to the opposite orientation, and (2) in , the interplay between orbital distortion and parabolic channel effects transforms a local minimum to a local maximum. To simulate orbital distortion and parabolic channel effects, we use the one-electron weak-field asymptotic theory including the first-order correction [OE-WFAT(1)] in the integral representation. Since OE-WFAT(1) incurs expensive computations when the number of orientation angles is large, we also reformulate the original OE-WFAT(1) algorithm into a partial-wave expansion form, which greatly enhances the efficiency of the method.}, archive = {J_PRA}, author = {Imam S. Wahyutama and Denawakage D. Jayasinghe and François Mauger and Kenneth Lopata and Kenneth J. Schafer}, doi = {10.1103/4xqd-yhdt}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033103}, shortjournal = {Phys. Rev. A}, title = {Orbital distortion and parabolic channel effects transforming minima in molecular ionization probabilities into maxima}, volume = {112}, year = {2025}, }
• (2025). Continuous pump-probe experiment to observe zeeman wave-packet dynamics. PRA, 112(3), 033102. (www)

  @article{ , abstract = {In this work, we study the coherent dynamics of an atomic Zeeman wave packet using a continuous pump-probe scheme. A polarized Zeeman wave packet is created in laser-cooled lithium atoms via few-photon excitation by a femtosecond laser pulse, producing a state with a magnetic moment tilted relative to an external magnetic field. The subsequent Larmor precession of the atomic magnetic moment is probed via continuous ionization by an optical dipole trap (ODT) laser. The resulting ionization fragments—photoelectrons and photoions—are detected in coincidence using a cold target recoil ion momentum spectrometer (COLTRIMS). While the ODT facilitates further cooling of the atoms, its continuous-wave laser field does not provide the pulsed timing reference typically required to extract photoelectron momentum distributions in COLTRIMS. Here, we present an extension of the standard COLTRIMS technique that exploits redundancies in the measured data to reconstruct the ionization time. The resulting time-dependent ionization signal reveals the coherent precession of the atomic magnetic moment, enabling real-time access to atomic dynamics on nanosecond timescales.}, archive = {J_PRA}, author = {K. L. Romans and K. Foster and S. Majumdar and B. P. Acharya and O. Russ and A. H. N. C. De Silva and D. Fischer}, doi = {10.1103/5fzd-g7qn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033102}, shortjournal = {Phys. Rev. A}, title = {Continuous pump-probe experiment to observe zeeman wave-packet dynamics}, volume = {112}, year = {2025}, }
• (2025). Towards trapping of hydrogen atoms for computable optical clock applications. PRA, 112(3), 033101. (www)

  @article{ , abstract = {Because of its simple structure, the hydrogen atom is often used as a testbed for quantum electrodynamics. Spectroscopy of trapped atomic samples can greatly improve the accuracy of these tests. Trapping atomic hydrogen in an optical dipole trap or an optical lattice has never been achieved. Only trapping in magnetic fields that lead to large Zeeman shifts has been demonstrated. Standard techniques of atomic physics are difficult to apply to atomic hydrogen. The small mass of the atom and the large photon energy of the 1 S -2 P cooling transition significantly complicate Doppler cooling. This proposal introduces a photon recoil-assisted loading scheme that uses these properties to our advantage to load atomic hydrogen into an optical dipole trap without laser cooling. The magic wavelength (515 nm) for the 1 S -2 S clock transition (1.3-Hz natural linewidth) is easily accessible with current laser technology. Since the 1 S -2 S clock transition can be driven Doppler free, we do not require a very low temperature. Besides improving spectroscopy for fundamental science, such a system can also be used as a “computable” atomic clock that may one day justify the redefinition of the SI second in terms of the Rydberg constant.}, archive = {J_PRA}, author = {O. Amit and D. Taray and V. Wirthl and V. Weis and M. W. Syed and A. Ozawa and J. Weitenberg and S. G. Karshenboim and J. T. M. Walraven and L. Maisenbacher and R. Pohl and Z. Burkley and F. Schmid and T. W. Hänsch and D. C. Yost and Th. Udem}, doi = {10.1103/3bnr-q23f}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {033101}, shortjournal = {Phys. Rev. A}, title = {Towards trapping of hydrogen atoms for computable optical clock applications}, volume = {112}, year = {2025}, }
• (2025). Extended locally monochromatic approximations of strong-field QED processes. PRA, 112(3), 032819. (www)

  @article{ , abstract = {Strong-field QED (SFQED) probability rates in the locally monochromatic approximation (LMA) have become an indispensable tool for simulations of processes like gamma-ray emission or electron-positron pair production in laser-particle collisions. We revisit the LMA derivation and explicitly demonstrate that it is based on the separation of timescales, neglect of the long-range interference effects, and subsequent averaging over the cycle scale. Doing so, we obtain unambiguously LMA rates for arbitrary polarizations of the plane-wave background. Additionally, we partially restore the finite bandwidth effects that are lost in the LMA derivation. We refer to the bandwidth-restored result as the LMA + and show that it agrees with the full SFQED predictions better than the standard LMA. We use LMA + to address previously inaccessible observables and formulate an additional limitation on the applicability of locally monochromatic approximations in general. We provide analytical results for the angular-integrated LMA + probability rate and the fully differential probability that account for the finite bandwidth effects.}, archive = {J_PRA}, author = {Nikita Larin and Daniel Seipt}, doi = {10.1103/cmmp-rt2g}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032819}, shortjournal = {Phys. Rev. A}, title = {Extended locally monochromatic approximations of strong-field QED processes}, volume = {112}, year = {2025}, }
• (2025). QED effects in quadratic zeeman splitting in highly charged hydrogen-like ions. PRA, 112(3), 032818. (www)

  @article{ , abstract = {We present ab initio calculations of one-electron quantum electrodynamical corrections to the second-order Zeeman splitting for the 1 s 1 / 2 , 2 s 1 / 2 , and 2 p 1 / 2 states in highly charged hydrogen-like ions. The self-energy correction is evaluated using the rigorous QED approach. The vacuum-polarization correction is evaluated within the electric-loop approximation. Calculations are performed for a wide range of nuclear charge number: Z = 14 – 92 .}, archive = {J_PRA}, author = {V. A. Agababaev and E. A. Prokhorchuk and D. A. Glazov and A. V. Malyshev and V. M. Shabaev and A. V. Volotka}, doi = {10.1103/cpbv-l4z1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032818}, shortjournal = {Phys. Rev. A}, title = {QED effects in quadratic zeeman splitting in highly charged hydrogen-like ions}, volume = {112}, year = {2025}, }
• (2025). Structure calculations for the low-charged sn2+ ion clock. PRA, 112(3), 032817. (www)

  @article{ , abstract = {The low-charged ion has emerged as an ideal candidate for developing Coulomb-crystal optical clocks capable of achieving precision below [Leibrandt et al. , Nat. Commun. 15 , 5663 (2024) ]. To systematically investigate the structure properties of the ion, we employ the -spline-based many-body perturbation theory combined with the configuration-interaction method. We conducted comprehensive calculations of energies, matrix elements, and electric and magnetic dipole polarizabilities. Furthermore, we determined the magic wavelengths and the sensitivity factor for variations in the fine-structure constant . Detailed comparisons with existing results demonstrate good agreement, validating the reliability of our method. Additionally, we derive a general formula to incorporate the contribution of negative-energy states to the magnetic dipole tensor polarizability, thereby elucidating their non-negligible impact on the calculation of high-accuracy magnetic polarizability.}, archive = {J_PRA}, author = {Hong-Yuan Zheng and Li-Yan Tang}, doi = {10.1103/fmyj-3fyn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032817}, shortjournal = {Phys. Rev. A}, title = {Structure calculations for the low-charged sn2+ ion clock}, volume = {112}, year = {2025}, }
• (2025). Theoretical characterization of the barium ii and radium ii ions. PRA, 112(3), 032816. (www)

  @article{ , abstract = {Motivated by recent experimental advances, including the ongoing development of an optical atomic clock in singly ionized radium, we perform a detailed theoretical characterization of Ra + and its lighter analog Ba + . Both ions are of interest for precision studies, including for atomic parity violation and searches for new physics beyond the standard model. Using the all-order correlation potential method, including Breit and radiative quantum electrodynamics corrections, we perform high-accuracy calculations of electric dipole ( E 1 ), electric quadrupole ( E 2 ), and magnetic dipole ( M 1 ) transition matrix elements between the low-lying s , p , and d states of these ions, as well as the excited-state lifetimes, polarizabilities, magic wavelengths, and magnetic dipole hyperfine-structure constants A . By combining lifetime measurements with accurate theoretical ratios, we extract high-precision determinations of the s − d 1 / 2 , 3 / 2 E 2 matrix elements. By combining hyperfine measurements with atomic theory, we extract parameters of the nuclear magnetization distribution (the Bohr-Weisskopf effect) for Ba 135 , 137 and Ra 223 , 225 . These results provide theoretical input for ongoing and future experimental programs in fundamental physics and precision metrology.}, archive = {J_PRA}, author = {Robin B. Cserveny and Benjamin M. Roberts}, doi = {10.1103/1rtb-8ymc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032816}, shortjournal = {Phys. Rev. A}, title = {Theoretical characterization of the barium ii and radium ii ions}, volume = {112}, year = {2025}, }
• (2025). Constrained search in imaginary time. PRA, 112(3), 032815. (www)

  @article{ , abstract = {We introduce an imaginary-time evolution method to evaluate the pure-state constrained-search functional from density-functional theory formulated on finite lattices. Simultaneously, it yields a potential that produces a prescribed density of an eigenstate. Besides being a computational scheme, this allows one to gain theoretical insights into the density-potential mapping. The method can be generalized to the optimization of the expectation value of a general self-adjoint operator on a finite-dimensional Hilbert space under a finite number of expectation-value constraints for commuting self-adjoint operators.}, archive = {J_PRA}, author = {Markus Penz and Robert van Leeuwen}, doi = {10.1103/g4ch-5x8m}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032815}, shortjournal = {Phys. Rev. A}, title = {Constrained search in imaginary time}, volume = {112}, year = {2025}, }
• (2025). Superkick effect in vortex scattering: Møller scattering. PRA, 112(3), 032814. (www)

  @article{ , abstract = {Vortex states of photons or electrons are a novel and promising experimental tool across atomic, nuclear, and particle physics. Various experimental schemes to generate high-energy vortex particles have been proposed. However, diagnosing the characteristics of vortex states at high energies remains a significant challenge, as traditional low-energy detection schemes become impractical for high-energy vortex particles due to their extremely short de Broglie wavelength. We recently proposed a novel experimental detection scheme based on a mechanism called superkick that is free from many drawbacks of the traditional methods and can reveal the vortex phase characteristics. In this paper, we present a complete theoretical framework for calculating the superkick effect in elastic Møller scattering and systematically investigate the impact of various factors on its visibility. In particular, we argue that the vortex phase can be identified either by detecting the two scattered electrons in coincidence or by analyzing the characteristic azimuthal asymmetry in individual final particles.}, archive = {J_PRA}, author = {Shiyu Liu and Bei Liu and Igor P. Ivanov and Liangliang Ji}, doi = {10.1103/qrfd-9356}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032814}, shortjournal = {Phys. Rev. A}, title = {Superkick effect in vortex scattering: Møller scattering}, volume = {112}, year = {2025}, }
• (2025). Isotope shift for total electron binding energy of atoms. PRA, 112(3), 032813. (www)

  @article{ , abstract = {We compute the isotope shifts of the total electron binding energy of neutral atoms and singly charged ions up to element , using the relativistic Hartree-Fock method including the Breit interaction. Field shift coefficients are extracted by varying the nuclear charge radius; a small quadratic term is retained to cover large radius changes relevant to superheavy nuclei. We tabulate isotope shift coefficients for closed-shell systems from Ne to Og and benchmark selected open-shell cases, used to test the interpolation formula. A simple power-law interpolation reproduces calculated field shifts to within about 1% across the table, with the effective exponent growing from roughly 5 near to about 12 at . Due to the domination of inner shells, differences between neutrals and singly charged ions does not exceed a few percent, becoming noticeable mainly when an outer electron is removed. Therefore, these results may also be used for higher charge ions.}, archive = {J_PRA}, author = {V. A. Dzuba and V. V. Flambaum}, doi = {10.1103/r1x5-1yjg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032813}, shortjournal = {Phys. Rev. A}, title = {Isotope shift for total electron binding energy of atoms}, volume = {112}, year = {2025}, }
• (2025). Hydrogen adsorption and scattering on graphene with electron dynamics: Effects of incident point and kinetic energy. PRA, 112(3), 032812. (www)

  @article{ , abstract = {We perform real-time time-dependent density-functional theory (TDDFT) simulations with Ehrenfest dynamics to investigate how the incident point and initial kinetic energy of hydrogen atom projectiles influence their interaction with a graphenelike structure. To evaluate the role of electronic excitations, we compare these nonadiabatic results against two adiabatic approaches: Born-Oppenheimer molecular dynamics and ground-state energy profiling. We find that the incident point strongly affects the hydrogen atom's postcollision kinetic energy, scattering angle, and the vibrational response of the graphene lattice. Trajectories that avoid direct collisions with carbon atoms lead to longer interaction times and reduced energy transfer, increasing the likelihood of hydrogen adsorption by facilitating penetration of the graphene's potential energy barrier. Comparison with adiabatic methods reveals that electronic excitations and other non-adiabatic effects—captured by TDDFT—play a significant role in modulating energy loss and scattering direction. These results underscore the importance of including electron dynamics to accurately model hydrogen-graphene interactions and highlight how both geometric and energetic factors govern adsorption and scattering outcomes.}, archive = {J_PRA}, author = {Samuel S. Taylor and Nicholas Skoufis and Hongbo Du and Cody Covington and Kálmán Varga}, doi = {10.1103/zkwl-sj59}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032812}, shortjournal = {Phys. Rev. A}, title = {Hydrogen adsorption and scattering on graphene with electron dynamics: Effects of incident point and kinetic energy}, volume = {112}, year = {2025}, }
• (2025). Fock-space perturbed relativistic coupled-cluster calculations of electric dipole polarizability and nuclear spin-dependent parity nonconservation in cs. PRA, 112(3), 032811. (www)

  @article{ , abstract = {We implement the Fock-space perturbed relativistic coupled-cluster (FSPRCC) theory to compute the electric dipole polarizability of ground and low-lying excited states and nuclear spin-dependent (NSD) parity nonconservation (PNC) transition amplitudes in Cs. Further, by combining our computed NSD-PNC transition amplitudes with a Cs experiment [C. S. Wood et al. , Science 275 , 1759 (1997) ], we extract the value of the nuclear anapole moment and pion-mediated meson-nucleon coupling constant f π . The deviation in our f π from the standard model value could be attributed to the existence of new particles such as Z ′ bosons. By combining our nuclear spin-independent PNC calculation with experiment [ Science 275 , 1759 (1997) ], we extract the mass of the Z ′ boson to be M Z ′ > 1.6 TeV/ c 2 . To check the accuracy of the wave functions used in the calculations, we compute the excitation energies, E 1 transition amplitudes, and magnetic dipole hyperfine constants for ground and low-lying excited states. To improve the accuracy of the computed properties, we incorporate the corrections from the relativistic and QED effects in our calculations. The contributions from triple excitations are accounted for perturbatively. Our results on excitation energies, E 1 transition amplitudes, and hyperfine constants are in good agreement with the available experimental results. Our polarizability results using the FSPRCC theory match well with the experimental values. The values of parity-violating transition amplitudes from our calculations are in general on the lower side of the previous values. From a detailed analysis of electron correlations, we find that the corrections from the Breit interaction and QED effects are important to get accurate results of NSD-PNC amplitudes in Cs. The largest cumulative contribution from the Breit and QED corrections is found to be approximately equal to 3.2% of the total value. The upper bound on the theoretical uncertainty in our calculated NSD-PNC amplitudes is estimated to be about 1%.}, archive = {J_PRA}, author = {Suraj Pandey and Ravi Kumar and D. Angom and B. K. Mani}, doi = {10.1103/6qrr-1lhf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032811}, shortjournal = {Phys. Rev. A}, title = {Fock-space perturbed relativistic coupled-cluster calculations of electric dipole polarizability and nuclear spin-dependent parity nonconservation in cs}, volume = {112}, year = {2025}, }
• (2025). Hyperfine van der waals repulsion between open-shell polar molecules. PRA, 112(3), 032810. (www)

  @article{ , abstract = {We describe a novel type of interaction between open-shell polar molecules at sub-millikelvin temperatures. This hyperfine van der Waals interaction occurs between two molecules in two rotational states that differ by one quantum. Normally, this induces resonant dipolar interactions that lead to rapid collisional loss. For specific hyperfine states, however, selection rules prevent this. One can effectively turn off the dipolar interaction by merely flipping a nuclear spin. The resulting van der Waals interaction can be repulsive and can suppress collisional loss. We focus on laser-coolable CaF, but show this effect occurs universally for open-shell molecules, including MgF, SrF, BaF and YO. We propose that this effect could be measured by merging molecules in optical tweezers, where flipping a spin in one of the tweezers enables tuning of collision rates by five orders of magnitude.}, archive = {J_PRA}, author = {Etienne F. Walraven and Tijs Karman}, doi = {10.1103/z2bv-9gw7}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032810}, shortjournal = {Phys. Rev. A}, title = {Hyperfine van der waals repulsion between open-shell polar molecules}, volume = {112}, year = {2025}, }
• (2025). Single-photon ionization of aligned diatomic molecules in near-circular laser fields with lower photon energy. PRA, 112(3), 032809. (www)

  @article{ , abstract = {We study single-photon ionization of aligned H 2 + in low-intensity near-circular laser fields with lower photon energy numerically and analytically. The photoelectron momentum distribution (PMD) within the laser polarization plane, obtained by numerical simulations, shows a remarkable offset angle, which changes with changing the internuclear distance and the laser frequency. This phenomenon is different from that observed in recent experiments [ Science 370 , 339 (2020) ], which is related to the PMD along the propagation direction of the laser. This phenomenon holds even for H 2 + with short-range Coulomb potentials but disappears for atoms, different from that observed in attoclock experiments. We show that the molecular Coulomb potential near the two atomic centers plays an important role here, and theoretical models associated with a more accurate continuum wave function of the molecule are needed for reproducing this phenomenon. This phenomenon also appears for other molecules such as N 2 . It can be useful for ultrafast probing of molecules with a high resolution of several attoseconds or even zeptoseconds.}, archive = {J_PRA}, author = {Z. Y. Chen and S. Q. Shen and M. Q. Liu and J. Y. Che and Y. J. Chen}, doi = {10.1103/x86t-s461}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032809}, shortjournal = {Phys. Rev. A}, title = {Single-photon ionization of aligned diatomic molecules in near-circular laser fields with lower photon energy}, volume = {112}, year = {2025}, }
• (2025). Landé g-factor measurements for the 5d6s3D2 hyperfine levels of lu+176. PRA, 112(3), 032808. (www)

  @article{ , abstract = {We report measurements of the Landé g factors for the 5 d 6 s 3 D 2 hyperfine levels of Lu + 176 to a fractional inaccuracy of 5 × 10 − 7 . Combining these measurements with theoretical calculations allows us to estimate hyperfine-mediated modifications to the quadrupole moments for each state and infer a value of δ Θ = 1.59 ( 34 ) × 10 − 4 e a 0 2 for the residual quadrupole moment of the 1 S 0 ↔ 3 D 2 hyperfine-averaged clock transition.}, archive = {J_PRA}, author = {Qi Zhao and M. D. K. Lee and Qin Qichen and Zhao Zhang and N. Jayjong and K. J. Arnold and M. D. Barrett}, doi = {10.1103/3gct-km6y}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032808}, shortjournal = {Phys. Rev. A}, title = {Landé g-factor measurements for the 5d6s3D2 hyperfine levels of lu+176}, volume = {112}, year = {2025}, }
• (2025). Precision spectroscopy of the fine structure in the a3Σu+(ν=0) and c3Σg+(ν=4) states of the helium dimer. PRA, 112(3), 032807. (www)

  @article{ , abstract = {With four electrons, is one of very few molecules for which first-principles quantum-chemical calculations that include the treatment of nonadiabatic, relativistic, and quantum-electrodynamics corrections are possible. Precise spectroscopic measurements are needed as references to test these calculations. We report here on a spectroscopic measurement of the electronic transition of at a precision ( ) of and with full resolution of the rotational, spin-spin, and spin-rotational fine structures. The focus of the investigation is placed on the measurement and analysis of transitions to the rotational levels of the state, which are located energetically above the dissociation limit and can decay by tunneling predissociation through a barrier in the potential of the state. The new data include a full set of the energy levels of the and states with rotational quantum numbers up to 9 and 10, respectively, and full sets of fine-structure intervals in these levels for comparison with the results of first-principles calculations carried out in a parallel investigation [Rácsai, Jeszenszki, Margócsy, and Mátyus, arXiv:2506.23879v1 [physics.chem-ph]. The new data were combined with data from earlier measurements of the spectrum of the band system of to derive full sets of molecular constants for the and states with much improved precision over previous experimental results. A pronounced broadening of the linewidths of the transitions to the fine-structure levels is attributed to tunneling predissociation through a barrier in the potential of the state and is quantitatively accounted for by calculations of the predissociation widths.}, archive = {J_PRA}, author = {V. Wirth and M. Holdener and F. Merkt}, doi = {10.1103/g7sb-44d6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032807}, shortjournal = {Phys. Rev. A}, title = {Precision spectroscopy of the fine structure in the a3Σu+(ν=0) and c3Σg+(ν=4) states of the helium dimer}, volume = {112}, year = {2025}, }
• (2025). Coupled-channel calculations of fully differential cross sections for ionization in 75-keV p+He collisions. PRA, 112(3), 032806. (www)

  @article{ , abstract = {The fully differential cross section is the most detailed quantity that can be measured or calculated to study ionization in few-body systems. For 75 keV proton collisions with helium, various experimental data are available. However, previous theoretical calculations found significant discrepancies across the entire range of data. In this work the wave-packet convergent close-coupling method is extended to calculating these cross sections for electrons ejected with energies from 1 to 75.4 eV. The approach utilizes a two-center expansion and correlated two-electron helium wave functions to describe the four-body proton-helium system. While there is good agreement with the experiment for electrons ejected with energies near the matching-velocity point, elsewhere, the results overall do not support the picture provided by the available measurements. Hence, further investigations, both theoretical and experimental, are necessary to resolve the intermediate-energy proton-helium differential ionization problem.}, archive = {J_PRA}, author = {K. H. Spicer and N. W. Antonio and M. S. Schöffler and M. Schulz and A. S. Kadyrov}, doi = {10.1103/czd2-865z}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032806}, shortjournal = {Phys. Rev. A}, title = {Coupled-channel calculations of fully differential cross sections for ionization in 75-keV p+He collisions}, volume = {112}, year = {2025}, }
• (2025). Transcorrelated theory for transition-metal atoms. PRA, 112(3), 032805. (www)

  @article{ , abstract = {We benchmark ionization and excitation energies of transition-metal atoms Sc–Zn with a transcorrelated Hamiltonian combined with pseudopotentials. The similarity transformed Hamiltonian provides compact transcorrelation (TC) wave functions in affordable aug-cc-pVTZ and aug-cc-pVQZ Gaussian bases and eliminates the need for complete basis set extrapolations. The use of Douglas-Kroll-Hess theory is omitted because scalar relativistic effects are included in the pseudopotentials. Treating the full semicore ( ) valence and freezing only – shells, we reach chemical accuracy for all atoms and properties with coupled cluster and full configuration interaction quantum Monte Carlo. Consistent total energies across disparate orbital sets and correlation solvers highlight the robustness of the TC workflow. Our study pushes benchmark-quality quantum chemistry into the block without large-scale basis sets and opens a practical route for transcorrelation to strongly correlated molecules and materials hosting heavier transition metals.}, archive = {J_PRA}, author = {Kristoffer Simula and Maria-Andreea Filip and Ali Alavi}, doi = {10.1103/2ttg-789l}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032805}, shortjournal = {Phys. Rev. A}, title = {Transcorrelated theory for transition-metal atoms}, volume = {112}, year = {2025}, }
• (2025). Velocity-map imaging and mechanisms of dissociative electron attachment to CH3I. PRA, 112(3), 032804. (www)

  @article{ , abstract = {We probe dissociative electron attachment (DEA) to methyl iodide, using the velocity-map imaging (VMI) technique. Our DEA-VMI spectrometer allows for preparation of the incident electron beam at electron energies low enough to record the images of the exothermic production channel. A clear forward-backward asymmetry visible in the angular distributions is attributed to contributions of different partial waves which are controlled by partial widths of the involved resonant state. This coupling of partial waves is facilitated primarily by the dipolar field of the target molecule.}, archive = {J_PRA}, author = {Samrat Saha and Soumya Ghosh and Jaroslav Kočišek and Roman Čurík and Dhananjay Nandi and Juraj Fedor and Pamir Nag}, doi = {10.1103/9414-ykjc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032804}, shortjournal = {Phys. Rev. A}, title = {Velocity-map imaging and mechanisms of dissociative electron attachment to CH3I}, volume = {112}, year = {2025}, }
• (2025). Multiply differential study of detachment with simultaneous target excitation in anion-atom collisions. PRA, 112(3), 032803. (www)

  @article{ , abstract = {We have measured momenta of electrons and recoil ions in triple coincidence with neutralized projectiles for slow collisions between various anions and target atoms. From the data we extracted triple differential momentum and angular distributions of electrons ejected in detachment, in detachment with simultaneous target ionization (DI), and in detachment with simultaneous target excitation (DE). The DI rates relative to the DE rates depend sensitively on the projectile speed and on the properties of the target.}, archive = {J_PRA}, author = {M. Schulz and F. Herrmann and W. Zhang and D. V. Chicharro and A. Dorn and M. Grieser and F. Grussie and H. Kreckel and O. Novotny and F. Trost and A. Wolf and T. Pfeifer and C. D. Schröter and R. Moshammer}, doi = {10.1103/vn2k-87xq}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032803}, shortjournal = {Phys. Rev. A}, title = {Multiply differential study of detachment with simultaneous target excitation in anion-atom collisions}, volume = {112}, year = {2025}, }
• (2025). Three-body fragmentation dynamics of C5H5N3+ produced by 200-eV electron-impact triple ionization. PRA, 112(3), 032802. (www)

  @article{ , abstract = {The three-body fragmentation dynamics of pyridine trications produced by 200-eV electron-impact triple ionization are investigated using a reaction microscope. The three complete deprotonation fragmentation channels of , and are determined by multiparticle coincidence momentum imaging. By analyzing the correlation maps as a function of kinetic energy release and the angle between the conjugate momenta of the first and second breakup steps as well as the momentum correlation spectra of three fragment ions (Newton diagram) in these three channels, we separate two distinct sequential mechanisms involving proton emission in the first or second step of sequential fragmentation. Moreover, we determine the relative ratio of the two dissociation pathways for each channel. We find that proton emission in the first step of the sequential dissociation is the dominant process (94% branching ratio) for the channel involving the H migration of . It can be explained by the pyridine trication undergoing ultrafast hydrogen migration and forming a more stable -isomeric ion, which attenuates the ring-opening reactions. Our study provides insight into the dynamics of deprotonation and ring-breaking reactions in the three-body fragmentation processes of heterocyclic molecules.}, archive = {J_PRA}, author = {Xintai Hao and Menhao Yang and Jiaqi Zhou and Xiaorui Xue and Qibo Ma and Lei Wang and Peng Li and Xueguang Ren}, doi = {10.1103/3fgn-ryjc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032802}, shortjournal = {Phys. Rev. A}, title = {Three-body fragmentation dynamics of C5H5N3+ produced by 200-eV electron-impact triple ionization}, volume = {112}, year = {2025}, }
• (2025). Rovibrational spectroscopy of state-selected HD+ ions through spatially resolved fluorescence collection. PRA, 112(3), 032801. (www)

  @article{ , abstract = {We demonstrate a novel method that integrates quantum state preparation of polar molecular ions and the detection of spatially resolved fluorescence in specific regions to study the high-precision spectroscopy of molecular ions in traps. The detection technique not only enables real-time signal measurement but also suppresses common-mode noise arising from fluorescence fluctuations and reduces the state redistribution induced by blackbody radiation. Thus, this method overcomes the key limitations encountered during quantum state preparation of polar molecules through resonance-enhanced threshold photoionization. By utilizing this approach, we measured the ( ): rovibrational transition of ions, with an unperturbed frequency of 303.396 506 7(20) THz. This value is in excellent agreement with the predictions of quantum electrodynamics (QED). Looking forward, our method could be extended to detect hot-band transitions of excited from highly excited rovibrational states. This provides high-precision tools for determining fundamental constants such as the proton-to-electron mass ratio and for exploring the unknown contributions of QED.}, archive = {J_PRA}, author = {Qian-Yu Zhang and Wen-Li Bai and Zhi-Yuan Ao and Wen-Cui Peng and Sheng-Guo He and Xin Tong}, doi = {10.1103/qxyn-jx1t}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032801}, shortjournal = {Phys. Rev. A}, title = {Rovibrational spectroscopy of state-selected HD+ ions through spatially resolved fluorescence collection}, volume = {112}, year = {2025}, }
• (2025). Dynamics and computation in linear open quantum walks. PRA, 112(3), 032627. (www)

  @article{ , abstract = {Open quantum walks (OQWs) are a type of quantum walk governed by the system's interaction with its environment. We explore the time evolution and the limit behavior of the OQW framework for quantum computation and show how we can represent random unitary quantum channels, such as the dephasing and depolarizing channels, in this model. We also develop a simulation protocol with circuit representation for this model, which is heavily inspired by the fact that graphs represent OQWs and are thereby local (meaning that the state in a particular node interacts only with its neighborhood). We obtain asymptotic advantages in the system's dimension, circuit depth, and cnot count compared to other simulation methods.}, archive = {J_PRA}, author = {Pedro Linck Maciel and Nadja K. Bernardes}, doi = {10.1103/lg6c-sgvn}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032627}, shortjournal = {Phys. Rev. A}, title = {Dynamics and computation in linear open quantum walks}, volume = {112}, year = {2025}, }
• (2025). Upgrading quantum metrology by combined sensitivity resources in mixed linear-nonlinear light-matter interactions with bias field. PRA, 112(3), 032626. (www)

  @article{ , abstract = {The major goal of quantum metrology (QM) is to exploit the quantum resources to raise the measurement precision (MP) as high as possible. While the quantum resources such as squeezing have been widely explored, light-matter interaction systems set up a highly controllable platform applicable for QM in novel pursuit of high MP. However, critical QM by the conventional linear interaction is confronted with the limitation of a local parameter regime, restriction of a low-frequency-limit condition, and the detrimental problem of diverging preparation time of probe state (PTPS). This work shows that mixed interactions by linear and nonlinear light-matter couplings in the presence of bias field can provide various quantum resources, including squeezing, degeneracy lifting, displacement, and quantum phase transition. These resources manifest high sensitivity for QM as demonstrated by analytically obtained critical exponents or exponential behavior of quantum Fisher information. We find that these sensitivity resources can be combined to upgrade the upper bound of MP by many orders over the widely applied squeezing resource. As further advantages in contrast to the linear critical QM, such an upgraded metrology protocol can have a global parameter regime, break the frequency-limit restriction, and avoid the diverging PTPS. Our work paves a way to exploit and combine all the resources in momentum, position, and spin spaces to maximize the MP and expand the applicable conditions simultaneously.}, archive = {J_PRA}, author = {Zu-Jian Ying}, doi = {10.1103/rtd9-z7cl}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032626}, shortjournal = {Phys. Rev. A}, title = {Upgrading quantum metrology by combined sensitivity resources in mixed linear-nonlinear light-matter interactions with bias field}, volume = {112}, year = {2025}, }
• (2025). Experimental realization of remote two-qubit state preparation using single-particle operations. PRA, 112(3), 032625. (www)

  @article{ , abstract = {Remote quantum state preparation allows one party to prepare a known quantum state at a distant node using local operations and classical communication. Conventional approaches for remotely preparing entangled states typically require joint operations on multiple particles at the local site, which poses practical challenges in scalable quantum networks. Here, we propose a general remote quantum state preparation scheme based on an asymmetric maximally entangled state, where only single-particle operations are needed at the local node to prepare arbitrary multiqubit states at the remote site. We demonstrate this scheme experimentally on a linear optical platform, using a three-photon asymmetric entangled state as a resource. By applying single-particle operations on a four-dimensional photonic ququart, we remotely prepare arbitrary two-qubit states with fidelities ranging from 0.8534 to 0.9444, all surpassing the classical threshold. This approach simplifies local control requirements and offers a scalable route for remote entanglement generation in quantum networks and distributed quantum computing.}, archive = {J_PRA}, author = {Ziyang Ou and Qiao Xu and Xiaoqi Zhou}, doi = {10.1103/vlhq-335q}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032625}, shortjournal = {Phys. Rev. A}, title = {Experimental realization of remote two-qubit state preparation using single-particle operations}, volume = {112}, year = {2025}, }
• (2025). Probabilistic pulse-position modulation for classical communication on quantum channels. PRA, 112(3), 032624. (www)

  @article{ , abstract = {Classical communication over lossy quantum channels is an essential topic in quantum information theory, with practical implications for optical-fiber and free-space communications. Multiphase Hadamard codes, based on coherent-state binary phase-shift keying (BPSK) modulation and decoded using vacuum-or-pulse (VP) detectors, offer a promising approach for achieving high communication rates while relying only on linear optics and single-photon detectors (SPDs). However, their performance does not reach the ultimate Holevo limit. In this work, we propose a generalization of Hadamard codes that distributes the signal across multiple modes with optimized probabilities, rather than concentrating it in a single mode, dubbed probabilistic pulse-position modulation (PPPM). We derive an achievable communication rate, demonstrating that our PPPM can outperform traditional Hadamard codes in certain intermediate energy regimes.}, archive = {J_PRA}, author = {Farzad Kianvash and Matteo Rosati}, doi = {10.1103/jx7h-nz4c}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032624}, shortjournal = {Phys. Rev. A}, title = {Probabilistic pulse-position modulation for classical communication on quantum channels}, volume = {112}, year = {2025}, }
• (2025). Variational quantum subspace construction via symmetry-preserving cost functions. PRA, 112(3), 032623. (www)

  @article{ , abstract = {Determining low-energy eigenstates in electronic many-body quantum systems is a key challenge in computational chemistry and condensed-matter physics. Hybrid quantum-classical approaches, such as the Variational Quantum Eigensolver and Quantum Subspace Methods, offer practical solutions but face limitations in circuit depth and measurement overhead. In this article, we propose a variational strategy based on symmetry-preserving cost functions to iteratively construct a reduced subspace for the extraction of low-lying energy states. We show that, under certain conditions, our approach leads to a tridiagonal representation similar to that obtained with the Lanczos algorithm. The iterative process allows control over the trade-off between circuit depth, the number of variational parameters, and the number of measurements required to achieve the desired accuracy, making it suitable for current quantum hardware. As a proof of concept, we test the proposed algorithms on a H 4 chain and ring, targeting both the ground-state energy and the charge gap.}, archive = {J_PRA}, author = {Hamzat A. Akande and Alexandre Perrin and Bruno Senjean and Matthieu Saubanère}, doi = {10.1103/6hpp-zl5h}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032623}, shortjournal = {Phys. Rev. A}, title = {Variational quantum subspace construction via symmetry-preserving cost functions}, volume = {112}, year = {2025}, }
• (2025). Mitigating multiple frequency-dependent errors in superconducting quantum chips using message-passing neural networks. PRA, 112(3), 032622. (www)

  @article{ , abstract = {Errors in superconducting quantum chips are inevitable for developing robust logical qubits and implementing complex quantum algorithms. These errors arise from various physical mechanisms, each with unique dependence on qubit frequencies. Here, we propose an algorithm for optimizing qubit frequencies to effectively mitigate multiple types of frequency-dependent errors. We employ multichannel message-passing neural networks, with each channel tailored to address a specific error type. Our neural-network model is trained to minimize the weighted sum of different errors, based on frequency-dependent error models, e.g., two-level-system defects that affect individual qubits, quantum crosstalk that depends on the graph structure formed by qubit couplings, and microwave crosstalk that relies on the spatial arrangement of qubits. The trained neural-network model is adaptable to chips with varying qubit arrangements and scales. Recognizing the diverse experimental conditions of different chips, we compare our algorithm with the snake algorithm across various scales and error weights, providing valuable guidance for experimenters in algorithm selection. Our results show that, in most scenarios, our algorithm achieves lower overall errors than the snake algorithm.}, archive = {J_PRA}, author = {Hao Ai and Guo-Zheng Zhu and Yu-xi Liu}, doi = {10.1103/tvsg-cm8p}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032622}, shortjournal = {Phys. Rev. A}, title = {Mitigating multiple frequency-dependent errors in superconducting quantum chips using message-passing neural networks}, volume = {112}, year = {2025}, }
• (2025). ISWAP gate with polar molecules: Robustness criteria for entangling operations. PRA, 112(3), 032621. (www)

  @article{ , abstract = {Ultracold polar molecules trapped in optical lattices or tweezer arrays are an emerging platform for quantum information processing and quantum simulation, thanks to their rich internal structure and long-range dipolar interactions. Recent experimental breakthroughs have enabled precise control over individual molecules, paving the way for implementing two-qubit quantum gates, based on the iSWAP gate. A key challenge is, however, the sensitivity to variations of the dipole-dipole interaction strength—stemming from motion of the molecules and uncertainty on the precise positioning of external confining potentials—that limits current gate fidelities. To address this, we develop a quantum optimal control framework, based on a perturbative approach, to design gates that are robust with respect to quasistatic deviations of either system Hamiltonian parameters, external control parameters, or both, and provide criteria to evaluate a priori whether a gate can be made robust for a given control Hamiltonian. By applying these criteria to exchange-coupled qubits, as polar molecules, we demonstrate that robustness cannot be achieved with global controls only, but can be attained by breaking the exchange symmetry through local controls, such as a local detuning. We determine the robust time-optimal solution for realizing an iSWAP gate, show that the control pulses can be designed to be smooth functions, and achieve theoretical gate fidelities compatible with error correction using reasonable experimental parameters. Additionally, we show that certain entangled-state preparations, such as Bell states, can be made robust even with global controls only. We demonstrate that, under the adiabatic approximation, i.e., where molecular motion occurs on timescales comparable to, or faster, than that of the exchange interaction, the noise arising from thermal motion can be effectively treated as quasistatic variations of Hamiltonian parameters. This allows us to extend our treatment to the concrete experimental case of polar molecules.}, archive = {J_PRA}, author = {Matteo Bergonzoni and Sven Jandura and Guido Pupillo}, doi = {10.1103/q9sd-rfp6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032621}, shortjournal = {Phys. Rev. A}, title = {ISWAP gate with polar molecules: Robustness criteria for entangling operations}, volume = {112}, year = {2025}, }
• (2025). Impact of polarization mode dispersion on entangled photon distribution. PRA, 112(3), 032620. (www)

  @article{ , abstract = {The polarization mode dispersion (PMD) in optical fibers poses a major challenge for maintaining the fidelity of quantum states for quantum communications. In this work, a comprehensive model linking the probability of quantum measurement errors (infidelity) to PMD is developed and validated by experimental measurements of differential group delay and quantum bit error rate (QBER). Our research proposes effective methods to mitigate PMD effects for broadband entangled photons and evaluates the impact of higher-order PMD effects. The model provides an experimentally verified framework for the optimization of commercial quantum key distribution systems in deployed fiber-optic lines.}, archive = {J_PRA}, author = {Vadim Rodimin and Konstantin Kravtsov and Rui Ming Chua and Gianluca De Santis and Aleksei Ponasenko and Yury Kurochkin and Alexander Ling and James A. Grieve}, doi = {10.1103/l2l7-b98w}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032620}, shortjournal = {Phys. Rev. A}, title = {Impact of polarization mode dispersion on entangled photon distribution}, volume = {112}, year = {2025}, }
• (2025). Local fermion-to-qudit mappings: A practical recipe for four-level systems. PRA, 112(3), 032619. (www)

  @article{ , abstract = {In this paper, we present a set of local fermion-to-qudit mappings for simulating fermionic lattice systems. We focus on the use of multilevel qudits, specifically ququarts. Traditional mappings, such as the Jordan-Wigner transformation (JWT), while useful, often result in nonlocal operators that scale unfavorably with system size. To address these challenges, we introduce mappings that efficiently localize fermionic operators on qudits, reducing the nonlocality and operator weights associated with JWT. We propose one mapping for spinless fermions and two mappings for spinful fermions, comparing their performance in terms of qudit weight, circuit depth, and gate complexity. Notably, for superconducting devices, the control complexity of qudits compared to qubits does not increase prohibitively for four-level systems, making them practical for near-term demonstrations, though control challenges grow with increasing dimensionality. Therefore, we provide solutions to the operator decompositions of the Trotterized quantum dynamics into one- and two-qudit gates for all mappings. By leveraging the extended local Hilbert space of qudits, we show that these mappings enable more efficient quantum simulations in terms of two-qudit gates, reducing hardware requirements without increasing computational complexity. We validate our approach by simulating prototypical models such as the spinless t − V model and the Fermi-Hubbard model in two dimensions, using Trotterized time evolution. Finally, we show the connection between the plaquette constraint of our mapping and the Z 2 toric code. This connection can be exploited to prove that the ground state of the localized qudit mapping can be efficiently prepared using quantum circuits or measurement-based feedback control. Our results highlight the potential of qudit-based quantum simulations in achieving scalability and efficiency for fermionic systems on near-term quantum devices.}, archive = {J_PRA}, author = {Rodolfo Carobene and Andrea Giachero and Stefano Barison and Jannes Nys}, doi = {10.1103/bcs4-hxl3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032619}, shortjournal = {Phys. Rev. A}, title = {Local fermion-to-qudit mappings: A practical recipe for four-level systems}, volume = {112}, year = {2025}, }
• (2025). Teleportation fidelity of quantum repeater networks. PRA, 112(3), 032618. (www)

  @article{ , abstract = {We show that the average of the maximum teleportation fidelities between all pairs of nodes in a large quantum repeater network is a measure of the resourcefulness of the network as a whole. It can be used to rank networks of arbitrary topologies, with and without loops. For demonstration purposes, we use simple Werner state-based models to characterize some fundamental topologies (the star, the chain, some trees, and also the ring and the complete graph) with this measure in three (semi)realistic scenarios. Most of our results are analytic and apply to arbitrary network sizes. We identify the parameter ranges where these networks can achieve quantum advantages and show the large- N behaviors.}, archive = {J_PRA}, author = {Ganesh Mylavarapu and Subrata Ghosh and Chittaranjan Hens and Indranil Chakrabarty and Subhadip Mitra}, doi = {10.1103/72jp-37k6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032618}, shortjournal = {Phys. Rev. A}, title = {Teleportation fidelity of quantum repeater networks}, volume = {112}, year = {2025}, }
• (2025). Measurement-based simulation of geometric gates in topological qubits on noisy intermediate-scale quantum devices. PRA, 112(3), 032617. (www)

  @article{ , abstract = {While the adiabatic exchange of Majorana zero modes (MZMs) enables a nonuniversal set of geometrically protected gates, realizing an experimental implementation of MZM braiding remains challenging. In an alternative proposal, charge-parity measurement of two neighboring MZMs supports braiding by teleportation. Moreover, owing to the lack of definitive evidence of MZMs in semiconducting systems, there have been several simulations of MZMs on noisy intermediate-scale quantum devices which more naturally lend themselves to braiding. In this work, measurement-based braiding about MZM Y junctions is simulated by multiqubit parity measurements of a logical qubit. Logical single-qubit geometric S ( † ) and entangling two-qubit braiding operations are shown using two-physical-qubit joint measurements alone, while T ( † ) gates corresponding to a kind of partial-braiding operation require at least one three-qubit joint measurement. These relatively small-scale circuits demonstrate potential applications of both measurement-based geometric gates and a measurement-based demonstration of quantum Hamiltonian simulation.}, archive = {J_PRA}, author = {Matthew Brooks and Foster Sabatino and Charles Tahan and Silas Hoffman}, doi = {10.1103/jjvg-jy3n}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032617}, shortjournal = {Phys. Rev. A}, title = {Measurement-based simulation of geometric gates in topological qubits on noisy intermediate-scale quantum devices}, volume = {112}, year = {2025}, }
• (2025). Understanding the physics of D-wave annealers: From schrödinger to lindblad to markovian dynamics. PRA, 112(3), 032616. (www)

  @article{ , abstract = {Understanding the physical nature of the D-Wave annealers remains a subject of active investigation. In this study, we analyze the sampling behavior of these systems and explore whether their results can be replicated using quantum and Markovian models. Employing the standard and the fast annealing protocols, we observe that the D-Wave annealers sample states with frequencies matching the Gibbs distribution for sufficiently long annealing times. Using Bloch equation simulations for single-qubit problems and Lindblad and Markovian master equations for two-qubit systems, we compare experimental data with theoretical predictions. Our results provide insights into the role of quantum mechanics in these devices.}, archive = {J_PRA}, author = {Vrinda Mehta and Hans De Raedt and Kristel Michielsen and Fengping Jin}, doi = {10.1103/3yk8-qn64}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032616}, shortjournal = {Phys. Rev. A}, title = {Understanding the physics of D-wave annealers: From schrödinger to lindblad to markovian dynamics}, volume = {112}, year = {2025}, }
• (2025). Superadditivity of quantum capacity in simple channels. PRA, 112(3), 032615. (www)

  @article{ , abstract = {The superadditivity of quantum channel capacity is an important feature of quantum information theory, different from classical theory, which has been attracting attention. Recently a special channel called “platypus channel” exhibits superadditive quantum capacity when combined with qudit erasure channels. Here we consider the generalized platypus channel, prove that it has computable channel capacities, such as both private and classical capacity equal to 1, and in particular, the generalized platypus channel still displays the superadditivity of quantum capacity when combined with qudit erasure channels and multilevel amplitude damping channels, respectively.}, archive = {J_PRA}, author = {Zhen Wu and Qi Zhao and Zhihao Ma}, doi = {10.1103/14j4-6tfc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032615}, shortjournal = {Phys. Rev. A}, title = {Superadditivity of quantum capacity in simple channels}, volume = {112}, year = {2025}, }
• (2025). Speeding up dissipation-based quantum state engineering with lyapunov control. PRA, 112(3), 032614. (www)

  @article{ , abstract = {We propose a Lyapunov control strategy to accelerate dissipative quantum state preparation by designing the control fields with respect to intermediate excited states instead of the target steady state. This approach, termed intermediate-state-based Lyapunov control (ISB-LC), allows for greater flexibility in designing control Hamiltonians and facilitates faster convergence without compromising robustness. We demonstrate the effectiveness of ISB-LC using several open quantum systems, including three-, four-, and six-level configurations, as well as entangled steady-state generation in interacting Rydberg atoms. Numerical simulations show that ISB-LC can reduce convergence times by more than an order of magnitude, offering a promising route for enhancing dissipation-based quantum control protocols.}, archive = {J_PRA}, author = {Du Ran and Qin Xie and Bai-Yun Zhang and Zhuo-Qing Zhang and Shuai Liu and Ze-Long He and Ya-dong Li and Sui-Hu Dang}, doi = {10.1103/25cm-l24h}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032614}, shortjournal = {Phys. Rev. A}, title = {Speeding up dissipation-based quantum state engineering with lyapunov control}, volume = {112}, year = {2025}, }
• (2025). Optimization of two-qubit gates in tunable-coupler architectures using single-flux-quantum control. PRA, 112(3), 032613. (www)

  @article{ , abstract = {We present a gradient-based method to construct high-fidelity, two-qubit quantum gates in a system consisting of two transmon qubits coupled via a tunable coupler. In particular, we focus on single-flux-quantum pulses as a promising and scalable alternative to traditional control schemes that use microwave electronics. We develop a continuous embedding scheme to optimize these discrete pulses, taking advantage of autodifferentiation of our model. This approach allows us to achieve fSim-type gates with average gate fidelities on the order of 99.99% and controlled- and controlled- not gates with fidelities above 99.9%. Furthermore, we provide an alternative semianalytical construction of these gates via an exact decomposition using a pair of fSim gates, which leads to the reduction in memory required to store the associated pulse sequences.}, archive = {J_PRA}, author = {Boyan Torosov and Bohdan Kulchytskyy and Florian Hopfmueller and John Gunderson and Xiangzhou Kong and Pooya Ronagh}, doi = {10.1103/9cvc-p9ww}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032613}, shortjournal = {Phys. Rev. A}, title = {Optimization of two-qubit gates in tunable-coupler architectures using single-flux-quantum control}, volume = {112}, year = {2025}, }
• (2025). Quantum-enhanced sensing of bosonic modes with cat states. PRA, 112(3), 032612. (www)

  @article{ , abstract = {Quantum coherence is critical resource for applications in quantum technology, among which quantum-enhanced sensing represents a typical example. Compared with quantum metrology with entangled states of multiple qubits, bosonic interferometers have the advantage of being hardware efficient, enabled by the infinite-dimension Hilbert space of bosonic modes. Phase estimations with precisions approaching the Heisenberg limit have been demonstrated with superpositions of Fock states of single bosonic modes. We here present a scheme for realizing quantum metrology based on a fundamentally distinct kind of superposition states, Schrödinger cat states, defined as quantum superpositions of two quasiclassial states of a bosonic mode. The interferometer aims to estimate the frequency shift of a photonic mode with respect to a reference frequency, which produces a phase-space rotation. We find that such a phase-space rotation can be extracted with a qubit, without mapping the state of the photonic mode to the qubit. This phase-space rotation is directly related to the qubit's population through the combination of a phase-space displacement, a dispersive qubit-photon interaction, and two qubit rotations. The signal-to-noise ratio exhibits a scaling approaching the Heisenberg limit, like interferometers based on Fock state superpositions, but without requiring a step-by-step procedure to prepare the resource state.}, archive = {J_PRA}, author = {Xiao-Wei Zheng and Jun-Cong Zheng and Xue-Feng Pan and Pengbo Li}, doi = {10.1103/ng3t-p1n1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032612}, shortjournal = {Phys. Rev. A}, title = {Quantum-enhanced sensing of bosonic modes with cat states}, volume = {112}, year = {2025}, }
• (2025). Scalable universal quantum gates between nitrogen-vacancy centers in levitated nanodiamond arrays. PRA, 112(3), 032611. (www)

  @article{ , abstract = {Nitrogen-vacancy (NV) centers in nanodiamond offer a promising platform for quantum information processing due to their room-temperature spin coherence and optical addressability. However, scalable quantum processors remain limited by the challenge of achieving strong, controllable interactions between distant NV spins. Here, we propose a scalable architecture utilizing optically levitated nanodiamond arrays, where torsional vibrations mediate the coherent coupling between the embedded NV centers. By optimizing the shape of ellipsoidal nanoparticles, we achieve a light-induced coupling strength exceeding 119 kHz between torsional modes of the distant levitated nanodiamonds, which are two orders of magnitude larger than the typical decoherence rates in this system. This strong interaction, combined with magnetic-field-enabled spin-torsion coupling, establishes an effective interaction between the spatially separated NV centers in the distant nanodiamonds. Numerical simulations confirm that dynamic decoupling can suppress both thermal noise and spin dephasing, enabling two-qubit gates with fidelity exceeding 99%. This work provides a foundation for reconfigurable quantum hybrid systems, with potential applications in rotational sensing and programmable quantum processing.}, archive = {J_PRA}, author = {Guangyu Zhang and Huaijin Zhang and Zhang-Qi Yin}, doi = {10.1103/zgk4-1556}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032611}, shortjournal = {Phys. Rev. A}, title = {Scalable universal quantum gates between nitrogen-vacancy centers in levitated nanodiamond arrays}, volume = {112}, year = {2025}, }
• (2025). Quantum simulation of dynamical response functions of equilibrium states. PRA, 112(3), 032610. (www)

  @article{ , abstract = {The computation of dynamical response functions is central to many problems in condensed matter physics. Owing to the rapid growth of quantum correlations following a quench, classical methods face significant challenges even if an efficient description of the equilibrium state is available. Quantum computing offers a promising alternative. However, existing approaches often assume access to the equilibrium state, which may be difficult to prepare in practice. In this work, we present a method that circumvents this by using energy filter techniques, enabling the computation of response functions and other dynamical properties in both microcanonical and canonical ensembles. Our approach only requires the preparation of states that have significant weight at the desired energy. The dynamical response functions are then reconstructed from measurements after quenches of varying duration by classical postprocessing. We illustrate the algorithm numerically by applying it to compute the dynamical conductivity of a free-fermion model, which unveils the energy-dependent localization properties of the model.}, archive = {J_PRA}, author = {Esther Cruz and Dominik S. Wild and Mari Carmen Bañuls and J. Ignacio Cirac}, doi = {10.1103/lpz2-j7vg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032610}, shortjournal = {Phys. Rev. A}, title = {Quantum simulation of dynamical response functions of equilibrium states}, volume = {112}, year = {2025}, }
• (2025). Superresolution of unequal-brightness thermal sources for stellar interferometry. PRA, 112(3), 032609. (www)

  @article{ , abstract = {Resolving high-contrast targets is a fundamental, yet highly challenging, task in astronomy. Using quantum estimation theory, we demonstrate that the ultimate limit for estimating the separation between two unequal-brightness thermal sources via interferometry remains constant, enabling the potential for superresolution. We give a comparative analysis of two primary stellar interferometric schemes: amplitude interferometry and intensity interferometry. Notably, the nulling strategy employed in amplitude interferometry, a configuration specifically proposed for exoplanet detection by leveraging destructive interference to suppress the brighter source, is quantum optimal for separation estimation. While intensity interferometry is less effective than amplitude interferometry in lossless scenarios and fails to achieve superresolution, it becomes competitive when optical loss in large-scale interferometry is considered. By applying these methodologies to modern stellar interferometry, we highlight the promise of large-scale interferometry for advancing high-resolution astronomical observation.}, archive = {J_PRA}, author = {Chenyu Hu and Ben Wang and Jiandong Zhang and Kunxu Wang and Huigen Liu and Jilin Zhou and Lijian Zhang}, doi = {10.1103/z157-q6n3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032609}, shortjournal = {Phys. Rev. A}, title = {Superresolution of unequal-brightness thermal sources for stellar interferometry}, volume = {112}, year = {2025}, }
• (2025). Generation of counterpropagating photon pairs in periodically poled rb-KTiOPO4. PRA, 112(3), 032608. (www)

  @article{ , abstract = {We demonstrate the generation of counterpropagating, twin-photon pairs in the optical communication band, utilizing periodically poled Rb-doped . The spectral and polarization indistinguishability of the photon pairs is confirmed through a Hong-Ou-Mandel interference measurement. At degeneracy, the photon-pair generation exhibits a broad angular distribution. Notably, the forward-propagating photon tunes with the pump frequency while the backward-propagating photon frequency remains nearly independent of the pump wavelength.}, archive = {J_PRA}, author = {Albert Peralta Amores and Andrius Zukauskas and Patrick Mutter and Fredrik Laurell and Valdas Pasiskevicius and Marcin Swillo}, doi = {10.1103/5b5f-x6nc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032608}, shortjournal = {Phys. Rev. A}, title = {Generation of counterpropagating photon pairs in periodically poled rb-KTiOPO4}, volume = {112}, year = {2025}, }
• (2025). Over-rotation coherent error induced by pseudotwirling of quantum gates. PRA, 112(3), 032607. (www)

  @article{ , abstract = {Quantum error mitigation (QEM) schemes have greatly enhanced the performance of quantum computers, mostly by reducing errors caused by interactions with the environment. Nevertheless, the presence of coherence errors, typically arising from miscalibration and interqubit crosstalk, is a significant challenge to the scalability of quantum computing. Such errors are often addressed using a refined Pauli twirling scheme called randomized compiling (RC) that converts the coherent errors into incoherent errors that can then be mitigated by conventional QEM. Unfortunately for multiqubit gates, RC is restricted to Clifford gates such as cnot and cphase . However, it has been demonstrated experimentally that a direct implementation of multiqubit non-Clifford gates, i.e., without using multiqubit Clifford gates, has reduced the depth of the circuit by a factor of four and more. Recently, a framework called pseudotwirling (PST) for treating coherent error in multiqubit non-Clifford gates has been introduced and experimentally demonstrated. We show analytically that a higher-order correction to the existing PST theory yields an over-rotation coherent error generated by the PST protocol itself. This PST effect has no analog in RC. Although the small induced over-rotation can amount to a significant coherent error in deep circuits, we explain why it does not degrade the performance of the gate. Interestingly, we find that a simplified twirling scheme that was introduced and exploited experimentally by Kim et al . also displays an induced over-rotation. We study the conditions under which the two twirling schemes display the same over-rotation behavior.}, archive = {J_PRA}, author = {Tanmoy Pandit and Raam Uzdin}, doi = {10.1103/lr5k-5fdc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032607}, shortjournal = {Phys. Rev. A}, title = {Over-rotation coherent error induced by pseudotwirling of quantum gates}, volume = {112}, year = {2025}, }
• (2025). Minimally universal parity quantum computing. PRA, 112(3), 032606. (www)

  @article{ , abstract = {In parity quantum computing, multiqubit logical gates are implemented by single-qubit rotations on a suitably encoded state involving auxiliary qubits. Consequently, there is a correspondence between qubit count and the size of the native gate set. One might then wonder, what is the smallest number of auxiliary qubits that still allows for universal parity computing? Here, we demonstrate that the answer is 1 if the number of logical qubits is even, and 2 otherwise. Furthermore, we present a sufficient condition for a given parity gate set to be universal. This leads to a variety of different universal parity gate sets corresponding to different numbers of auxiliary qubits and more generally contributes to the understanding of which entangling gates are required to augment the set of single-qubit unitaries to perform universal quantum computing. As a consequence, we obtain (i) minimal implementations of the parity framework on, e.g., a triangular lattice, (ii) hardware-specific implementations of the parity flow framework on, e.g., a heavy-hex lattice, and (iii) novel universal resources for measurement-based quantum computation.}, archive = {J_PRA}, author = {Isaac D. Smith and Berend Klaver and Hendrik Poulsen Nautrup and Wolfgang Lechner and Hans J. Briegel}, doi = {10.1103/9q8k-5378}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032606}, shortjournal = {Phys. Rev. A}, title = {Minimally universal parity quantum computing}, volume = {112}, year = {2025}, }
• (2025). Universal quantum control by non-hermitian hamiltonian. PRA, 112(3), 032605. (www)

  @article{ , abstract = {Conventional manipulations over quantum systems for, such as coherent population trapping and unidirectional transfer, focus on Hamiltonian engineering while regarding the system's manifold geometry and constraint equation as secondary causes. Here, we treat them on equal footing in controlling a finite-dimensional quantum system under a time-dependent non-Hermitian Hamiltonian, which is inspired by the D'Alembert principle of regarding active force, constraint force, and inertial force in an unbiased way. Under the biorthogonal condition, the non-Hermitian Hamiltonian could be triangularized in a constraint picture spanned by a set of completed and orthonormal basis states, which is found to be a sufficient condition to construct at least one universal nonadiabatic passage in both bra and ket spaces. The passage ends up with a desired target state that is automatically normalized without artificial normalization in the existing treatments for non-Hermitian quantum systems. Moreover, the passage is found to be robust against the parametric deviation when the real part of its global phase is rapidly varying with time. Our protocol is explicitly verified for the perfect population transfer in the two-level system and the chiral population transfer in the three-level system. It generalizes our framework of universal quantum control to the field of the biorthogonal quantum mechanics.}, archive = {J_PRA}, author = {Zhu-yao Jin and Jun Jing}, doi = {10.1103/7h6g-1z57}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032605}, shortjournal = {Phys. Rev. A}, title = {Universal quantum control by non-hermitian hamiltonian}, volume = {112}, year = {2025}, }
• (2025). Quantum-enhanced change detection and joint communication detection. PRA, 112(3), 032604. (www)

  @article{ , abstract = {Quick detection of transmittance changes in an optical channel is crucial for secure communication. We demonstrate that preshared entanglement using two-mode squeezed vacuum states significantly reduces detection latency compared to classical and entanglement-augmented coherent-state probes. The change-detection latency is inversely proportional to the quantum relative entropy (QRE), which goes to infinity in the absence of thermal noise, suggesting idealized instantaneous detection. However, in realistic scenarios, we show that QRE scales logarithmically with the inverse of the thermal-noise mean photon number. We propose a receiver that achieves this scaling and quantify its performance gains over existing methods. Additionally, we explore the fundamental trade-off between communication capacity and change-detection latency, highlighting how preshared entanglement enhances both.}, archive = {J_PRA}, author = {Zihao Gong and Saikat Guha}, doi = {10.1103/fpc3-lmql}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032604}, shortjournal = {Phys. Rev. A}, title = {Quantum-enhanced change detection and joint communication detection}, volume = {112}, year = {2025}, }
• (2025). Verifiable blind quantum computation for two types of clients via iterated gate teleportation. PRA, 112(3), 032603. (www)

  @article{ , abstract = {Blind quantum computation (BQC) provides a secure framework for clients to delegate quantum computations to servers without revealing their private information. Among BQC protocols, those built on iterated gate teleportation (IGTBQC) have demonstrated promising potential in overcoming the constraints imposed by the no-programming theorem and significantly reducing communication overhead. However, existing IGTBQC protocols lack mechanisms for clients to verify the correctness of computation results and deal with only one type of clients capable of preparing qubits. To address these limitations, we first extend the current IGTBQC protocol to be a verifiable one and then propose another verifiable IGTBQC protocol tailored for a different type of clients with the capability of measuring single-qubit states. Furthermore, both protocols are shown to satisfy blindness and verification simultaneously in a relatively formal way. Our results not only broaden the applicability to a wider range of clients but also enhance the practicality of delegated quantum computation.}, archive = {J_PRA}, author = {Yuxun Wang and Qunfeng Dai and Qin Li}, doi = {10.1103/67zx-lk2j}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032603}, shortjournal = {Phys. Rev. A}, title = {Verifiable blind quantum computation for two types of clients via iterated gate teleportation}, volume = {112}, year = {2025}, }
• (2025). Quantum detection of millimeter wave electric fields with driving surface-state electrons. PRA, 112(3), 032602. (www)

  @article{ , abstract = {We introduce a spin-based receiver to sensitively detect the electric fields of millimeter waves by using a quantum interferometric approach. The proposed quantum sensor consists of many surface-state electrons trapped individually on liquid helium by an electrode network at the bottom of the liquid helium film. A dc current in this chip is biased to generate strong spin-orbit coupling of each of the trapped electrons. The millimeter wave signals are conducted to nondissipatedly drive the orbital motions of the trapped electrons and result in Stark shifts of the spin-orbit dressed states of the electrons. As a consequence, the electric fields of the conducted millimeter waves could be detected sensitively by using Hahn echo interferometry with the long-lived spin states of the electrons trapped on liquid helium.}, archive = {J_PRA}, author = {Miao Zhang and Y. F. Wang and X. Y. Peng and X. N. Feng and S. R. He and Y. F. Li and L. F. Wei}, doi = {10.1103/pvc5-1hwb}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032602}, shortjournal = {Phys. Rev. A}, title = {Quantum detection of millimeter wave electric fields with driving surface-state electrons}, volume = {112}, year = {2025}, }
• (2025). Statistical analysis of multipath entanglement purification in quantum networks. PRA, 112(3), 032601. (www)

  @article{ , abstract = {In quantum networks, a set of entangled states distributed over multiple, alternative, distinct paths between a pair of source-destination nodes can be purified to obtain a higher fidelity entangled state between the nodes. This multipath entanglement purification (MP-EP) strategy can exploit the network's complex structure to strengthen the entanglement connection between node pairs separated by appropriate graph distances. We investigate the network scenarios in which MP-EP outperforms entanglement distribution over single network paths utilizing a statistical model of a quantum network and find that MP-EP can be an effective entanglement distribution strategy over a range of node separations determined by the average edge fidelities and probabilities of the network. We find that MP-EP can boost the entanglement connection between suitably separated node pairs to reach fidelities sufficient for a given quantum task thereby increasing the functionality of a quantum network. Further, we provide statistical criteria for the feasibility of MP-EP in terms of network parameters that can determine the regions of the network where MP-EP can be a useful entanglement distribution strategy.}, archive = {J_PRA}, author = {Rajni Bala and Md Sohel Mondal and Siddhartha Santra}, doi = {10.1103/l9xq-zlcq}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032601}, shortjournal = {Phys. Rev. A}, title = {Statistical analysis of multipath entanglement purification in quantum networks}, volume = {112}, year = {2025}, }
• (2025). Single-photon-triggered quantum entanglement between two qubits or at least 2,000 identical qubits. PRA, 112(3), 032441. (www)

  @article{ , abstract = {In this paper, we primarily investigate the generation of quantum entanglement triggered by a single photon between two qubits or multiple qubits and analyze the impact of decoherence of the light field. In the model of single-photon interaction with two qubits, we first study the effect of the initial excited-state weight of the qubits on the entanglement triggered by a single photon. We find that the greater the initial excited-state weight, the smaller the maximum quantum entanglement triggered by the single photon between the two qubits. Specifically, when both qubits are in the excited state, a single photon cannot trigger quantum entanglement between the two qubits. We then examine the impact of the initial coherence of the two qubits on the entanglement triggered by a single photon, and find that a single photon can trigger the maximum quantum entanglement between two qubits when both qubits initially have maximum coherence. In the model of single-photon interaction with multiple qubits, in the limit of a large number of qubits, we find that when the initial excited-state weight of each qubit is larger than the ground-state weight, or when all qubits are initially in the ground state, a single photon cannot trigger quantum entanglement between any two qubits in the multiqubit system. Interestingly, we find that a single photon can trigger quantum entanglement between any two qubits from at least 2000 qubits. Moreover, in this limit, the maximum quantum entanglement between any two qubits in the multiqubit system triggered by a single photon changes with the initial-state parameters and almost no longer depends on the number of qubits. Finally, we discuss the effect of decoherence of the light field, and we find that a higher decoherence strength of the light field weakens the generation of quantum entanglement between qubits in both the single-photon interaction with two qubits and the single-photon interaction with multiple qubits models. However, interestingly, the initial coherence of the qubits can resist the impact of decoherence, especially when the two nonidentical qubits, both having maximum coherence, can maintain the maximum quantum entanglement between the two qubits at 0.5 even as the decoherence strength of the light field increases.}, archive = {J_PRA}, author = {Wangjun Lu and Cuilu Zhai and Hong Tao and Yaju Song and Jibing Yuan and Lan Xu and Jintao Tan and Shiqing Tang}, doi = {10.1103/t5mb-lg4t}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032441}, shortjournal = {Phys. Rev. A}, title = {Single-photon-triggered quantum entanglement between two qubits or at least 2,000 identical qubits}, volume = {112}, year = {2025}, }
• (2025). Quantum-resource-theoretical analysis of the role of vibrational structure in photoisomerization. PRA, 112(3), 032440. (www)

  @article{ , abstract = {Thermodynamical systems at the nanoscale, such as single molecules interacting with highly structured vibrational environments, typically undergo nonequilibrium physical processes that lack precise microscopic descriptions. Photoisomerization is such an example, which has emerged as a platform on which to study single-molecule ultrafast photochemical processes from a quantum resource theoretic perspective. However, the upper bounds on its efficiency have only been obtained under significant simplifications that make the mathematics of the resource-theoretical treatment manageable. Here we generalize previous models for the photoisomers, while retaining the full vibrational structure, and still obtain analytical bounds on the efficiency of photoisomerization. We quantify the impact of such a vibrational structure on the optimal photoisomerization quantum yield both when the vibrational coordinate has no dynamics of its own and when we take into account the vibrational dynamics. This work serves as an example of how to bridge the gap between the abstract language of quantum resource theories and the open system formulation of nanoscale processes.}, archive = {J_PRA}, author = {Siddharth Tiwary and Giovanni Spaventa and Susana F. Huelga and Martin B. Plenio}, doi = {10.1103/ws4m-rt7y}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032440}, shortjournal = {Phys. Rev. A}, title = {Quantum-resource-theoretical analysis of the role of vibrational structure in photoisomerization}, volume = {112}, year = {2025}, }
• (2025). Saturation of the quantum cramér-rao bound for distributed sensing via error sensitivity in SU(1,1)-SU(m) interferometry. PRA, 112(3), 032439. (www)

  @article{ , abstract = {Breaking the standard quantum limit in the sensing of parameters at different spatial locations, such as in a quantum network, is of great importance. Using the framework of quantum Fisher information, many strategies based on squeezed quantum probes and multipath multiphoton or multiqubit entangled states have been considered. In this context there is always the question of what the simplest measurement is that would saturate the quantum Cramér-Rao bound (QCRB). The simplest quantity to measure would be characteristics of photon flux or population distribution in the case of qubits. Previous studies have shown that the error sensitivity in SU(1,1) interferometry, also known by several other terms such as nonlinear interferometry and time-reversed measurements, does saturate the QCRB for single parameters such as phase, displacement, and loss. In this work we reveal the great utility of generalized SU(1,1) interferometry in distributed sensing. Generalized SU(1,1) interferometry is a combination of SU ( m ) and SU(1,1) elements, where m is the number of nodes in the network. The SU ( m ) element is used to produce distributed entanglement starting from a squeezed photonic or matter probe. We demonstrate how error sensitivity measurement or more precisely the method of moment sensitivity at just one output port can saturate or nearly saturate the QCRB and thus results in Heisenberg sensitivity of network sensing.}, archive = {J_PRA}, author = {Girish S. Agarwal}, doi = {10.1103/h2x6-dz96}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032439}, shortjournal = {Phys. Rev. A}, title = {Saturation of the quantum cramér-rao bound for distributed sensing via error sensitivity in SU(1,1)-SU(m) interferometry}, volume = {112}, year = {2025}, }
• (2025). Nonsymmetric greenberger-horne-zeilinger states: Weighted hypergraph and controlled-unitary graph representations. PRA, 112(3), 032438. (www)

  @article{ , abstract = {Nonsymmetric GHZ states ( n − GHZ α ), defined by unequal superpositions of | 00 ... 0 〉 and | 11 ... 1 〉 , naturally emerge in experiments due to decoherence, control errors, and state preparation imperfections. Despite their relevance in quantum communication, relativistic quantum information, and quantum teleportation, these states lack a stabilizer formalism and a graph representation, hindering their theoretical and experimental analysis. We establish a graph-theoretic framework for nonsymmetric GHZ states, proving their local unitary (LU) equivalence to two structures: fully connected weighted hypergraphs with controlled-phase interactions and star-shaped controlled-unitary (CU) graphs. While weighted hypergraphs generally lack stabilizer descriptions, we demonstrate that nonsymmetric GHZ states can be efficiently stabilized using local operations and a single ancilla, independent of system size, thereby enabling entanglement witness construction and offering a pathway toward qudit quantum error correction. We extend this framework to qudit systems, constructing LU-equivalent weighted qudit hypergraphs and showing that general nonsymmetric qudit GHZ states can be described as star-shaped CU graphs. Our results provide a systematic approach to characterizing and stabilizing nonsymmetric multipartite entanglement in both qubit and qudit systems, with implications for quantum error correction and networked quantum protocols.}, archive = {J_PRA}, author = {Hrachya Zakaryan and Konstantinos-Rafail Revis and Zahra Raissi}, doi = {10.1103/7zxj-jp34}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032438}, shortjournal = {Phys. Rev. A}, title = {Nonsymmetric greenberger-horne-zeilinger states: Weighted hypergraph and controlled-unitary graph representations}, volume = {112}, year = {2025}, }
• (2025). Quantifying nonclassicality via metric-adjusted skew information. PRA, 112(3), 032437. (www)

  @article{ , abstract = {Nonclassical correlations represent fundamental physical resources that play a crucial role in quantum information processing. In this work, we introduce a generalized nonclassicality quantifier based on metric-adjusted skew information, which aims to characterize the intrinsic nonclassical features of bosonic field states. The proposed nonclassicality quantifier is formally defined as the maximum metric-adjusted skew information between a quantum state and the homodyne rotated quadrature operator, which can effectively reflect the phase-dependent characteristics of the light field and is therefore suitable for capturing nonclassical effects. Notably, our findings reveal that coherent states exhibit a distinct threshold behavior, enabling a precise distinction between classical and nonclassical regimes. Furthermore, through rigorous analysis and comparative evaluation across a set of representative quantum states, we demonstrate that the quantifier not only captures essential nonclassical merits, but also detects entanglement by identifying violations of the additivity property that holds for separable states. As a result, this framework establishes a unified and mathematically rigorous approach for quantifying nonclassicality in both separable and entangled systems, thereby contributing valuable insights to the advancement of quantum resource theories.}, archive = {J_PRA}, author = {Liang Tang and Fan Wu}, doi = {10.1103/wwjf-lh44}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032437}, shortjournal = {Phys. Rev. A}, title = {Quantifying nonclassicality via metric-adjusted skew information}, volume = {112}, year = {2025}, }
• (2025). Distillation of multipartite entangled states for arbitrary subsets of parties in noisy quantum networks of increasing size. PRA, 112(3), 032436. (www)

  @article{ , abstract = {Quantum network states are multipartite states built from distributing pairwise entanglement among parties and underpin the paradigm of quantum networks for quantum information processing. In this work we introduce the problem of partial distillability in noisy quantum networks. This corresponds to the possibility of distilling by local operations and classical communication an arbitrary pure state for an arbitrary subset of parties starting from a single copy of a quantum network state of an increasing number of parties that share noisy (i.e., mixed) bipartite entangled states. Here, distillation means that the target state is obtained with fidelity as close to 1 as desired, as the size of the network increases when the pairwise entangled links support a constant amount of noise. While we prove an obstruction to multipartite distillation protocols after teleportation with channels with constant noise, we show that partial distillability is indeed possible if certain well-established graph-theoretic parameters that measure the connectivity in the network grow fast enough with its size. We give necessary as well as sufficient conditions for partial distillability in terms of these parameters and we, moreover, provide explicit constructions of networks with partial distillability and a relatively slow connectivity growth.}, archive = {J_PRA}, author = {Aitor Balmaseda and Julio I. de Vicente}, doi = {10.1103/psw9-lfwc}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032436}, shortjournal = {Phys. Rev. A}, title = {Distillation of multipartite entangled states for arbitrary subsets of parties in noisy quantum networks of increasing size}, volume = {112}, year = {2025}, }
• (2025). Qudit vs. qubit: Simulated performance of error-correction codes in higher dimensions. PRA, 112(3), 032435. (www)

  @article{ , abstract = {Qudits can be described by a state vector in a -dimensional Hilbert space, enabling a more extensive encoding and manipulation of information compared to qubits. This implies that conducting fault-tolerant quantum computations using qudits rather than qubits might entail less overhead. In this work, we investigate the viability of qudits in error-correction codes by creating and simulating the quantum circuitry for the smallest qudit error-correction code with a multidimensional circuit-level noise model and specifically adapted decoders. After introducing a flag qudit to protect the code from hook errors, comparable error thresholds of the order of are obtained for qudits of dimensions 2, 3, and 5.}, archive = {J_PRA}, author = {James Keppens and Quinten Eggerickx and Vukan Levajac and George Simion and Bart Sorée}, doi = {10.1103/2w52-qd2j}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032435}, shortjournal = {Phys. Rev. A}, title = {Qudit vs. qubit: Simulated performance of error-correction codes in higher dimensions}, volume = {112}, year = {2025}, }
• (2025). Bosonic quantum error correction using squeezed fock states. PRA, 112(3), 032434. (www)

  @article{ , abstract = {In the paper, we develop a bosonic quantum error correction code based on squeezed Fock states. We compare our proposed code with one based on squeezed Schrödinger's cat states using the Knill-Laflamme cost function and the Petz map fidelity. We demonstrate that squeezed Fock states are competitive in protecting information in a channel with particle loss and dephasing.}, archive = {J_PRA}, author = {E. N. Bashmakova and S. B. Korolev and T. Yu. Golubeva}, doi = {10.1103/97yt-nzg2}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032434}, shortjournal = {Phys. Rev. A}, title = {Bosonic quantum error correction using squeezed fock states}, volume = {112}, year = {2025}, }
• (2025). All multipartite entanglements are quantum coherences in locally distinguishable bases. PRA, 112(3), 032433. (www)

  @article{ , abstract = {We find that the m -separability and k -partite entanglement of a multipartite quantum system is correlated with quantum coherence of the same with respect to complete orthonormal bases, distinguishable under local operations and classical communication in certain partitions. In particular, we show that the geometric measure of m -inseparable entanglement of a multipartite quantum state is equal to the square of minimum fidelity-based quantum coherence of the state with respect to complete orthonormal bases, which are locally distinguishable in a partition into m parties.}, archive = {J_PRA}, author = {Ahana Ghoshal and Swati Choudhary and Ujjwal Sen}, doi = {10.1103/3pxs-vpst}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032433}, shortjournal = {Phys. Rev. A}, title = {All multipartite entanglements are quantum coherences in locally distinguishable bases}, volume = {112}, year = {2025}, }
• (2025). Witnessing the dynamics of entanglement and manipulating the sudden death of entanglement under the influence of a squeezed thermal reservoir. PRA, 112(3), 032432. (www)

  @article{ , abstract = {This study investigates the entanglement dynamics of a bipartite system comprising two two-level atoms, initially prepared in a pure entangled state and independently coupled to spatially separated cavities under local squeezed thermal environments. We demonstrate that environmental interactions induce entanglement sudden death (ESD), leading to the abrupt loss of quantum correlations. To mitigate this effect, we propose a protocol involving local unitary operations—X gate and XX gate —applied to the time-evolved state. We further analyze the impact of these operations under symmetric and asymmetric probability amplitudes of the atomic states, considering variations in thermal and squeezing parameters across different reservoirs. Our results show that these operations extend entanglement duration in specific reservoir conditions, while in the case of a vacuum reservoir, they transform ESD into asymptotic decay for both symmetric and asymmetric probability amplitudes of the atomic states. Moreover, independent variations of the thermal and squeezing parameters in each reservoir influence the dynamics of local gate operations, thereby affecting the overall entanglement evolution. Additionally, applying these operations at an earlier stage of the system's evolution can further delay ESD. This scheme offers valuable insights into entanglement behavior and its resilience under various noisy environmental conditions.}, archive = {J_PRA}, author = {M. Hunza and Ming-Da Huang and Qi Qin and T. Abbas}, doi = {10.1103/k9sg-c987}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032432}, shortjournal = {Phys. Rev. A}, title = {Witnessing the dynamics of entanglement and manipulating the sudden death of entanglement under the influence of a squeezed thermal reservoir}, volume = {112}, year = {2025}, }
• (2025). Quantum curriculum learning. PRA, 112(3), 032431. (www)

  @article{ , abstract = {Quantum machine learning (QML) requires significant quantum resources to address practical real-world problems. When the underlying quantum information exhibits hierarchical structures in the data, limitations persist in training complexity and generalization. Research should prioritize both the efficient design of quantum architectures and the development of learning strategies to optimize resource usage. We propose a framework called quantum curriculum learning (Q-CurL) for quantum data, where the curriculum introduces simpler tasks or data to the learning model before progressing to more challenging ones. Q-CurL exhibits robustness to noise and data limitations, which is particularly relevant for current and near-term noisy intermediate-scale quantum devices. We achieve this through a curriculum design based on quantum data density ratios and a dynamic learning schedule that prioritizes the most informative quantum data. Empirical evidence shows that Q-CurL significantly enhances training convergence and generalization for unitary learning and improves the robustness of quantum phase recognition tasks. Q-CurL is effective with physical learning applications in physics and quantum chemistry.}, archive = {J_PRA}, author = {Quoc Hoan Tran and Yasuhiro Endo and Hirotaka Oshima}, doi = {10.1103/fm4p-wl5d}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032431}, shortjournal = {Phys. Rev. A}, title = {Quantum curriculum learning}, volume = {112}, year = {2025}, }
• (2025). Improved entanglement entropy estimates from filtered bitstring probabilities. PRA, 112(3), 032430. (www)

  @article{ , abstract = {Using the bitstring probabilities of ground states of bipartitioned ladders of Rydberg atoms, we calculate the mutual information, which is a lower bound on the corresponding bipartite von Neumann quantum entanglement entropy S A vN . We show that in many cases these lower bounds can be improved by removing the bitstrings with a probability lower than some value p min and renormalizing the remaining probabilities (filtering). We propose a heuristic based on the change of the conditional entropy under filtering that very effectively improves the estimate of S A vN . We consider various sizes, lattice spacings, and bipartitions. Our numerical investigation suggest that the filtered mutual information obtained with samples having just a few thousand bitstrings can provide reasonably close estimates of S A vN . We briefly discuss practical implementations with QuEra's Aquila device.}, archive = {J_PRA}, author = {Avi Kaufman and James Corona and Zane Ozzello and Blake Senseman and Muhammad Asaduzzaman and Yannick Meurice}, doi = {10.1103/lbv3-2z7r}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032430}, shortjournal = {Phys. Rev. A}, title = {Improved entanglement entropy estimates from filtered bitstring probabilities}, volume = {112}, year = {2025}, }
• (2025). Long-distance device-independent conference key agreement. PRA, 112(3), 032429. (www)

  @article{ , abstract = {Device-independent quantum key distribution (DI-QKD) enables two remote parties to share an information-theoretically secure key without any assumptions on the inner workings of the devices used. Device-independent conference key agreement (DI-CKA) is multipartite DI-QKD in which more than two parties share a common secure key. The performance of DI-CKA, however, is strictly limited because of its susceptibility to losses due to, e.g., imperfect detection efficiency and channel transmission. Here, we propose a DI-CKA protocol which reduces this limitation by using a heralding scheme to distribute multipartite entanglement. We analyze key rates of our protocol for two different measurement scenarios, and we show that our protocol outperforms a previous DI-CKA protocol even with an experimentally feasible measurement.}, archive = {J_PRA}, author = {Makoto Ishihara and Anders J. E. Bjerrum and Wojciech Roga and Jonatan B. Brask and Ulrik L. Andersen and Masahiro Takeoka}, doi = {10.1103/2qyl-3rk1}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032429}, shortjournal = {Phys. Rev. A}, title = {Long-distance device-independent conference key agreement}, volume = {112}, year = {2025}, }
• (2025). Dynamical decoupling protection for three-level systems. PRA, 112(3), 032428. (www)

  @article{ , abstract = {In addition to the traditional two-level system, the three-level system serves as another important elemental building block for the manipulation of qubits. However, the quantum information processing in the three-level system is also subject to the decoherence induced by the interaction between the quantum system and its environment or by the crosstalk between different qutrits. In this work, we construct a sequence of physically feasible dynamical decoupling operators for the three-level system to mitigate not only the transverse dephasing between the excited state and ground states, but also the longitudinal relaxation among them. Combining the Hamiltonian engineering and our constructed dynamical decoupling sequence, we further realize the dynamical decoupling protection of qutrit-based quantum gates. Our scheme can effectively enhance the fidelity of three-level-based quantum gates through filtering out the environmental noises, which may provide a new horizon to improve the accuracy of three-level-based quantum manipulation.}, archive = {J_PRA}, author = {P. Z. Zhao and Lei Qiao}, doi = {10.1103/39d3-xmkh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032428}, shortjournal = {Phys. Rev. A}, title = {Dynamical decoupling protection for three-level systems}, volume = {112}, year = {2025}, }
• (2025). Efficient sampling for pauli-measurement-based shadow tomography in direct fidelity estimation. PRA, 112(3), 032427. (www)

  @article{ , abstract = {A constant number of random Clifford measurements allows the classical shadow protocol to perform direct fidelity estimation (DFE) with high precision. However, estimating properties of an unknown quantum state is expected to be more feasible with random Pauli measurements than with random Clifford measurements in the near future. Inspired by the importance sampling technique applied to sampling Pauli measurements for DFE, we show that similar strategies can be derived from classical shadows. Specifically, we describe efficient methods using only local Pauli measurements to perform DFE with Greenberger-Horne-Zeilinger (GHZ), and Dicke states, establishing tighter bounds (by factors of 14.22 and 16 for GHZ and /Dicke, respectively) on the number of measurements required for desired precision. These protocols are derived by adjusting the distribution of observables. Notably, they require no preprocessing steps other than the sampling algorithms.}, archive = {J_PRA}, author = {Hyunho Cha and Jungwoo Lee}, doi = {10.1103/4pzk-lznf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032427}, shortjournal = {Phys. Rev. A}, title = {Efficient sampling for pauli-measurement-based shadow tomography in direct fidelity estimation}, volume = {112}, year = {2025}, }
• (2025). Global locations of schmidt-number witnesses. PRA, 112(3), 032426. (www)

  @article{ , abstract = {We investigate global locations of Schmidt number witnesses which are outside of the convex set of all bipartite states. Their locations are classified by interiors of faces of the convex set of all states, by considering the line segments from them to the maximally mixed state. In this way, a nonpositive Hermitian matrix of trace 1 is located outside of one and only one face. Faces of the convex set of all states are classified by subspaces, which are range spaces of states belonging to specific faces. For a given subspace, we show that there exist Schmidt number k + 1 witnesses outside of the face arising from this subspace if and only if every vector in the orthogonal complement of the subspace has Schmidt rank greater than k . Once we have Schmidt number k + 1 witnesses outside of a face, we also have Schmidt number 2 , 3 , ⋯ , k witnesses outside of the face.}, archive = {J_PRA}, author = {Kyung Hoon Han and Seung-Hyeok Kye}, doi = {10.1103/bl7f-45vy}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032426}, shortjournal = {Phys. Rev. A}, title = {Global locations of schmidt-number witnesses}, volume = {112}, year = {2025}, }
• (2025). Exploring nonmultiplicativity in the geometric measure of entanglement. PRA, 112(3), 032425. (www)

  @article{ , abstract = {The geometric measure of entanglement (GME) quantifies how close a multipartite quantum state is to the set of separable states under the Hilbert-Schmidt inner product. The GME can be nonmultiplicative, meaning that the closest product state to two states is entangled across subsystems. In this work, we explore the GME in two families of states: those that are invariant under bilateral orthogonal transformations, and mixtures of singlet states. In both cases, a region of GME nonmultiplicativity is identified around the antisymmetric projector state. We employ state-of-the-art numerical optimization methods and models to quantitatively analyze nonmultiplicativity in these states for . We also investigate a constrained form of GME that measures closeness to the set of real product states and show that this measure can be nonmultiplicative even for real separable states.}, archive = {J_PRA}, author = {Daniel Dilley and Jerry Chang and Jeffrey Larson and Eric Chitambar}, doi = {10.1103/4ct9-2xhs}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032425}, shortjournal = {Phys. Rev. A}, title = {Exploring nonmultiplicativity in the geometric measure of entanglement}, volume = {112}, year = {2025}, }
• (2025). Multipartite entanglement measures based on the thermodynamic framework. PRA, 112(3), 032424. (www)

  @article{ , abstract = {In this work, we introduce a unified method to characterize and measure multipartite entanglement using the framework of thermodynamics. A family of entanglement measures is proposed: ergotropic-gap concentratable entanglement . Furthermore, we establish that ergotropic-gap concentratable entanglement constitutes a well-defined entanglement measure within a specific parameter regime, satisfying key properties including continuity, majorization monotonicity, and monogamy. We demonstrate the utility of this measure by showing it effectively distinguishes between multiqubit Greenberger-Horne-Zeilinger states and W states. It also proves effective in detecting entanglement in specific classes of four-partite star quantum network states.}, archive = {J_PRA}, author = {Chen-Ming Bai and Yu Luo}, doi = {10.1103/rg65-sh1f}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032424}, shortjournal = {Phys. Rev. A}, title = {Multipartite entanglement measures based on the thermodynamic framework}, volume = {112}, year = {2025}, }
• (2025). Encoding quantumlike information in classical synchronizing dynamics. PRA, 112(3), 032423. (www)

  @article{ , abstract = {In previous work we introduced a formalism that maps classical networks of nonlinear oscillators onto a quantumlike Hilbert space. We demonstrated that specific network transformations correspond to quantum gates, underscoring the potential of classical many-body systems as platforms for quantum-inspired information processing. In this paper we extend this framework by systematically identifying the classical dynamics best suited for this purpose. Specifically, we address the following question: Can the collective steady state of a classical network encode signatures of quantum information? We prove that the answer is affirmative for a special class of synchronizing many-body systems, namely, a complex-field extension of the Kuramoto model of nonlinearly coupled classical oscillators. Through this approach, we investigate how quantumlike entangled states can emerge from classical synchronization dynamics.}, archive = {J_PRA}, author = {Graziano Amati and Gregory D. Scholes}, doi = {10.1103/nvdp-sr11}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032423}, shortjournal = {Phys. Rev. A}, title = {Encoding quantumlike information in classical synchronizing dynamics}, volume = {112}, year = {2025}, }
• (2025). Time-optimal control based on path distance. PRA, 112(3), 032422. (www)

  @article{ , abstract = {The average energy and energy spread of a quantum system are two important factors that affect a system's evolution speed, which is usually defined as the changing rate of the distance between a quantum state and the state during its evolution. Alternatively, the evolution speed of a quantum system could also be studied based on its evolution path. It is found that if we define the evolution speed of a quantum unitary system as the changing rate of the path distance between a quantum state and the state during its evolution, the instantaneous evolution speed is determined by the Hamiltonian's eigenvalues, rather than its expectation value or variance imposed on any quantum state. More specifically, the range of the Hamiltonian's eigenvalues determines the evolution speed of a quantum system through the relation ω H = 1 2 ( λ max − λ min ) , which is independent of the quantum state. Given an initial state ρ 0 in a quantum unitary system, the minimum time required to evolve it to a target state ρ τ is τ min = L min ( ρ 0 , ρ τ ) ω H , where L min ( ρ 0 , ρ τ ) is the path distance contained in the shortest evolution from ρ 0 to ρ τ . This lower bound of the evolution time is tight and achievable in a finite-energy system.}, archive = {J_PRA}, author = {Lin-Feng Du and Li-Guo Qin and Qin Guo and Xue-Xiang Xu and Jie-Hui Huang}, doi = {10.1103/mv26-qytj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032422}, shortjournal = {Phys. Rev. A}, title = {Time-optimal control based on path distance}, volume = {112}, year = {2025}, }
• (2025). Stabilizer configuration interaction: Finding molecular subspaces with error detection properties. PRA, 112(3), 032421. (www)

  @article{ , abstract = {In this work, we explore a new approach to designing both algorithms and error detection codes for preparing approximate ground states of molecules. We propose a classical algorithm to find the optimal stabilizer state by using excitations of the Hartree-Fock state, followed by constructing quantum error-detection codes based on this stabilizer state using codeword-stabilized codes. Through various numerical experiments, we confirm that our method finds the best stabilizer approximations to the true ground states of molecules up to 36 qubits in size. Additionally, we construct generalized stabilizer states that offer a better approximation to the true ground states. Furthermore, for a simple noise model, we demonstrate that both the stabilizer and (some) generalized stabilizer states can be prepared with higher fidelity using the error-detection codes we construct. Our work represents a promising step toward designing algorithms for early fault-tolerant quantum computation.}, archive = {J_PRA}, author = {Abhinav Anand and Kenneth R. Brown}, doi = {10.1103/jkcp-6km5}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032421}, shortjournal = {Phys. Rev. A}, title = {Stabilizer configuration interaction: Finding molecular subspaces with error detection properties}, volume = {112}, year = {2025}, }
• (2025). Extremality of stabilizer states. PRA, 112(3), 032420. (www)

  @article{ , abstract = {We investigate the extremality of stabilizer states to reveal their exceptional role in the space of all -qubit and -qudit states. We establish uncertainty principles for the characteristic function and the Wigner function of states, respectively. We find that only stabilizer states achieve saturation in these principles. Furthermore, we prove a general theorem that stabilizer states are extremal for convex information measures invariant under local unitaries. We explore this extremality in the context of various quantum information and correlation measures, including entanglement entropy, conditional entropy, and other entanglement measures. Additionally, leveraging the recent discovery that stabilizer states are the limit states under quantum convolution, we establish the monotonicity of the entanglement entropy and conditional entropy under quantum convolution. These results highlight the remarkable Gaussian properties of stabilizer states in qudit and qubit systems.}, archive = {J_PRA}, author = {Kaifeng Bu}, doi = {10.1103/ln8j-ytcj}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032420}, shortjournal = {Phys. Rev. A}, title = {Extremality of stabilizer states}, volume = {112}, year = {2025}, }
• (2025). High-rate extended binomial codes for multiqubit encoding. PRA, 112(3), 032419. (www)

  @article{ , abstract = {We introduce a class of bosonic quantum error-correcting codes, termed extended binomial codes , which generalize the structure of one-mode binomial codes by incorporating ideas from high-rate qubit stabilizer codes. These codes are constructed in close analogy to [ [ n , k , d ] ] qubit codes, where the parameter n corresponds to the total excitation budget rather than the number of physical qubits. Our construction achieves a significant reduction in average excitation per mode while preserving error-correcting capabilities, offering improved compatibility with hardware constraints in the strong-dispersive regime. We demonstrate that extended binomial codes not only reduce the mean excitation required for encoding but also simplify syndrome extraction and logical gate implementation, particularly the logical X ¯ operation. These advantages suggest that extended binomial codes offer a scalable and resource-efficient approach for bosonic quantum error correction.}, archive = {J_PRA}, author = {En-Jui Chang}, doi = {10.1103/hwfz-c6vy}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032419}, shortjournal = {Phys. Rev. A}, title = {High-rate extended binomial codes for multiqubit encoding}, volume = {112}, year = {2025}, }
• (2025). Subuniversal variational circuits for combinatorial optimization problems. PRA, 112(3), 032418. (www)

  @article{ , abstract = {Quantum variational circuits have gained significant attention due to their applications in the quantum approximate optimization algorithm and quantum machine learning research. This work introduces a novel class of classical probabilistic circuits designed for generating approximate solutions to combinatorial optimization problems constructed using two-bit stochastic matrices. Through a numerical study, we investigate the performance of our proposed variational circuits in solving the Max-Cut problem on various graphs of increasing sizes. Our classical algorithm demonstrates improved performance for several graph types to the quantum approximate optimization algorithm. Our findings suggest that evaluating the performance of quantum variational circuits against variational circuits with subuniversal gate sets is a valuable benchmark for identifying areas where quantum variational circuits can excel.}, archive = {J_PRA}, author = {Gal Weitz and Lirandë Pira and Chris Ferrie and Joshua Combes}, doi = {10.1103/v1sh-fg6f}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032418}, shortjournal = {Phys. Rev. A}, title = {Subuniversal variational circuits for combinatorial optimization problems}, volume = {112}, year = {2025}, }
• (2025). Regularizing quantum loss landscapes by noise injection. PRA, 112(3), 032417. (www)

  @article{ , abstract = {The difficulty of training variational quantum algorithms and quantum machine learning models is well established. In particular, quantum loss landscapes are often highly nonconvex and dominated by poor local minima. While this renders their training NP hard in general, efficient heuristics that work well for typical instances may still exist. Here we propose a protocol that uses a targeted noise injection to smooth and regularize quantum loss landscapes. It works by exponentially suppressing the high-frequency components in the Fourier expansion of the quantum loss function. The protocol can be efficiently implemented in both hardware and simulations. We observe significant and robust improvements of solution quality across various problem types. Our method can be combined with existing techniques mitigating the local minima, such as the quantum natural gradient optimizer, and adds to the toolbox of methods for optimizing quantum loss functions.}, archive = {J_PRA}, author = {Daniil S. Bagaev and Maxim A. Gavreev and Alena S. Mastiukova and Aleksey K. Fedorov and Nikita A. Nemkov}, doi = {10.1103/zmmm-ymdq}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032417}, shortjournal = {Phys. Rev. A}, title = {Regularizing quantum loss landscapes by noise injection}, volume = {112}, year = {2025}, }
• (2025). Achieving the heisenberg limit of metrology via measurement on an ancillary qubit. PRA, 112(3), 032416. (www)

  @article{ , abstract = {In the scenario of the probe-ancilla interaction, we propose a quantum metrology protocol by the unconditional measurement on the ancillary qubit after an optimized period of joint evolution from a product state. Its key element is the construction of two parallel evolution paths by the measurement that can transform the probe system (a spin ensemble) from an eigenstate of a collective angular momentum operator | 𝑗 , 𝑚 ⟩ to a superposed state ( | 𝑗 , 𝑚 ⟩ + | 𝑗 , − 𝑚 ⟩ ) / ⁢ √ 2 . With synchronous parametric encoding and qubit measurement, the quantum Fisher information about the phase encoded in the probe system with optimized initial states can exactly attain the Heisenberg scaling 𝑁 2 with respect to the probe size (spin number) 𝑁 . The quadratic scaling behavior is not sensitive to the imprecise control over the joint evolution time, the time delay between encoding and measurement, and the coherence in the probe ensemble or the ancillary system that would be degraded by local dephasing. The classical Fisher information of the spin ensemble is found to saturate with its quantum counterpart, irrespective of the idle joint evolution after the parametric encoding. We suggest that both Greenberger-Horne-Zeilinger (GHZ)-like states and nonlinear Hamiltonian are not necessary resources for exceeding the standard quantum limit in metrology precision since in our protocol even thermal states can hold an asymptotic quadratic scaling.}, archive = {J_PRA}, author = {Peng Chen and Jun Jing}, doi = {10.1103/f79z-vjsb}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032416}, shortjournal = {Phys. Rev. A}, title = {Achieving the heisenberg limit of metrology via measurement on an ancillary qubit}, volume = {112}, year = {2025}, }
• (2025). Phase transitions, symmetries, and tunneling in kerr parametric oscillators. PRA, 112(3), 032415. (www)

  @article{ , abstract = {Quantum Kerr parametric oscillators (KPOs) are systems out of equilibrium with a wide range of applications in quantum computing, quantum sensing, and fundamental research. They have been realized in superconducting circuits and photonic platforms. In this work, we explore the onset of ground-state and excited-state quantum phase transitions in KPOs, focusing on the role of the phase-space rotational symmetry when the driving frequency is times the oscillator's natural frequency, specifically for . These cases are experimentally accessible in superconducting circuits, where the Floquet quasienergy spectrum can also be studied as a function of tunable control parameters. Using the classical Hamiltonian of the system, we identify the stationary points associated with quantum phase transitions and analyze the emergence of both real and avoided level crossings, examining their influence on the energy spectrum and tunneling dynamics. Our findings provide insights into the engineering of robust quantum states, quantum dynamics control, and onset of quantum phase transitions with implications for critical quantum sensing.}, archive = {J_PRA}, author = {Miguel A. Prado Reynoso and Edson M. Signor and Jamil Khalouf-Rivera and Alexandre D. Ribeiro and Francisco Pérez-Bernal and Lea F. Santos}, doi = {10.1103/6vj6-v7yh}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032415}, shortjournal = {Phys. Rev. A}, title = {Phase transitions, symmetries, and tunneling in kerr parametric oscillators}, volume = {112}, year = {2025}, }
• (2025). Improving quantum channel discrimination with resourceful states. PRA, 112(3), 032414. (www)

  @article{ , abstract = {One of the key issues in quantum discrimination problems is understanding the extent of the advantages in discrimination performance when using resource states compared to resourceless states. We show that in any resource theory of states, which may not be convex, the extent to which the maximum average success probability can be improved in quantum channel discrimination problems without using auxiliary systems can be precisely quantified by the robustness measure. This result offers an intuitive operational meaning of the robustness measure in any convex resource theory. Furthermore, we demonstrate that the robustness measure can also quantify the improvement in channel discrimination problems that use auxiliary systems. Using these findings, resources can be fully characterized to achieve higher success probabilities than any state without the given resource in channel discrimination problems.}, archive = {J_PRA}, author = {Kenji Nakahira}, doi = {10.1103/fw4d-3t9j}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032414}, shortjournal = {Phys. Rev. A}, title = {Improving quantum channel discrimination with resourceful states}, volume = {112}, year = {2025}, }
• (2025). Entanglement, steering, and separability in compton-scattered annihilation photons. PRA, 112(3), 032413. (www)

  @article{ , abstract = {This work analyzes quantum correlations of photon pairs initially prepared in a Bell state, where one photon undergoes Compton scattering from a stationary, unpolarized electron. The evolved two-photon density matrix is analytically derived and spectrally decomposed. Concurrence and the Clauser-Horne-Shimony-Holt (CHSH) inequality evaluations identify angular regions demonstrating quantum steering correlations, entanglement without steering, and complete separability. The Peres conjecture is applied to interpret regions of entanglement lacking steering, emphasizing their limited practicality for quantum-information tasks. These results provide details potentially useful for employing Compton-scattered annihilation photons in various quantum protocols.}, archive = {J_PRA}, author = {Peter Caradonna and Kenji Shimazoe}, doi = {10.1103/j7p7-ckp9}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032413}, shortjournal = {Phys. Rev. A}, title = {Entanglement, steering, and separability in compton-scattered annihilation photons}, volume = {112}, year = {2025}, }
• (2025). Recycling reflections for perfect photon capture. PRA, 112(3), 032412. (www)

  @article{ , abstract = {Efficient photon capture in optical cavities is essential for quantum networks and computing, yet single-pass methods suffer from uncaptured reflections due to finite capture windows and coupling strengths, precluding perfect transfer of arbitrary photonic states. We introduce a two-pass "pitch-and-catch" method that recycles initial reflections to achieve perfect capture of arbitrary pulses in the noiseless regime and enhances fidelity under intrinsic losses. The method extends to photon emission, enabling arbitrary pulse shaping. This advance offers significant improvements for quantum repeaters, memories, and transduction, enhancing the toolkit for quantum information processing.}, archive = {J_PRA}, author = {Yat Wong and Liang Jiang}, doi = {10.1103/ysnl-8krl}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032412}, shortjournal = {Phys. Rev. A}, title = {Recycling reflections for perfect photon capture}, volume = {112}, year = {2025}, }
• (2025). Quantum noise spectroscopy by qudit spectators. PRA, 112(3), 032411. (www)

  @article{ , abstract = {Quantum noise spectroscopy is a well-known method for detecting environmental noise spectrum and has various applications in quantum sensing, quantum network design, and quantum computing. In this work, a protocol for quantum noise spectroscopy is presented by qudit spectators, that are arbitrary -level quantum systems passively spectating noises, which possess stochastic and stationary Gaussian distributions. The protocol uses Weyl basis decomposition, consisting of generalized Pauli matrices, as the theoretical tool, and the Alvarez-Suter noise spectroscopy method, by which the qudit is being exposed to a series of pulse sequences, and the noise polyspectra is extracted by multiple measurements of an observable of the qudit. The formalism is further developed and simulated for three theoretical frameworks: The first two frameworks utilize a simplified Weyl basis and are capable of detecting -type dephasing noise. One is specifically modeled for a qutrit ( = 3), and the second framework is designed for all qudits and has been tested through simulations of a ququad ( = 4) and a quoct ( = 8). The third framework employs the full Weyl basis, enabling it to identify all types of XYZ -dephasing noise. The simulations for this framework have been conducted for a quoct ( = 8) implemented by the antimony atom. The analytical protocol for noise spectroscopy that has been introduced transforms qudit systems into quantum spectators, and the presented simulations demonstrate the accuracy and reliability of this noise spectroscopy protocol.}, archive = {J_PRA}, author = {Clara Javaherian and Chris Ferrie}, doi = {10.1103/drc2-8qbg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032411}, shortjournal = {Phys. Rev. A}, title = {Quantum noise spectroscopy by qudit spectators}, volume = {112}, year = {2025}, }
• (2025). Quantum algorithm for vector set orthogonal normalization and matrix QR decomposition with polynomial speedup. PRA, 112(3), 032410. (www)

  @article{ , abstract = {Vector set orthogonal normalization and matrix QR decomposition are fundamental problems in matrix analysis with important applications in many fields. We know that the Gram-Schmidt process is a widely used method to solve these two problems. However, existing methods, including the Gram-Schmidt process, have problems of high complexity, scaling in the system dimension , which leads to difficulties when calculating large-scale or ill-conditioned problems. With the development of quantum information processing, a series of quantum algorithms have been proposed, providing advantages and speedups over classical algorithms in many fields. In this paper we propose quantum algorithms to solve these two problems based on the idea of the Gram-Schmidt process and quantum phase estimation. The complexity of proposed quantum algorithms is theoretically and numerically analyzed. We find that our algorithms provide polynomial acceleration over the best-known quantum algorithms and a potential polynomial acceleration over the best-known classical algorithms on these two problems, scaling in the dimension of the system when ignoring the complexity of state readout or when considering the complexity of state readout.}, archive = {J_PRA}, author = {Zi-Ming Li and Yu-xi Liu}, doi = {10.1103/79h3-jspt}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032410}, shortjournal = {Phys. Rev. A}, title = {Quantum algorithm for vector set orthogonal normalization and matrix QR decomposition with polynomial speedup}, volume = {112}, year = {2025}, }
• (2025). Bogoliubov-born-green-kirkwood-yvon hierarchy for quantum error mitigation. PRA, 112(3), 032409. (www)

  @article{ , abstract = {Mitigation of quantum errors is critical for current NISQ devices. In the present work, we address this task by treating the execution of quantum algorithms as the time evolution of an idealized physical system. We use knowledge of its physics to assist the mitigation of the quantum noise produced on the real device. In particular, the time evolution of the idealized system obeys a corresponding Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy of equations. This is the basis for the novel error mitigation scheme that we propose. Specifically, we employ a subset of the BBGKY hierarchy as supplementary constraints in the zero-noise extrapolation (ZNE) method for error mitigation. We ensure that the computational cost of the scheme scales polynomially with the system size. We test our method on digital quantum simulations of the lattice Schwinger model under noise levels mimicking realistic quantum hardware. We demonstrate that our scheme systematically improves the error mitigation for the measurements of the particle number and the charge within this system. Relative to ZNE, we obtain an average reduction of the error by ( 18.2 ± 0.5 ) % and ( 52.8 ± 6.3 ) % for the respective above observables. We propose further applications of the BBGKY hierarchy for quantum error mitigation.}, archive = {J_PRA}, author = {Theo Saporiti and Oleg Kaikov and Vasily Sazonov and Mohamed Tamaazousti}, doi = {10.1103/slbz-3r4b}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032409}, shortjournal = {Phys. Rev. A}, title = {Bogoliubov-born-green-kirkwood-yvon hierarchy for quantum error mitigation}, volume = {112}, year = {2025}, }
• (2025). Passive leakage removal unit based on a disordered transmon array. PRA, 112(3), 032408. (www)

  @article{ , abstract = {Leakage out from the qubit subspace compromises standard quantum error correction protocols and poses a challenge for practical quantum computing. We propose here a passive leakage removal unit based on an array of coupled disordered transmons and last-site reset by feedback-measurement or dissipation. We find that the unit effectively removes leakage with minimal effect on the qubit subspace by taking advantage of energy level disorder for the qubit subspace and resonant leakage energy levels. There are two optimal measurement rates for removing leakage, which we show analytically to correspond to the characteristic timescales of the propagation and disintegration of the leakage excitation. The performance of the leakage removal unit depends on the strength of disorder, coupling between the transmons, and the length of the array. We simulate the system under experimentally feasible parameters and present an optimal configuration. Our approach is readily compatible with existing superconducting quantum processors, considering realistic conditions.}, archive = {J_PRA}, author = {Gonzalo Martín-Vázquez and Taneli Tolppanen and Matti Silveri}, doi = {10.1103/bxqs-y662}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032408}, shortjournal = {Phys. Rev. A}, title = {Passive leakage removal unit based on a disordered transmon array}, volume = {112}, year = {2025}, }
• (2025). Scalability challenges in variational quantum optimization under stochastic noise. PRA, 112(3), 032407. (www)

  @article{ , abstract = {With rapid advances in quantum hardware, a central question is whether quantum devices with or without full error correction can outperform classical computers on practically relevant problems. Variational quantum algorithms (VQAs) have gained significant attention as promising candidates in this pursuit, particularly for combinatorial optimization problems. While reports of their challenges and limitations continue to accumulate, many studies remain optimistic based on small-scale, idealized testing setups, leaving doubt about the scalability of VQAs for large-scale problems. We systematically investigate this scaling behavior by analyzing how classical optimizers minimize variational quantum loss functions for random Quadratic Unconstrained Binary Optimization instances in the presence of uncertainty, modeled as effective Gaussian noise. We find that the critical noise threshold for successful optimization decreases rapidly as system size grows. This decline exceeds what can be explained solely by shrinking loss variance, confirming deeper, fundamental limitations in the loss landscapes of VQAs beyond barren plateaus. Translating these thresholds into required measurement shots reveals that achieving sufficient precision in the evaluated loss values quickly becomes impractical, even for moderatelysized problems. Our findings demonstrate serious scalability challenges for VQAs in optimization stemming from mere uncertainty, indicating potential barriers to achieving practical quantum advantage with current hybrid approaches.}, archive = {J_PRA}, author = {Adelina Bärligea and Benedikt Poggel and Jeanette Miriam Lorenz}, doi = {10.1103/rgyh-8xw8}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032407}, shortjournal = {Phys. Rev. A}, title = {Scalability challenges in variational quantum optimization under stochastic noise}, volume = {112}, year = {2025}, }
• (2025). Characterizing gaussian quantum processes with gaussian resources. PRA, 112(3), 032406. (www)

  @article{ , abstract = {Characterizing quantum processes is indispensable for the implementation of any task in quantum information processing. In this paper, we develop an efficient method to fully characterize arbitrary Gaussian processes in continuous-variable quantum systems. This is done by directly obtaining all elements of the symplectic matrix that describes the process. Only Gaussian resources such as coherent probes and quadrature measurements are needed for this task. The method is efficient, involving only steps to characterize an -mode system. Further, the method is resilient to uniform loss. We simulate this procedure using the Python package Strawberry Fields. We observe that heterodyne measurements outperform homodyne measurements for reconstructing Gaussian processes.}, archive = {J_PRA}, author = {Logan W. Grove and Pratik J. Barge and Kevin Valson Jacob}, doi = {10.1103/sxd2-5z5d}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032406}, shortjournal = {Phys. Rev. A}, title = {Characterizing gaussian quantum processes with gaussian resources}, volume = {112}, year = {2025}, }
• (2025). Continuous majorization in quantum phase space for wigner-positive states and proposals for wigner-negative states. PRA, 112(3), 032405. (www)

  @article{ , abstract = {In quantum resource theory, one is often interested in identifying which states serve as the best resources for particular quantum tasks. If a relative comparison between quantum states can be made, this gives rise to a partial order, where states are ordered according to their suitability to act as a resource. In the literature, various different partial orders for a variety of quantum resources have been proposed. In discrete variable systems, vector majorization of Wigner functions in discrete phase space provides a natural partial order between quantum states. In the continuous variable case, a natural counterpart would be continuous majorization of Wigner functions in quantum phase space. Indeed, this concept was recently proposed and explored (mostly restricting to the single-mode case) by Van Herstraeten et al. [ Quantum 7 , 1021 (2023) ]. In this work, we develop the theory of continuous majorization in the general N -mode case. In addition, we propose extensions to include states with finite Wigner negativity. For the special case of the convex hull of N -mode Gaussian states, we prove a conjecture made by Van Herstraeten, Jabbour, and Cerf. We also prove a phase space counterpart of Uhlmann's theorem of majorization.}, archive = {J_PRA}, author = {Jan de Boer and Giuseppe Di Giulio and Esko Keski-Vakkuri and Erik Tonni}, doi = {10.1103/w561-h3z5}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032405}, shortjournal = {Phys. Rev. A}, title = {Continuous majorization in quantum phase space for wigner-positive states and proposals for wigner-negative states}, volume = {112}, year = {2025}, }
• (2025). Self-testing of the m-partite greenberger-horne-zeilinger state and observables using the svetlichny inequality. PRA, 112(3), 032404. (www)

  @article{ , abstract = {Self-testing, a correlation-based protocol, enables certification of both the quantum state and measurements without requiring knowledge of the internal workings of the device. While well studied in bipartite Bell scenarios, its extension to the multipartite regime remains limited due to the complex structure of multipartite correlations. In this work, we derive the optimal quantum bound of the -partite Svetlichny inequality by finding suitable sum-of-squares decomposition, without assuming any fixed Hilbert space dimension. This enables us to self-test both the -partite Greenberger-Horne-Zeilinger state and the local anticommuting observables (up to local unitaries and complex conjugation). Applying the self-testing relations obtained from the sum-of-squares decompositions in a swap circuit framework, we can assess the closeness of the reference states and measurements to their ideal counterparts in the presence of noise and imperfections, thereby demonstrating the robustness of our protocol. Our analysis additionally enables certified randomness generation from correlations achieving the optimal Svetlichny violation.}, archive = {J_PRA}, author = {Ritesh K. Singh and Souradeep Sasmal and A. K. Pan}, doi = {10.1103/x6ct-vmnx}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032404}, shortjournal = {Phys. Rev. A}, title = {Self-testing of the m-partite greenberger-horne-zeilinger state and observables using the svetlichny inequality}, volume = {112}, year = {2025}, }
• (2025). Decoherence mitigation for geometric quantum computation. PRA, 112(3), 032403. (www)

  @article{ , abstract = {Geometric phases depend only on the evolution path determined by the closed circuit in the projective Hilbert space but not on evolution details of the quantum system, leading to geometric quantum computation possessing some intrinsic robustness against control errors. Coordinated with dynamical decoupling, geometric quantum computation admits additional resilience to the environment-induced decoherence. However, the previous schemes of geometric quantum computation protected by dynamical decoupling require multiple physical qubits to encode a logical qubit, which undoubtedly increases the consumption of physical-qubit resources and the difficulty in the implementation of the logical-qubit manipulation based on physical-qubit driving. In this work, we put forward a scheme of decoherence-mitigated geometric quantum computation based only on physical qubits rather than logical qubits, hence avoiding the additional overhead of physical-qubit resources for logical-qubit encoding as well as the difficulty in the manipulation of logical qubits. Moreover, our scheme focuses on the most general interaction between an individual qubit and its environment so that it mitigates not just dephasing noise but rather regular decoherence. Our proposal thus represents a more realistic and effective approach towards the realization of geometric control with decoherence mitigation.}, archive = {J_PRA}, author = {X. Y. Sun and P. Z. Zhao}, doi = {10.1103/7y8p-85k3}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032403}, shortjournal = {Phys. Rev. A}, title = {Decoherence mitigation for geometric quantum computation}, volume = {112}, year = {2025}, }
• (2025). Multipartite continuous-variable quantum nondemolition interaction and entanglement certification and monitoring. PRA, 112(3), 032402. (www)

  @article{ , abstract = {The quantum nondemolition (QND) measurement is one of the most studied quantum measurement procedures. Usually, such a process involves the coupling of a single system of interest, called signal, with a single probe system, so that the relevant information in the signal system is indirectly measured by observing the probe system. Here we extend the concept of quantum nondemolition interaction to the cases in which the signal and the probe systems are each one multipartite continuous-variable system. Specifically, we propose a general scheme that performs the multipartite QND interactions, relying on beam-splitter couplings between the signal and probe modes with only two ancillary modes prepared offline in squeezed states. The scheme is also composed of homodyne detection and feedforward modulation. The ancillary modes are detected in the process, providing photocurrents for postmodulation of the output systems, as well as sufficient information to calculate genuine multipartite entanglement conditions of the input systems and to monitor similar conditions of the output systems.}, archive = {J_PRA}, author = {Vinícius V. Seco and Alencar J. de Faria}, doi = {10.1103/g531-tfkw}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032402}, shortjournal = {Phys. Rev. A}, title = {Multipartite continuous-variable quantum nondemolition interaction and entanglement certification and monitoring}, volume = {112}, year = {2025}, }
• (2025). Network nonlocality without entanglement of all sources. PRA, 112(3), 032401. (www)

  @article{ , abstract = {Entanglement and nonlocality are two important nonclassical features of quantum correlations. Recently the study of quantum correlations in networks has undergone remarkable progress owing to technological development towards scalable quantum networks. However, compared to the standard Bell scenario, manifestation of the interplay between these two aspects has received less attention in network scenarios featuring independent sources. In this work we have analyzed the relation between entanglement content of the sources and detectable non- -locality in two distinct network topologies (linear and star). We have studied the extremal violations of -local inequalities (compatible with linear and star network) for any fixed amount of entanglement (in terms of concurrence) of the independent sources. It is observed that each of the sources must be entangled for detecting non- -locality in a linear network. However, the same is not true for star -local network. The present analysis reveals that entanglement of all the independent sources is not a necessity for generation of non- -local correlations in star topology. Characterization of sources in terms of the minimum entanglement requirement for any fixed violation amount of the -local inequalities is also provided. Interestingly, detection of non- -locality is ensured in the network if product of concurrence of all the sources involved exceeds}, archive = {J_PRA}, author = {Kaushiki Mukherjee and Biswajit Paul}, doi = {10.1103/hypy-f9bf}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032401}, shortjournal = {Phys. Rev. A}, title = {Network nonlocality without entanglement of all sources}, volume = {112}, year = {2025}, }
• (2025). Quantum stirling heat engine based on two-qubit quantum rabi model with spin-spin coupling. PRA, 112(3), 032226. (www)

  @article{ , abstract = {Enhancing the efficiency of quantum heat engines (QHEs) is crucial for advancing fundamental research and quantum technologies. We explore a quantum Stirling cycle using a two-qubit quantum Rabi model with spin-spin coupling as a working medium. We propose parameter optimization strategies to maximize the efficiency of the heat engine, as there are multiple ways for the effective coupling constant to move toward its critical point. In the normal phase, enhancing the temperature ratio of hot-to-cold reservoirs and spin-mode coupling strength can boost QHE efficiency, while increasing the spin-spin coupling strength will reduce the efficiency. In the superradiant phase, when the temperature ratio is held constant, lowering the cold reservoir temperature moves the efficiency closer to the Carnot limit. Furthermore, when the cold reservoir temperature is fixed, increasing the ratio between spin-mode coupling and mode frequency will improve the efficiency. While the spin-spin coupling is fixed, the cycle with a higher-temperature ratio between the hot and cold reservoirs demands a higher ratio between the spin-mode coupling and mode frequency to improve efficiency. Our work deepens the understanding of QHE performance under various conditions and provides operative methods for optimizing the efficiency of QHE.}, archive = {J_PRA}, author = {Luxin Xu and Chunfeng Wu and Changliang Ren}, doi = {10.1103/zqbv-j3jv}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032226}, shortjournal = {Phys. Rev. A}, title = {Quantum stirling heat engine based on two-qubit quantum rabi model with spin-spin coupling}, volume = {112}, year = {2025}, }
• (2025). Theory of tunneling splitting in symmetric double well systems: Equivalence of the two-state approximation and the herring formula. PRA, 112(3), 032225. (www)

  @article{ , abstract = {The computation of tunneling splitting in physical systems, such as molecular systems, qubits, and more, is still quite challenging because of its very small magnitude, as compared with the typical vibrational spacing between doublet levels. Thus, it is important to understand and develop methods that can reproduce the physics of the tunneling splitting in a simple and direct way. Herring's formula is probably the most popular expression in this sense. To shed light on the implications of this formula, which was first proposed by Herring [C. Herring, Rev. Mod. Phys. 34 , 631 (1962) ], we investigate the connection between the two-state approximation, as employed for nonadiabatic-induced tunneling splitting, and the Herring formula, which is relevant to adiabatic tunneling splitting. We show that the two-state approximation and the Herring formula, which may be derived as a weak value of the flux operator and is a derivative result, are identical for a symmetric double well potential. This unveils the physics underlying Herring's formula and provides further justification for the two-state approximation for the nonadiabatic tunneling splitting estimate. We conclude that, when Herring's formula is used with approximate eigenfunctions, it will not be accurate when the two-state approximation is not valid, i.e., when the energy splitting is comparable to the eigenenergy spacing. More generally, Herring's formula will fail when the two-state approximation fails. We also show how the identity between the integral two-state approximation form and Herring's formula may be used to obtain analytic expressions for some nontrivial integrals.}, archive = {J_PRA}, author = {Eli Pollak and Michele Ceotto}, doi = {10.1103/yt3d-nxs7}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032225}, shortjournal = {Phys. Rev. A}, title = {Theory of tunneling splitting in symmetric double well systems: Equivalence of the two-state approximation and the herring formula}, volume = {112}, year = {2025}, }
• (2025). Exact WKB analysis for dynamical and geometric exponents in generalized and nonlinear landau-zener transitions. PRA, 112(3), 032224. (www)

  @article{ , abstract = {The Berry phase is a geometric phase that is important in explaining topological quantum phenomena. The Berry phase is also important in nonperturbative phenomena, as the imaginary part of the phase explains the nonperturbative transitions. However, problems arose because the singular perturbation with respect to the Planck constant has not been treated adequately in conventional calculations, where the most serious problem is the arbitrariness of approximate calculations. To solve this problem, we consider the exact WKB approach, which is a mathematical method that treats perturbative expansion with respect to the Planck constant as a rigorous singular perturbation. This method is also a powerful computational tool that makes analytical computation much easier for mathematical software. Using the exact WKB, we analyze the derivation of the dynamical and the geometric exponents in generalized Landau-Zener models, highlighting the differences from other calculational methods. The discontinuity of complex geometric factor is a universal phenomenon that manifests itself in phase transitions, boundaries, particle generation, and topology changes. These phenomena are “nonperturbative” in physics, while mathematically, these discontinuities can be deeply related to the singular structure of complex analysis. The mathematical structure of these phenomena will be revealed by using the exact WKB.}, archive = {J_PRA}, author = {Tomohiro Matsuda}, doi = {10.1103/8c6k-bbpb}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032224}, shortjournal = {Phys. Rev. A}, title = {Exact WKB analysis for dynamical and geometric exponents in generalized and nonlinear landau-zener transitions}, volume = {112}, year = {2025}, }
• (2025). Searching for bloch wave packets with almost definite momentum direction. PRA, 112(3), 032223. (www)

  @article{ , abstract = {The motion of a quantum particle in a one-dimensional periodic potential can be described in terms of Bloch wave packets. Like free-particle wave packets, they can propagate without attenuation. Here, we examine this similarity more closely by investigating whether Bloch wave packets can maintain a definite—or nearly definite—momentum direction, a property inherent in free-particle wave packets. This question is particularly relevant to the feasibility of using solid-state-based systems in the search for the first experimental realization of quantum backflow, a quantum interference effect in which a particle's probability density flows in a direction opposite to its momentum.}, archive = {J_PRA}, author = {Arseni Goussev and Gregory V. Morozov}, doi = {10.1103/k9km-k3dm}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032223}, shortjournal = {Phys. Rev. A}, title = {Searching for bloch wave packets with almost definite momentum direction}, volume = {112}, year = {2025}, }
• (2025). Coherence-assisted entanglement activation during open evolution. PRA, 112(3), 032222. (www)

  @article{ , abstract = {The fact that, in the course of open evolution, the creation of system-environment entanglement out of the initial coherence occurs in the vast majority of cases has been known for many years. However, how much entanglement can be created under general assumptions has not been analyzed yet. In this work, we investigate system-environment entanglement generation under a broad and important class of interactions known as pure-dephasing interactions for arbitrary initial conditions. Our main results are the following bounds on the relative entropy of entanglement after evolution: , connecting it on one side to the initial relative entropy of coherence and information extractable from the environment and on the other side to the decoherence strength, making the statement that larger entanglement leads to more decoherence quantitatively precise. As an illustration, we apply our results to the spin-boson model, where a qubit interacts with a bosonic bath, showing the time evolution of the entanglement and the crossover between Markovian and non-Markovian dynamics. Our results help us better understand and quantify the complicated correlations produced during open evolution, which will hopefully lead to better and new decoherence-mitigation techniques.}, archive = {J_PRA}, author = {Masaya Takahashi and Jarosław K. Korbicz}, doi = {10.1103/8vc7-64fk}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032222}, shortjournal = {Phys. Rev. A}, title = {Coherence-assisted entanglement activation during open evolution}, volume = {112}, year = {2025}, }
• (2025). Constructing the nonclassical lifetime distribution of two-level systems via quantum reliability. PRA, 112(3), 032220. (www)

  @article{ , abstract = {To characterize the aging process of quantum devices, the concept of quantum reliability has recently been proposed as a process-based metric that quantifies the duration during which operations remain unaffected by noise. This duration is referred to as the lifetime of a quantum system. In this paper, we investigate the lifetime of a two-level atomic system undergoing spontaneous emission. We construct an exact statistical ensemble of the lifetimes for two-level systems using quantum reliability theory, incorporating comprehensive information such as mean values, fluctuations, and non-classical properties. Notably, we demonstrate that the ensemble exhibits can be represented by a density matrix, which is recorded in the monitoring apparatus by an observation process. Under the Born-Markov approximation, the diagonal elements decay exponentially at a state-dependent rate related to quantum fidelity. Beyond this approximation, the off-diagonal elements arise from interference between radiation pathways and are determined by the first-order coherence of the field. This feature indicates that the off-diagonal elements encode spectral information beyond the Markovian decay rate, suggesting a potential protocol for probing the environmental spectral density using two-level atoms.}, archive = {J_PRA}, author = {Yaotian Li and Y.-M. Du and Wenkui Ding and Zhaoyu Fei and Libin Fu and Xiaoguang Wang}, doi = {10.1103/w98h-hqb2}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032220}, shortjournal = {Phys. Rev. A}, title = {Constructing the nonclassical lifetime distribution of two-level systems via quantum reliability}, volume = {112}, year = {2025}, }
• (2025). Interplay between defects and the non-hermitian skin effect. PRA, 112(3), 032219. (www)

  @article{ , abstract = {The non-Hermitian skin effect (NHSE) is an intriguing phenomenon in which an extensive number of bulk eigenstates localize at the boundaries of a non-Hermitian system with nonreciprocal hoppings. Here, we study the interplay of this effect and a defect in nonreciprocal one-dimensional lattices. We show that the interplay of the NHSE and defects is size-dependent. We demonstrate a novel class of hybrid skin-defect states in finite-size systems resulting from the coupling between the skin and defect states. Next, we consider a single defect in a topologically nontrivial lattice with time-reversal symmetry based on the nonreciprocal Su-Schrieffer-Heeger configuration. We unveil how topologically nontrivial defect states and non-Hermiticity interplay by competing with each other, exhibiting a transition from topologically nontrivial defect states to skin states. In addition, we show that decreasing the defect strength can result in a transition from trivial defect states to skin states. Our work promotes the understanding of the interplay between defects and the NHSE and especially the importance of the energy spectra of the system with the defect under periodic boundary conditions.}, archive = {J_PRA}, author = {Yin Huang and Wenna Zhang and Yu Zhou and Yuecheng Shen and Georgios Veronis and Wenchen Luo}, doi = {10.1103/622m-d2q6}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032219}, shortjournal = {Phys. Rev. A}, title = {Interplay between defects and the non-hermitian skin effect}, volume = {112}, year = {2025}, }
• (2025). Space-time-symmetric nonrelativistic quantum mechanics in 3+1 dimensions: Time and position of arrival from complementary wave functions. PRA, 112(3), 032218. (www)

  @article{ , abstract = {We generalize a space-time-symmetric (STS) extension of nonrelativistic quantum mechanics (QM) to describe a particle moving in three spatial dimensions. In addition to the conventional time-conditional (Schrödinger) wave function ψ ( x , y , z | t ) , we introduce space-conditional wave functions such as ϕ ( t , y , z | x ) , where x plays the role of the evolution parameter. The function ϕ ( t , y , z | x ) represents the probability amplitude for the particle to arrive on the plane x = constant at time t and transverse position ( y , z ) . More generally, within our framework, any coordinate x μ ∈ { t , x , y , z } can be conveniently chosen as the evolution parameter, depending on the experimental context. This leads to a unified formalism governed by a generalized Schrödinger-type equation P ̂ μ | ϕ μ ( x μ ) 〉 = i ℏ η μ ν d d x ν | ϕ μ ( x μ ) 〉 . It reproduces standard QM when x μ = t , with | ϕ 0 ( x 0 ) 〉 = | ψ ( t ) 〉 , and recovers the STS extension when x μ = x i ∈ { x , y , z } . For a free particle, we show that ϕ ( t , y , z | x ) = 〈 t , y , z | ϕ ( x ) 〉 naturally reproduces the same dependence on the momentum wave function as the axiomatic Kijowski distribution. Possible experimental tests of these predictions are discussed. Finally, we demonstrate that the different states | ϕ μ ( x μ ) 〉 can emerge by conditioning (i.e., projecting) a timeless and spaceless physical state onto the eigenstate | x μ 〉 , leading to constraint equations of the form P ̂ μ | Φ μ 〉 = 0 . Rather than privileging time as the sole evolution parameter, this formulation treats all coordinates on equal footing.}, archive = {J_PRA}, author = {Eduardo O. Dias}, doi = {10.1103/9pj6-th1m}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032218}, shortjournal = {Phys. Rev. A}, title = {Space-time-symmetric nonrelativistic quantum mechanics in 3+1 dimensions: Time and position of arrival from complementary wave functions}, volume = {112}, year = {2025}, }
• (2025). Bounding the sample fluctuation for pure-state certification with local random measurement. PRA, 112(3), 032217. (www)

  @article{ , abstract = {Remarkable breakthroughs in quantum science and technology are demanding more efficient methods in analyzing quantum many-body states. A significant challenge in this field is to verify whether a quantum state prepared by quantum devices in the laboratory accurately matches the desired target pure state. Recent advancements in randomized measurement techniques have provided fresh insights in this area. Specifically, protocols such as classical shadow tomography and shadow overlap have been proposed. Building on these developments, we investigate the fundamental properties of schemes that certify pure quantum states through random local Haar measurements. We derive bounds for sample fluctuations that are applicable regardless of the specific estimator construction. These bounds depend on the operator size distribution of either the observable used to estimate fidelity or the valid variation of the reduced density matrix for arbitrary observables. Our results unveil the intrinsic interplay between operator complexity and the efficiency of quantum algorithms, serving as an obstacle to local certification of pure states with long-range entanglement.}, archive = {J_PRA}, author = {Langxuan Chen and Pengfei Zhang}, doi = {10.1103/8zth-7n97}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032217}, shortjournal = {Phys. Rev. A}, title = {Bounding the sample fluctuation for pure-state certification with local random measurement}, volume = {112}, year = {2025}, }
• (2025). Spin textures in curved paths on a curved surface. PRA, 112(3), 032216. (www)

  @article{ , abstract = {This study investigates the quantum dynamics of a spin-1/2 particle confined to a curved path from the dynamics of a two-dimensional curved thin-layer system incorporating spin connection contributions. We demonstrate that the geodesic curvature, normal curvature, and geodesic torsion govern the emergent non-Abelian gauge potential, while the geodesic and Gaussian curvatures govern the effective scalar potential in the Hamiltonian. The resulting spin precession dynamics induced by the gauge potential are analyzed with and without the adiabatic approximation. Under this approximation, the surface topology is linked to the rotation angle of spin orientation along a surface boundary and to the pseudomagnetic flux. Spin texture evolution along helices illustrates distinct behaviors under geodesic versus nongeodesic propagation. Furthermore, the spin evolution along Viviani's curve exemplifies surface dependence. The curve's topology ensures closure of the spin direction and independence of the spin from the path direction. Our theory establishes a framework for spin-state manipulation via engineered nanostructured channels, enabling topological quantum control strategies.}, archive = {J_PRA}, author = {Guo-Hua Liang and Ai-Guo Mei and Zhi-Hui Yang and Ze-Lin Wei}, doi = {10.1103/bcls-nx77}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032216}, shortjournal = {Phys. Rev. A}, title = {Spin textures in curved paths on a curved surface}, volume = {112}, year = {2025}, }
• (2025). Optimizing the incident electron momentum for resonant few-photon kapitza-dirac scattering in bichromatic laser fields. PRA, 112(3), 032215. (www)

  @article{ , abstract = {Nonrelativistic Kapitza-Dirac scattering of electrons from counterpropagating bichromatic laser waves is studied in the resonant Bragg regime, taking the electron spin into account. We show that the intrinsic field-induced detuning, which arises in the Rabi oscillation dynamics between initial and scattering state of the electron, can be compensated by a suitable adjustment of its incident momentum. Analytical formulas of the optimized electron momentum for spin-dependent three-photon and spin-independent four-photon Kapitza-Dirac scattering are obtained from simplified model systems in reduced dimensionality, which preserve the characteristic properties of the process.}, archive = {J_PRA}, author = {Ingo Elsner and Carsten Müller}, doi = {10.1103/q7tp-p9vd}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032215}, shortjournal = {Phys. Rev. A}, title = {Optimizing the incident electron momentum for resonant few-photon kapitza-dirac scattering in bichromatic laser fields}, volume = {112}, year = {2025}, }
• (2025). Conserved operators and exact conditions for pair condensation. PRA, 112(3), 032214. (www)

  @article{ , abstract = {We determine the necessary and sufficient conditions which ensure that an N = 2 m -particle fermionic or bosonic state has the form | Ψ 〉 ∝ ( A † ) m | 0 〉 , where A † = 1 2 ∑ i , j A i j c i † c j † is a general pair creation operator. These conditions can be cast as an eigenvalue equation for a modified two-body density matrix and enable an exact reconstruction of the operator A † , providing as well a measure of the proximity of a given state to an exact pair condensate. Through a covariance-based formalism, it is also shown that such states are fully characterized by a set of L “conserved” one-body operators which have | Ψ 〉 as exact eigenstate, with L determined just by the single-particle space dimension involved. The whole set of two-body Hamiltonians having | Ψ 〉 as exact eigenstate is in this way determined, while a general subset having | Ψ 〉 as nondegenerate ground state is also identified. Extension to states ∝ f ( A † ) | 0 〉 with f an arbitrary function is also discussed.}, archive = {J_PRA}, author = {Federico Petrovich and R. Rossignoli}, doi = {10.1103/qbwh-c3gp}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032214}, shortjournal = {Phys. Rev. A}, title = {Conserved operators and exact conditions for pair condensation}, volume = {112}, year = {2025}, }
• (2025). Reviving coherence and time crystals with nonreciprocal coupling. PRA, 112(3), 032213. (www)

  @article{ , abstract = {The interplay between coherence, dissipation, and nonreciprocal interactions plays a crucial role in engineering novel dynamical phases of open quantum systems. Here, we consider two collective spin ensembles, each coupled to its own driven-dissipative bosonic mode, and interacting via a common dissipative bosonic field. By introducing nonreciprocity through asymmetric couplings to the shared field, we demonstrate that quantum coherence can be revived from fully decohered states. This revival signals a transition from a time-translational symmetric phase to a spontaneously time-translation symmetry-broken phase, realizing a continuous time crystal. Remarkably, steady-state entanglement emerges even in regions where macroscopic coherence is absent, underscoring the nontrivial impact of engineered dissipation. The phase transitions are characterized using numerical simulations of the full quantum master equation, mean-field analysis in the thermodynamic limit, and Liouvillian spectral properties. Our work provides a robust framework to realize coherence enhancement, steady-state entanglement, and time-crystalline behavior in driven-dissipative quantum systems.}, archive = {J_PRA}, author = {K. Karthiga and D. V. Senthilkumar and V. K. Chandrasekar}, doi = {10.1103/ht7n-bdp9}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032213}, shortjournal = {Phys. Rev. A}, title = {Reviving coherence and time crystals with nonreciprocal coupling}, volume = {112}, year = {2025}, }
• (2025). Unpolarized prethermal discrete time crystal. PRA, 112(3), 032212. (www)

  @article{ , abstract = {Prethermal discrete time crystals (DTCs) are a novel phase of periodically driven matter that exhibits robust subharmonic oscillations without requiring disorder. However, previous realizations of prethermal DTCs have relied on the presence of polarization, either spontaneous or induced. Here we introduce a class of prethermal DTCs termed “unpolarized prethermal discrete time crystals” (UPDTCs) that arise without any uniform or staggered polarization and propose an experiment to observe them in current trapped-ion quantum simulators. By studying a model of trapped ions using a quantum circuit simulator, we demonstrate that robust period-doubled dynamics can persist in the autocorrelation function of the staggered magnetization, even though its expectation value does not exhibit such dynamics. The period-doubled dynamics is not explained by the classical picture of flipping spins but by quantum fluctuations. We establish that UPDTCs are exponentially long-lived in the high-frequency driving regime, a hallmark of prethermalization. These results expand the known phenomenology and mechanism of prethermal time crystals and underscore the role of quantum effects in stabilizing novel nonequilibrium phases.}, archive = {J_PRA}, author = {Takeru Yokota and Tatsuhiko N. Ikeda}, doi = {10.1103/9gml-hf8q}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032212}, shortjournal = {Phys. Rev. A}, title = {Unpolarized prethermal discrete time crystal}, volume = {112}, year = {2025}, }
• (2025). Symplectic structures in quantum entanglement. PRA, 112(3), 032211. (www)

  @article{ , abstract = {In this work we explore the implications of applying the formalism of symplectic geometry to quantum mechanics, particularly focusing on many-particle systems. We extend the concept of a symplectic indicator of entanglement, originally introduced by Sawicki et al ., Commun. Math. Phys. 305 , 441 (2011) , to these complex systems. Specifically, we demonstrate that the restriction of the symplectic structure to manifolds comprising all states characterized by isospectral reduced one-particle density matrices exhibits degeneracy for nonseparable states. We prove that the degree of degeneracy at any given state corresponds to the degree of degeneracy of the symplectic form when restricted to the manifold of states that are locally unitary equivalent with . Additionally, we provide a physical interpretation of this symplectic indicator of entanglement, articulating it as an inherent ambiguity within the associated classical dynamical framework. Our findings underscore the pivotal role of symplectic geometry in elucidating entanglement properties in quantum mechanics and suggest avenues for further exploration into the geometric structures underlying quantum state spaces.}, archive = {J_PRA}, author = {Piotr Dulian and Adam Sawicki}, doi = {10.1103/qktr-8vsd}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032211}, shortjournal = {Phys. Rev. A}, title = {Symplectic structures in quantum entanglement}, volume = {112}, year = {2025}, }
• (2025). Characterizing quantum measurement through environmental stochastic entropy production in a two-spin-1/2 system. PRA, 112(3), 032210. (www)

  @article{ , abstract = {Quantum state diffusion is a framework within which measurement may be described as the continuous and gradual collapse of a quantum system to an eigenstate as a result of interaction with its environment. The irreversible nature of the quantum trajectories that arise may be characterized by the environmental stochastic entropy production associated with the measurement. We consider a system of two spin-1/2 particles undergoing either single-particle measurements or measurements of the total -spin component . The mean asymptotic rates of environmental stochastic entropy production associated with collapse can depend on the eigenstate of selected and on the initial state of the system, offering an additional avenue for characterizing quantum measurement.}, archive = {J_PRA}, author = {Sophia M. Walls and Adam Bloss and Ian J. Ford}, doi = {10.1103/jdwl-rv38}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032210}, shortjournal = {Phys. Rev. A}, title = {Characterizing quantum measurement through environmental stochastic entropy production in a two-spin-1/2 system}, volume = {112}, year = {2025}, }
• (2025). Ergotropic mpemba effect in non-markovian quantum systems. PRA, 112(3), 032209. (www)

  @article{ , abstract = {The Mpemba effect has garnered growing attention and diverse interpretations within the realm of quantum physics. Recently, Medina et al. [ Phys. Rev. Lett. 134 , 220402 (2025) ] introduced the ergotropic Mpemba effect in quantum batteries governed by Markovian dynamics, highlighting the anomalous phenomenon where batteries in higher ergotropy states discharge faster than those in lower ergotropy states. Building on this foundation, our research proposes an all-optical scheme to realize the ergotropic Mpemba effect in open quantum systems, and further investigates its implications in systems exhibiting non-Markovian dynamics. We find that the ergotropic Mpemba effect persists in non-Markovian dynamics. In the strong non-Markovian regime, prior to the occurrence of the ergotropic Mpemba effect, the ergotropy evolution shows multiple crossings, which we refer to as the quasiergotropic Mpemba effect . Moreover, we derive the analytical solution for the critical point at which the ergotropic Mpemba effect occurs, and we establish the necessary conditions for this effect to emerge. Finally, we propose an experimental scheme based on continuous-variable quantum circuits to realize our theoretical prediction.}, archive = {J_PRA}, author = {Yan Li and Wenlin Li and Xingli Li}, doi = {10.1103/5xrr-x2rm}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032209}, shortjournal = {Phys. Rev. A}, title = {Ergotropic mpemba effect in non-markovian quantum systems}, volume = {112}, year = {2025}, }
• (2025). Retrodiction of measurement outcomes on a single quantum system revealing entanglement with its environment. PRA, 112(3), 032208. (www)

  @article{ , abstract = {The density matrix yields probabilistic information about the outcome of measurements on a quantum system, but it does not distinguish between classical randomness in the preparation of the system and entanglement with its environment. Here we show that retrodiction, employing both prior and posterior knowledge, gives rise to conditional probabilities for measurements on a single system, that can witness if it is part of a larger composite system. The degree of certainty with which one can retrodict the outcomes of multiple measurements on a system can witness both the existence and the quantitative nature of its entanglement with the environment.}, archive = {J_PRA}, author = {Julien Pinske and Klaus Mølmer}, doi = {10.1103/kfn4-1fx4}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032208}, shortjournal = {Phys. Rev. A}, title = {Retrodiction of measurement outcomes on a single quantum system revealing entanglement with its environment}, volume = {112}, year = {2025}, }
• (2025). Vector space constructions of kochen-specker sets using hadamard matrices. PRA, 112(3), 032207. (www)

  @article{ , abstract = {We analyze and generalize a construction method of Kochen-Specker (KS) sets given by Waegell and Aravind. In this method the bases that participate in a KS set are formed by modifying a seed basis using a vector space of shifts. We show that any real or generalized Hadamard matrix can be used as the seed basis, and that the space of shifts can be much smaller than originally proposed. Main benefits of these generalizations are a vastly extended set of available seed matrices, and significantly smaller KS sets produced. Analytical constructions of infinite families of Hadamard matrices combined with our generalized approach allow us to construct an infinite family of KS sets.}, archive = {J_PRA}, author = {Petr Lisoněk and Liam Salt}, doi = {10.1103/bdrr-q25l}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032207}, shortjournal = {Phys. Rev. A}, title = {Vector space constructions of kochen-specker sets using hadamard matrices}, volume = {112}, year = {2025}, }
• (2025). Dissipative qutrit-mediated stable charging. PRA, 112(3), 032206. (www)

  @article{ , abstract = {In this work, we propose a stable charging scheme mediated by a three-level system (qutrit), which renders a unidirectional energy flow from an external power source to an ( )-dimensional quantum battery. By virtue of the qutrit dissipation, the battery avoids the spontaneous discharging induced by the time-reversal symmetry of any unitary-charging scheme. Irrespective of the initial state, the battery can be eventually stabilized at the maximal-ergotropy state as long as the charger-battery interaction is present. We use a Dyson series of Lindbladian superoperator to obtain an effective master equation for the battery, which is found to be equivalent to the high-order Fermi's golden rule adapted to the non-Hermitian Hamiltonian and spontaneous decay. We extract the optimization condition for charging efficiency and justify it in the finite-size battery with uniform energy splitting, the large spin battery, and the truncated harmonic-oscillator battery.}, archive = {J_PRA}, author = {Chen-yi Zhang and Jun Jing}, doi = {10.1103/v7pq-ffxz}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032206}, shortjournal = {Phys. Rev. A}, title = {Dissipative qutrit-mediated stable charging}, volume = {112}, year = {2025}, }
• (2025). Strongest quantum nonlocality in N-partite systems. PRA, 112(3), 032205. (www)

  @article{ , abstract = {The strongest quantum nonlocality is a stronger form of nonlocality than that manifested by locally indistinguishable quantum states. It has efficient applications in quantum information hiding and quantum secret sharing. Constructing a smaller-size set with the strongest nonlocality contributes to reducing resource consumption. In this paper we establish a sufficient and necessary condition for the strongest nonlocality in general -partite systems. Then we derive the minimum size of the strongest nonlocal set with symmetry in the system . Notably, the genuinely entangled sets constructed in our previous work [ Phys. Rev. A 109 , 022220 (2024) ] achieved this minimum size. In addition, we construct the strongest nonlocal genuinely entangled sets in the system for , which have a smaller size than the existing sets as increases. Our results provide a meaningful complement to the current understanding of the strongest nonlocality.}, archive = {J_PRA}, author = {Mengying Hu and Ting Gao and Fengli Yan}, doi = {10.1103/69z8-sk86}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032205}, shortjournal = {Phys. Rev. A}, title = {Strongest quantum nonlocality in N-partite systems}, volume = {112}, year = {2025}, }
• (2025). Coarse-grained dynamics in quantum many-body systems using the maximum entropy principle. PRA, 112(3), 032204. (www)

  @article{ , abstract = {Starting from a coarse-grained map of a quantum many-body system, we construct the inverse map that assigns a microscopic state to a coarse-grained state based on the maximum entropy principle. Assuming unitary evolution in the microscopic system, we examine the resulting dynamics in the coarse-grained system using the assignment map. We investigate both a two-qubit system, with swap and controlled- not gates, and -qubit systems, configured either in an Ising spin chain or with all-to-all interactions. We demonstrate that these dynamics exhibit atypical quantum behavior, such as nonlinearity and non-Markovianity. Furthermore, we find that these dynamics depend on the initial coarse-grained state and establish conditions for general microscopic dynamics under which linearity is preserved. As the effective dynamics induced by our coarse-grained description of many-body quantum systems diverge from conventional quantum behavior, we anticipate that this approach could aid in describing the quantum-to-classical transition and provide deeper insights into the effects of coarse graining on quantum systems.}, archive = {J_PRA}, author = {Adán Castillo and Carlos Pineda and Erick Sebastián Navarrete and David Davalos}, doi = {10.1103/shy4-8h5g}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032204}, shortjournal = {Phys. Rev. A}, title = {Coarse-grained dynamics in quantum many-body systems using the maximum entropy principle}, volume = {112}, year = {2025}, }
• (2025). Proposal for implementing quantum walks on multidimensional networks. PRA, 112(3), 032203. (www)

  @article{ , abstract = {Discrete-time quantum walks (DTQWs) have broad applications in quantum computation and simulation, particularly in universal quantum computing. Prior research in circuit quantum electrodynamics (QED) has focused on implementing DTQWs in one-dimensional chains. However, to achieve practical quantum tasks, it is crucial to extend DTQWs to multidimensional networks with diverse structures. Here, we propose a protocol for realizing DTQWs in multidimensional networks, which accommodate nodes with different numbers of neighbors. Using this protocol, we numerically simulate a Grover walk search algorithm in a cubic network with circuit QED. Our simulations, which consider decoherence, align well with theoretical predictions. Our universal protocol can be adapted for various quantum systems and paves the way for DTQWs in multidimensional networks, which has potential applications in quantum computing and simulation.}, archive = {J_PRA}, author = {Qi-Ping Su and Rui-Qi Shen and Li Yu and Yu Wang and Yi-Hao Kang and Lijiong Shen and Wei Feng and Guo-Qiang Zhang and Chui-Ping Yang}, doi = {10.1103/f3kt-qf1d}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032203}, shortjournal = {Phys. Rev. A}, title = {Proposal for implementing quantum walks on multidimensional networks}, volume = {112}, year = {2025}, }
• (2025). Robust quantification of spectral transitions in perturbed quantum systems. PRA, 112(3), 032202. (www)

  @article{ , abstract = {A quantum system subject to an external perturbation can experience leakage between uncoupled regions of its energy spectrum separated by a gap. To quantify this phenomenon, we present two complementary results. First, we establish time-independent bounds on the distances between the true dynamics and the dynamics generated by block-diagonal effective evolutions constructed via the Schrieffer-Wolff and Bloch methods. Second, we prove that, under the right conditions, this leakage remains small eternally . That is, we derive a time-independent bound on the leakage itself, expressed in terms of the spectral gap of the unperturbed Hamiltonian and the norm of the perturbation, ensuring its validity for arbitrarily large times. Our approach only requires a finite spectral gap, thus accommodating continuous and unbounded spectra. Finally, we apply our bounds to specific systems of practical interest.}, archive = {J_PRA}, author = {Zsolt Szabó and Stefan Gehr and Paolo Facchi and Kazuya Yuasa and Daniel Burgarth and Davide Lonigro}, doi = {10.1103/j44p-13j7}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032202}, shortjournal = {Phys. Rev. A}, title = {Robust quantification of spectral transitions in perturbed quantum systems}, volume = {112}, year = {2025}, }
• (2025). Quantum information engines: Bounds on performance metrics by measurement time. PRA, 112(3), 032201. (www)

  @article{ , abstract = {Information engines, sometimes referred to as Maxwell Demon engines, utilize information obtained through measurement to control the conversion of energy into useful work. Discussions around such devices often assume the measurement step to be instantaneous, assessing its cost by Landauer's information erasure within the measurement device. While this simplified perspective is sufficient for classical feedback-controlled engines, for nanoengines that often operate in the quantum realm, the overall performance may be significantly affected by the measurement duration (which may be comparable to the engine's cycle time) and cost (energy needed to create the system-meter correlation). In this study, we employ a generalized von Neumann measurement model to highlight that obtaining a finite amount of information requires a finite measurement time and incurs an energetic cost. We investigate the crucial role of these factors in determining the engine's performance, particularly in terms of efficiency and power output. Furthermore, for the information engine model under consideration, we establish a precise relationship between the acquired information in the measurement process and the maximum energy extractable through the measurement. We also discuss ways to extend our considerations using these concepts, such as in measurement-enhanced photochemical reactions.}, archive = {J_PRA}, author = {Henning Kirchberg and Abraham Nitzan}, doi = {10.1103/vdm1-4ryg}, journal = {Physical Review a}, month = {9}, number = {3}, pages = {032201}, shortjournal = {Phys. Rev. A}, title = {Quantum information engines: Bounds on performance metrics by measurement time}, volume = {112}, year = {2025}, }
• (2025). Effective non-hermitian formulation of the lindblad equation for interacting quantized fields at finite temperature. PRA, 112(2), L021702. (www)

  @article{ , abstract = {We analyze the Markovian dynamics of a quantum system composed of two interacting quantized fields, each coupled to a thermal reservoir with the same average number of thermal excitations , but with different decay rates (with ). By employing superoperator techniques and applying two nonunitary transformations, the Lindblad master equation is reformulated into a von Neumann-like form governed by an effective non-Hermitian Hamiltonian. Under these conditions, the structure of the effective Hamiltonian remains equivalent to that of the zero-temperature case, indicating that the essential features of the system dynamics are preserved even in the presence of thermal excitations. As an illustrative example of the method, photon coincidence rates are presented for an initial state composed of two indistinguishable photons.}, archive = {J_PRA}, author = {L. Hernández-Sánchez and I. A. Bocanegra-Garay and I. Ramos-Prieto and F. Soto-Eguibar and H. M. Moya-Cessa}, doi = {10.1103/gwzr-cjp6}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021702}, shortjournal = {Phys. Rev. A}, title = {Effective non-hermitian formulation of the lindblad equation for interacting quantized fields at finite temperature}, volume = {112}, year = {2025}, }
• (2025). Exact steady state of the quantum van der pol oscillator: Critical phenomena and enhanced metrology. PRA, 112(2), L021701. (www)

  @article{ , abstract = {Quantum criticality of open many-body systems has attracted lots of interest for emergent phenomena and universality. Here we present the exact steady state of the quantum van der Pol oscillator using the complex P -representation. We show the threshold corresponds to a dissipative phase transition with abrupt changes of steady-state properties and enhanced metrology. The critical behaviors and finite-size effects are investigated through the analytical steady state. We obtain divergent quantum Fisher information (QFI) in the thermodynamic limit both at the critical point and in the time crystal phase, but only the QFI at the critical point approaches the Heisenberg limit. We further prove that the steady-state photon number is the optimized estimated observable with the largest signal-to-noise ratio. We show that the Heisenberg-limited metrology originates from the enhancement of the photon number's susceptibility with a scaling larger than the enhancement of the standard deviation of the photon number. Our work reveals the underlying relation between the time crystal, dissipative phase transition, and enhanced metrology.}, archive = {J_PRA}, author = {Yaohua Li and Xuanchen Zhang and Yong-Chun Liu}, doi = {10.1103/zybb-vxfz}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021701}, shortjournal = {Phys. Rev. A}, title = {Exact steady state of the quantum van der pol oscillator: Critical phenomena and enhanced metrology}, volume = {112}, year = {2025}, }
• (2025). Electromagnetic symmetry dislocations. PRA, 112(2), L021504. (www)

  @article{ , abstract = {Singular optics studies light's topological defects, pioneered by the discovery that phase vortex lines, strands of destructive interference, naturally occur in scalar wave fields. General electromagnetic waves, however, are described by three-dimensional vectors making scalar phase vortices, which depend on the choice of coordinate basis, less meaningful. Polarization singularities instead capture the vector texture of nonparaxial light with separate descriptions for the electric and magnetic fields. But these polarization textures cannot be fundamental because electromagnetic laws can be expressed not only by separate electric and magnetic fields, but by linear combinations of the two. We propose fundamental, basis-independent topological features generic in electromagnetic fields: one- and two-dimensional structures that relate to time-averaged symmetries held locally by the combined electric- and magnetic-field polarization geometry.}, archive = {J_PRA}, author = {Alex J. Vernon and Sebastian Golat and Francisco J. Rodríguez-Fortuño}, doi = {10.1103/9z11-fw8m}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021504}, shortjournal = {Phys. Rev. A}, title = {Electromagnetic symmetry dislocations}, volume = {112}, year = {2025}, }
• (2025). Photoinduced flipping of optical chirality during backward-wave parametric amplification in a chiral nonlinear medium. PRA, 112(2), L021503. (www)

  @article{ , abstract = {We discuss the nonlinear process of backward-wave parametric amplification and oscillation, phase matched using a nonlinear grating inside a chiral medium. Our theory shows a remarkable feature manifesting as photoinduced flipping of optical chirality between the signal and the idler waves, without any change in the structural chirality of the medium. We show that circular birefringence, induced by chirality, leads to two different nonlinear processes with different phase-matching conditions that are associated with opposite states of circular polarizations. When the incident pump and signal beams are linearly polarized initially, their state of polarization evolves in an elliptical fashion because of the two competing nonlinear processes taking place in parallel. We also discuss the properties of such cavityless optical parametric oscillators based on distributed feedback provided by the nonlinear grating used for quasi phase matching.}, archive = {J_PRA}, author = {Christos Flytzanis and Fredrik Jonsson and Govind P. Agrawal}, doi = {10.1103/wx25-7m1y}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021503}, shortjournal = {Phys. Rev. A}, title = {Photoinduced flipping of optical chirality during backward-wave parametric amplification in a chiral nonlinear medium}, volume = {112}, year = {2025}, }
• (2025). Ideal magnetic-resonance scatterers in the visible range. PRA, 112(2), L021502. (www)

  @article{ , abstract = {We demonstrate that a nonmagnetic silicon nanoparticle dimer can scatter visible light as a pure magnetic scatterer under plane-wave illumination, with magnetic resonance dominant and electric dipole responses suppressed. This is achieved by spectrally overlapping the magnetic dipole resonance with the electric toroidal and magnetic quadrupole modes. Then the destructive interference between the Cartesian electric dipole and the electric toroidal mode suppresses the spherical electric dipole response and thus generates a nonradiating anapole mode, enabling ideal magnetic resonance scattering with overlapping magnetic dipole and quadrupole responses in the far field. Moreover, the wavelengths of magnetic resonance responses are tunable in the visible light range.}, archive = {J_PRA}, author = {Zhihui Liu and YaFei Li and Meng Wang and Mansha Li and Lexiang Zhao and Jianhong Rong and Peijie Wang and Ze Li}, doi = {10.1103/g6zw-dz42}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021502}, shortjournal = {Phys. Rev. A}, title = {Ideal magnetic-resonance scatterers in the visible range}, volume = {112}, year = {2025}, }
• (2025). Controlled displacement of stored light at room temperature. PRA, 112(2), L021501. (www)

  @article{ , abstract = {We report the demonstration of spatially translating a stored optical pulse at room temperature over distances exceeding one optical wavelength. By implementing an interferometric scheme, we further measure the average speed of this linear translation, thus harnessing a stopped-light experiment for a sensing application. This work extends the use of quantum memories beyond quantum communication and information contexts, opening a pathway to novel methods of velocity measurements with high sensitivity.}, archive = {J_PRA}, author = {Arash Ahmadi and Yağız Murat and Pei-Chen Kuan and Mustafa Gündoğan and Markus Krutzik}, doi = {10.1103/dckj-h2wd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021501}, shortjournal = {Phys. Rev. A}, title = {Controlled displacement of stored light at room temperature}, volume = {112}, year = {2025}, }
• (2025). Measuring the chern-simons invariant in quantum gases. PRA, 112(2), L021304. (www)

  @article{ , abstract = {The Chern-Simons (CS) invariant is a fundamental topological invariant describing the topological invariance of three-dimensional (3D) space based on the Chern-Simons field theory. To date, direct measurement of the CS invariant in a physical system remains elusive. Here, the CS invariant is experimentally measured by quenching a 2D optical Raman lattice with 1/2 spin in ultracold atoms. With a recently developed Bloch state tomography, we measure the expectation values of three Pauli matrices in 2D quasimomentum space plus 1D time , and then respectively extract the Berry curvature and the corresponding Berry connection. By integrating the product of these two quantities, we obtain the CS invariants near and 0, which are consistent with theoretical predictions. We also observe transitions among these values, which indicates the change of the topology of the quantum state in quantum dynamics.}, archive = {J_PRA}, author = {Chang-Rui Yi and Jinlong Yu and Huan Yuan and Xin Chen and Jia-Yu Guo and Jinyi Zhang and Shuai Chen and Jian-Wei Pan}, doi = {10.1103/7wkb-lxg9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021304}, shortjournal = {Phys. Rev. A}, title = {Measuring the chern-simons invariant in quantum gases}, volume = {112}, year = {2025}, }
• (2025). Anomalous dispersion of shear waves in dipolar supersolids. PRA, 112(2), L021303. (www)

  @article{ , abstract = {Dipolar supersolids—quantum states that are simultaneously superfluid and solid—have had their superfluid nature rigorously tested, while their solid nature remain uncharted. Arguably, the defining characteristic of a solid is the existence of elastic shear waves. In this work we investigate transverse wave packet propagation in dipolar supersolids with triangular and honeycomb structure. Remarkably, the honeycomb supersolid displays anomalous dispersion, supporting waves traveling faster than the transverse speed of sound. While the distinction between anomalous and normal dispersion appears subtle, it has a profound influence on both the transport and scattering properties. For both supersolid phases, we calculate the shear modulus, a key parameter that quantifies the material's rigidity. Our findings are pertinent to current experimental efforts scrutinizing the fundamental properties of supersolids.}, archive = {J_PRA}, author = {P. Senarath Yapa and T. Bland}, doi = {10.1103/xz57-52ft}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021303}, shortjournal = {Phys. Rev. A}, title = {Anomalous dispersion of shear waves in dipolar supersolids}, volume = {112}, year = {2025}, }
• (2025). Cooling a strongly interacting quantum gas by interaction modulation. PRA, 112(2), L021302. (www)

  @article{ , abstract = {We present a cooling method for a strongly interacting trapped quantum gas. By applying a magnetic-field modulation with frequencies close to the binding energy of a molecular bound state we selectively remove dimers with high kinetic energy from the sample. We demonstrate cooling of the sample over a wide range of interaction strengths and measure a high cooling efficiency of that exceeds all previous cooling near Feshbach resonances.}, archive = {J_PRA}, author = {D. Eberz and A. Kell and M. Breyer and M. Köhl}, doi = {10.1103/rvt9-hkll}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021302}, shortjournal = {Phys. Rev. A}, title = {Cooling a strongly interacting quantum gas by interaction modulation}, volume = {112}, year = {2025}, }
• (2025). Mitigating higher-band heating in floquet-hubbard lattices via two-tone driving. PRA, 112(2), L021301. (www)

  @article{ , abstract = {Multiphoton resonances to high-lying energy levels represent an unavoidable source of Floquet heating in strongly driven quantum systems. In this work, we extend the recently developed two-tone approach of “canceling” multiphoton resonances to shaken lattices in the Hubbard regime. Our experiments show that even for strong lattice shaking, the inclusion of a weak second drive leads to cancellation of multiphoton heating resonances. Surprisingly, the optimal canceling amplitude depends on the Hubbard interaction strength , in qualitative agreement with exact diagonalization calculations. Our results call for novel analytical approaches to capture the physics of strongly driven, strongly interacting many-body systems.}, archive = {J_PRA}, author = {Yuanning Chen and Zijie Zhu and Konrad Viebahn}, doi = {10.1103/tzg7-v7nh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021301}, shortjournal = {Phys. Rev. A}, title = {Mitigating higher-band heating in floquet-hubbard lattices via two-tone driving}, volume = {112}, year = {2025}, }
• (2025). Manipulating intracluster ion-molecule reactions in the ethylene dimer via femtosecond-laser intensity. PRA, 112(2), L021101. (www)

  @article{ , abstract = {Manipulating intracluster ion-molecule reactions via the control of vibrational excitation states of the parent cluster ion holds significant promise. Herein, we studied the effect of vibrational excitation on intracluster ion-molecule reactions within the ethylene dimer ion focusing on the formation of , and ions, utilizing femtosecond laser pulses and ab initio calculations. Via coincident photoelectron and ion detection, we reconstructed the initial vibrational excitation state population (IVP) of the parent ion and found a correlation between the IVP and product formation. Our study shows that the branching ratios for , and ions are dominated by low, medium, and high vibrational states, respectively, and there is a clear competition among them. Further analysis confirmed that laser intensity affects the IVP, which determines the yield of each decay channel. Our study establishes a direct link between IVP and product distribution in intracluster ion-molecule reactions and demonstrates the potential to steer reaction outcomes by varying laser field intensity, which opens avenues to the tailored control of reactions in various intracluster systems.}, archive = {J_PRA}, author = {Chenyu Tao and Chen Liang and Shuncheng Yan and Jianting Lei and Xuan Yu and Tao Yang and Dongmei Zhao and Ziqi Zhang and Shaofeng Zhang and Xinwen Ma}, doi = {10.1103/l2rl-dyds}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L021101}, shortjournal = {Phys. Rev. A}, title = {Manipulating intracluster ion-molecule reactions in the ethylene dimer via femtosecond-laser intensity}, volume = {112}, year = {2025}, }
• (2025). Thermal resonance-enhanced transparency in room-temperature rydberg gases. PRA, 112(2), L020801. (www)

  @article{ , abstract = {We report the enhanced optical transmission in the coherent, off-resonant excitation of Rydberg atom gases at room temperature via a two-photon process. Here thermal resonance-enhanced transparency (TRET) is induced when the detuning of the two lasers is adjusted to compensate the atomic thermal-motion-induced energy shifts, i.e., single- and two-photon Doppler shifts. We show that the atomic velocity is mapped into the transmission of the probe fields, which can be altered by independently and selectively exciting different velocity groups through sweeping the detuning. The maximal transmission in TRET is about 8 times higher than that under electromagnetically induced transparency (EIT). Utilizing the TRET effect, we enhance the sensitivity of a Rydberg microwave receiver to be 28.7 nV cm − 1 Hz − 1 / 2 , ultimately reaching a factor of 2.1 of the EIT case. When atoms of separate velocity groups are excited simultaneously by multiple laser sets of different detuning, the receiver sensitivity increases with the number of laser sets. Our study paves the way to exploit light-matter interaction via the TRET, and contributes to current efforts in developing quantum sensing, primary gas thermometry, and wireless communication with room-temperature atomic gases.}, archive = {J_PRA}, author = {Jinlian Hu and Yuechun Jiao and Yuwen Yin and Cheng Lu and Jingxu Bai and Suotang Jia and Weibin Li and Zhengyang Bai and Jianming Zhao}, doi = {10.1103/yrs8-jg4r}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L020801}, shortjournal = {Phys. Rev. A}, title = {Thermal resonance-enhanced transparency in room-temperature rydberg gases}, volume = {112}, year = {2025}, }
• (2025). Optimized noise-resilient surface code teleportation interfaces. PRA, 112(2), L020403. (www)

  @article{ , abstract = {Connecting two surface-code patches may require significantly higher noise at the interface. We show, via circuit-level simulations under a depolarizing noise model with idle errors, that surface codes remain fault tolerant despite substantially elevated interface error rates. Specifically, we compare three strategies—direct noisy links, gate teleportation, and a CAT-state gadget—for both rotated and unrotated surface codes, and demonstrate that careful design can mitigate hook errors in each case so that the full code distance is preserved for both and . Although these methods differ in space and time overhead and performance, each offers a viable route to modular surface-code architectures. Our results, obtained with stim and pymatching , confirm that high-noise interfaces can be integrated fault-tolerantly without compromising the code's essential properties, indicating that fault-tolerant scaling of error-corrected modular devices is within reach with current technology.}, archive = {J_PRA}, author = {Mohamed A. Shalby and Renyu Wang and Denis Sedov and Leonid P. Pryadko}, doi = {10.1103/xqrn-wdw1}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L020403}, shortjournal = {Phys. Rev. A}, title = {Optimized noise-resilient surface code teleportation interfaces}, volume = {112}, year = {2025}, }
• (2025). Quantum contextuality of spin-1 massive particles. PRA, 112(2), L020402. (www)

  @article{ , abstract = {Contextuality is a fundamental property of quantum mechanics. Contrary to entanglement, which can only exist in composite systems, contextuality is also present for single entities. The case of a three-level system is of particular interest because—in agreement with the Bell-Kochen-Specker theorem—it is the simplest in which quantum contextuality is necessarily present. We verify that the polarizations of spin-1 massive particles produced at collider experiments indeed exhibit contextuality. To this purpose we consider W gauge bosons produced in top-quark decays, J / ψ and K * ( 892 ) 0 mesons created in B -meson decays, and ϕ mesons resulting from χ c 0 charmonium decays, making use of the data collected and analyzed by the ATLAS, LHCb, and BESIII collaborations, respectively. The polarizations of all these four particles show contextuality with a significance of more than 5 σ .}, archive = {J_PRA}, author = {M. Fabbrichesi and R. Floreanini and E. Gabrielli and L. Marzola}, doi = {10.1103/9bvc-2w4m}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L020402}, shortjournal = {Phys. Rev. A}, title = {Quantum contextuality of spin-1 massive particles}, volume = {112}, year = {2025}, }
• (2025). Quadratic spin-phonon coupling and bipolarons in trapped ions. PRA, 112(2), L020401. (www)

  @article{ , abstract = {We consider the quantum simulation of quadratic spin-phonon coupling in a crystal of trapped ions. The coupling is implemented using tightly focused optical tweezers on each ion that change the local trapping potential in a state-dependent way. By encoding spins in the internal states of the ions and adding a tunneling term via Mølmer-Sørensen-type interactions, we calculate the emergence of mobile bipolarons driven by the zero-point energy of the ion crystal phonons. We show that thermal occupation may pin the bipolarons for ion crystals at finite temperature. Our scheme can be used to study and illustrate the emergence of mobile bipolarons as a function of temperature.}, archive = {J_PRA}, author = {L. P. H. Gallagher and M. Mazzanti and Z. E. D. Ackerman and R. J. C. Spreeuw and A. Safavi-Naini and R. Gerritsma}, doi = {10.1103/mcl9-27tj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {L020401}, shortjournal = {Phys. Rev. A}, title = {Quadratic spin-phonon coupling and bipolarons in trapped ions}, volume = {112}, year = {2025}, }
• (2025). Hybrid measurement scheme for generating non-gaussian spin states. PRA, 112(2), 023715. (www)

  @article{ , abstract = {We present a protocol for generating nonclassical states of atomic spin ensembles through the backaction induced by a hybrid measurement of light that is entangled with atoms, combining both homodyne and single-photon detection. In phase I of the protocol we create a spin-squeezed state by measuring the light's polarization rotation due to the Faraday effect in a balanced polarimeter, equivalent to a homodyne measurement. In phase II we send a second probe beam through the sample and detect single photons scattered into the signal mode. Before doing so, we rotate the uncertainty bubble to increase the projection fluctuations of the measured spin component. This increases the coupling strength between the atoms and photons and thus the rate of scattering of single photons into the signal mode. In the ideal case, the result is a squeezed Dicke state, with substantial quantum advantage for sensing spin rotations. We benchmark the protocol's utility in the presence of inevitable decoherence due to optical pumping using the Fisher information as a measure of quantum advantage. We show that in the presence of decoherence, the quantum Fisher information associated with the non-Gaussian mixed state we prepare is substantially larger than the classical Fisher information obtained from the standard measurement of spin rotations. We deduce a measurement basis that is close to optimal for achieving the quantum Cramér-Rao bound in the presence of decoherence.}, archive = {J_PRA}, author = {Andrew Kolmer Forbes and Ivan H. Deutsch}, doi = {10.1103/t238-tkhm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023715}, shortjournal = {Phys. Rev. A}, title = {Hybrid measurement scheme for generating non-gaussian spin states}, volume = {112}, year = {2025}, }
• (2025). Collectively enhanced ground-state cooling in subwavelength atomic arrays. PRA, 112(2), 023714. (www)

  @article{ , abstract = {Subwavelength atomic arrays feature strong light-induced dipole-dipole interactions, resulting in subradiant collective resonances characterized by narrowed linewidths. In this work, we present a sideband cooling scheme for atoms trapped in subwavelength arrays that utilizes these narrow collective resonances. Working in the Lamb-Dicke regime, we derive an effective master equation for the atomic motion by adiabatically eliminating the internal degrees of freedom of the atoms and validate its prediction with numerical simulations of the full system. Our results demonstrate that subradiant resonances enable the cooling of ensembles of atoms to temperatures lower than those achievable without dipole interactions, provided the atoms have different trap frequencies. Remarkably, narrow collective resonances can be sideband-resolved even when the individual atomic transition is not. In such scenarios, ground-state cooling becomes feasible solely due to light-induced dipole-dipole interactions. This approach could be utilized for future quantum technologies based on dense ensembles of emitters, and paves the way towards harnessing many-body cooperative decay for enhanced motional control.}, archive = {J_PRA}, author = {Oriol Rubies-Bigorda and Raphael Holzinger and Ana Asenjo-Garcia and Oriol Romero-Isart and Helmut Ritsch and Stefan Ostermann and Carlos Gonzalez-Ballestero and Susanne F. Yelin and Cosimo C. Rusconi}, doi = {10.1103/bhwv-ndtj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023714}, shortjournal = {Phys. Rev. A}, title = {Collectively enhanced ground-state cooling in subwavelength atomic arrays}, volume = {112}, year = {2025}, }
• (2025). Dispersive regime of multiphoton qubit-oscillator interactions. PRA, 112(2), 023713. (www)

  @article{ , abstract = {The dispersive regime of n -photon qubit-oscillator interactions is analyzed using Schrieffer-Wolff perturbation theory. Effective Hamiltonians are derived up to the second order in the perturbation parameters. These effective descriptions reveal higher-order qubit-oscillator cross-Kerr and oscillator self-Kerr terms. The cross-Kerr term combines a qubit Pauli operator with an n -degree polynomial in the oscillator photon number operator, while the self-Kerr term is an ( n − 1 ) -degree polynomial in the oscillator photon number operator. In addition to the higher-order Kerr terms, a qubit-conditional 2 n -photon squeezing term appears in the effective non-rotating-wave-approximation Hamiltonian. Furthermore, perturbation theory is applied to the case of multiple qubits coupled to a shared oscillator. A photon-number-dependent qubit-qubit interaction emerges in this case, which can be leveraged to tune the effective multiqubit system parameters using the oscillator state. Results for the converse setup of multiple oscillators and a single qubit are also derived. In this case, a qubit-conditional oscillator-oscillator nonlinear interaction is found. The spectral instabilities plaguing multiphoton qubit-oscillator models are carefully treated by introducing stabilizing higher-order terms in the Hamiltonian. The stabilizing terms preserve low-photon subspaces, avoid negative infinite energies, and facilitate reliable numerical calculations used to validate analytical predictions. The effective descriptions developed here offer a simple and intuitive physical picture of dispersive multiphoton qubit-oscillator interactions that can aid in the design of implementations harnessing various nonlinear effects.}, archive = {J_PRA}, author = {Mohammad Ayyash and Sahel Ashhab}, doi = {10.1103/hrc2-7nqg}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023713}, shortjournal = {Phys. Rev. A}, title = {Dispersive regime of multiphoton qubit-oscillator interactions}, volume = {112}, year = {2025}, }
• (2025). Sub-planck structures and phase-space sensitivity of circular states. PRA, 112(2), 023712. (www)

  @article{ , abstract = {The superposition of coherent states has attracted extensive and intensive attention, exemplified by intriguing instances such as Schrödinger cat states and compass states. In this study, we derive analytical expressions of the Wigner functions and phase-space displacement sensitivity of circular states, which are superpositions of coherent states distributed equidistantly on a circle. The visualization of these phase-space functions exhibits fascinating quantum kaleidoscopic patterns, and intuitively reveals the internal coherence and symmetric structure in these states. Moreover, we unveil the inherent sub-Planck structure of circular states in terms of the zeros of sensitivity functions.}, archive = {J_PRA}, author = {Siting Tang and Shunlong Luo and Yue Zhang}, doi = {10.1103/llhr-hn2y}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023712}, shortjournal = {Phys. Rev. A}, title = {Sub-planck structures and phase-space sensitivity of circular states}, volume = {112}, year = {2025}, }
• (2025). Quantum excitation transfer in an artificial photosynthetic light-harvesting system. PRA, 112(2), 023711. (www)

  @article{ , abstract = {We analytically derive transfer probabilities and efficiencies for an artificial light-harvesting photosynthetic system, which consists of a ring coupled to a central acceptor. For an incident photon pair, we find near-perfect single excitation transfer efficiency with negligible double excitation transfer in the weak-coupling regime. In the strong-coupling regime, single excitation transfer efficiency was greater than , while the double excitation efficiency was approximately . We have found that the three main factors which determine high transfer efficiencies are large acceptor probabilities, long acceptor decay times, and strong photon-ring coupling. A possible implementation of the theoretical framework to bio-inspired solar energy devices is also discussed.}, archive = {J_PRA}, author = {Stephon Alexander and Roger Andrews and Oliver Fox and Sarben Sarkar}, doi = {10.1103/xyjw-lrf4}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023711}, shortjournal = {Phys. Rev. A}, title = {Quantum excitation transfer in an artificial photosynthetic light-harvesting system}, volume = {112}, year = {2025}, }
• (2025). Experimental noiseless quantum amplification of coherent states of light by two-photon addition and subtraction. PRA, 112(2), 023710. (www)

  @article{ , abstract = {Noiseless quantum amplifiers are probabilistic quantum devices that enhance the amplitude of coherent states without adding any noise, which has far reaching applications in quantum optics and quantum information processing. Here, we report on an experimental implementation of an advanced noiseless quantum amplifier for coherent states of light that is based on the conditional addition of two photons followed by the conditional subtraction of two photons. We comprehensively characterize the noiselessly amplified coherent states via quantum state tomography and analyze the amplification gain and noise properties of the amplifier. We observe very good agreement between the experiment and theoretical predictions. Our work reveals that sequences of multiple photon additions and subtractions represent an efficient and experimentally feasible alternative to multiplexing that was originally proposed to boost the performance of noiseless quantum amplifiers. Beyond noiseless quantum amplification, our experiment represents a significant step forward towards engineering complex quantum operations on traveling light beams by coherent combinations of various sequences of multiphoton additions and subtractions.}, archive = {J_PRA}, author = {Michal Neset and Jiří Fadrný and Martin Bielak and Jaromír Fiurášek and Miroslav Ježek and Jan Bílek}, doi = {10.1103/k52v-hzcr}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023710}, shortjournal = {Phys. Rev. A}, title = {Experimental noiseless quantum amplification of coherent states of light by two-photon addition and subtraction}, volume = {112}, year = {2025}, }
• (2025). Magnon cat states in a cavity-magnon-qubit system via two-magnon driving and dissipation. PRA, 112(2), 023709. (www)

  @article{ , abstract = {We propose an efficient method for dissipative generation of magnonic cat states in a cavity-magnon-qubit hybrid system by exploiting a two-magnon driving and dissipation mechanism. When both the magnon and qubit are driven, a coherent nonlinear two-magnon interaction is induced, wherein the qubit and the magnon mode exchange energy through magnon pairs. The dissipation of the qubit is exploited to steer the magnon mode into a quantum superposition of distinct coherent states, where the magnon mode evolves into either an even or odd cat state, depending on the parity of the magnon initial state. For the case where the magnon initial state is a superposition state, e.g., of | 0 〉 and | 1 〉 , the magnon mode can evolve into a weighted mixture of the even and odd cat states. We also find that magnon squeezed states may emerge during the short-time evolution, showcasing the capability of our mechanism in preparing diverse magnon nonclassical states. Magnonic cat and squeezed states are macroscopic quantum states and have applications in macroscopic quantum studies and quantum sensing, e.g., in the dark-matter search using ferromagnetic axion haloscopes.}, archive = {J_PRA}, author = {Gang Liu and Gen Li and Huatang Tan and Jie Li}, doi = {10.1103/zhgm-p3ss}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023709}, shortjournal = {Phys. Rev. A}, title = {Magnon cat states in a cavity-magnon-qubit system via two-magnon driving and dissipation}, volume = {112}, year = {2025}, }
• (2025). Experimental observation of subabsorption. PRA, 112(2), 023708. (www)

  @article{ , abstract = {We predict and experimentally demonstrate a type of collective (cooperative) coupling effect where a disordered atomic ensemble absorbs light with a rise time longer (i.e., at a rate slower) than what is dictated by single-atom physics. This effect, which we name subabsorption, can be viewed as the absorptive analog of subradiance. The experiment is performed using a dilute ensemble of ultracold Rb 87 atoms with a low optical depth, and time resolving the absorption of a weak (tens of photons per pulse) resonant laser beam. In this dilute regime, the collective interaction relies on establishing dipole-dipole correlations over many atoms; i.e., the interaction is not dominated by the nearest neighbors. As a result, subabsorption is highly susceptible to motional dephasing: even a temperature increase of 60 µ K is enough to completely extinguish the subabsorption signal. We also present a theoretical model whose results are in reasonable agreement with the experimental observations. The model uses the density-dependent dephasing rate of the long-range dipole-dipole correlations as a single adjustable parameter. Experiment-theory comparison indicates a dephasing coefficient of β / 2 π = 4.9 × 10 − 5 Hz cm 3 , which is more than two orders of magnitude larger than the known dipole-dipole line broadening coefficient in Rb 87 .}, archive = {J_PRA}, author = {D. C. Gold and U. Saglam and S. Carpenter and A. Yadav and M. Beede and T. G. Walker and M. Saffman and D. D. Yavuz}, doi = {10.1103/6xnl-814s}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023708}, shortjournal = {Phys. Rev. A}, title = {Experimental observation of subabsorption}, volume = {112}, year = {2025}, }
• (2025). Controllable single-photon scattering via coupling of a driven Λ system with a topological waveguide. PRA, 112(2), 023707. (www)

  @article{ , abstract = {We investigate the coherent single-photon scattering process in a topological waveguide coupled to a driven three-level atom in the configuration, where two ground states are optically connected to a common excited state. We derive an analytical expression for transmittance by using the scattering formalism for three distinct sublattice sites (A, B, and AB) of the waveguide, which couple to the system. We have demonstrated that the system's response is topology independent for A and B sublattice-site coupling and becomes topology dependent for AB sublattice-site coupling. In a weak-control-field regime, the system behaves as a perfect mirror in all of these configurations. Upon control field strength enhancement, the transmission spectrum evolves from Electromagnetically Induced Transparency to Autler-Townes splitting in A and B sublattice-site coupling. The manipulation of transmission from opaque to transparent holds the key mechanism of a single-photon switching. Furthermore, the topology-dependent AB sublattice configuration allows multiple-path-induced quantum interference, resulting in the sharper Fano line shape. This topological Fano resonance is not only tunable via the control field and coupling strength but also robust against structural imperfections due to the topological nature of the waveguide. These combined features such as tunability and topological protection make our system a promising platform for next-generation quantum technologies, including single-photon switches, high-resolution sensors, and communication devices.}, archive = {J_PRA}, author = {Gunjan Yadav and Madan Mohan Mahana and Tarak Nath Dey}, doi = {10.1103/dkbz-thfh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023707}, shortjournal = {Phys. Rev. A}, title = {Controllable single-photon scattering via coupling of a driven Λ system with a topological waveguide}, volume = {112}, year = {2025}, }
• (2025). Developing a practical model for noise in entangled-photon detection. PRA, 112(2), 023706. (www)

  @article{ , abstract = {We develop a comprehensive model for the effective two-photon density matrix produced by a parametric source of entangled-photon pairs under a variety of detector configurations commonly seen in a laboratory setting: two and four photon-number-resolving (PNR) and threshold detectors. We derive the probability of obtaining a single coincidence assuming Poisson-distributed photon pairs, nonunit detection efficiency, and dark counts; obtain the effective density matrix; and use this quantity to compute the fidelity of this state with respect to the maximally entangled ideal. The four-detector PNR case admits an analytic result valid for any combination of parameters, while all other cases leverage low-efficiency approximations to arrive at closed-form expressions. Interestingly, our model reveals appreciable fidelity improvements from four detectors as opposed to two but minimal advantages for PNR over threshold detectors in the regimes explored. Overall, our work provides a valuable tool for the quantitative design of two-photon experiments under realistic nonidealities.}, archive = {J_PRA}, author = {Taman Truong and Christian Arenz and Joseph M. Lukens}, doi = {10.1103/64lg-dwnm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023706}, shortjournal = {Phys. Rev. A}, title = {Developing a practical model for noise in entangled-photon detection}, volume = {112}, year = {2025}, }
• (2025). Hidden quantum correlations in cavity-based quantum optics. PRA, 112(2), 023705. (www)

  @article{ , abstract = {In multimode optical systems, the spectral covariance matrix encodes all the information about quantum correlations between the quadratures of Gaussian states. Recent research has revealed that, in scenarios that are more common than previously thought, part of these correlations remains inaccessible to standard homodyne detection schemes. Formally, this effect can be attributed to a nonreal spectral covariance matrix. In this work, we provide a systematic framework and explicit criteria for identifying experimental configurations leading to such a behavior. This study will facilitate the proper exploitation and optimal engineering of continuous-variable quantum resources.}, archive = {J_PRA}, author = {Bakhao Dioum and Virginia D'Auria and Giuseppe Patera}, doi = {10.1103/8sjn-rb9b}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023705}, shortjournal = {Phys. Rev. A}, title = {Hidden quantum correlations in cavity-based quantum optics}, volume = {112}, year = {2025}, }
• (2025). Dissipative superradiant phase transitions and multicriticality induced by two-mode squeezing. PRA, 112(2), 023704. (www)

  @article{ , abstract = {We investigate dissipative superradiant phase transitions and multicritical effects in an open dual-coupling Jaynes-Cummings model, where two cavity fields are simultaneously coupled to a single atom. The cavity fields are squeezed via a nondegenerate optical parametric amplification process. We show that the interplay between interactions, two-mode squeezing, and dissipation leads to rich critical behaviors, including both first-order and second-order superradiant phase transitions. The critical points are governed by the detunings between atomic (or photonic) frequencies and external pump field. Thus, these transitions can occur in the strong-coupling regime and can be easily controlled by tuning the external pump field. Utilizing the mean-field theory that explicitly neglects quantum fluctuations, we determine the phase-transition boundaries in the steady state. Additionally, we employ a full quantum description of the lowest-energy Hamiltonian in the large atomic detuning limit to analyze the quantum fluctuations. Notably, the phase diagram features two tricritical points where the critical lines of first-order and second-order phase transitions meet. Furthermore, when the two coupling pathways have specific coupling strengths, increasing the external pump strength can drive the system from the normal phase to the superradiant phase. Our work offers new insights into dissipative phase transitions and multicriticality, with potential applications in quantum sensing and information processing.}, archive = {J_PRA}, author = {Han Song and Gui-Lei Zhu and Xiaoguang Wang}, doi = {10.1103/4wkp-rtt4}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023704}, shortjournal = {Phys. Rev. A}, title = {Dissipative superradiant phase transitions and multicriticality induced by two-mode squeezing}, volume = {112}, year = {2025}, }
• (2025). Time-resolved second-order autocorrelation function of parametric down-conversion. PRA, 112(2), 023703. (www)

  @article{ , abstract = {We study a possibility of measuring the time-resolved second-order autocorrelation function of one of two beams generated in type-II parametric down-conversion by means of temporal magnification of this beam, bringing its correlation time from the picosecond to the nanosecond scale, which can be resolved by modern photodetectors. We show that such a measurement enables one to infer directly the degree of global coherence of that beam, which is linked by a simple relation to the number of modes characterizing the entanglement between the two generated beams. We illustrate the proposed method by an example of photon pairs generated in a periodically poled potassium titanyl phosphate (KTP) crystal with a symmetric group velocity matching for various durations of the pump pulse, resulting in different numbers of modes. Our theoretical model also shows that the magnified double-heralded autocorrelation function of one beam exhibits a local maximum around zero delay time, corresponding to photon bunching at a short time scale.}, archive = {J_PRA}, author = {Dmitri B. Horoshko and Shivang Srivastava and Filip Sośnicki and Michał Mikołajczyk and Michał Karpiński and Benjamin Brecht and Mikhail I. Kolobov}, doi = {10.1103/7ckm-tm3r}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023703}, shortjournal = {Phys. Rev. A}, title = {Time-resolved second-order autocorrelation function of parametric down-conversion}, volume = {112}, year = {2025}, }
• (2025). Husimi phase distribution in non-gaussian operations. PRA, 112(2), 023702. (www)

  @article{ , abstract = {The Husimi phase distribution, an experimentally measurable quantity, is investigated for single-mode and two-mode squeezed vacuum states. The analysis highlights that non-Gaussian operations, i.e., photon subtraction (PS), photon addition (PA), and photon catalysis (PC), are effective tools for localizing phase distribution and enhancing phase robustness in the presence of noise, while PC results in comparatively slower delocalization accompanied by more intricate phase features. The work highlights the perspective that the combined effects of squeezing, beam-splitter transmittance, and environmental interactions must be carefully considered when quantum state engineering protocols are designed, and phase properties provide a valuable insight into this endeavor.}, archive = {J_PRA}, author = {Ramniwas Meena and Chandan Kumar and Subhashish Banerjee}, doi = {10.1103/2bkt-vr3p}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023702}, shortjournal = {Phys. Rev. A}, title = {Husimi phase distribution in non-gaussian operations}, volume = {112}, year = {2025}, }
• (2025). Parity-dependent photon-subtracted two-mode squeezed vacuum states. PRA, 112(2), 023701. (www)

  @article{ , abstract = {The removal of photons from certain quantum light sources produces so-called photon-subtracted states with enhanced mean photon numbers and intricate quantum correlations. Here, we propose an integrated photon-subtraction scheme that, contrary to previous approaches, is not heralded by photon correlation (coincidence) measurements. In this way, our technique exploits the “Welcher Weg” (“which way”) information problem, as it does not provide information about the modes from which the subtracted photons emanated. We show that this lack of information allows the generation of multiphoton states endowed with rich quantum correlations that strongly depend on the parity, evenness or oddness, of the number of subtracted photons.}, archive = {J_PRA}, author = {Ananga Mohan Datta and Andrea Blanco-Redondo and Kurt Busch and Armando Perez-Leija}, doi = {10.1103/4x83-y4bg}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023701}, shortjournal = {Phys. Rev. A}, title = {Parity-dependent photon-subtracted two-mode squeezed vacuum states}, volume = {112}, year = {2025}, }
• (2025). Enhanced-resolution chirped-pulse interferometry. PRA, 112(2), 023525. (www)

  @article{ , abstract = {Chirped-pulse interferometry (CPI) is a classical low-coherence interferometry technique with automatic dispersion cancellation and improved resolution over white-light interference. Previous work showed that CPI with linearly chirped Gaussian laser pulses achieves a improvement in resolution over conventional white-light interferometry, but this is less than the factor of 2 improvement exhibited by a comparable quantum technique. In this work, we show how a particular class of nonlinearly chirped laser pulses can meet, and even exceed, the factor of 2 improvement in resolution. This enhanced-resolution CPI removes the resolution advantage of quantum interferometers in dispersion-cancelled interferometry.}, archive = {J_PRA}, author = {M. M. Bérubé and M. D. Mazurek and K. J. Resch}, doi = {10.1103/5vd5-srqg}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023525}, shortjournal = {Phys. Rev. A}, title = {Enhanced-resolution chirped-pulse interferometry}, volume = {112}, year = {2025}, }
• (2025). Classical optical realization of a joint weak measurement through optical beam shifts. PRA, 112(2), 023524. (www)

  @article{ , abstract = {Quantum weak measurements became extremely popular in classical optics to amplify small optical signals for fundamental interests and potential applications. Later, as a more general extension, joint weak measurement has been proposed to extract the weak value from a joint quantum measurement. However, unlike traditional weak measurements, the detection of a joint weak value in the realm of classical optics remains less explored. Here, using the polarization-dependent longitudinal and transverse optical beam shift as a platform, we experimentally realize a classical optical analog of the quantum joint weak measurement. Polarization states are cleverly pre- and postselected, and different single and joint canonical position-momentum observables of the beam are experimentally extracted and subsequently analyzed for successful detection of the complex joint weak value. We envision that this work will find usefulness for gaining fundamental insights on quantum measurements and to tackle analogous problems in optics.}, archive = {J_PRA}, author = {Ritwik Dhara and Shyamal Guchhait and Meghna Sarkar and Swain Ashutosh and Niladri Modak and Nirmalya Ghosh}, doi = {10.1103/3p8k-b8t8}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023524}, shortjournal = {Phys. Rev. A}, title = {Classical optical realization of a joint weak measurement through optical beam shifts}, volume = {112}, year = {2025}, }
• (2025). Optomechanically induced transparency in a laguerre-gaussian vortex cavity system assisted by a four-wave-mixing atomic ensemble. PRA, 112(2), 023523. (www)

  @article{ , abstract = {We investigate the steady-state optical response of a Laguerre-Gaussian vortex cavity system integrated with cold atoms featuring a double- energy level structure. Within this hybrid system, the atoms are driven by a cavity mode and three coherent vortex beams, each carrying independent orbital angular momentum. We first check the steady-state output spectrum of the hybrid system in the passive (active) case [without (with) external cavity driving]. Our findings reveal that the optomechanically induced transparency spectrum is modulated by the orbital angular momentum difference from the atomic component throughout the four-wave-mixing process. The resulting loop phase ( ) can achieve a switching effect on the absorption and gain behavior of the hybrid system for the probe beam. Additionally, the group delay, indicative of fast or slow light phenomena, is also tuned by . We further display how the atomic orbital angular momentum modulates the periodicity of the output spot pattern in the hybrid system. This research provides valuable insights into the modulation of optical responses in Laguerre-Gaussian vortex cavity systems.}, archive = {J_PRA}, author = {Yue-Tong Hao and Yi-Mou Liu}, doi = {10.1103/5ngk-lkqm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023523}, shortjournal = {Phys. Rev. A}, title = {Optomechanically induced transparency in a laguerre-gaussian vortex cavity system assisted by a four-wave-mixing atomic ensemble}, volume = {112}, year = {2025}, }
• (2025). Modulation instability and frequency-comb generation in hybrid quadratic-cubic resonators with spectral filtering. PRA, 112(2), 023522. (www)

  @article{ , abstract = {We present an analytical and numerical investigation into the phenomenon of filter-induced modulation instability in passive hybrid optical resonators exhibiting quadratic and cubic nonlinearity. We show that asymmetric spectral losses, with respect to the continuous-wave solution frequency, can trigger sideband amplification in the normal dispersion regime. We calculate the parametric gain and demonstrate the associated pattern formation process. We furthermore show how this parametric process can be exploited to generate optical frequency combs with a tunable repetition rate.}, archive = {J_PRA}, author = {Minji Shi and Nicolas Englebert and François Leo and Dmitry V. Skryabin and Auro M. Perego}, doi = {10.1103/3byt-r77p}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023522}, shortjournal = {Phys. Rev. A}, title = {Modulation instability and frequency-comb generation in hybrid quadratic-cubic resonators with spectral filtering}, volume = {112}, year = {2025}, }
• (2025). Critical disorder inflating thermal relaxation in nonlinear multimoded systems. PRA, 112(2), 023521. (www)

  @article{ , abstract = {We establish a connection between the thermal relaxation rate of optical beams in weakly nonlinear multimoded systems and the spatial correlations among the system's linear supermodes. We implement this methodology for tailored network arrangements supporting various spatial mode profiles. For critical disorder configurations giving rise to metal-insulator transitions, fractal supermodes extremize the correlations, inflating the relaxation rates. Our results inform a design of the physical platforms (their topology, disorder, etc.) supporting targeted relaxation rates.}, archive = {J_PRA}, author = {Emily Kabat and Alba Y. Ramos and Lucas J. Fernández-Alcázar and Tsampikos Kottos}, doi = {10.1103/xqyx-g3tn}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023521}, shortjournal = {Phys. Rev. A}, title = {Critical disorder inflating thermal relaxation in nonlinear multimoded systems}, volume = {112}, year = {2025}, }
• (2025). Full analytical description of ultrashort dissipative solitons in resonant media. PRA, 112(2), 023520. (www)

  @article{ , abstract = {We develop a theoretical approach for the full analytical description of dissipative optical solitons, which takes into account all relaxation processes in the medium. Most analytical solutions available today for ultrashort optical solitons are obtained upon neglecting a number of relaxation terms in the governing equations for the medium response. The suggested method is based on finding explicit analytical expressions for the extended soliton tails distant enough from the soliton central part, when taking into consideration all relaxation processes. These soliton tails can be described by the linearized equations for the medium response both at the soliton leading and trailing edges. Afterwards, the analytical expressions for the soliton tails and its central part can be matched to yield the full analytical description of ultrashort dissipative solitons with all relaxation processes in the resonant medium properly treated. The proposed approach is demonstrated for ultrashort dissipative solitons in a resonant medium consisting either of only amplifying resonant two-level centers or of a mixture of amplifying and absorbing two-level centers.}, archive = {J_PRA}, author = {Anton Pakhomov}, doi = {10.1103/vv81-sp5k}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023520}, shortjournal = {Phys. Rev. A}, title = {Full analytical description of ultrashort dissipative solitons in resonant media}, volume = {112}, year = {2025}, }
• (2025). Terahertz waveform shifting and broadening along a dc-electric-field-biased femtosecond laser plasma filament. PRA, 112(2), 023519. (www)

  @article{ , abstract = {Longitudinally resolved terahertz radiations from tip-electrodes dc-electric-field-biased laser filament were generated. The terahertz waveform undergoes a shifting of 0.43 ps and broadening of 0.46 ps in the time domain during its propagation in the 40-mm-long filament. Both experimental and numerical results have proved that the propagation of THz in a dc-biased filament waveguide lead to the terahertz waveform shifting and broadening.}, archive = {J_PRA}, author = {Juan Long and Tiejun Wang and Yaoxiang Liu and Yingxia Wei and Chaopeng Yang and Xianwang Li and Rao Adeel Un Nabi and Ying Xu and Yuxin Leng}, doi = {10.1103/55w8-m9jv}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023519}, shortjournal = {Phys. Rev. A}, title = {Terahertz waveform shifting and broadening along a dc-electric-field-biased femtosecond laser plasma filament}, volume = {112}, year = {2025}, }
• (2025). Photonic spin hall effect induced by collective strong coupling of molecular ensembles in a plasmonic nanocavity. PRA, 112(2), 023517. (www)

  @article{ , abstract = {We propose a molecular cavity optomechanical (MCOM) framework that exploits the collective vibrational modes of a molecular ensemble coupled to a plasmonic nanocavity. Our approach replaces traditional mechanical elements in cavity optomechanics with molecular vibrations, allowing optomechanically induced transparency (OMIT) to emerge even in regimes with ultralow optical quality factor ( Q ) that are typically inaccessible to standard cavity optomechanics. We observe that the OMIT window exhibits gain at very low Q factor and with a large number of molecular ensembles. Specifically, we demonstrate dynamic control of the photonic spin Hall effect (PSHE) by tuning the optical susceptibility through parameters such as molecular resonance, collective coupling strength, and the Q factor. Our method first computes the coefficients of the transverse electric (TE) and transverse magnetic (TM) components of reflected light using the Fresnel formula, demonstrating the transverse shift of reflected light from positive to negative at the Brewster angle. Our findings suggest that molecular ensembles are a viable platform for room-temperature nanophotonics, facilitating spin-controlled signal processing and quantum-enhanced sensing through integrated optomechanics and spin-orbit coupling.}, archive = {J_PRA}, author = {Akhtar Munir and Muhammad Jibran and Chunfang Wang}, doi = {10.1103/ztlg-j77l}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023517}, shortjournal = {Phys. Rev. A}, title = {Photonic spin hall effect induced by collective strong coupling of molecular ensembles in a plasmonic nanocavity}, volume = {112}, year = {2025}, }
• (2025). Long-wavelength spectral shift in an ultraviolet filament. PRA, 112(2), 023516. (www)

  @article{ , abstract = {Our experiments on focusing of ultraviolet , 0.2-mJ pulses into a cuvette filled with diatomic air or monatomic argon show similar spectral transformations regardless of the gas if the pressure is the same. The spectra experience broadening and the long-wavelength shift, which increases monotonically with the pressure and reaches 2 nm at 1 atm. This long-wavelength shift cannot be explained by instantaneous Kerr nonlinear response and multiphoton ionization as two additive contributions to the nonlinear refractive index. The simulations based on the 1D time-dependent Schrödinger equation reveal that the cubic nonlinearity is delayed by as with regard to the driving field. This intraperiod delay comparable with the field cycle shifts the polarization spectrum to longer wavelengths and can be obtained solely from the quantum-mechanical approach, which we uniquely applied to the description of ultraviolet femtosecond filamentation.}, archive = {J_PRA}, author = {D. E. Shipilo and N. R. Vrublevskaya and I. A. Nikolaeva and L. V. Seleznev and D. V. Pushkarev and G. E. Rizaev and M. V. Levus and A. A. Ionin and N. A. Panov and O. G. Kosareva}, doi = {10.1103/mgvk-wscf}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023516}, shortjournal = {Phys. Rev. A}, title = {Long-wavelength spectral shift in an ultraviolet filament}, volume = {112}, year = {2025}, }
• (2025). Optical force density and surface displacements in transparent dielectrics due to nonionizing sub-picosecond laser excitation. PRA, 112(2), 023515. (www)

  @article{ , abstract = {The optical force density acting in transparent dielectric media due to short laser excitation is theoretically analyzed. For typical laser pulses with picosecond duration, the momentum component of the optical force becomes of the same order of magnitude as the stress component, enhancing the overall optomechanical effects. Simulations of the optically induced surface displacements in fused silica glass are also presented. With careful choice of realistic simulation parameters, dispersive and nonlinear effects were shown to be suppressed and displacements of 50 pm were found for single-pulse excitation with 100-fs duration, where the momentum component of the force is dominant. A possibility of measuring these displacements with piezoelectric detection is also discussed, providing a way to attain spatiotemporal characterization of the optical momentum force in continuum media. Such a description would significantly advance our current knowledge of the behavior of optical forces, potentially contributing to more versatile optomechanical applications while also clarifying the ongoing Abraham-Minkowski fundamental problem on the momentum transferred by light.}, archive = {J_PRA}, author = {B. Anghinoni and L. C. Malacarne and G. V. B. Lukasievicz and B. Lendl and M. L. Baesso and N. G. C. Astrath}, doi = {10.1103/9lfj-vc1n}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023515}, shortjournal = {Phys. Rev. A}, title = {Optical force density and surface displacements in transparent dielectrics due to nonionizing sub-picosecond laser excitation}, volume = {112}, year = {2025}, }
• (2025). Real-time and high-precision optical time-delay estimation via weak measurement with double-edge filter. PRA, 112(2), 023514. (www)

  @article{ , abstract = {Optical time delays play a pivotal role in modern physics and practical applications. We propose and experimentally validate a weak measurement system with a double-edge filter, which enables the real-time, high-precision estimation of varying time delays, and the effective suppression of technical noise. In the experiment, the postselected probe light is processed by the double-edge filter, which is formed by a pair of fiber Bragg gratings positioned symmetrically about the center frequency of the probe light, and subsequently detected by photodetectors. The experimental results demonstrate a time-delay precision of 1.66 attoseconds (as) and real-time estimation capability. With a postselection angle of and the system operating within the most sensitive linear dynamic range, the precision can be further improved to as. The approach benefits from its high sensitivity and rapid detection, which shows great potential applications in real-time and high-precision time-delay measurements.}, archive = {J_PRA}, author = {Zhiqiang Liu and Hongjing Li and Qi Song and Jingzheng Huang and Guihua Zeng}, doi = {10.1103/6nlm-lj76}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023514}, shortjournal = {Phys. Rev. A}, title = {Real-time and high-precision optical time-delay estimation via weak measurement with double-edge filter}, volume = {112}, year = {2025}, }
• (2025). Selective enhancement of long trajectories in high-harmonic generation using a solid-gas dual-target configuration. PRA, 112(2), 023513. (www)

  @article{ , abstract = {A novel solid-gas dual-target configuration is employed to investigate the process of ultraviolet-assisted high harmonic generation (HHG) in gases. A distinct phenomenon of spectral splitting and bandwidth widening was observed in the experiment. The theoretical simulations are in good agreement with the experimental results, confirming the selective enhancement of long trajectory contributions in HHG under this experimental configuration. Once a delay control element is added, our scheme has the potential to precisely enhance different quantum path in HHG.}, archive = {J_PRA}, author = {Baichuan Xie and Xinkui He and Gefei Li and Shiyang Zhong and Lizhi Duan and Shuai Wang and Hao Teng and Zhiyi Wei}, doi = {10.1103/m593-ybsp}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023513}, shortjournal = {Phys. Rev. A}, title = {Selective enhancement of long trajectories in high-harmonic generation using a solid-gas dual-target configuration}, volume = {112}, year = {2025}, }
• (2025). Quantum backaction evasion with reservoir engineering. PRA, 112(2), 023512. (www)

  @article{ , abstract = {We propose a backaction evading scheme for a free mass that combines reservoir engineering with velocity measurement. The underlying principle follows the double-pass-type speed meter, which measures the mirror's velocity using a nonreciprocal interaction. In our method, the nonreciprocal coupling is realized through reservoir engineering, following the recipe proposed by Metelmann and Clerk [ Phys. Rev. X 5 , 021025 (2015) ]. We show that reservoir engineering can reproduce the double-pass speed meter with optimal feedforward, using only reciprocal interactions. The resulting force sensitivity surpasses the standard quantum limit, providing an alternative route to quantum backaction evasion in cavity optomechanical systems.}, archive = {J_PRA}, author = {Yohei Nishino and James W. Gardner and Yanbei Chen and Kentaro Somiya}, doi = {10.1103/bv8m-fpv9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023512}, shortjournal = {Phys. Rev. A}, title = {Quantum backaction evasion with reservoir engineering}, volume = {112}, year = {2025}, }
• (2025). Wavelength-dependent interband contributions to high-order harmonics in MgO crystals. PRA, 112(2), 023511. (www)

  @article{ , abstract = {By numerically solving semiconductor Bloch equations under the three-band model, we investigate the high-order harmonic emission of bulk MgO crystals irradiated by linearly polarized laser pulses. Our results reveal that as the laser wavelength increases, interband polarization dominates over intraband current near the minimum band gap (7.8 eV) in the orientation, with contributions shifting toward lower-energy regions. This shift arises from enhanced electron density accumulation at the Brillouin zone boundary and increased interband harmonics between conduction bands. The findings highlight the critical role of laser wavelength in shaping harmonic contributions and deepen our understanding of high-order harmonic generation in crystalline materials.}, archive = {J_PRA}, author = {Wenli Jiang and Yue Qiao and Shicheng Jiang and Yong Zhou and Yujun Yang and Jigen Chen}, doi = {10.1103/jr88-1k17}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023511}, shortjournal = {Phys. Rev. A}, title = {Wavelength-dependent interband contributions to high-order harmonics in MgO crystals}, volume = {112}, year = {2025}, }
• (2025). Mechanisms of third harmonic generation through pulse cumulative effect from femtosecond laser filament in air. PRA, 112(2), 023510. (www)

  @article{ , abstract = {We experimentally observed a spectral broadening of the third harmonic in the long-wavelength range accompanied by intensity enhancement as the laser repetition rates increased. A correction for the simulation of the third harmonic at different repetition rates is proposed. Simulation and analysis confirm that the pulse accumulation effect changes the spatiotemporal evolution of the electric field within the filament, thus enhancing the cross-phase modulation and self-phase modulation of the third harmonic, leading to the broadening of the third harmonic, with a quantitative analysis establishing the cross-phase modulation as the dominant mechanism. These findings provide a comprehensive physical framework for understanding third harmonic generation in a high-repetition-rate filament. The demonstrated repetition-rate-dependent mechanism presents new opportunities for advancing intense UV pulse generation techniques, with promising applications in precision laser machining and remote UV detection technology.}, archive = {J_PRA}, author = {Chaopeng Yang and Zheng Sun and Yaoxiang Liu and Rao Adeel Un Nabi and Xianwang Li and Ying Xu and Juan Long and Yingxia Wei and Tiejun Wang and Yuxin Leng}, doi = {10.1103/wrkd-chzh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023510}, shortjournal = {Phys. Rev. A}, title = {Mechanisms of third harmonic generation through pulse cumulative effect from femtosecond laser filament in air}, volume = {112}, year = {2025}, }
• (2025). Dynamic switching of unidirectional radiation without wavelength shift. PRA, 112(2), 023509. (www)

  @article{ , abstract = {Unidirectional light emission is essential for various optoelectronic applications. Moreover, dynamically switching the emission direction while maintaining a stable wavelength is highly desirable. In this work, switchable unidirectional guided resonances are achieved through mode coupling between a grating and a waveguide, enabled by a phase-change material. The emission direction can be dynamically switched from upward to downward without altering the wavelength. Through systematic parameter sweeping, feasible geometric configurations that support this directional switching are identified and analyzed. This study offers valuable insights for advancing dynamic light control in optoelectronic devices.}, archive = {J_PRA}, author = {Kai Wang and Dezhuan Han and Hong Xiang}, doi = {10.1103/c492-c2fs}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023509}, shortjournal = {Phys. Rev. A}, title = {Dynamic switching of unidirectional radiation without wavelength shift}, volume = {112}, year = {2025}, }
• (2025). Angle-insensitive nonlinear enhancement in an all-dielectric metasurface via brillouin-zone folding. PRA, 112(2), 023508. (www)

  @article{ , abstract = {Metasurfaces have become a powerful platform for strengthening light-matter interactions. Recent research has shown that all-dielectric metasurfaces supporting high-quality ( ) factor resonances, such as anapole modes and quasibound states in the continuum (BIC), can significantly enhance third harmonic generation (THG) efficiency. Nevertheless, a key challenge remains: precisely controlling the factor of these resonances is difficult, and maintaining a high- factor across a wide range of incident angles is even more demanding. Here, we achieve substantial enhancement of THG by introducing perturbations within the metasurface. The guided modes below the light line can be folded into the light cone, resulting in high- resonant modes. Compared with previous BICs, this folded resonance exhibits a persistent high- characteristic in momentum space, which makes it possible to achieve angular insensitive nonlinear enhancement. The angular robustness of the proposed metasurface ensures consistent high nonlinear performance, making it a viable candidate for practical applications in nonlinear optics, such as frequency conversion and photonic signal processing.}, archive = {J_PRA}, author = {Siyu Fan and Yuqiang Wang and Xi Cao}, doi = {10.1103/gw9j-9dxk}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023508}, shortjournal = {Phys. Rev. A}, title = {Angle-insensitive nonlinear enhancement in an all-dielectric metasurface via brillouin-zone folding}, volume = {112}, year = {2025}, }
• (2025). Nonlinear dynamics and self-healing properties of elliptical airy beams in kerr media. PRA, 112(2), 023507. (www)

  @article{ , abstract = {By numerically solving the nonlinear Schrödinger equation, we theoretically study the nonlinear propagation dynamics and self-healing properties of elliptical Airy beams (EABs) propagating in water under Kerr nonlinearity. Compared with linear propagation, EABs exhibit extended propagation distances and enhanced stability in nonlinear media. Furthermore, particular emphasis is placed on the impact of Kerr nonlinearity strength on the propagation and self-healing properties of EABs. By varying the input power, it is found that EABs within a moderate power range can propagate longer distances while maintaining higher intensity and exhibit improved robustness after being blocked, indicating better self-healing performance. Based on this analysis, an explanation of the physical mechanism related to the enhanced self-healing capability by Kerr nonlinearity is proposed. Finally, we propose an optimal input power for EABs through a quantitative analysis of the impact of Kerr nonlinearity, enabling them to achieve the greatest propagation distance and maintain the highest stability. Our work provides new insights into the interaction between EABs and Kerr nonlinearity, with potential applications for long-distance laser transmission.}, archive = {J_PRA}, author = {Qinjun Jian and Jing Hu and Lihe Yan and Jinhai Si and Xun Hou}, doi = {10.1103/2rpt-2trt}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023507}, shortjournal = {Phys. Rev. A}, title = {Nonlinear dynamics and self-healing properties of elliptical airy beams in kerr media}, volume = {112}, year = {2025}, }
• (2025). Photonic-spin-governed absorption in a μ-near-zero subwavelength gyromagnetic cylinder. PRA, 112(2), 023506. (www)

  @article{ , abstract = {Realizing nonreciprocal scattering and absorption from subwavelength elements has several applications across the electromagnetic frequency spectrum. Here we show that gyromagnetic cylindrical rods with subwavelength dimensions exhibit strong absorption with diminished scattering in a narrow frequency band for an incident plane wave. We show that the strong narrowband absorption depends on the photonic spin of the incident wave. Further, it is shown that this spin-dependent absorption leads to nonreciprocal reflection and absorption characteristics of an array of gyromagnetic cylinders suspended over a reflecting plane. The theoretical claims of strong spin-dependent absorption in subwavelength elements is validated by experimentally demonstrating nonreciprocal absorption and transmission from a single gyromagnetic rod placed in a substrate integrated waveguide.}, archive = {J_PRA}, author = {Rajarshi Sen and Sarang Pendharker}, doi = {10.1103/8kyf-gcd1}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023506}, shortjournal = {Phys. Rev. A}, title = {Photonic-spin-governed absorption in a μ-near-zero subwavelength gyromagnetic cylinder}, volume = {112}, year = {2025}, }
• (2025). Multistability and noise-induced transitions in dispersively coupled nonlinear nanomechanical modes. PRA, 112(2), 023505. (www)

  @article{ , abstract = {We study the noisy dynamics of two coupled bistable modes of a nanomechanical beam. When decoupled, each driven mode obeys the Duffing equation of motion, with a well-defined bistable region in the frequency domain. When both modes are driven, intermodal dispersive coupling emerges due to the amplitude dependence of the modal frequencies and leads to coupled states of the two modes. We map out the dynamics of the system by sweeping the drive frequencies of both modes in the presence of added noise. The system then samples all accessible states at each combination of frequencies, with the probability of each stable state being proportional to its occupancy time at steady state. In the frequency domain, the system exhibits four stable regions—one for each coupled state—which are separated by five curves. These curves are reminiscent of coexistence curves in an equilibrium phase diagram: each curve is defined by robust interstate transitions, with equal probabilities of finding the system in the two contiguous states. Remarkably, the curves intersect in two triple points, where the system now transitions between three distinct contiguous states. A physical analogy can be made between this nonequilibrium system and a multiphase thermodynamic system, with possible applications in computing, precision sensing, and signal processing.}, archive = {J_PRA}, author = {David Allemeier and I. I. Kaya and M. S. Hanay and K. L. Ekinci}, doi = {10.1103/dtlz-pmnr}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023505}, shortjournal = {Phys. Rev. A}, title = {Multistability and noise-induced transitions in dispersively coupled nonlinear nanomechanical modes}, volume = {112}, year = {2025}, }
• (2025). Dissipative soliton combs with spectral filtering. PRA, 112(2), 023504. (www)

  @article{ , abstract = {The paradigmatic Lugiato-Lefever model describes the electric field envelope in a ring cavity filled with a Kerr medium and driven by a coherent injected laser beam. This model is applied to the formation of frequency combs associated with localized structures in micro and macroresonators. Including temporal filtering, we derive a generalized Lugiato-Lefever equation. This equation includes diffusion, linear, and nonlinear convection, and third-order dispersion with purely imaginary coefficients. Multiscale analysis enables us to disregard higher-order terms, such as nonlinear convection and third-order dispersion. We investigate the formation of periodic and localized structures resulting from the combined action of temporal spectral filtering effect together with Kerr nonlinearity, pumping, dissipation, and frequency detuning. We show that spectral filtering reduces the intensity of the output field and increases the period of traveling solutions. Similarly, the maximum intensity of moving localized structures, often called dissipative solitons, is reduced. In addition, we show that the threshold associated with breathers is shifted toward large input intensities and that the associated domain of existence is significatively reduced. We show that, when the drift is absent, dissipative solitons exhibit a homoclinic snaking bifurcation. Increasing the strength of the temporal filter reduces the pinning range. The presence of the drift breaks the homoclinic snaking and transforms it into isolas of solutions.}, archive = {J_PRA}, author = {M. Bataille-Gonzalez and M. G. Clerc and B. Kostet and Y. Soupart and M. Tlidi}, doi = {10.1103/mlqm-6g6h}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023504}, shortjournal = {Phys. Rev. A}, title = {Dissipative soliton combs with spectral filtering}, volume = {112}, year = {2025}, }
• (2025). Electrodynamics of nonstationary lattices. PRA, 112(2), 023503. (www)

  @article{ , abstract = {A model of a nonstationary metamaterial is introduced and its electromagnetic properties are studied. The metamaterial is composed of two sublattices: a stationary one and an activated one. It is shown that an initial polariton excites not only the usual frequency-shifted polaritons but also a mode consisting of almost out-of-phase sublattice oscillations coupled to the electromagnetic field and possessing a small negative group velocity. The presented framework forms a basic description of the processes in time-varying media with spatial dispersion.}, archive = {J_PRA}, author = {A. V. Maslov}, doi = {10.1103/p38d-2pbk}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023503}, shortjournal = {Phys. Rev. A}, title = {Electrodynamics of nonstationary lattices}, volume = {112}, year = {2025}, }
• (2025). Desorption-induced decoherence of nanoparticle motion. PRA, 112(2), 023502. (www)

  @article{ , abstract = {We derive the quantum master equation predicting how the translational and rotational dynamics of a nanoparticle is affected by the emission of surface adsorbates. This is motivated by recent experiments which prepared the motion of internally hot silica particles in the deep quantum regime. In the limit of a well localized nanoparticle the rotranslational dynamics can be characterized by diffusion rates in quantitative agreement with classical expectations. The theory is also suited to describe the decoherence effect of outgassing and sublimation.}, archive = {J_PRA}, author = {Jonas Schäfer and Benjamin A. Stickler and Klaus Hornberger}, doi = {10.1103/4yxn-48c6}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023502}, shortjournal = {Phys. Rev. A}, title = {Desorption-induced decoherence of nanoparticle motion}, volume = {112}, year = {2025}, }
• (2025). Vector kerr cavity solitons in a pulse-pumped normal-dispersion fiber kerr resonator. PRA, 112(2), 023501. (www)

  @article{ , abstract = {We demonstrate the formation of vector Kerr cavity solitons in a pulse-pumped normal dispersion fiber Kerr resonator. Such solitonic structures formed in normal-dispersion resonators typically manifest as flat-top solitonic pulses, known as platicons. The two orthogonally polarized modes inside the fiber resonator are pumped with the same conditions and the generation of vector platicons (VPs) is achieved via a spontaneous symmetry breaking (SSB) of the intracavity structures in a process when scanning the pump frequency from the blue-shift to the red-shift detuning side. The characteristics of the SSB are studied in detail. Also, the impact of the third-order dispersion (TOD) and the desynchronization on the VP dynamics are studied, revealing that the oscillating structure on the leading edge of VPs can be alleviated by introducing a desynchronization effect. What's interesting is that desynchronization can be used as an additional degree of freedom to control VP behaviors. For a small desynchronization, we observe the energy exchange between the two orthogonally polarized modes. For a large desynchronization, periodic and deterministic switching dynamics between the two orthogonally polarized modes can be obtained.}, archive = {J_PRA}, author = {Hongbin Hu and Zhiqiang Wang and Shilong Liu and You Yu and Zuxing Zhang}, doi = {10.1103/ck6k-db5z}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023501}, shortjournal = {Phys. Rev. A}, title = {Vector kerr cavity solitons in a pulse-pumped normal-dispersion fiber kerr resonator}, volume = {112}, year = {2025}, }
• (2025). Hierarchy of pairing in an imbalanced three-component one-dimensional fermi gas. PRA, 112(2), 023322. (www)

  @article{ , abstract = {We study a one-dimensional three-component Fermi gas with population imbalance using the Bogoliubov–de Gennes mean-field approach. We specifically consider pairing in two channels while deliberately excluding the third by setting its interaction strength to zero. By systematically varying the interaction strength and population imbalance, we identify a rich set of spatially modulated superfluid states, including structures akin to the Larkin-Ovchinnikov phase and phase-separated domains. A clear hierarchy emerges in the pairing behavior, shaped by the competition between the local density of states and the Fermi-momentum mismatch. A fidelity-based analysis of the density further distinguishes smooth crossovers from sharp spatial reorganizations. Our results shed light on how pairing symmetry and population imbalance determine the structure of spatially inhomogeneous superfluid phases in multicomponent systems with reduced dimensionality.}, archive = {J_PRA}, author = {Buğra Tüzemen and Tomasz Sowiński}, doi = {10.1103/yf54-cg95}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023322}, shortjournal = {Phys. Rev. A}, title = {Hierarchy of pairing in an imbalanced three-component one-dimensional fermi gas}, volume = {112}, year = {2025}, }
• (2025). Vortex and fractional quantum hall phases in a rotating anisotropic bose gas. PRA, 112(2), 023321. (www)

  @article{ , abstract = {Realizing fractional quantum Hall (FQH) states in ultracold atomic systems remains a major goal despite numerous experimental advances in the last few decades. Recent progress in trap anisotropy control under rapid rotation has renewed interest in ultracold atomic FQH physics, enabling experiments that impart much larger angular momentum per particle and offer in situ imaging with resolution finer than the cyclotron orbit size. In this paper, we present a theoretical investigation of a rapidly rotating anisotropic Bose gas. By projecting the full Hamiltonian, including both kinetic and interaction terms, onto the lowest Landau level, we derive a compact two-parameter model that captures the effects of interaction strength, rotation rate, and anisotropy. Using exact diagonalization and density matrix renormalization group, we obtain a phase diagram that features broken-symmetry phases and topologically ordered quantum Hall states, while also highlighting the distinctive physics arising from the system's edges. Our results demonstrate the potential for future theoretical and experimental exploration of anisotropic quantum fluids, offering a unified framework for weakly interacting Bose condensates, vortex matter, and strongly correlated topological phases.}, archive = {J_PRA}, author = {U. Tanyeri and A. Kallushi and R. O. Umucalılar and A. Keleş}, doi = {10.1103/bsvm-vgnb}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023321}, shortjournal = {Phys. Rev. A}, title = {Vortex and fractional quantum hall phases in a rotating anisotropic bose gas}, volume = {112}, year = {2025}, }
• (2025). Field-induced quantum interference of inelastic scattering in ultracold atomic collisions. PRA, 112(2), 023320. (www)

  @article{ , abstract = {Exploiting quantum interference presents a significant challenge in ultracold inelastic scattering. In this study we propose a method to verify quantum interference within the two-body loss rate that arises from multiple inelastic-scattering channels, where the colliding particles are initially prepared in their individual hyperfine states. Our approach employs a ring-coupling configuration, accomplished by combining external radio-frequency and static electric fields during ultracold atomic collisions. To validate our proposal, we perform close-coupling calculations for collisions at the ultracold limit. The results reveal that the interference profile, as manifested in the two-body loss rate, can be verified with optimized external field parameters. Notably, our findings indicate that the two-body loss rate coefficient exhibits a distinct pattern of constructive or destructive interference when crossing a magnetically induced -wave resonance in the incoming channel. These interference patterns become increasingly pronounced as the intensities of the external fields increase. This work presents a potential approach to controlling inelastic-scattering processes in ultracold collisions.}, archive = {J_PRA}, author = {Ting Xie and Chuan-Cun Shu}, doi = {10.1103/q274-8kkw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023320}, shortjournal = {Phys. Rev. A}, title = {Field-induced quantum interference of inelastic scattering in ultracold atomic collisions}, volume = {112}, year = {2025}, }
• (2025). Ultracold collisions of a neutral atom with a trapped ion in one dimension. PRA, 112(2), 023319. (www)

  @article{ , abstract = {We present a fully quantum mechanical description of a free atom scattering from a trapped ion in one dimension. By reformulating the system in polar coordinates and employing the adiabatic representation, we extract a set of coupled adiabatic potentials representing the atom interacting with the ion in different trap states. In an approach similar to quantum defect theory, we leverage the vast difference in energy scale between the interaction, the trap, and the scattering energy to encapsulate the short-range atom-ion scattering behavior in a single phase parameter. The presence of trapped molecular-ion states leads to a series of roughly evenly spaced resonances in the scattering cross section. The predicted distribution of resonances at low collision energies is at odds with the expectation of quantum chaos and the Bohigas-Giannoni-Schmit conjecture.}, archive = {J_PRA}, author = {Seth T. Rittenhouse and Lorenzo Oghittu and Arghavan Safavi-Naini and Rene Gerritsma and Angela D. Graf and Nirav P. Mehta}, doi = {10.1103/jgz3-xrvc}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023319}, shortjournal = {Phys. Rev. A}, title = {Ultracold collisions of a neutral atom with a trapped ion in one dimension}, volume = {112}, year = {2025}, }
• (2025). Bubbles in a box: Eliminating edge nucleation in cold-atom simulators of vacuum decay. PRA, 112(2), 023318. (www)

  @article{ , abstract = {The decay of metastable false-vacuum states via bubble nucleation plays a crucial role in many cosmological scenarios. Cold-atom analog experiments will soon provide the first empirical probes of this process, with potentially far-reaching implications for early-universe cosmology and high-energy physics. However, an inevitable difference between these analog systems and the early universe is that the former have a boundary. We show, using a combination of Euclidean calculations and real-time lattice simulations, that these boundaries generically cause rapid bubble nucleation on the edge of the experiment, obscuring the bulk nucleation that is relevant for cosmology. We demonstrate that implementing a high-density trench region at the boundary completely eliminates this problem and recovers the desired cosmological behavior. Our findings are relevant for ongoing efforts to probe vacuum decay in the laboratory, providing a practical solution to a key experimental obstacle.}, archive = {J_PRA}, author = {Alexander C. Jenkins and Hiranya V. Peiris and Andrew Pontzen}, doi = {10.1103/lrc6-49q1}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023318}, shortjournal = {Phys. Rev. A}, title = {Bubbles in a box: Eliminating edge nucleation in cold-atom simulators of vacuum decay}, volume = {112}, year = {2025}, }
• (2025). Spatially periodic states in a strongly dipolar Dy164−Dy162 mixture. PRA, 112(2), 023317. (www)

  @article{ , abstract = {We demonstrate the formation of a novel eigenstate in a strongly dipolar binary Dy 164 − Dy 162 mixture, where the inter- and intraspecies dipolar lengths are larger than the corresponding scattering lengths. When this mixture is confined by a quasi-two-dimensional harmonic trap, the total density exhibits the formation of droplets on a spatially symmetric triangular or square lattice, where each droplet is formed of a single species of atoms; two types of atoms never exist on the same lattice site. The density of any of the species shows a partially filled incomplete lattice; only the total density exhibits a completely full lattice structure. In this theoretical investigation we employ the numerical solution of an improved mean-field model including a Lee-Huang-Yang-type interaction in the intraspecies components alone, meant to stop a collapse of the atoms at high atom density.}, archive = {J_PRA}, author = {S. K. Adhikari}, doi = {10.1103/lqds-zb7d}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023317}, shortjournal = {Phys. Rev. A}, title = {Spatially periodic states in a strongly dipolar Dy164−Dy162 mixture}, volume = {112}, year = {2025}, }
• (2025). Precision thermodynamics of the fermi polaron at strong coupling. PRA, 112(2), 023316. (www)

  @article{ , abstract = {The Fermi polaron problem, which describes a mobile impurity that interacts with a spin-polarized Fermi sea, is a paradigmatic system in quantum many-body physics and has been challenging to address quantitatively in its strong-coupling regime. We present controlled thermodynamic calculations for the Fermi polaron at strong coupling using finite-temperature auxiliary-field quantum Monte Carlo methods in the framework of the canonical ensemble. Modeled as a spin-imbalanced system, the Fermi polaron has a Monte Carlo sign problem, but we show that it is moderate over a wide range of temperatures and coupling strengths beyond the unitary limit of the BCS-BEC crossover. We calculate the contact, a quantity which measures the strength of the short-range correlations, as a function of temperature at unitarity and as a function of the coupling strength at fixed temperature and find good agreement with a variational approach based on a single particle-hole excitation of the Fermi sea. We compare our results for the contact with recent experiments and find good agreement at unitarity (within error bars) but we observe discrepancies away from unitarity on the BEC side of the crossover. We also calculate the impurity thermal energy at unitarity as a function of temperature.}, archive = {J_PRA}, author = {S. Ramachandran and S. Jensen and Y. Alhassid}, doi = {10.1103/vvd1-639l}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023316}, shortjournal = {Phys. Rev. A}, title = {Precision thermodynamics of the fermi polaron at strong coupling}, volume = {112}, year = {2025}, }
• (2025). Stochastic gross-pitaevskii theory for a spin-1 bose gas: Application to superfluidity in two dimensions. PRA, 112(2), 023315. (www)

  @article{ , abstract = {This paper develops and implements the stochastic projected Gross-Pitaevskii equation for spin-1 Bose gases, addressing key considerations for numerical simulations. As an application of the theory we explore equilibrium phases in a two-dimensional spin-1 gas, where quasi-long-range order emerges via a Berezinskii-Kosterlitz-Thouless transition. Our analysis includes the definition of superfluid densities for both mass and spin degrees of freedom in a manner suitable for implementation within a stochastic projected Gross-Pitaevskii equation simulation. We present a finite-temperature phase diagram for the ferromagnetic spin-1 Bose gas and identify three distinct superfluid phases: two exhibiting conventional Berezinskii-Kosterlitz-Thouless-like behavior and an additional phase that simultaneously supports independent mass and spin superflows. As temperature increases, the stability region of this additional phase shrinks. We provide a characterization of the phase transitions through consideration of the spin-component densities and the unbinding of multiple types of vortices. This work provides a foundation for further studies of nonequilibrium and finite-temperature phenomena in spinor Bose gases.}, archive = {J_PRA}, author = {Andrew P. C. Underwood and P. B. Blakie}, doi = {10.1103/slxb-df37}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023315}, shortjournal = {Phys. Rev. A}, title = {Stochastic gross-pitaevskii theory for a spin-1 bose gas: Application to superfluidity in two dimensions}, volume = {112}, year = {2025}, }
• (2025). Thermal phase fluctuations in narrow superfluid rings. PRA, 112(2), 023314. (www)

  @article{ , abstract = {We have characterized the effects of thermal phase fluctuations in narrow rings of ultracold Fermi superfluids in the unitary regime and demonstrated that matter-wave interference may be reliably used to measure angular variations in the phase difference between two concentric, coplanar superfluid rings. When one of the rings is cut with a barrier, we find that phase fluctuations around that ring can be large enough to degrade the reliability of protocols for control of quantized circulation states. The effect is greatest when the one-dimensional density is low and the coupling between rings is negligible. In this limit, our measurements are consistent with a correlation length smaller than the system size, as expected from theory. These results establish the crucial role of phase fluctuations for experiments involving ultracold superfluids in elongated circuit-like geometries.}, archive = {J_PRA}, author = {Parth Sabharwal and Daniel G. Allman and Pradipta Debnath and Kevin C. Wright}, doi = {10.1103/hrdb-g2nd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023314}, shortjournal = {Phys. Rev. A}, title = {Thermal phase fluctuations in narrow superfluid rings}, volume = {112}, year = {2025}, }
• (2025). Miscibility-immiscibility transition of strongly interacting bosonic mixtures in optical lattices. PRA, 112(2), 023313. (www)

  @article{ , abstract = {Interaction plays a key role in the mixing properties of a multicomponent system. The miscibility-immiscibility transition (MIT) in a weakly interacting mixture of Bose gases is predominantly determined by the strengths of the intra- and intercomponent two-body contact interactions. However, in the strongly interacting regime interaction-induced processes become relevant. Despite previous studies on bosonic mixtures in optical lattices, the effects of the interaction-induced processes on the MIT remains unexplored. In this work, we investigate the MIT in the strongly interacting phases of two-component bosonic mixture trapped in a homogeneous two-dimensional square optical lattice. Particularly we examine the MIT condition when both the components are in superfluid, one-body staggered superfluid, or supersolid phases. Our study uncovers that MIT condition is significantly shaped by the interplay of competing nonlocal intra- and intercomponent density-induced tunneling effects, as well as off-site interactions. Notably, we demonstrate that the MIT condition for the staggered superfluid phase exhibits an inequality that is inverted compared to the conventional MIT condition associated with superfluid or supersolid phases driven by local contact interactions. In addition, we present the phase diagram of the Bose-Hubbard model incorporating nonlocal processes, derived using a site-decoupling mean-field approach with the Gutzwiller ansatz. Our study contributes to the better understanding of miscibility properties of multicomponent systems in the strongly interacting regime.}, archive = {J_PRA}, author = {Rukmani Bai and Soumik Bandyopadhyay}, doi = {10.1103/r52b-bsrd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023313}, shortjournal = {Phys. Rev. A}, title = {Miscibility-immiscibility transition of strongly interacting bosonic mixtures in optical lattices}, volume = {112}, year = {2025}, }
• (2025). Controlled dissipation for rydberg atom experiments. PRA, 112(2), 023312. (www)

  @article{ , abstract = {We demonstrate a simple technique for adding controlled dissipation to Rydberg atom experiments. In our experiments we excite cold rubidium atoms in a magneto-optical trap to 70 Rydberg states, while simultaneously inducing forced dissipation by resonantly coupling the Rydberg state to a hyperfine level of the short-lived 6 state. The resulting effective dissipation can be varied in strength and switched on and off during a single experimental cycle.}, archive = {J_PRA}, author = {Bleuenn Bégoc and Giovanni Cichelli and Sukhjit P. Singh and Fabio Bensch and Valerio Amico and Francesco Perciavalle and Davide Rossini and Luigi Amico and Oliver Morsch}, doi = {10.1103/w3x9-ll79}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023312}, shortjournal = {Phys. Rev. A}, title = {Controlled dissipation for rydberg atom experiments}, volume = {112}, year = {2025}, }
• (2025). Interaction quench dynamics and stability of quantum vortices in rotating bose-einstein condensates. PRA, 112(2), 023311. (www)

  @article{ , abstract = {We theoretically investigate the nonequilibrium dynamics of quantum vortices in a two-dimensional rotating Bose-Einstein condensate following an interaction quench. Using an ab initio and numerically exact quantum many-body approach, we systematically tune the interplay between interaction strength and angular velocity to prepare quantum vortices in various configurations and examine their postquench dynamics. Our study reveals distinct dynamical regimes: first, vortex distortion accompanied by density cloud fragmentation, matching the initial vortex number, and second, vortex revival, where fragmented densities interact and merge. Notably, we observe complete vortex revival dynamics in the single-vortex case, pseudorevival in double- and triple-vortex configurations, and irregular many-body dynamics in systems with multiple vortices. The observed dynamics is analyzed by the measures of many-body information entropy dynamics establishing the key role played by the dynamical fragmentation and delocalization in Fock space. Our results reveal a universal out-of-equilibrium response of quantum vortices to interaction quenches, highlighting the importance of many-body effects with a possible exploration in quantum simulation with ultracold quantum fluids.}, archive = {J_PRA}, author = {L. A. Machado and B. Chatterjee and M. A. Caracanhas and L. Madeira and V. S. Bagnato and B. Chakrabarti}, doi = {10.1103/8cdt-n3l2}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023311}, shortjournal = {Phys. Rev. A}, title = {Interaction quench dynamics and stability of quantum vortices in rotating bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Tilted dipolar bosons in the quasi-two-dimensional regime: From liquid stripes to droplets. PRA, 112(2), 023310. (www)

  @article{ , abstract = {We characterize a system of tilted dipoles in a quasi-two-dimensional (flattened) geometry and in the thermodynamic limit. We consider a finite trapping in the z axis achievable in current experiments. We compute the phase diagram of the system at its equilibrium density for high tilting angles, where it becomes self-bound, and a striped liquid state emerges. To characterize the system, we perform a variational calculation, which is benchmarked with the solution of the extended Gross-Pitaevskii equation. We connect the phenomenology in the thermodynamic limit to the physics of the finite-size system, provide parameters for the realization of potentially supersolid striped states, and study the critical number for dipolar droplet formation. Our results are helpful to guide potential experiments in the study of dipolar atoms in quasi-two-dimensional geometries in the dipole-dominated regime.}, archive = {J_PRA}, author = {J. Sánchez-Baena}, doi = {10.1103/bnp2-4tj5}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023310}, shortjournal = {Phys. Rev. A}, title = {Tilted dipolar bosons in the quasi-two-dimensional regime: From liquid stripes to droplets}, volume = {112}, year = {2025}, }
• (2025). Theoretical description of atomtronic josephson junctions in an optical lattice. PRA, 112(2), 023309. (www)

  @article{ , abstract = {Experimental realizations of “atomtronic” Josephson junctions have recently been created in annular traps in relative rotation with respect to potential barriers that generate the weak links. If these devices are additionally subjected to an optical lattice potential, then they can incorporate strong-coupling Mott physics within the design, which can modify the behavior and can allow for interesting new configurations of barriers and of superfluid flow patterns. We examine theoretically the behavior of a Bose superfluid in an optical lattice in the presence of an annular trap and a barrier across the annular region which acts as a Josephson junction. As the superfluid is rotated, circulating supercurrents appear. Beyond a threshold superfluid velocity, phase slips develop, which generate vortices. We use a finite-temperature strong-coupling expansion about the mean-field solution of the Bose-Hubbard model to calculate various properties of such devices. In addition, we discuss some of the rich behavior that can result when there are Mott regions within the system.}, archive = {J_PRA}, author = {Manjari Gupta and H. R. Krishnamurthy and J. K. Freericks}, doi = {10.1103/1r19-1tkm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023309}, shortjournal = {Phys. Rev. A}, title = {Theoretical description of atomtronic josephson junctions in an optical lattice}, volume = {112}, year = {2025}, }
• (2025). Unveiling quantum criticality of disordered aubry-andré-harper models via typical fidelity susceptibility. PRA, 112(2), 023308. (www)

  @article{ , abstract = {In this study, we investigate the localization transition and quantum criticality in the ground state of the disordered Aubry-André-Harper (AAH) model, where a quasiperiodic potential is hybridized with a disordered potential. In the clean limit, the AAH model undergoes a localization transition from an extended phase to a localized phase via an intermediate critical phase as the strength of the quasiperiodic potential is varied. While the staggered potential merely shifts the critical point to a lower value, Fibonacci and Thue-Morse potentials induce immediate localization. This contrast reveals the sensitivity of localization behavior to the structural complexity of the potential, with the onset of localization correlating with the sequence's complexity. More specifically, the system follows a hierarchy defined by the complexity measures of the applied potentials. In addition, the typical fidelity susceptibility exhibits a power-law scaling behavior at the localization transition, enabling reliable extraction of the critical exponent. We focus on the AAH model with the Fibonacci potential due to its minimal finite-size effects compared to other cases. For the disordered AAH model with the Fibonacci potential, we determine critical exponents that differ from those of the AAH model without disorder and the Anderson model. Moreover, despite differences in localization behavior, we find that the disordered AAH models with the staggered potential and the Fibonacci potential share the same correlation-length critical exponent. These findings provide a unified framework for understanding localization transitions in quasiperiodic systems and are amenable to experimental validation using emerging techniques.}, archive = {J_PRA}, author = {Tian-Cheng Yi and Ying-Ying Fang and Wen Chen and Wen-Long You and Yunbo Zhang}, doi = {10.1103/pwfy-2j1v}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023308}, shortjournal = {Phys. Rev. A}, title = {Unveiling quantum criticality of disordered aubry-andré-harper models via typical fidelity susceptibility}, volume = {112}, year = {2025}, }
• (2025). Observation of interaction-induced asymmetric chiral currents in a synthetic zigzag ladder. PRA, 112(2), 023307. (www)

  @article{ , abstract = {Engineering artificial gauge fields in synthetic lattices offers an efficient avenue for exploring topological states in cold atomic physics and photonics in recent years. Interactions between the system constituents in synthetic dimensions become long ranged, and can induce more striking features. Here, we report the experimental observation of asymmetric chiral currents induced by interactions in a synthetic zigzag ladder with tunable staggered flux, based on the laser-driven coupling of discrete momentum states of ultracold atoms. We observe that the staggered flux induces the symmetric chiral dynamics along two legs of the zigzag ladder in a noninteracting regime. However, the flux-dependent chiral currents along the two legs become asymmetric with increasing interactions, and the chiral trajectory is changed dramatically under strong interactions. Our finding opens the way for future exploration of exotic dynamics dictated by an interplay of inhomogeneous gauge fields and interactions in synthetic lattices.}, archive = {J_PRA}, author = {Hongxing Zhao and Huiying Du and Yunfei Wang and Yuqing Li and Chaojie Ren and Jizhou Wu and Wenliang Liu and Liantuan Xiao and Suotang Jia and Qunchao Fan and Jie Ma}, doi = {10.1103/9ldj-wqk4}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023307}, shortjournal = {Phys. Rev. A}, title = {Observation of interaction-induced asymmetric chiral currents in a synthetic zigzag ladder}, volume = {112}, year = {2025}, }
• (2025). Controlling the dynamical phase diagram of a spinor bose-einstein condensate using time-dependent potentials. PRA, 112(2), 023306. (www)

  @article{ , abstract = {We theoretically investigate the spin-mixing dynamics of a spinor BEC subject to a time-dependent confining potential. Our study provides a theory framework for the experimental results reported in Phys. Rev. A 109 , 043309 (2024) . We exploit the disparity of energy scales associated with the spatial and internal (spin) degrees of freedom under typical experimental conditions to develop an effective few-mode description of the spin dynamics. Our model demonstrates how the details of the potential, such as driving frequency and amplitude, can be used to independently control spin-changing and spin-preserving collision processes as well as the effective Zeeman energy of the internal states. We obtain the dynamical phase diagram of the effective model and discuss how its structure is altered relative to a spinor BEC with frozen spatial degrees of freedom. The applicability of our effective model is verified through Gross-Pitaevskii simulations that capture the interplay of spin and spatial degrees of freedom, and we identify parameter regimes that can be feasibly explored by future experiments. Our findings highlight the utility of dynamical confining potentials for the control of nonequilibrium spin-mixing dynamics in spinor BECs.}, archive = {J_PRA}, author = {Q. Guan and D. Blume and R. J. Lewis-Swan}, doi = {10.1103/7fsn-g61x}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023306}, shortjournal = {Phys. Rev. A}, title = {Controlling the dynamical phase diagram of a spinor bose-einstein condensate using time-dependent potentials}, volume = {112}, year = {2025}, }
• (2025). Third-order exceptional point in non-hermitian spin-orbit-coupled cold atoms. PRA, 112(2), 023305. (www)

  @article{ , abstract = {Exceptional points (EPs) have seen substantial advances in both experiment and theory. However, in quantum systems, higher-order EPs remain of great interest and possess numerous intriguing properties yet to be fully explored. Here we describe a parity-time symmetry-protected three-level non-Hermitian system with dissipative spin-orbit-coupled fermions in which a third-order exceptional point (EP3) emerges when both the eigenvalues and eigenstates of the system collapse into one. The band structure and its spin dynamics are explored for the fermion. We highlight the enhanced sensitivity to the external perturbation of the EP3 with cubic-root energy dispersion. Additionally, we investigate the second-order EP (EP2) with square-root energy dispersion in a three-level quantum system in the absence of parity symmetry, which proves that the enhanced sensitivity closely relates to the symmetries of the non-Hermitian system. Furthermore, we analyze the encircling behavior of the EP3 in terms of the slowly evolving limit and the nonadiabatic dynamics beyond the slowly evolving limit and discover some results different from those of the EP2.}, archive = {J_PRA}, author = {Yu-Jun Liu and Ka Kwan Pak and Peng Ren and Mengbo Guo and Entong Zhao and Chengdong He and Gyu-Boong Jo}, doi = {10.1103/w93l-s2dd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023305}, shortjournal = {Phys. Rev. A}, title = {Third-order exceptional point in non-hermitian spin-orbit-coupled cold atoms}, volume = {112}, year = {2025}, }
• (2025). Double sine-gordon class of universal coarsening dynamics in a spin-1 bose gas. PRA, 112(2), 023304. (www)

  @article{ , abstract = {Far from equilibrium, universal dynamics prevails in many different situations, from pattern coarsening to turbulence. A central longstanding problem concerns the development of a theory of coarsening that rests on the microscopic properties of the system and allows identifying the interaction mechanisms underlying a possible overarching universality class of the associated scaling dynamics. In quantum systems, this is complicated by the existence of nonlinear and topological excitations due to the compact nature of phase degrees of freedom. We show that the double sine-Gordon model as a noncompact low-energy effective model of the spin-1 Bose gas accounts for subdiffusive coarsening dynamics, identifying field configurations spread over multiple wells of the sinusoidal potential as a precondition for the slow scaling. This is in contrast to diffusion-type scaling, which the model is known to exhibit as well, where field configurations are seen to not extend over more than two wells. Experimental observations of a spinor BEC support these characteristics, thus constituting a platform for the investigation of sine-Gordon dynamics. Our results point to a path towards a classification of pattern coarsening in many-body systems on the basis of microscopic models.}, archive = {J_PRA}, author = {Ido Siovitz and Anna-Maria E. Glück and Yannick Deller and Alexander Schmutz and Felix Klein and Helmut Strobel and Markus K. Oberthaler and Thomas Gasenzer}, doi = {10.1103/df5w-3yfd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023304}, shortjournal = {Phys. Rev. A}, title = {Double sine-gordon class of universal coarsening dynamics in a spin-1 bose gas}, volume = {112}, year = {2025}, }
• (2025). Electric-field-augmented magnetic feshbach resonance for selective spin-exchange loss control in ultracold 6Li-40K collisions. PRA, 112(2), 023303. (www)

  @article{ , abstract = {We investigate the control of two-body inelastic spin-exchange loss in ultracold atoms by applying an electric field to modulate magnetic Feshbach resonances. While conventional magnetic tuning can enhance or suppress two-body spin-exchange losses, the incorporation of an electric field introduces an additional degree of freedom, enabling more flexible control over resonances for different partial waves. Taking the collision as an example, we demonstrate how this approach can be employed to control - and -wave inelastic loss processes and improve the suppression of the loss rate coefficient. This study may open a new possibility for the control of ultracold atomic inelastic collisions.}, archive = {J_PRA}, author = {Bo-Wen Si and Bing-Kuan Lyu and Shu-Lin Cong}, doi = {10.1103/n318-63hc}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023303}, shortjournal = {Phys. Rev. A}, title = {Electric-field-augmented magnetic feshbach resonance for selective spin-exchange loss control in ultracold 6Li-40K collisions}, volume = {112}, year = {2025}, }
• (2025). Bose-einstein condensation on axially symmetric surfaces. PRA, 112(2), 023302. (www)

  @article{ , abstract = {We investigate the phenomenon of Bose-Einstein condensation in ideal bosonic gases confined to axially symmetric surfaces of revolution. The single-particle Schrödinger equation is formulated on a general surface and then explicitly solved in the ellipsoidal and toroidal geometries to determine the one-body energy spectrum. We discuss how the curved geometry impacts the quantum statistical properties of ideal Bose gases confined on these surfaces. Specifically, we observe that Bose-Einstein condensation is suppressed when the surface aspect ratio is increased and, correspondingly, it becomes highly elongated and acquires a one-dimensional character. We also evaluate the Bogoliubov excitation spectrum, providing insights into the collective excitations of the condensate. Our results establish the conditions to achieve quantum degeneracy in curved manifolds, thus guiding forthcoming experiments with thin shells, and set the basis for solving the few-to-many body problem in general surfaces of revolution.}, archive = {J_PRA}, author = {Andrea Tononi and Gregory E. Astrakharchik}, doi = {10.1103/vxy6-skdq}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023302}, shortjournal = {Phys. Rev. A}, title = {Bose-einstein condensation on axially symmetric surfaces}, volume = {112}, year = {2025}, }
• (2025). Expansion of one-dimensional spinor gases from power-law traps. PRA, 112(2), 023301. (www)

  @article{ , abstract = {Free expansion following the removal of axial confinement represents a fundamental nonequilibrium scenario in the study of many-body ultracold gases. Using the stationary phase approximation, we analytically demonstrate that for all one-dimensional spinor gases with repulsive contact interactions, whether bosonic or fermionic, the asymptotic density and momentum distribution can be directly determined from the quasimomentum distribution (Bethe rapidities) of the trapped gas. We efficiently obtain the quasimomentum distribution numerically by solving the integral equations that characterize the ground state of the integrable system within the local density approximation. Additionally, we derive analytical solutions for both weakly and strongly interacting regimes. Unlike in bosonic gases, where rapidity distributions and density profiles vary significantly across interaction regimes, fermionic gases maintain similar profiles in both weakly and strongly interacting limits. Notably, the gas expands self-similarly only when released from a harmonic trap. For other power-law trapping potentials, the asymptotic density profile is strongly influenced by the initial confinement geometry. Our results extend readily to Bose-Fermi mixtures and finite temperatures.}, archive = {J_PRA}, author = {Ovidiu I. Pâţu and Gianni Aupetit-Diallo}, doi = {10.1103/clxm-5yd9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023301}, shortjournal = {Phys. Rev. A}, title = {Expansion of one-dimensional spinor gases from power-law traps}, volume = {112}, year = {2025}, }
• (2025). Direct measurement of the p03 clock state natural lifetime in sr87. PRA, 112(2), 023121. (www)

  @article{ , abstract = {Optical lattice clocks based on the narrow transition in neutral strontium (Sr) are among the most precise and accurate measurement devices in existence. Although this transition is completely forbidden by selection rules, state mixing from the hyperfine interaction in provides a weakly allowed transition that can be coherently driven with practical clock laser intensities. While the coherent interrogation times of optical clocks are typically set by the linewidth of the probe laser, this limitation can be overcome in synchronous differential comparisons between ensembles. In such measurements the natural lifetime of the clock transition becomes the fundamental limiting factor to the duration of a single run of the experiment. However, a direct measurement of the decay rate of the clock excited state is quite challenging due to the competing effects of other loss channels such as Raman scattering, inelastic collisions, and atom loss due to background gas. In this work, we monitor the decay of Sr atoms trapped in an optical lattice and initialized in the state. By making measurements of high and low density ensembles of both and across varying lattice trap depths, we isolate radiative decay, which accounts for a significant fraction of the observed decays at low depths. We obtain a natural radiative decay lifetime of s for the clock state in , a value that is consistent with previously reported measurements and theoretical predictions. We also introduce an additional measurement scheme that involves repeated measurements of the ground-state population within a single experimental sequence, validating our model and the consistency of the measured rates. We expect that the techniques introduced in this work are applicable to lifetime measurements of long-lived metastable states in other atoms and ions used for clocks and quantum computing. The results presented in this work inform performance estimates of proposed gravitational wave detectors and long-baseline atom interferometers making use of .}, archive = {J_PRA}, author = {Jonathan Dolde and Dhruva Ganapathy and Xin Zheng and Shuo Ma and Kyle Beloy and Shimon Kolkowitz}, doi = {10.1103/f6pt-flnt}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023121}, shortjournal = {Phys. Rev. A}, title = {Direct measurement of the p03 clock state natural lifetime in sr87}, volume = {112}, year = {2025}, }
• (2025). Complete and robust population transfer between the two ground states of a three-state loop quantum system by amplitude composite pulse control. PRA, 112(2), 023120. (www)

  @article{ , abstract = {This work presents a method for achieving complete, robust, and efficient population transfer between the two ground states in a three-level loop quantum system. The approach utilizes composite pulse sequences by effectively mapping the three-state system onto an equivalent two-level system. This transformation allows the use of broadband composite pulses designed initially for conventional two-state quantum systems. Unlike traditional implementations, the composite pulses in the three-level system are not controlled through phase adjustments; instead, they are realized via the amplitude ratio of the Rabi frequencies.}, archive = {J_PRA}, author = {Peter Chernev and Andon A. Rangelov}, doi = {10.1103/8f8d-vbzw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023120}, shortjournal = {Phys. Rev. A}, title = {Complete and robust population transfer between the two ground states of a three-state loop quantum system by amplitude composite pulse control}, volume = {112}, year = {2025}, }
• (2025). Below-threshold nonsequential double ionization with linearly polarized two-color fields. II. quantum interference. PRA, 112(2), 023119. (www)

  @article{ , abstract = {We perform a systematic analysis of intrachannel quantum interference in laser-induced nonsequential double ionization with linearly polarized bichromatic fields, focusing on the recollision-excitation with subsequent ionization (RESI) mechanism and employing the strong-field approximation. We generalize and elaborate several analytic interference conditions for RESI in arbitrary driving fields, with a focus on the interference arising from the specific symmetries of bichromatic fields. For example, for waves of comparable strengths, multiple events per half-cycle for the direct electron must be considered. Furthermore, interference breaks some of the symmetries arising from the field. We detangle the superimposed interference fringes originating from phase differences related to symmetrization due to electron exchange, temporal shifts, and a combination of exchange and event interference. We show that the hierarchy between exchange-only and exchange-temporal interference is fluid and can be manipulated by an appropriate choice of driving-field parameters. This is enabled by different types of interference occupying specific regions of the plane spanned by the electron momentum components parallel to the driving-field polarization.}, archive = {J_PRA}, author = {S. Hashim and D. Habibović and C. Figueira de Morisson Faria}, doi = {10.1103/g5wr-2gbz}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023119}, shortjournal = {Phys. Rev. A}, title = {Below-threshold nonsequential double ionization with linearly polarized two-color fields. II. quantum interference}, volume = {112}, year = {2025}, }
• (2025). Below-threshold nonsequential double ionization with linearly polarized two-color fields. i. symmetry and dominance. PRA, 112(2), 023118. (www)

  @article{ , abstract = {We investigate laser-induced nonsequential double ionization with linearly polarized bichromatic fields, focusing on the recollision-excitation with subsequent ionization (RESI) mechanism. Using the strong-field approximation, we assess how the symmetries of the field influence the dominant events. Furthermore, we show that, by manipulating the field parameters such as the field frequencies and relative phase between the two driving waves, one can influence the correlated electron-momentum distributions. Specific features of a linearly polarized bichromatic field are that the momentum distributions of the second electron are no longer centered around vanishing momenta and that there may be more than one ionization event per half-cycle. This can be used to confine the RESI distributions to specific momentum regions and to determine a hierarchy of parameters that make an event dominant.}, archive = {J_PRA}, author = {S. Hashim and D. Habibović and C. Figueira de Morisson Faria}, doi = {10.1103/b6b3-mt29}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023118}, shortjournal = {Phys. Rev. A}, title = {Below-threshold nonsequential double ionization with linearly polarized two-color fields. i. symmetry and dominance}, volume = {112}, year = {2025}, }
• (2025). Numerical modeling for trapped-ion thermometry using dark resonances. PRA, 112(2), 023117. (www)

  @article{ , abstract = {The simulation of vibrational energy transport and quantum thermodynamics with trapped ions requires good methods for the estimation of temperatures. One valuable tool for this purpose is based on the fit of dark resonances in the fluorescence spectrum. However, this fit demands numerical simulations of the coupled electronic-motional dynamics which usually involve a trade-off between accuracy and speed. Here, we discuss several techniques with simplified dynamical equations for the simulation of the spectrum of a trapped ion that undergoes thermal motion, identifying the advantages and limitations of each method. We start with a three-level model to provide a better insight into the approximations involved, and then move on to tackle the experimentally relevant case of an eight-level calcium ion. We observe that mimicking the effect of thermal motion by means of additional dephasing is computationally very convenient, but can lead to significant errors in the estimation of the temperature. Nevertheless, this can be counteracted by a proper calibration, supporting the use of dark resonances as a practical thermometer.}, archive = {J_PRA}, author = {Muriel Bonetto and Nicolás Adrián Nuñez Barreto and Christian Tomás Schmiegelow and Cecilia Cormick}, doi = {10.1103/117l-94nf}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023117}, shortjournal = {Phys. Rev. A}, title = {Numerical modeling for trapped-ion thermometry using dark resonances}, volume = {112}, year = {2025}, }
• (2025). Fast chiral resolution with optimal control. PRA, 112(2), 023116. (www)

  @article{ , abstract = {In this work, we formulate the problem of achieving in minimum time perfect chiral resolution with bounded control fields as an optimal control problem on two noninteracting spins 1 / 2 . We assume the same control bound for the two Raman fields (pump and Stokes) and a different bound for the field directly connecting the two lower-energy states. Using control theory, we show that the optimal fields can only take the boundary values or be zero, with the latter corresponding to singular control. Subsequently, using numerical optimal control and intuitive arguments, we identify some three-stage symmetric optimal pulse sequences for relatively large values of the ratio between the two control bounds and analytically calculate the corresponding pulse timings as a function of this ratio. For smaller values of the bound ratio, numerical optimal control indicates that the optimal pulse sequence loses its symmetry and the number of stages increases in general. In all cases, the analytical or numerical optimal protocol achieves a faster perfect chiral resolution than other pulsed protocols, mainly because of the simultaneous action of the control fields. The present work is expected to be useful in the wide spectrum of applications across the natural sciences in which enantiomer separation is a crucial task.}, archive = {J_PRA}, author = {Dionisis Stefanatos and Ioannis Thanopulos and Emmanuel Paspalakis}, doi = {10.1103/fkmb-b4k4}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023116}, shortjournal = {Phys. Rev. A}, title = {Fast chiral resolution with optimal control}, volume = {112}, year = {2025}, }
• (2025). Plasma environmental effect on auger electron spectroscopy of an ion embedded in a dense plasma. PRA, 112(2), 023115. (www)

  @article{ , abstract = {The characteristic kinetic energies of electrons emitted in Auger decay processes of inner-vacancy states carries valuable information of the element and its chemical environment in atoms, molecules, clusters, liquids, and solids. Thus, Auger electron spectroscopy (AES) is widely used as an important experimental tool in both fundamental and applied research. In a dense plasma environment, however, the kinetic energies of Auger electrons are significantly modified and therefore AES shows new features compared with that of the isolated species. Here, we theoretically investigated the AES of K- and -vacancy states for different charge states of iron ions embedded in dense plasma. It is found that the kinetic energy of the Auger electron is evidently shifted toward higher energy compared with the isolated ion; The higher the mass density and ionization stage, the larger shift the kinetic energy of the Auger electron. The shift of kinetic energy of the Auger electron is also weakly temperature dependent with a lower shift at a higher temperature of the plasma. The Auger widths of the -vacancy states are more evidently affected by the plasma environment than the K-vacancy states, especially at a higher plasma density. The findings of the present work are helpful for the study of Auger processes and radiative properties in dense plasmas such as astrophysical plasmas in the interior of stars and laboratory plasmas produced in interaction of x-ray free-electron lasers with solids, liquids, nanoplasmas, and clusters.}, archive = {J_PRA}, author = {Jiaolong Zeng and Yihua Huang and Aihua Deng and Cheng Gao and Yong Hou and Jianmin Yuan}, doi = {10.1103/mlkr-69h4}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023115}, shortjournal = {Phys. Rev. A}, title = {Plasma environmental effect on auger electron spectroscopy of an ion embedded in a dense plasma}, volume = {112}, year = {2025}, }
• (2025). Ultrafast proton transfer in femtosecond-laser-induced double ionization of HCOOH−H2O complexes. PRA, 112(2), 023114. (www)

  @article{ , abstract = {We report the experimental observation of ultrafast proton transfer in the complex following double ionization induced by a linearly polarized two-color femtosecond laser field with controlled relative phase. This process leads to the formation of ionic fragments and , which are detected in coincidence. The measured anisotropic momentum distributions of the fragments reveal a preferential emission direction aligned with the laser polarization. Analysis of molecular orbitals and potential energy surfaces indicates that both electrons involved in the proton transfer process predominantly originate from the HCOOH moiety. Ab initio molecular dynamics simulations show that proton transfer is initiated promptly after ionization and completes within 100 fs. Furthermore, by tuning the relative phase of the two-color laser field, we demonstrate control over the emission direction of the fragments. This directional emission is attributed to orientation-dependent tunneling ionization, as supported by simulations based on weak-field asymptotic theory.}, archive = {J_PRA}, author = {Junyang Ma and Mingyu Zhu and Zhubin Hu and Hongcheng Ni and Haitao Sun and Yan Yang and Zhenrong Sun}, doi = {10.1103/2t5k-6n9s}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023114}, shortjournal = {Phys. Rev. A}, title = {Ultrafast proton transfer in femtosecond-laser-induced double ionization of HCOOH−H2O complexes}, volume = {112}, year = {2025}, }
• (2025). Spin polarization of auger electrons following inner-shell photoionization of highly charged boronlike ions by circularly polarized light. PRA, 112(2), 023113. (www)

  @article{ , abstract = {Spin polarization of the Auger electrons emitted from the nonradiative Auger decay following inner-shell photoionization of boronlike ions by circularly polarized light is studied using the multiconfigurational Dirac-Hartree-Fock method and the relativistic distorted-wave theory. Special attention is paid to the effect of the Breit interaction and also to the circular polarization transfer of the ionizing light to the spin polarization. The orientation and alignment parameters of the autoionizing level and the intrinsic anisotropy and spin polarization parameters of the Auger decay are calculated for boronlike , and ions. The transferred spin-polarization components and and the dynamic one of the Auger electrons are then obtained. The dynamic polarization is found to be much smaller than the transferred ones due to weak alignment of the autoionizing level. It is found that the Breit interaction hardly contributes to , whereas the situation is much different for . For medium- and high- ions, for example, the transferred polarization is significantly enhanced by the Breit interaction for the Auger electrons emitted perpendicularly to the ionizing light beam but is weakened for those along the beam. Moreover, a quite strong circular polarization transfer of the ionizing light to the Auger electrons is found, which is comparable to the polarization transfer in the linear polarization of characteristic photons [Sharma et al. , Phys. Rev. A 81 , 023419 (2010) ] but reveals evidence of the spin polarization of Auger electrons emitted from highly charged ions. Beyond the fundamental significance, the strong circular polarization transfer to the spin polarization of the Auger electrons enables a more detailed characterization of nonmagnetic systems, magnetically ordered materials, and (anti)ferromagnets at the atomic scale.}, archive = {J_PRA}, author = {Y. Li and J. Q. Wang and Z. Q. Tian and Y. Yang and Z. W. Wu}, doi = {10.1103/wnfg-kn2v}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023113}, shortjournal = {Phys. Rev. A}, title = {Spin polarization of auger electrons following inner-shell photoionization of highly charged boronlike ions by circularly polarized light}, volume = {112}, year = {2025}, }
• (2025). Effects of finite trapping on the decay, recoil, and decoherence of dark states of quantum emitter arrays. PRA, 112(2), 023112. (www)

  @article{ , abstract = {The collective interaction of electronic excitations with the electromagnetic field in atomic arrays can lead to reduced decay rates, forming subradiant states with applications in quantum information and memories. By including quantized vibrational excitations, we examine the effects of finite trap strength and light-mediated forces on highly subradiant singly excited states for two, three, and many atoms in a one-dimensional waveguide or free space. For waveguide-coupled and tightly trapped atoms, the recoil energy from photon emission can reach a vibrational quantum, even in the Lamb-Dicke regime. For weakly trapped atoms, the vibrational wave packets are shifted or distorted due to induced forces and uneven decay. These effects lead to a time-dependent decay rate, extra vibrational energy transfer, and mixing of different electronic and vibrational states. The resulting entanglement entropy and infidelity can be mitigated by decreasing the induced forces or increasing trap strength. For quantum information storage, these findings suggest optimal array configurations in geometry and polarization. Our results provide insights for quantum memories and atom array experiments.}, archive = {J_PRA}, author = {M. Eltohfa and F. Robicheaux}, doi = {10.1103/qv4c-s9xw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023112}, shortjournal = {Phys. Rev. A}, title = {Effects of finite trapping on the decay, recoil, and decoherence of dark states of quantum emitter arrays}, volume = {112}, year = {2025}, }
• (2025). Nondipole circularly polarized laser-assisted photoelectron emission. PRA, 112(2), 023111. (www)

  @article{ , abstract = {We theoretically study atomic laser-assisted photoelectric emission (LAPE) beyond the electric dipole approximation. We present a theoretical description based on the strong-field approximation (SFA) for first-order nondipole corrections , where is the speed of light] to the nonrelativistic description of the laser-atom interaction for a strong circularly polarized IR laser field combined with a train of extreme-ultraviolet pulses. We investigate the photoelectron momentum distribution (PMD) as the product of two main contributions: the intra- and interpulse factors. Whereas the interpulse factor gives rise to a sideband pattern with a shift opposite to the IR beam propagation direction, the intrapulse factor forms an angular streaking pattern following the IR time-dependent polarization direction. We explore the transition of the PMD from the dipole to the nondipole framework, showing the gradual break of the forward-backward symmetry as the laser parameters are varied. Furthermore, we find nonzero contributions in dipole forbidden directions independent of the IR polarization state, wherein Cooper-like minima are observed. Our work lays a theoretical foundation for understanding time-resolved nondipole LAPE in cutting-edge ultrafast experiments.}, archive = {J_PRA}, author = {R. Della Picca and J. M. Randazzo and S. D. López and M. F. Ciappina and D. G. Arbó}, doi = {10.1103/hpnr-gwpr}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023111}, shortjournal = {Phys. Rev. A}, title = {Nondipole circularly polarized laser-assisted photoelectron emission}, volume = {112}, year = {2025}, }
• (2025). Two-photon spin-noise spectroscopy of cs atoms. PRA, 112(2), 023110. (www)

  @article{ , abstract = {We present a novel spectroscopic technique, two-color two-photon spin-noise spectroscopy, and demonstrate its application to atoms. This approach encompasses both the pump-probe and nonlinear two-photon schemes, as well as an interference noise arising due to Doppler shift. In the pump-probe scheme, the pump laser populates the excited states, while the probe laser monitors spin fluctuations, enabling the study of density fluctuations in these states. The pure two-photon scheme can be used to study a spin noise in the ground state, where fluctuations in the probe beam polarization are governed by the third-order susceptibility , offering additional advantages. We also theoretically analyze the structure of the susceptibility tensor to qualitatively interpret observed effects, such as a dependence on the pump-laser polarization plane and appearance of high harmonics of the Larmor frequency in the spin noise.}, archive = {J_PRA}, author = {S. Lukashov and M. Bayer and A. Greilich}, doi = {10.1103/ngvk-b6sv}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023110}, shortjournal = {Phys. Rev. A}, title = {Two-photon spin-noise spectroscopy of cs atoms}, volume = {112}, year = {2025}, }
• (2025). Efficient algorithms to solve atom reconfiguration problems. III. the bird and batching algorithms and other parallel implementations on GPUs. PRA, 112(2), 023109. (www)

  @article{ , abstract = {We present efficient implementations of atom reconfiguration algorithms for both CPUs and GPUs, along with a batching algorithm to merge displacement operations for parallel execution. Leveraging graph-theoretic methods, our approach derives improved algorithms that achieve reduced time complexity and faster operational running times. First, we introduce an enhanced version of the redistribution-reconfiguration (red-rec) algorithm, which offers superior operational and runtime performance. We detail its efficient implementation on a GPU using a parallel approach. Next we present an optimized version of the assignment-reconfiguration-ordering (ARO) algorithm, specifically tailored for unweighted grid graphs. Finally, we introduce the bird algorithm to solve reconfiguration problems on grids, achieving performance gains over both red-rec and ARO. These algorithms can be used to prepare defect-free configurations of neutral atoms in arrays of optical traps, serve as subroutines in more complex algorithms, or cross benchmark the operational and runtime performance of new algorithms. They are suitable for realizing quantum circuits incorporating displacement operations and are optimized for real-time operation in systems relying on increasingly large arrays of optical traps.}, archive = {J_PRA}, author = {Fouad Afiouni and Remy El Sabeh and Naomi Nishimura and Izzat El Hajj and Amer E. Mouawad and Alexandre Cooper}, doi = {10.1103/2rds-k4n9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023109}, shortjournal = {Phys. Rev. A}, title = {Efficient algorithms to solve atom reconfiguration problems. III. the bird and batching algorithms and other parallel implementations on GPUs}, volume = {112}, year = {2025}, }
• (2025). Selective ionization of rydberg atoms to reduce the energy spread of a cold-atom focused ion beam. PRA, 112(2), 023108. (www)

  @article{ , abstract = {The energy spread of a focused ion beam causes chromatic aberration that limits the focal spot size and resolution for imaging and fabrication. Ion beams based on photoionization of neutral atoms can have a much smaller energy spread and higher brightness than conventional liquid metal ion sources and are thus capable of higher resolution. We present a method for using selective ionization of Rydberg atoms to reduce the beam energy spread in a cold-atom focused ion beam. We produce experimental maps of the ionization rate of near the classical ionization threshold, predict the energy spread of an ion beam produced from these states, and demonstrate energy spread reduction in situ in a focused ion beam. We use a novel method to measure the energy spread from images, using only components present in many commercial focused ion beam systems. We choose two states to illustrate the technique and show a 50% difference in energy spread, with opportunities to further reduce the energy spread by constructing a more favorable electric field gradient and finding atomic states with better ionization characteristics.}, archive = {J_PRA}, author = {Kaih T. Mitchell and Allan Pennings and Rory W. Speirs and Christopher J. Billington and Andrew J. McCulloch and Alexander A. Wood and Robert E. Scholten}, doi = {10.1103/r7g8-ws2t}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023108}, shortjournal = {Phys. Rev. A}, title = {Selective ionization of rydberg atoms to reduce the energy spread of a cold-atom focused ion beam}, volume = {112}, year = {2025}, }
• (2025). Linear dichroism signals due to the alignment in the ground state of hydrogenlike atoms and their inversion in a single-beam optical pumping scheme. PRA, 112(2), 023107. (www)

  @article{ , abstract = {We present the results of theoretical and experimental investigation of optical linear dichroism signals caused by alignment, and arising under the action of pumping with linearly polarized light in a magnetic field transverse to the pumping in an ensemble of hydrogenlike (including alkali) atoms. Several simple models implying mixing of Zeeman sublevels of the excited state are considered, and common patterns among them are identified. It is shown that in the general case the properties of the medium causing dichroism can be characterized by only two parameters of the longitudinal and transverse linear polarizability, while in the case of complete mixing, by a single linear polarizability parameter. Expressions that relate these parameters to the transition probabilities are provided, as is an extension of the theory for the case of incomplete mixing of sublevels of the excited state. The single-beam scheme for recording linear dichroism signals, which is of greatest interest from a practical point of view, is investigated. It is shown that incomplete mixing can lead to inversion of dichroism signals in systems including more than one optical transition. A comparison with the results of an experimental study of dichroism in alkali-metal (cesium) vapors is made.}, archive = {J_PRA}, author = {M. V. Petrenko and A. S. Pazgalev and A. K. Vershovskii}, doi = {10.1103/wjyb-vf2y}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023107}, shortjournal = {Phys. Rev. A}, title = {Linear dichroism signals due to the alignment in the ground state of hydrogenlike atoms and their inversion in a single-beam optical pumping scheme}, volume = {112}, year = {2025}, }
• (2025). Pseudospin mapping of a multilevel scheme for rovibronic stabilization of weakly bound diatomic molecules. PRA, 112(2), 023106. (www)

  @article{ , abstract = {We propose a multilevel scheme to coherently transfer the population of a diatomic molecule, either polar or nonpolar, from a rovibrational level to a target rovibrational level of the same electronic state or another. It involves a linear chain of rovibrational levels alternating between the initial electronic state and a second electronic state, conveniently selected according to the dipole couplings between consecutive levels. A set of simultaneous weak ( ) laser pulses, with simple analytical shapes, each in resonance between two neighbors of the chain, transfers the population from the initial rovibronic state gradually and consecutively through the chain, until at the end of the process it resides in the target rovibronic state, as in a kind of ping-pong game between the two electronic states. Using the partial-wave expansion of the molecular wave function, vibrational bases within the manifolds of each electronic state, and the rotating-wave approximation (RWA), we map the radial Hamiltonian to the one of a spin under a static magnetic field, providing an analytical formula for the populations of the linked states. As an illustration, we apply this pseudospin representation to the stabilization into the absolute ground state of a KRb molecule initially in the high-lying level of the ground electronic state . With a chain of seven rovibronic states, three of them belonging to the excited electronic state, and pulses of 0.4 ns of duration, the population is fully transferred into the target state in about 1 ns. In addition, we perform a numerical simulation of the ping-pong process, taking into account the entire rovibrational space of both electronic states and without invoking the RWA, finding a good agreement with the results of the pseudospin model.}, archive = {J_PRA}, author = {Diego F. Uribe and Mateo Londoño and Julio C. Arce}, doi = {10.1103/zt28-q4pn}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023106}, shortjournal = {Phys. Rev. A}, title = {Pseudospin mapping of a multilevel scheme for rovibronic stabilization of weakly bound diatomic molecules}, volume = {112}, year = {2025}, }
• (2025). Multiphoton ionization distributions beyond the dipole approximation: Retardation versus recoil corrections. PRA, 112(2), 023105. (www)

  @article{ , abstract = {We study nondipole effects in multiphoton ionization of a two-dimensional hydrogen-like atom by a flat-top laser pulse of varied intensity. For this purpose, we solve numerically a two-dimensional Schrödinger equation treating a propagating laser pulse exactly. The resulting distributions are then compared to those calculated in the dipole approximation. By investigating the energy-angular photoelectron distributions, we demonstrate that the multiphoton peaks shift toward either smaller or larger energies depending on the photoelectron emission angle. This is analytically interpreted based on the leading-order relativistic expansion of the electron Volkov state, showing a significant contribution of the electron recoil to that behavior. In contrast, the retardation correction originating from the space- and time dependence of the laser field leads to a tiny redshift of the photoelectron energy spectra. Other features of ionization distributions are also analyzed, including the sidelobes and the double-hump structures of multiphoton peaks, or their disappearance for intense propagating laser pulses.}, archive = {J_PRA}, author = {J. Z. Kamiński and K. Krajewska}, doi = {10.1103/df6g-tpt9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023105}, shortjournal = {Phys. Rev. A}, title = {Multiphoton ionization distributions beyond the dipole approximation: Retardation versus recoil corrections}, volume = {112}, year = {2025}, }
• (2025). Adiabatic dynamics in a V-type quantum system by oppositely chirped counterrotating circularly polarized laser pulses. PRA, 112(2), 023104. (www)

  @article{ , abstract = {Shaped free electron vortices (SEVs) have recently been studied using atomic ( ) resonance-enhanced multiphoton ionization (REMPI) by oppositely chirped counterrotating circularly polarized (OC-CRCP) femtosecond laser pulses. By transitioning from the perturbative to the nonperturbative REMPI regime, we identify an adiabatic excitation mechanism in a resonant V-type three-level system, termed V-RAP due to its similarities to rapid adiabatic passage (RAP). Experimentally, we observe a pronounced change in the shape of the measured three-dimensional (3D) photoelectron momentum distribution (PMD), which we trace back to this mechanism via analytical calculations and numerical simulations of the bound state and ionization dynamics. In V-RAP, the atom adiabatically follows the OC-CRCP field, with the two excited states driven in antiphase, leading to an adiabatic cancellation of specific ionization pathways and explaining the observed changes in the PMD. In the experiment, we combine supercontinuum polarization pulse shaping to generate OC-CRCP femtosecond laser pulses with velocity map imaging-based photoelectron tomography to reconstruct the 3D PMD. The reconstructed PMDs are decomposed by 3D Fourier analysis into SEVs of different rotational symmetry, revealing a significant enhancement of the -symmetric contribution, which is the signature of the V-RAP.}, archive = {J_PRA}, author = {D. Köhnke and T. Bayer and M. Wollenhaupt}, doi = {10.1103/78w7-wc89}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023104}, shortjournal = {Phys. Rev. A}, title = {Adiabatic dynamics in a V-type quantum system by oppositely chirped counterrotating circularly polarized laser pulses}, volume = {112}, year = {2025}, }
• (2025). Nuclear clock based on the th v ion. PRA, 112(2), 023103. (www)

  @article{ , abstract = {We propose that a nuclear clock based on the Th v ion can surpass the accuracy of clocks built with other thorium ions. The Th 4 + ion has a rigid closed-shell core with zero total electron angular momentum, suppressing frequency shifts from black-body radiation and stray external fields that act mainly on electrons. We calculate the energy shift of the nuclear clock transition frequency in Th 229 due to the Coulomb field of atomic electrons and find a relative frequency difference of 2.8 × 10 − 7 between Th iv and Th v , 12 orders of magnitude larger than the projected 10 − 19 fractional uncertainty of a nuclear clock. We also perform calculations for Th v energy levels, ionization potential, static polarizability, quadratic Zeeman shift, and the black-body radiation shift of the nuclear line. Additionally, we determine the nuclear transition frequencies in two thorium ions and a neutral atom: ν N = 2 , 020 , 406.964 ( 70 ) GHz in Th iii , ν N = 2 , 020 , 408.264 ( 100 ) GHz in Th ii , and ν N = 2 , 020 , 408.364 ( 100 ) GHz in Th i .}, archive = {J_PRA}, author = {V. V. Flambaum and V. A. Dzuba and E. Peik}, doi = {10.1103/zcsk-3lw5}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023103}, shortjournal = {Phys. Rev. A}, title = {Nuclear clock based on the th v ion}, volume = {112}, year = {2025}, }
• (2025). Relativistic spin-flip effect in the attoclock. PRA, 112(2), 023102. (www)

  @article{ , abstract = {We study the effect of spin flip on tunneling ionization in the attoclock settings. Our study is based on a fully relativistic approach in which we seek a numerical solution of the time-dependent Dirac equation. We find that spin flip during strong field ionization significantly increases the attoclock offset angle, indicating longer tunneling delay relative to electrons with no spin flip. To interpret our numerical findings, we conduct additional modeling within the perturbative Breit-Pauli approach, which allows us to elucidate the role of different relativistic mechanisms. We show that the spin-orbit interaction is mainly responsible for the spin flip, rather than interaction with the magnetic component of the laser field. We further discuss the dynamic mechanisms of the spin-flip effect, suggesting that it takes place while the electron is still bound. Our findings indicate that the attoclock can be used to investigate electron spin-flip dynamics during the tunnel ionization process.}, archive = {J_PRA}, author = {I. A. Ivanov and A. S. Kheifets and A. S. Landsman}, doi = {10.1103/pfxy-2j96}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023102}, shortjournal = {Phys. Rev. A}, title = {Relativistic spin-flip effect in the attoclock}, volume = {112}, year = {2025}, }
• (2025). Collision-induced interaction dynamics of hyperpolarized nuclear spins in functionalized microfabricated vapor cells for chip-scale quantum devices. PRA, 112(2), 023101. (www)

  @article{ , abstract = {We theoretically modeled and experimentally demonstrated the collision-induced interaction of nuclear spins, including the Fermi contact interaction and wall-dependent quadrupole relaxation. We utilized heater-integrated, wafer-level microfabricated atomic vapor cells with a single-chamber cylindrical structure and a single-beam absorption-based atomic magnetometer to probe hyperpolarized nuclei precession in situ . We investigated the interaction of nuclear spins with alkali-metal vapor atoms and atomic vapor cell walls consistent with the theoretical model. Furthermore, we measured a Fermi contact factor of approximately , which reveals an enhancement in the spin-exchange collisions for , and an activation energy of eV, which characterizes the desorption and diffusion process of induced by the wall collision process. These results can inspire the development of chip-scale atomic spin devices with enhanced stability and sensitivity.}, archive = {J_PRA}, author = {Yintao Ma and Yao Chen and Mingzhi Yu and Yanbin Wang and Ju Guo and Liubo Zhang and Ping Yang and Qijing Lin and Dejiang Lu and Libo Zhao}, doi = {10.1103/hrvj-vgdx}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {023101}, shortjournal = {Phys. Rev. A}, title = {Collision-induced interaction dynamics of hyperpolarized nuclear spins in functionalized microfabricated vapor cells for chip-scale quantum devices}, volume = {112}, year = {2025}, }
• (2025). In situ doppler-free spectroscopy with pulsed optical fields. PRA, 112(2), 022825. (www)

  @article{ , abstract = {We propose a novel pulsed optical method based on saturated absorption spectroscopy, where the pump beam is periodically switched on and off using pulse amplitude modulation. This periodic alternation enables time-division multiplexing of the same probe beam into both probe and reference signals, achieving differential Doppler-free spectroscopy with a deterministic zero background. This method effectively mitigates Doppler broadening and common-mode optical noise by addressing disturbances such as nonuniform background absorption and environmental noise, thereby offering enhanced accuracy and robustness. Using this technique, we measured the transition frequency of isotopes in the transition. By employing an error signal derived from the dispersive signal of , we achieved efficient stabilization of a 369.5-nm ultraviolet diode laser, demonstrating a frequency stability of (26 kHz) over a 1500-s averaging period and a locking point standard deviation of 850 kHz sustained over 10 days. Furthermore, we report the first in situ observation of Doppler-free Zeeman sublevel spectra in a hot ion system, highlighting the precision of this method and its potential application in measuring magnetic field gradients.}, archive = {J_PRA}, author = {Yuxin Wang and Zhiyue Zheng and Qiuxin Zhang and Yonglang Lai and Zongqi Ge and Tianyi Wang and Liangyu Ding and Vasilii Smirnov and Ilya Semerikov and Shuaining Zhang and Wei Zhang and Xiang Zhang}, doi = {10.1103/w8tl-stvh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022825}, shortjournal = {Phys. Rev. A}, title = {In situ doppler-free spectroscopy with pulsed optical fields}, volume = {112}, year = {2025}, }
• (2025). Postcollision interaction in the liquid phase: The role of electron scattering. PRA, 112(2), 022824. (www)

  @article{ , abstract = {We report a detailed study of postcollision interaction (PCI) in a liquid medium. We investigate PCI for the Auger KLL electrons of solvated , and . All three isoelectronic ions exhibit a very similar PCI behavior, which is little affected by changing the solvent from water to methanol or ethanol. The two main factors modifying the PCI interaction in condensed media are the screening of Coulombic interactions and scattering of the electrons. The experimental results are compared with the predictions of a previously reported semiclassical PCI theory modified to account for screening and scattering. We show that a better agreement with experiment can be obtained by instead modeling scattering using electron transport Monte Carlo simulations. We suggest that, in turn, PCI experimental data could be used as another experimental constraint to refine the currently insufficiently well-known scattering parameters of low-energy electrons in water, which are crucial in many fields.}, archive = {J_PRA}, author = {Rémi Dupuy and Francis Penent and Bastien Lutet-Toti and Vincent Duval and Jérome Palaudoux and Denis Céolin}, doi = {10.1103/w8nr-cmw1}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022824}, shortjournal = {Phys. Rev. A}, title = {Postcollision interaction in the liquid phase: The role of electron scattering}, volume = {112}, year = {2025}, }
• (2025). Nuclear-electric-quadrupole-moment-induced parity doubling in molecules for symmetry-violation searches. PRA, 112(2), 022823. (www)

  @article{ , abstract = {Searches for the nuclear magnetic quadrupole moment (MQM) and nuclear Schiff moment (NSM) have high discovery potential for violations of time- and parity- reversal symmetries beyond the standard model. Molecules containing heavy nuclei are typically used to enhance the sensitivity to MQMs and NSMs due to their strong internal electric fields and potential octupole deformation. To extract these effects in the laboratory frame, a bias electric field is required to polarize the molecule by mixing states of opposite parity (parity doublets). Typical heavy nuclei that are sensitive to symmetry violation also possess large nuclear electric quadrupole moments (EQMs) when the nuclear spin is . We show that EQMs can significantly modify the energy splitting between parity-doublet states and thus change the required polarizing electric field. As a result, the EQM-induced energy splitting must be taken into account in designing such experiments. We provide qualitative estimates of parity doubling from EQMs and supporting ab initio calculations, along with implications for candidate molecules in symmetry-violation searches.}, archive = {J_PRA}, author = {X. Fan and L. Cheng}, doi = {10.1103/tydw-3ksd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022823}, shortjournal = {Phys. Rev. A}, title = {Nuclear-electric-quadrupole-moment-induced parity doubling in molecules for symmetry-violation searches}, volume = {112}, year = {2025}, }
• (2025). Floquet-engineered nondispersive wave packets in helium under combined periodic and static fields. PRA, 112(2), 022822. (www)

  @article{ , abstract = {We report the numerical observation of two-electron nondispersive wave packets in fully three-dimensional helium subjected to a linearly polarized monochromatic field. These localized quantum states follow periodic trajectories of the classical three-body Coulomb system without dispersion. The system is modeled using a spectral configuration interaction approach based on Coulomb-Sturmian functions, combined with Floquet theory and complex scaling. The resulting quasienergy spectrum reveals the existence of long-lived Floquet states arising from near-resonant coupling between frozen planet configurations.}, archive = {J_PRA}, author = {Alejandro González-Melan and John Fitzgerald León Ocampo and Javier Madroñero}, doi = {10.1103/6l7f-c2ks}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022822}, shortjournal = {Phys. Rev. A}, title = {Floquet-engineered nondispersive wave packets in helium under combined periodic and static fields}, volume = {112}, year = {2025}, }
• (2025). Valence (S1) and nonvalence (dipole-bound) spectroscopy of chromophore models of the photoactive yellow protein probed by cryogenic action spectroscopy. PRA, 112(2), 022821. (www)

  @article{ , abstract = {We investigated two deprotonated paracoumaric acid model chromophores of the photoactive yellow protein, and , using action-absorption spectroscopy. Employing cryogenic cooling, we determined the band origins and associated vibrational resonances, which were found to reside within the electronic continuum, rendering them susceptible to autodetachment. Resonances observed below the electron-detachment threshold were attributed to dipole-bound states of the neutral radical core, probed via resonant two-photon excitation and detachment. Above the electron-detachment limit, we identified dipole-resonance states susceptible to autodetachment. The experimental approach, combining 6 K helium-buffer gas cooling with an ion-storage ring, proved effective in resolving vibrational modes of both the neutral radical core and the valence-excited state, revealing soft-mode resonances down to 50–100 . Time-resolved action detection indicates that internal conversion competes with autodetachment.}, archive = {J_PRA}, author = {L. H. Andersen and A. P. Rasmussen and H. B. Pedersen and N. Klinkby}, doi = {10.1103/k3n9-3897}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022821}, shortjournal = {Phys. Rev. A}, title = {Valence (S1) and nonvalence (dipole-bound) spectroscopy of chromophore models of the photoactive yellow protein probed by cryogenic action spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Spectroscopy and recurrent fluorescence from cryogenically cooled c4−. PRA, 112(2), 022820. (www)

  @article{ , abstract = {We report on the direct observation of recurrent fluorescence (RF) from initially cold anions obtained at specific photoexcitations from the electronic ground state ( ) under conditions mimicking the environment in interstellar space. Using a combination of buffer gas cooling in a (small) radio-frequency ion trap and laser excitation in an electrostatic ion storage ring, we explicitly illustrate the cooling of a molecular system due to RF and meet an experimental challenge posed almost 40 years ago. In the effort to directly observe RF, we also reexamine the spectroscopy of the transition in as probed by two-photon photodetachment spectroscopy and assign all observed transitions from cold . Our assignment and modeling of the observed photoabsorption spectrum allow us to determine spin-orbit coupling constants for both the ground ( ) and third excited ( ) state of and reveal their variation with vibrational excitation energy for the symmetric stretch mode and the asymmetric stretch mode of the excited state.}, archive = {J_PRA}, author = {H. B. Pedersen and L. H. Andersen}, doi = {10.1103/g4m2-6drv}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022820}, shortjournal = {Phys. Rev. A}, title = {Spectroscopy and recurrent fluorescence from cryogenically cooled c4−}, volume = {112}, year = {2025}, }
• (2025). Electron affinity of CH. PRA, 112(2), 022819. (www)

  @article{ , abstract = {We measured the thresholds for photodetachment from the first and second excited rotational levels of to the lowest vibrational, rotational, and fine-structure level of CH to be and , respectively. Based on these measurements and the rigid rotor approximation, we arrive at an electron affinity of . This value deviates from earlier experimental results but agrees with the calculation by Feller [ J. Chem. Phys. 144 , 014105 (2016) ]. In the present experiment, we stored ensembles of initially hot in the cryogenic ion-beam storage ring Double ElectroStatic Ion-Ring ExpEriment (DESIREE) for tens of seconds such that the vast majority of the ions were in the few lowest excited rotational levels of the electronic and vibrational ground state. We identified the initial states for photodetachment channels with threshold energies and by comparing the time dependences of measured photodetachment signals with radiative rotational-cooling rates calculated using the literature values of the dipole moment of . The conditions of a few occupied rotational levels are superior to those of previous studies of this system and an important step toward future studies with an all-rotational-ground-state ion beam.}, archive = {J_PRA}, author = {Gustav Eklund and Moa K. Kristiansson and K. C. Chartkunchand and Emma K. Anderson and Malcolm Simpson and Roland Wester and Henning T. Schmidt and Henning Zettergren and Henrik Cederquist and Wolf D. Geppert}, doi = {10.1103/sjyb-dt3c}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022819}, shortjournal = {Phys. Rev. A}, title = {Electron affinity of CH}, volume = {112}, year = {2025}, }
• (2025). Close-coupling approach to a model problem for resonant collisions of electrons with diatomic molecules. PRA, 112(2), 022818. (www)

  @article{ , abstract = {In the theoretical study of electron-molecule collisions, resonant processes such as vibrational excitation and dissociative electron attachment and recombination are difficult to model due to the breakdown of common techniques such as the adiabatic-nuclei approximation. For this reason, it is useful to have an exactly solvable model so that the validity of different theories can be tested, such as the two-dimensional model introduced by Houfek et al. [ Phys. Rev. A 73 , 032721 (2006) ] and extended to charged targets by Hvizdoš et al. [ Phys. Rev. A 97 , 022704 (2018) ]. We have applied the convergent close-coupling method, a well-established approach for solving a variety of scattering problems, to this two-dimensional model problem. Dissociative attachment and recombination are treated within the same formalism, and the direct and resonant contributions to vibrational excitation are both fully accounted for as a result of solving the close-coupling equations. To accurately model these processes at all energies, the two-center approach is used, in which the states of the dissociated fragments are explicitly included in the expansion of the wave function of the scattering system. Cross sections for vibrational excitation, dissociative attachment, and direct dissociation are calculated for NO-like and -like targets, and excellent agreement is found with existing results. Cross sections for vibrational excitation and dissociative recombination are calculated for a -like target, and despite challenges with modeling the many resonances of the cross section, we find reasonably good agreement with existing results.}, archive = {J_PRA}, author = {Jamie M. Erak and Dmitry V. Fursa and Igor Bray and Liam H. Scarlett}, doi = {10.1103/w6sg-g7r9}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022818}, shortjournal = {Phys. Rev. A}, title = {Close-coupling approach to a model problem for resonant collisions of electrons with diatomic molecules}, volume = {112}, year = {2025}, }
• (2025). Fragmentation dynamics of NCCN2+ and NCCN3+ induced by 1-keV electron impact. PRA, 112(2), 022817. (www)

  @article{ , abstract = {The fragmentation dynamics of produced by 1-keV electron impact have been investigated using the ion momentum imaging technique. Five two-body and two three-body fragmentation channels are identified including two isomerization pathways. The reaction coordinates of isomerization channels were investigated by quantum chemistry calculation. By measuring the momentum vectors of the fragment ions, the kinetic energy release distributions have been determined. With the help of the Dalitz plot, Newton diagram, and native-frame method, we investigated the fragmentation mechanisms of the three-body fragmentation channels. It is found that the channel only dissociates via the concerted mechanism, while channel presents two sequential fragmentation processes with and as intermediate moieties in addition to the concerted fragmentation.}, archive = {J_PRA}, author = {Wenchao Zhao and Enliang Wang and Xingyu Guo and Wenguang Wu and Zhaopeng Xing and Lei Chen and Xu Shan and Xiangjun Chen}, doi = {10.1103/4bns-psps}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022817}, shortjournal = {Phys. Rev. A}, title = {Fragmentation dynamics of NCCN2+ and NCCN3+ induced by 1-keV electron impact}, volume = {112}, year = {2025}, }
• (2025). Sturmian basis set for the dirac equation with finite nuclear size: Application to polarizability, zeeman and hyperfine splitting, and vacuum polarization. PRA, 112(2), 022816. (www)

  @article{ , abstract = {We investigate the application of the Sturmian basis set to relativistic atomic structure calculations. We propose a simple implementation of this approach and demonstrate its ability to provide various quantities for hydrogenlike ions, including binding energies, static dipole polarizability, the factor, hyperfine splitting, and nuclear magnetic shielding. Finally, we calculate the all-order (Wichmann-Kroll) vacuum-polarization charge density, which was a challenge for the finite-basis-set approach until recently. We present a comparison of the obtained results with previously published numerical and analytical calculations. All calculations are performed with nuclei of a finite size and can, in principle, be extended to arbitrary binding potentials.}, archive = {J_PRA}, author = {V. K. Ivanov and D. A. Glazov and A. V. Volotka}, doi = {10.1103/tf1t-wj6w}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022816}, shortjournal = {Phys. Rev. A}, title = {Sturmian basis set for the dirac equation with finite nuclear size: Application to polarizability, zeeman and hyperfine splitting, and vacuum polarization}, volume = {112}, year = {2025}, }
• (2025). Characterization of the electronic ground state of he2+ by high-resolution photoelectron spectroscopy. PRA, 112(2), 022815. (www)

  @article{ , abstract = {Excluding the very shallow potential minimum of the electronic ground state, all bound electronic states of He 2 have Rydberg character. Their potential-energy functions are very similar to the potential-energy functions of the He 2 + states to which the Rydberg series converge. Photoionization and electron-impact ionization of the metastable a 3 Σ u + state of He 2 are thus characterized by diagonal Franck-Condon factors and only provide access to low vibrational levels of the He 2 + X + 2 Σ u + electronic ground state. For this reason, hardly any experimental information is available on the excited vibrational levels of He 2 + . We report on a measurement, by high-resolution photoelectron spectroscopy, of 17 vibrational levels of the X + 2 Σ u + state of 4 He 2 + , with vibrational quantum number v + ranging from 3 to 19 and covering more than 95% of the potential well. To access these states, we exploit a hump in the potential-energy function of the c 3 Σ g + state, which has vibrational wave functions extending to large internuclear distance by quantum-mechanical tunneling through the potential barrier. Combining these new results with data available on the lowest ( v + = 0 – 2 ) and highest ( v + = 22 , 23 ) vibrational levels of 4 He 2 + , we derive a full map of the rovibrational level structure of He 2 + and use it to determine, in a least-squares fit, an empirical effective potential-energy function that describes all experimental data within their uncertainties. This potential-energy function is used to calculate the positions of the 409 bound rovibrational levels and the positions and widths of the 74 shape resonances of the X + 2 Σ u + electronic ground state of 4 He 2 + . The dissociation energy of He 2 + is determined to be D e = 19 956.10 ( 10 ) cm − 1 [ D 0 ( 4 He 2 + ) = 19 101.29 ( 10 ) cm − 1 ] .}, archive = {J_PRA}, author = {M. Holdener and V. Wirth and N. A. Shahin and M. Beyer and F. Merkt}, doi = {10.1103/w95m-w7hc}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022815}, shortjournal = {Phys. Rev. A}, title = {Characterization of the electronic ground state of he2+ by high-resolution photoelectron spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Precision measurement of Cs(nFJ) quantum defects and calculations of scalar and tensor polarizabilities of the nS1/2, nPJ, nDJ, and nFJ series. PRA, 112(2), 022814. (www)

  @article{ , abstract = {In this paper, we extend our recent work on cesium S and D states [P. Shen et al. , Phys. Rev. Lett. 133 , 233005 (2024) ] to the F states. We present absolute frequency measurements of the | 6 S 1 / 2 , F = 3 〉 → n F 5 / 2 , 7 / 2 ( n = 28 – 68 ) Rydberg series to measure the spectrum of Cs 133 . Atomic spectra are obtained using a three-photon excitation scheme referenced to an optical frequency comb in a sample of ultracold Cs 133 . By globally fitting the absolute-frequency measurements to the modified Ritz formula, we determine the quantum defects of the n F 5 / 2 and n F 7 / 2 series. The ionization potential extracted for both series from the modified Ritz formula agrees with our measurements based on the S and D series. Fine-structure intervals are calculated and parameterized. The wave functions computed for the energies from the quantum defects are used to calculate transition dipole moments. We compare the reduced electric-dipole matrix elements with available benchmarks and find agreement within the precision of those works. The scalar and tensor polarizabilities of the n S 1 / 2 , n P J , n D J , and n F J series are calculated based on the now more accurate set of wave functions. Moreover, we report the polarizability as a series in powers of the effective principal quantum number and find the main coefficients of the expansion. The results will be useful for calculating properties of Cs 133 such as collision and decay rates, polarizabilities, and magic wavelengths.}, archive = {J_PRA}, author = {Pinrui Shen and Mariusz Pawlak and Donald Booth and Kent Nickerson and Haddad Miladi and H. R. Sadeghpour and James Shaffer}, doi = {10.1103/dkb4-kb5b}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022814}, shortjournal = {Phys. Rev. A}, title = {Precision measurement of Cs(nFJ) quantum defects and calculations of scalar and tensor polarizabilities of the nS1/2, nPJ, nDJ, and nFJ series}, volume = {112}, year = {2025}, }
• (2025). Relativistic corrections of order mα6: Singular operators and regularization. PRA, 112(2), 022813. (www)

  @article{ , abstract = {The finite operators are derived for the nonrecoil [leading order in the expansion] relativistic corrections in hydrogenlike atoms and ions at order in the two- and three-body formalisms beyond the adiabatic approximation. Singular operators that appear in the derivation are analyzed, and various regularization methods are discussed.}, archive = {J_PRA}, author = {V. I. Korobov}, doi = {10.1103/l5hv-yx2p}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022813}, shortjournal = {Phys. Rev. A}, title = {Relativistic corrections of order mα6: Singular operators and regularization}, volume = {112}, year = {2025}, }
• (2025). Compton ionization of atomic hydrogen by a twisted photon under the conditions of the electron-ion coincidence method. PRA, 112(2), 022812. (www)

  @article{ , abstract = {Electron-ion coincidence method, in particular cold-target recoil-ion momentum spectroscopy (COLTRIMS), is currently the most advanced tool for detailed study of the processes of Compton ionization of atoms. We have performed a theoretical analysis of the capabilities of this method as applied to Compton ionization of an atom by a twisted x-ray photon. Our analysis uses the nonstationary formalism of quantum scattering theory, which, unlike the generally accepted stationary formalism, allows one to take into account the specifics of real initial states (wave packets) of a photon and an atom. We have shown that the energy and angular distribution of ionized electrons measured in coincidence with recoil ions does not depend on the orbital angular momentum of the twisted photon, but depends on its cone angle (opening angle), which determines the characteristic angular shift in the distribution.}, archive = {J_PRA}, author = {K. A. Bornikov and K. A. Kouzakov and Yu. V. Popov}, doi = {10.1103/nlk1-1v39}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022812}, shortjournal = {Phys. Rev. A}, title = {Compton ionization of atomic hydrogen by a twisted photon under the conditions of the electron-ion coincidence method}, volume = {112}, year = {2025}, }
• (2025). Search for variations of the fine-structure constant via the hyperfine electronic bridge in highly charged th229 ions. PRA, 112(2), 022811. (www)

  @article{ , abstract = {The search for variations of the fine-structure constant by using atomic clocks has driven the development of novel atomic clock technologies. Among these, the nuclear clock based on nuclear transition stands out due to its high sensitivity. Previous studies on the variation in atomic clocks have typically focused purely either on a nuclear or electronic transition but not on the hyperfine electronic bridge (HEB) transitions, which involve simultaneous changes in both nuclear and electronic structures. In this work, we propose to search for the variation by measuring the 3.14-eV HEB transition between the hyperfine levels and of ions, and the 2.39-eV HEB transition between and of ions. These two HEB transitions exhibit remarkably large sensitivity factors of about and , respectively. Compared to the nuclear-clock transition in bare ions, the sensitivity factors are significantly enhanced by factors of 2.7 and 3.5. Moreover, both the 3.14- and 2.39-eV HEB transitions are well supported by current high-precision laser technology, making our approach promising for improving the precision of variation detection.}, archive = {J_PRA}, author = {Wu Wang and Stephan Fritzsche and Yong Li}, doi = {10.1103/64n6-9b44}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022811}, shortjournal = {Phys. Rev. A}, title = {Search for variations of the fine-structure constant via the hyperfine electronic bridge in highly charged th229 ions}, volume = {112}, year = {2025}, }
• (2025). Chiral environment effects on the dynamics of a central chiral molecule. PRA, 112(2), 022810. (www)

  @article{ , abstract = {In this work, we develop a system plus environment approach for interacting chiral molecules under a quantum-classical description of the spin-spin model using a Caldeira-Leggett-like coupling. After presenting the interacting model, we show that a long-ranged parity-nonconserving interaction, encoded within a nonlinear Schrödinger equation, produces an energy difference between the two enantiomers of the central chiral molecule when it interacts with a chiral environment. Three examples of such interactions are considered, with particular focus on -photon vacuum polarization. Finally, we reveal a chirality transmission effect phenomenon, where the time-averaged population difference of the central molecule is amplified when the chiral asymmetry of the environment is considered.}, archive = {J_PRA}, author = {Daniel Martínez-Gil and Pedro Bargueño and Salvador Miret-Artés}, doi = {10.1103/x577-1nzd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022810}, shortjournal = {Phys. Rev. A}, title = {Chiral environment effects on the dynamics of a central chiral molecule}, volume = {112}, year = {2025}, }
• (2025). Determination of a set of fundamental constants from molecular hydrogen ion spectroscopy: A modeling study. PRA, 112(2), 022809. (www)

  @article{ , abstract = {The rovibrational transition frequencies of molecular hydrogen ions can be accurately computed using ab initio nonrelativistic quantum electrodynamics. A subset of the fundamental constants is required input. We analyze how, once upcoming ultra-high-accuracy spectroscopy data have been obtained, that subset of constants can be determined with greater accuracy. Our analysis shows that under realistic assumptions the uncertainties of the mass ratios of the proton, deuteron, and triton, relative to the electron, and of the triton charge radius can be reduced more than 100-fold compared to today (CODATA 2022). Furthermore, the Rydberg constant, as well as the proton and deuteron charge radii, can be determined with uncertainties similar to those of today, but solely using data from electronic systems. The implications are discussed.}, archive = {J_PRA}, author = {J.-Ph. Karr and S. Schiller and V. I. Korobov and S. Alighanbari}, doi = {10.1103/jz54-7f7b}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022809}, shortjournal = {Phys. Rev. A}, title = {Determination of a set of fundamental constants from molecular hydrogen ion spectroscopy: A modeling study}, volume = {112}, year = {2025}, }
• (2025). Relativistic recoil corrections of order m(Zα)6(m/M): Hydrogenlike atoms and hydrogen molecular ions. PRA, 112(2), 022808. (www)

  @article{ , abstract = {The finite operators are derived for the relativistic recoil corrections of order m α 6 ( m / M ) to spin-averaged energy levels in hydrogenlike atoms and ions in two- and three-body formalisms beyond the adiabatic approximation. Results are presented in a form suitable for numerical evaluation.}, archive = {J_PRA}, author = {V. I. Korobov}, doi = {10.1103/ctjy-f8ft}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022808}, shortjournal = {Phys. Rev. A}, title = {Relativistic recoil corrections of order m(Zα)6(m/M): Hydrogenlike atoms and hydrogen molecular ions}, volume = {112}, year = {2025}, }
• (2025). Theoretical study of transition matrix elements in cadmium for vacuum-ultraviolet generation in th229 nuclear clock applications. PRA, 112(2), 022807. (www)

  @article{ , abstract = {The relativistic Fock-space coupled-cluster methods are applied to the cadmium atom. A large number of transition energies and matrix elements are calculated for the , and transitions for a wide range of states accounting for relativistic and electron-correlation effects. The results obtained within two different approaches (Fock-space coupled cluster and configuration interaction) are compared with available experimental and theoretical data. Good agreement is found between the two methods for transitions involving low-lying excited states, whereas for high-lying states the discrepancy becomes large. The calculated values are used to determine the third-order nonlinear susceptibility of cadmium vapor, with an agreement within 5% between the different methods. The results of the present computations support the feasibility of generating vacuum-ultraviolet light in Cd vapor via a four-wave mixing process for the direct excitation of the nucleus.}, archive = {J_PRA}, author = {Gleb Penyazkov and Yanmei Yu and Leonid V. Skripnikov and Shiqian Ding}, doi = {10.1103/q6b3-mcfp}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022807}, shortjournal = {Phys. Rev. A}, title = {Theoretical study of transition matrix elements in cadmium for vacuum-ultraviolet generation in th229 nuclear clock applications}, volume = {112}, year = {2025}, }
• (2025). Electron-impact cross sections for dissociation processes of the vibrationally excited CH radical. PRA, 112(2), 022806. (www)

  @article{ , abstract = {This paper presents a theoretical investigation of the cross sections for dissociative electron attachment and dissociative excitation processes in vibrationally excited CH radicals induced by electron impact. Resonant electron-CH collisions are analyzed using the ab initio -matrix method, while nuclear dynamics are explored within the local complex potential framework. A comprehensive set of vibrationally resolved cross sections and rate coefficients is provided for both the ground and first excited electronic states of the CH molecule. These findings contribute to a better understanding of the kinetics of nonequilibrium systems containing CH molecules with applications in plasma technologies for reduction, combustion processes, and various astrophysical contexts.}, archive = {J_PRA}, author = {O. Abidi and I. Jendoubi and M. Telmini and R. Ghosh and K. Chakrabarti and V. Laporta}, doi = {10.1103/jdw1-rqg7}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022806}, shortjournal = {Phys. Rev. A}, title = {Electron-impact cross sections for dissociation processes of the vibrationally excited CH radical}, volume = {112}, year = {2025}, }
• (2025). Total cross sections for electron capture in arq+ (q=7,8) with he and h2 collisions. PRA, 112(2), 022805. (www)

  @article{ , abstract = {This study systematically measures the absolute cross sections for single and double electron capture in collisions of (1.4–20 keV/u) and (1.05–17.5 keV/u) ions with and He targets. We investigate the influence of the target's first ionization potential, projectile charge state, and collision energy on electron capture cross sections, with comparative analysis against scaling laws and predictions from the absorbing sphere model. These results provide insights into the mechanisms governing collisions between highly charged ions and atomic systems, offering valuable references for theoretical development and practical applications in plasma collisions.}, archive = {J_PRA}, author = {Y. Wu and H. Yin and X. Tan and P. Ma and T. Meng and J. Xiao and K. Yao and Y. Zou and B. Tu and B. Wei}, doi = {10.1103/36yc-3dwb}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022805}, shortjournal = {Phys. Rev. A}, title = {Total cross sections for electron capture in arq+ (q=7,8) with he and h2 collisions}, volume = {112}, year = {2025}, }
• (2025). Second-order hyperfine structure and its impact on searches for new physics using isotope-shift spectroscopy. PRA, 112(2), 022804. (www)

  @article{ , abstract = {Recent precision isotope shift spectroscopy experiments have reported King plot nonlinearities that may uncover previously hidden nuclear properties or hint at new force-carrying bosons. Interpreting the data requires many isotope pairs, but sufficient stable spin-zero nuclei are not always available. In this paper we consider the use of isotopes with nonzero nuclear spin for these studies. We confirm that observed King plot nonlinearity in strontium is explained by a second-order hyperfine shift in the fermionic nucleus, and we discuss the limitations of using Yb isotopes with nonzero spin in King plot studies. By introducing a specific difference of two isotopes with nuclear spin, we allow for a promising addition to future experimental schemes.}, archive = {J_PRA}, author = {Julian C. Berengut and Natalia S. Oreshkina}, doi = {10.1103/qkv8-z8z1}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022804}, shortjournal = {Phys. Rev. A}, title = {Second-order hyperfine structure and its impact on searches for new physics using isotope-shift spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Rotational-hyperfine cooling of TlF205 in a cryogenic beam. PRA, 112(2), 022803. (www)

  @article{ , abstract = {The aim of the Cold Molecule Nuclear Time-Reversal Experiment (CeNTREX) is to search for a time-reversal symmetry violation in the thallium nucleus by measuring the Schiff moment of in the polar molecule thallium fluoride (TlF). CeNTREX uses a cryogenic beam of TlF with a rotational temperature of 6.3(2) K. This results in a population spread over dozens of rotational and hyperfine sublevels of TlF, although only a single level is useful for the Schiff-moment measurement. Here, we present a protocol for cooling the rotational and hyperfine degrees of freedom in the CeNTREX beam, transferring the majority of the Boltzmann distribution into a single rotational and hyperfine sublevel by using a single ultraviolet laser and a pair of microwave beams. We achieve a factor of 20.1(4) gain in the population of the hyperfine sublevel of the TlF ground state.}, archive = {J_PRA}, author = {CeNTREX Collaboration and Olivier Grasdijk and David DeMille and Jakob Kastelic and Steve Lamoreaux and Oskari Timgren and Konrad Wenz and Tanya Zelevinsky and David Kawall}, doi = {10.1103/vb31-f2c3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022803}, shortjournal = {Phys. Rev. A}, title = {Rotational-hyperfine cooling of TlF205 in a cryogenic beam}, volume = {112}, year = {2025}, }
• (2025). Use of wigner expansion and path-integral method for quantum correction of the low-order spectral moments and collision-induced absorption profiles. PRA, 112(2), 022802. (www)

  @article{ , abstract = {This study aims at examination of the lower-order spectral moments in collision-induced absorption (CIA), taking the translational He-Ar band as an example. Quantum corrections for the zeroth and first spectral moments of the translational profile are derived on the basis of the Wigner expansion up to the order of and , respectively. These corrections were then explored for numerical simulation of the He-Ar moments over the temperature range 50–500 K. The accuracy of the obtained temperature dependencies is validated through the comparison with direct quantum solution of the scattering and bound-state problems as well as with the results obtained using the path-integral (PI) approach. Close agreement was achieved as a result of the application of the two independent ways of approximate accounting for the quantum nature of absorption. The robustness of the Wigner expansion and PI corrections was thus demonstrated, both of which can be used to obviate direct quantum simulation of the CIA spectral moments. The approximate method is suggested for an accurate simulation of the CIA spectral profile on the basis of the obtained quantum-corrected moments and the classical trajectory-based formalism.}, archive = {J_PRA}, author = {Daniil N. Chistikov and Artem A. Finenko}, doi = {10.1103/19g3-fwf3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022802}, shortjournal = {Phys. Rev. A}, title = {Use of wigner expansion and path-integral method for quantum correction of the low-order spectral moments and collision-induced absorption profiles}, volume = {112}, year = {2025}, }
• (2025). Dirac equation for positronium with breit interaction. PRA, 112(2), 022801. (www)

  @article{ , abstract = {The two-body Dirac equation for positronium is studied with the Coulomb and Breit interactions. When adding an annihilation correction, its energies agree with experiment up to fourth order in powers of the fine structure constant if the Breit term is treated perturbatively. We analyze why this is not true if the Dirac equation is solved numerically. Symmetries of the 16-component Dirac spinors are first detailed. For each symmetry, coupled differential equations verified by their radial components are established in a self-adjoint form convenient for numerical calculations. Nondifferential relations between these components are derived. The coupled equations are first solved in the Coulomb case with the Lagrange-mesh method. With only four mesh points, accurate binding energies are obtained which match the best published results except for the and states. A detailed study of the radial spinor components of the ground states of para- and orthopositronium explains why the convergence of their energies stops at an accuracy of about atomic units. A curious property of the Lagrange-mesh method is emphasized. Analytical approximations of these radial components are derived and compared with numerical solutions. The obtained Coulomb-Dirac spinors provide an original variant of first-order perturbation treatment of the Breit operator. The Coulomb-Breit-Dirac coupled equations are then solved under the numerical conditions tested with the Coulomb case. The differences between these numerical energies and the correct perturbation results at fourth order are analyzed. The unphysical numerical values of energies are shown to be due to couplings with the negative continua.}, archive = {J_PRA}, author = {Daniel Baye and Ergash M. Tursunov}, doi = {10.1103/74cl-325x}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022801}, shortjournal = {Phys. Rev. A}, title = {Dirac equation for positronium with breit interaction}, volume = {112}, year = {2025}, }
• (2025). Predicting fermionic densities using a projected-quantum-kernel method. PRA, 112(2), 022620. (www)

  @article{ , abstract = {We use support vector regression based on a projected-quantum-kernel method to predict the density structure of one-dimensional fermionic systems of interest in quantum chemistry and quantum matter. The kernel is built upon with the observables of a quantum reservoir implementable with interacting Rydberg atoms. Training and test data of the fermionic system are generated using a density-functional theory approach. We test the performance of the method for several Hamiltonian parameters, finding a general common behavior of the error as a function of measurement time. At sufficiently long measurement times, we find that the method outperforms the classical linear kernel method and becomes competitive with the radial basis function method.}, archive = {J_PRA}, author = {F. Perciavalle and F. Plastina and M. Pisarra and N. Lo Gullo}, doi = {10.1103/tdj2-wltj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022620}, shortjournal = {Phys. Rev. A}, title = {Predicting fermionic densities using a projected-quantum-kernel method}, volume = {112}, year = {2025}, }
• (2025). High-efficiency quantum-key-distribution error-correction algorithm based on the gilbert-elliott model and the low-density parity-check code. PRA, 112(2), 022619. (www)

  @article{ , abstract = {For the post-processing of the quantum-key-distribution (QKD) system, the error correction is the most important step, whose efficiency significantly influences the final key generation rate. Traditionally, the error-correction algorithm is developed based on the binary symmetrical channel model. However, this may not comply with the actual channel status. For example, for the fiber-based QKD system, differentiable statuses of the fiber (unstable or steady) should exist for some time and cause different bit error rates. If this channel feature can be exploited, it may considerably improve the error-correction efficiency. This paper proposes to introduce the Gilbert-Elliott (GE) model to analyze the QKD channel. The error-correction algorithm adopts the low-density parity-check (LDPC) code. The GE nodes are added into the traditional belief propagation (BP) algorithm of the LDPC decoder. Simulation results showed that the remaining frame error rate could be improved from (or ) to . An actual QKD system with the quantum channel state under manual control was adopted to collect the key bit string. By analyzing the occurrence probability of the consecutive "1," the key bit string showed closely matched distribution with the GE model prediction. After the error correction, the remaining bit error rate of the modified BP algorithm was significantly smaller than that of the standard BP algorithm with an improvement of more than 2 orders of magnitude. Both simulation and actual experimental results demonstrate that our proposed method can greatly improve the error-correction efficiency if the channel characteristic of the QKD system is accurately exploited, which provides an efficient way to generate a higher key rate.}, archive = {J_PRA}, author = {Ke Cui and Xianglong Xia and Simeng Li and Ming Zhu and Jian Sun and Shibiao Tang}, doi = {10.1103/xnb7-cghn}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022619}, shortjournal = {Phys. Rev. A}, title = {High-efficiency quantum-key-distribution error-correction algorithm based on the gilbert-elliott model and the low-density parity-check code}, volume = {112}, year = {2025}, }
• (2025). Application of the pontryagin maximum principle to the robust time-optimal control of two-level quantum systems. PRA, 112(2), 022618. (www)

  @article{ , abstract = {We study the time-optimal robust control of a two-level quantum system subjected to field inhomogeneities. We apply the Pontryagin maximum principle and we introduce a reduced space onto which the optimal dynamics is projected down. This reduction leads to a complete analytical derivation of the optimal solution in terms of elliptic functions and elliptic integrals. Necessary optimality conditions are then obtained for the original system. These conditions are verified numerically and lead to the optimal control protocol. Various examples, ranging from state-to-state transfer to the generation of a NOT gate, illustrate this study. The connection with other geometric optimization approaches that have been used to solve this problem is also discussed. Finally, we show how this method can be combined with numerical optimization algorithms to design robust control for higher-dimensional quantum systems, as illustrated by a Bose-Einstein condensate in an optical lattice.}, archive = {J_PRA}, author = {O. Fresse-Colson and S. Guérin and Xi Chen and D. Sugny}, doi = {10.1103/rn5j-kjq3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022618}, shortjournal = {Phys. Rev. A}, title = {Application of the pontryagin maximum principle to the robust time-optimal control of two-level quantum systems}, volume = {112}, year = {2025}, }
• (2025). Multiple quantum many-body clustering probed by dynamical decoupling. PRA, 112(2), 022617. (www)

  @article{ , abstract = {The manipulation of quantum information in large systems requires precise control of quantum systems that are out of equilibrium. As the size of the system increases, its fragility in response to external perturbations and intrinsic decoherence processes also increases. The degradation of the system response makes accurate measurements a challenging and time-consuming task. However, quantum information lifetime enhancement can be achieved by dynamical decoupling techniques, where an external drive with a frequency much higher than the system's internal evolution renders signal acquisition with decay times greater than 1000-fold. In this study, we demonstrate that the system response during a prethermal period, subject to Floquet control, can be utilized to probe the multiple quantum evolution of dense and highly connected spin systems. This approach exhibits an enhanced sensitivity at a reduced experimental time. The enhanced signal-to-noise ratio achieved enabled the use of numerical inversion strategies to model the evolution of the excited multiple quantum coherences, which describe the number of correlated spins within a cluster. We observed that the increase in the number of correlated spins with multiple quantum evolution is accompanied by an increase in the distribution of spin cluster sizes, which follows a quadratic law.}, archive = {J_PRA}, author = {Gerónimo Sequeiros and Claudia M. Sánchez and Lisandro Buljubasich and Ana K. Chattah and Horacio M. Pastawski and Rodolfo H. Acosta}, doi = {10.1103/q39p-yjnm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022617}, shortjournal = {Phys. Rev. A}, title = {Multiple quantum many-body clustering probed by dynamical decoupling}, volume = {112}, year = {2025}, }
• (2025). Neutral-atom entangling gate in the ultrastrong coupling regime. PRA, 112(2), 022616. (www)

  @article{ , abstract = {We propose a method to deterministically entangle qubits or ensembles of qubits interacting with a shared bosonic mode in the ultrastrong coupling regime. We show that the resulting gate is a product of two unitaries: one unitary acts only on the quantum state of the qubits and entangles them, while the other acts only on the quantum state of the boson, producing a phase shift. We find that the gate time is inversely proportional to the qubit-boson interaction strength, and by tuning the qubit-boson interaction strength, one can prepare a maximally entangled state or a squeezed state. Applying the quantum gate to multiple qubit ensembles, we show that the quantum gate prepares a Schrödinger cat state. We also examine imperfections such as including free evolution of the qubits and show that this produces an effective mixing. Our proposal is feasible for ultrastrong coupling experiments.}, archive = {J_PRA}, author = {Ebubechukwu O. Ilo-Okeke and Tongzhou Wang and Valentin Ivannikov and Tim Byrnes}, doi = {10.1103/lzpl-5jwc}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022616}, shortjournal = {Phys. Rev. A}, title = {Neutral-atom entangling gate in the ultrastrong coupling regime}, volume = {112}, year = {2025}, }
• (2025). Unique quantum advantages by manipulation of atoms in quantum batteries. PRA, 112(2), 022615. (www)

  @article{ , abstract = {The advent of quantum batteries (QBs) has coincided with the accelerated progress in quantum science and technology. Here, we propose a novel double-cavity QB design, wherein the maximum charging power can be enhanced to times or even higher, up to times, through the manipulation of atomic distribution, which surpasses the upper limit of reported in previous study. The advantage of this manipulation is pronounced with an increasing number of atoms in the QB. A significant atom number discrepancy between the two cavities results in the simultaneous optimization of charging power and battery capacity, thereby enhancing charging efficiency without compromising energy storage capacity. Additionally, by modulating the number of atoms within each cavity, the QB is theoretically capable of transitioning between “fast charging” and “slow charging” modes. Notably, in an open system environment, the superiority of the QB is even more pronounced, with negligible energy loss at the final steady state relative to the maximum energy storage of an isolated system.}, archive = {J_PRA}, author = {Dayang Zhang and Shuangquan Ma and Youbin Yu and Guangri Jin and Aixi Chen}, doi = {10.1103/3tm5-vsqw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022615}, shortjournal = {Phys. Rev. A}, title = {Unique quantum advantages by manipulation of atoms in quantum batteries}, volume = {112}, year = {2025}, }
• (2025). Proposal for realizing quantum-spin systems on a two-dimensional square lattice with dzyaloshinskii-moriya interaction by floquet engineering using rydberg atoms. PRA, 112(2), 022614. (www)

  @article{ , abstract = {We theoretically propose a method for implementing a Hamiltonian incorporating Heisenberg and Dzyaloshinskii-Moriya (DM) interactions within Rydberg atoms arranged in a two-dimensional square lattice, utilizing Floquet engineering. In our scheme, we use both global and local operations of the spins. The global operations can be realized by applying microwave pulses, and the local operations can be realized by locally addressing atoms with off-resonant lasers, which induce the site-dependent ac-Stark shift. Since our engineered Hamiltonian contains bond-dependent DM interactions, we expect the emergence of quantum skyrmions in the ground state.}, archive = {J_PRA}, author = {Hiroki Kuji and Masaya Kunimi and Tetsuro Nikuni}, doi = {10.1103/5sh7-cgyr}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022614}, shortjournal = {Phys. Rev. A}, title = {Proposal for realizing quantum-spin systems on a two-dimensional square lattice with dzyaloshinskii-moriya interaction by floquet engineering using rydberg atoms}, volume = {112}, year = {2025}, }
• (2025). Petz recovery maps of single-qubit decoherence channels in an ion trap quantum processor. PRA, 112(2), 022613. (www)

  @article{ , abstract = {The Petz recovery map provides a near-optimal reversal of quantum noise, yet proposals for its implementation are only recent. We propose a physical realization of the exact state-specific Petz map in an ion trap for qubit decoherence channels. Our circuit constructions require at most ancilla qubits and cnot gates for channels with Kraus rank . We analyze typical ion trap errors and construct corresponding Petz maps, simulating their performance under realistic noise modeled by residual spin-motion coupling. Quantum circuits are provided for depolarizing, dephasing, and amplitude damping channels. Focusing on single-shot recovery, suited for present-day devices, we also quantify the precision of prior knowledge required to achieve a recovery error below 0.01 across varying decoherence levels and state purities.}, archive = {J_PRA}, author = {Wen-Han Png and Valerio Scarani}, doi = {10.1103/7f8x-n2np}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022613}, shortjournal = {Phys. Rev. A}, title = {Petz recovery maps of single-qubit decoherence channels in an ion trap quantum processor}, volume = {112}, year = {2025}, }
• (2025). Quantum natural gradient optimizer on noisy platforms: Quantum approximate optimization algorithm as a case study. PRA, 112(2), 022612. (www)

  @article{ , abstract = {We investigate the performance of the quantum natural gradient (QNG) optimizer in the presence of noise. Specifically, we evaluate the efficacy of QNG within the quantum approximate optimization algorithm for finding the ground state of the transverse field Ising model. Its performance is benchmarked against the vanilla gradient descent optimizer across two prominent quantum computing platforms: Rydberg atoms and superconducting circuits. Our analysis includes simulations under both idealized noise-free conditions and realistic noisy environments based on calibration data from actual devices. Results demonstrate that QNG consistently outperforms vanilla gradient descent, exhibiting faster convergence on average and greater robustness against random initializations of parameters. This robustness is attributed to the distance regularization in parameter space inherent to QNG. Additionally, QNG achieves a higher convergence rate to the solution, effectively avoiding certain local minima. These findings highlight QNG as a promising tool for optimizing variational quantum algorithms in noisy intermediate-scale quantum devices.}, archive = {J_PRA}, author = {Federico Dell'Anna and Rafael Gómez-Lurbe and Armando Pérez and Elisa Ercolessi}, doi = {10.1103/62wx-tvk5}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022612}, shortjournal = {Phys. Rev. A}, title = {Quantum natural gradient optimizer on noisy platforms: Quantum approximate optimization algorithm as a case study}, volume = {112}, year = {2025}, }
• (2025). Quality of service in aggregated quantum networks. PRA, 112(2), 022611. (www)

  @article{ , abstract = {Future quantum networks will enable the interconnection of multiple users distributed across vast geographic distances. Due to these large separations and limited physical resources, communication will often rely on multipath routing strategies, where physical resources are distributed across channels of varying lengths and delivered to end users. Efficient long-distance quantum communication therefore requires optimizing the allocation of these resources across available paths. In this work we introduce a performance-oriented approach to quantum network routing by extending the classical concept of quality of service (QOS) to the context of multipath quantum resource distribution. Unlike prior models that consider entanglement generation or quantum memory coherence in isolation, we investigate the interplay between path assignment strategies, coherence time constraints, and quantum error correction (QEC) and how they jointly impact end-to-end communication fidelity. We analyze both unencoded and encoded transmissions over aggregated network paths, quantifying the effects of resource allocation on transmission success. Our findings show that fidelity cannot be optimized independently of memory lifetimes and that while QEC can enhance performance under specific conditions, it also imposes additional constraints depending on network topology and path-length asymmetries. This work provides a foundation for developing QOS-aware quantum routing protocols that balance fidelity, throughput, and memory utilization, key considerations for near-term quantum repeater networks.}, archive = {J_PRA}, author = {Nicolò Lo Piparo and William J. Munro and Kae Nemoto}, doi = {10.1103/ph6d-qqwk}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022611}, shortjournal = {Phys. Rev. A}, title = {Quality of service in aggregated quantum networks}, volume = {112}, year = {2025}, }
• (2025). Arbitrarily-high-dimensional reconciliation via cross-rotation for continuous-variable quantum key distribution. PRA, 112(2), 022610. (www)

  @article{ , abstract = {Multidimensional rotation serves as a powerful tool for enhancing information reconciliation and extending the transmission distance in continuous-variable quantum key distribution (CV-QKD). However, the lack of closed-form orthogonal transformations for high-dimensional rotations has limited the maximum reconciliation efficiency to channels with eight dimensions over the past decade. This paper presents a cross-rotation scheme to overcome this limitation and enable reconciliation in arbitrarily high dimensions, constrained to even multiples of eight. The key treatment involves reshaping the string vector into matrix form and applying orthogonal transformations to its columns and rows in a cross manner, thereby increasing the reconciliation dimension by one order per cross rotation while significantly reducing the communication overhead over the classical channel. A rigorous performance analysis is also presented from the perspective of achievable sum-rate. Simulation results demonstrate that 64-dimensional cross rotation nearly approaches the upper bound, making it a recommended choice for practical implementations.}, archive = {J_PRA}, author = {Jisheng Dai and Xue-Qin Jiang and Tao Wang and Peng Huang and Guihua Zeng}, doi = {10.1103/q3s4-ht52}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022610}, shortjournal = {Phys. Rev. A}, title = {Arbitrarily-high-dimensional reconciliation via cross-rotation for continuous-variable quantum key distribution}, volume = {112}, year = {2025}, }
• (2025). Simulating large one-dimensional neutral-atom quantum systems. PRA, 112(2), 022609. (www)

  @article{ , abstract = {While abstract models of quantum computation assume a closed system of two-level states, practical quantum devices inevitably couple to the environment in some way, creating sources of noise. Understanding the tolerance to noise of specific quantum algorithms run on specific devices is important for determining the feasibility of quantum computing in the current noisy intermediate-scale quantum era. Of particular interest is understanding the noise sensitivity of these devices as more qubits are added to the system. Classical simulations are a useful tool to understand the effects of this noise, but direct classical simulations of open quantum systems are burdened by an exponentially growing cost in the number of qubits and a large local Hilbert space dimension. For one-dimensional, shallow circuits, using tensor networks can replace this exponential cost with a linear one and simulate far wider systems than what would normally be available. In this paper, we describe a tensor network simulation of a neutral atom quantum system under the presence of noise, while introducing a purity-preserving truncation technique that compromises between the simplicity of the matrix product state and the positivity of the matrix product density operator. We apply this simulation to a near-optimized iteration of the quantum approximate optimization algorithm on a transverse field Ising model in order to investigate the influence of large system sizes on the performance of the algorithm. We find that while circuits with a large number of qubits fail more often under noise that depletes the qubit population, their outputs on a successful measurement are just as robust under Rydberg atom dissipation or qubit dephasing as smaller systems. However, such circuits might not perform as well under coherent multiqubit errors such as Rydberg atom crosstalk. We also find that the optimized parameters are especially robust to noise, suggesting that a noisier quantum system can be used to find the optimal parameters before switching to a cleaner system for measurements of observables.}, archive = {J_PRA}, author = {James Allen and Matthew Otten and Stephen K. Gray and Bryan K. Clark}, doi = {10.1103/wlcd-zrxm}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022609}, shortjournal = {Phys. Rev. A}, title = {Simulating large one-dimensional neutral-atom quantum systems}, volume = {112}, year = {2025}, }
• (2025). Top manifold connectedness of quantum control landscapes. PRA, 112(2), 022608. (www)

  @article{ , abstract = {The control of quantum systems has been proven to possess trap-free optimization landscapes under the satisfaction of proper assumptions. However, many details of the landscape geometry and the search required for reaching particular goals still need to be fully understood. This paper numerically explores the path-connectedness of globally optimal control solutions forming the top manifold of the landscape. We randomly sample a plethora of optimal controls on the top manifold to assess the existence of a continuous path at the top of the landscape that connects two arbitrary optimal solutions. It is shown that for different quantum control objectives, including state-to-state transition probabilities, observable expectation values, and unitary transformations, such a continuous path can be readily found, implying that these top manifolds are fundamentally path-connected. The significance of the latter conjecture lies in seeking locations on the top manifold where an ancillary objective can also be optimized while maintaining the full optimality of the original objective that defined the landscape.}, archive = {J_PRA}, author = {Yidian Fan and Re-Bing Wu and Tak-San Ho and Gaurav Bhole and Herschel Rabitz}, doi = {10.1103/rrzb-zm1l}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022608}, shortjournal = {Phys. Rev. A}, title = {Top manifold connectedness of quantum control landscapes}, volume = {112}, year = {2025}, }
• (2025). Slack-variable approach for variational quantum semidefinite programming. PRA, 112(2), 022607. (www)

  @article{ , abstract = {Solving optimization problems is a key task for which quantum computers could possibly provide a speedup over the best known classical algorithms. Particular classes of optimization problems including semidefinite programming (SDP) and linear programming (LP) have wide applicability in many domains of computer science, engineering, mathematics, and physics. Here we focus on semidefinite and linear programs for which the dimensions of the variables involved are exponentially large, so that standard classical SDP and LP solvers are not helpful for such large-scale problems. We propose the QSlack and CSlack methods for estimating their optimal values, respectively, which work by (1) introducing slack variables to transform inequality constraints to equality constraints, (2) transforming a constrained optimization to an unconstrained one via the penalty method, and (3) replacing the optimizations over all possible nonnegative variables by optimizations over parameterized quantum states and parameterized probability distributions. Under the assumption that the SDP and LP inputs are efficiently measurable observables, it follows that all terms in the resulting objective functions are efficiently estimable by either a quantum computer in the SDP case or a quantum or probabilistic computer in the LP case. Furthermore, by making use of SDP and LP duality theory, we prove that these methods provide a theoretical guarantee that, if one could find global optima of the objective functions, then the resulting values sandwich the true optimal values from both above and below. Finally, we showcase the QSlack and CSlack methods on a variety of example optimization problems and discuss details of our implementation, as well as the resulting performance. We find that our implementations of both the primal and dual for these problems approach the ground truth, typically achieving errors of the order .}, archive = {J_PRA}, author = {Jingxuan Chen and Hanna Westerheim and Zoë Holmes and Ivy Luo and Theshani Nuradha and Dhrumil Patel and Soorya Rethinasamy and Kathie Wang and Mark M. Wilde}, doi = {10.1103/lwxq-4myj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022607}, shortjournal = {Phys. Rev. A}, title = {Slack-variable approach for variational quantum semidefinite programming}, volume = {112}, year = {2025}, }
• (2025). Optimized readout strategies for neutral-atom quantum processors. PRA, 112(2), 022606. (www)

  @article{ , abstract = {Neutral atom quantum processors have emerged as a promising platform for scalable quantum information processing, offering high-fidelity operations and exceptional qubit scalability. A key challenge in realizing practical applications is efficiently extracting readout outcomes while maintaining high system throughput, i.e., the rate of quantum task executions. In this work, we develop a theoretical framework to quantify the trade-off between readout fidelity and atomic retention. Moreover, we introduce a metric of quantum circuit iteration rate (qCIR) and employ normalized quantum Fisher information to characterize system overall performance. Further, by carefully balancing fidelity and retention, we demonstrate a readout strategy for optimizing information acquisition efficiency. Considering the experimentally feasible parameters for atoms, we demonstrate that qCIRs of and are achievable using single-photon detectors and cameras, respectively. These results provide practical guidance for constructing scalable and high-throughput neutral atom quantum processors for applications in sensing, simulation, and near-term algorithm implementation.}, archive = {J_PRA}, author = {Liang Chen and Wen-Yi Zhu and Zi-Jie Chen and Zhu-Bo Wang and Ya-Dong Hu and Qing-Xuan Jie and Guang-Can Guo and Chang-Ling Zou}, doi = {10.1103/k2w2-83kc}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022606}, shortjournal = {Phys. Rev. A}, title = {Optimized readout strategies for neutral-atom quantum processors}, volume = {112}, year = {2025}, }
• (2025). Variational tensor network simulation of gaussian boson sampling and beyond. PRA, 112(2), 022605. (www)

  @article{ , abstract = {The continuous variable quantum computing platform constitutes a promising candidate for realizing quantum advantage, as exemplified in Gaussian boson sampling. While noise in the experiments makes the computation attainable for classical simulations, it has been suggested that the addition of nonlinear elements to the experiment will help retain the quantum advantage. We propose a classical simulation tool for general continuous variable sampling problems, including Gaussian boson sampling and beyond. We reformulate the sampling problem as that of finding the ground state of a simple few-body Hamiltonian. This allows us to employ powerful variational methods based on tensor networks and to read off the simulation error directly from the expectation value of the Hamiltonian. We validate our method by simulating Gaussian boson sampling, where we achieve results comparable to the state of the art. We also consider a non-Gaussian sampling problem, for which we develop alternative local basis optimization techniques based on a nonlinear parametrization of the implicit basis, resulting in high effective cutoffs with diminished computational overhead.}, archive = {J_PRA}, author = {Jonas Vinther and Michael J. Kastoryano}, doi = {10.1103/z463-7gqy}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022605}, shortjournal = {Phys. Rev. A}, title = {Variational tensor network simulation of gaussian boson sampling and beyond}, volume = {112}, year = {2025}, }
• (2025). Steganographic entanglement sharing. PRA, 112(2), 022604. (www)

  @article{ , abstract = {In a previous work [Avritzer and Brun, Phys. Rev. A 109 , 032401 (2024) ] we discussed a theoretical grounding for classical steganography using quantum Fock and coherent states in an optical channel, building on previous work by Wu et al. [ Opt. Express 14 , 3738 (2006) ; Opt. Express 21 , 2065 (2013) ]. In that work, we discussed protocols that disguise communications to mimic the thermal state of a harmonic oscillator. In this work we extend this to transmission of quantum information and demonstrate the utility of steganographic entanglement sharing in practical contexts like nonclassical state teleportation. We show that non-Gaussian entangled resources can be transmitted covertly while mimicking a Gaussian thermal state and still retain sufficient entanglement to violate a qubit Bell inequality, even with an eavesdropper present. We also examine the performance of other quantum protocols that utilize entanglement, such as dense coding and teleportation of unentangled but nonclassical states, to determine the effectiveness of the steganographic entanglement sharing under a variety of active and passive eavesdropper conditions.}, archive = {J_PRA}, author = {Bruno Avritzer and Todd A. Brun}, doi = {10.1103/kxpv-46v3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022604}, shortjournal = {Phys. Rev. A}, title = {Steganographic entanglement sharing}, volume = {112}, year = {2025}, }
• (2025). Quantum metrology in a nonlinear interferometer with feedback. PRA, 112(2), 022603. (www)

  @article{ , abstract = {In this paper, we propose a nonlinear interferometer with feedback loops and explore its efficiency for phase estimation. We analyze two feedback schemes, one where both modes of the interferometer are fed back into the device and another where only one mode is fed back. The quantum Fisher information (QFI) for phase estimation in each feedback scheme increases with each feedback loop, and similar to the standard SU(1,1) nonlinear interferometer, phase estimation in this scheme is sensitive to photon loss when the inputs are vacuum state. In terms of resources, we show that, in the low-loss regime, our scheme performs better than the standard nonlinear interferometer. The feedback scheme provides the minimum phase variance when the unknown phase is small. We also provide a special case where the feedback scheme provided enhanced QFI even for large phase values. This is achieved by switching between squeezing and antisqueezing operators after every few loops.}, archive = {J_PRA}, author = {Shivani Singh and Craig S. Hamilton and Igor Jex}, doi = {10.1103/4qm6-6bzl}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022603}, shortjournal = {Phys. Rev. A}, title = {Quantum metrology in a nonlinear interferometer with feedback}, volume = {112}, year = {2025}, }
• (2025). Preparing greenberger-horne-zeilinger states on ground levels of neutral atoms. PRA, 112(2), 022602. (www)

  @article{ , abstract = {We propose a scalable protocol in the Rydberg atomic system to generate the Greenberger-Horne-Zeilinger (GHZ) states, where the qubits are encoded on the hyperfine ground levels. Our system is featured with off-resonant driving fields rather than strong Rydberg interaction sufficient for blockade. Closely it can follow the desired nonadiabatic passage during the time evolution and avoid the unwanted transition by imposing the passage-dependent and fast-varying global phase, that serves as an error correction to the universal quantum control. In our protocol, an N -qubit GHZ state is prepared in N − 1 steps, which is found to be robust against both environmental noise and systematic deviation. Our protocol therefore provides an avenue toward large-scale entanglement, which is essential for quantum information processing and computation based on neutral atoms.}, archive = {J_PRA}, author = {Zhu-yao Jin and Jun Jing}, doi = {10.1103/c47j-cw46}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022602}, shortjournal = {Phys. Rev. A}, title = {Preparing greenberger-horne-zeilinger states on ground levels of neutral atoms}, volume = {112}, year = {2025}, }
• (2025). Mitigation of correlated readout errors without randomized measurements. PRA, 112(2), 022601. (www)

  @article{ , abstract = {Quantum simulation, the study of strongly correlated quantum matter using synthetic quantum systems, has been the most successful application of quantum computers to date. It often requires determining observables with high precision, for example when studying critical phenomena near quantum phase transitions. Thus, readout errors must be carefully characterized and mitigated in data postprocessing, using scalable and noise-model agnostic protocols. We present a readout error-mitigation protocol that uses only single-qubit Pauli measurements and avoids experimentally challenging randomized measurements. The proposed approach captures a very broad class of correlated noise models and is scalable to large qubit systems. It is based on a complete and efficient characterization of few-qubit correlated positive operator-valued measures, using overlapping detector tomography. To assess the effectiveness of the protocol, observables are extracted from simulations involving up to 100 qubits employing readout errors obtained from experiments with superconducting qubits.}, archive = {J_PRA}, author = {Adrian Skasberg Aasen and Andras Di Giovanni and Hannes Rotzinger and Alexey V. Ustinov and Martin Gärttner}, doi = {10.1103/6p6s-t8b7}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022601}, shortjournal = {Phys. Rev. A}, title = {Mitigation of correlated readout errors without randomized measurements}, volume = {112}, year = {2025}, }
• (2025). Dynamical logical qubits in the bacon-shor code. PRA, 112(2), 022436. (www)

  @article{ , abstract = {The Bacon-Shor code is a quantum error correcting subsystem code composed of weight-2 check operators that admits a single logical qubit, and has distance on a square lattice. We show that when viewed as a Floquet code, by choosing an appropriate measurement schedule of the check operators, it can additionally host several dynamical logical qubits. Specifically, we identify a period-4 measurement schedule of the check operators that preserves logical information between the instantaneous stabilizer groups. Such a schedule not only measures the usual stabilizers of the Bacon-Shor code, but also measures and promotes gauge operators of the parent subsystem code to additional temporary stabilizers that protect the dynamical logical qubits against errors. We show that the code distance of these Floquet-Bacon-Shor codes scales as on an lattice with dynamical logical qubits, along with the logical qubit of the parent subsystem code. Unlike the usual Bacon-Shor code, the Floquet-Bacon-Shor code family introduced here can therefore saturate the subsystem bound . Moreover, several errors are shown to be self-corrected purely by the measurement schedule itself. This work provides insights into the design space for dynamical codes and expands the known approaches for constructing Floquet codes.}, archive = {J_PRA}, author = {M. Sohaib Alam and Eleanor Rieffel}, doi = {10.1103/nfxv-3dp7}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022436}, shortjournal = {Phys. Rev. A}, title = {Dynamical logical qubits in the bacon-shor code}, volume = {112}, year = {2025}, }
• (2025). Multilevel dynamical decoupling for a coupled superconducting two-qubit system. PRA, 112(2), 022435. (www)

  @article{ , abstract = {Recent advances have significantly enhanced the coherence times of superconducting qubits. However, high-fidelity storage of multiqubit quantum states in large-scale circuits is still limited by factors such as the flux noise and crosstalk. We propose an X-iSwap decoupling sequence combining single-qubit gates and two-qubit iSwap gates to effectively mitigate dephasing from the low-frequency flux noise and eliminate crosstalk between qubits. Numerical simulations of noisy random evolution show excellent agreement with the theoretical models. In quantum memory applications, our method substantially extends the decay time of two-qubit fidelity and eliminates fidelity oscillations caused by the ZZ crosstalk. Compared to the traditional decoupling methods based on single-qubit gates, the X-iSwap sequence exhibits superior robustness against small system errors, which holds promise for widespread application in two-qubit systems and large-scale quantum processors for tasks such as long-term quantum memory and entanglement protection.}, archive = {J_PRA}, author = {Wenqu Xu and Tianshi Zhou and Kaixuan Zhang and Zishuo Li and Tingting Guo and Quan Zuo and Mingyuan Yu and Junliang Jiang and Jiazheng Pan and Jinpeng Li and Lingxiao Jing and Huashi Ma and Shunhong Zhou and Binglin Li and Shiyao Yang and Yongyang Yu and Junzhou Zhang and Jiyuan Zhu and Ziru Hou and Haifeng Song and Chunhai Cao and Guozhu Sun and Peiheng Wu}, doi = {10.1103/6wd3-wc5s}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022435}, shortjournal = {Phys. Rev. A}, title = {Multilevel dynamical decoupling for a coupled superconducting two-qubit system}, volume = {112}, year = {2025}, }
• (2025). Real randomized measurements for analyzing properties of quantum states. PRA, 112(2), 022434. (www)

  @article{ , abstract = {Randomized measurements are useful for analyzing quantum systems, especially when quantum control is not fully perfect. However, their practical realization typically requires multiple rotations in the complex space due to the adoption of random unitaries. Here, we introduce two simplified randomized measurements that limit rotations in a subspace of the complex space. The first is real randomized measurements (RRMs) with orthogonal evolution and real local observables. The second is partial real randomized measurements (PRRMs) with orthogonal evolution and imaginary local observables. We show that these measurement protocols exhibit different abilities in capturing correlations of bipartite systems. We explore various applications of RRMs and PRRMs in different quantum information tasks such as characterizing high-dimensional entanglement, quantum imaginarity, and predicting properties of quantum states with classical shadow.}, archive = {J_PRA}, author = {Jin-Min Liang and Satoya Imai and Shuheng Liu and Shao-Ming Fei and Otfried Gühne and Qiongyi He}, doi = {10.1103/3nt1-jh38}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022434}, shortjournal = {Phys. Rev. A}, title = {Real randomized measurements for analyzing properties of quantum states}, volume = {112}, year = {2025}, }
• (2025). Noise effects on diabatic quantum annealing protocols. PRA, 112(2), 022433. (www)

  @article{ , abstract = {Diabatic quantum annealing aims to mitigate the challenges posed by small energy gaps and decoherence in quantum optimization by exploiting nonadiabatic transitions. In this paper, we compare the performance of two diabatic protocols in a realistic, dissipative setting using the maximum weighted independent set problem as a test case, showing that the potential advantages of diabatic protocols are strongly reduced in the presence of dissipation. Our results highlight the importance of evaluating quantum annealing strategies under practical conditions.}, archive = {J_PRA}, author = {Giulia Salatino and Maximilian Matzler and Annarita Scocco and Procolo Lucignano and Gianluca Passarelli}, doi = {10.1103/x9hw-xhvj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022433}, shortjournal = {Phys. Rev. A}, title = {Noise effects on diabatic quantum annealing protocols}, volume = {112}, year = {2025}, }
• (2025). Shadow ansatz for the many-fermion wave function in scalable molecular simulations on quantum computing devices. PRA, 112(2), 022432. (www)

  @article{ , abstract = {Here we show that shadow tomography can generate an efficient and exact ansatz for the many-fermion wave function on quantum devices. We derive the shadow ansatz—a product of transformations applied to the mean-field wave function—by exploiting a critical link between measurement and preparation. Each transformation is obtained by measuring a classical shadow of the residual of the contracted Schrödinger equation (CSE), the many-electron Schrödinger equation (SE) projected onto the space of two electrons. We show that the classical shadows of the CSE vanish if and only if the wave function satisfies the SE and, hence, that randomly sampling only the two-electron space yields an exact ansatz regardless of the total number of electrons. We demonstrate the ansatz's advantages for scalable simulations—fewer measurements and shallower circuits—by computing on simulators and a quantum device.}, archive = {J_PRA}, author = {Yuchen Wang and Irma Avdic and David A. Mazziotti}, doi = {10.1103/1nml-xjqw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022432}, shortjournal = {Phys. Rev. A}, title = {Shadow ansatz for the many-fermion wave function in scalable molecular simulations on quantum computing devices}, volume = {112}, year = {2025}, }
• (2025). Learning entanglement from tomography data: Contradictory measurement importance for neural networks and random forests. PRA, 112(2), 022431. (www)

  @article{ , abstract = {We study the effectiveness of two distinct machine learning techniques, neural networks and random forests, in the quantification of entanglement from two-qubit tomography data. Although we predictably find that neural networks yield better accuracy, we also find that the way the two methods reach their prediction is starkly different. This is seen by the measurements which are the most important for the classification. Neural networks follow the intuitive prediction that measurements containing information about nonlocal coherences are most important for entanglement, but random forests signify the dominance of information contained in occupation measurements. This is because occupation measurements are necessary for the extraction of data about all other density matrix elements from the remaining measurements. The same discrepancy does not occur when the models are used to learn entanglement directly from the elements of the density matrix, so it is the result of the scattering of information and interdependence of measurement data. As a result, the models behave differently when noise is introduced to various measurements, which can be harnessed to obtain more reliable information about entanglement from noisy tomography data.}, archive = {J_PRA}, author = {Pavel Baláž and Mateusz Krawczyk and Jarosław Pawłowski and Katarzyna Roszak}, doi = {10.1103/zgfy-yyw8}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022431}, shortjournal = {Phys. Rev. A}, title = {Learning entanglement from tomography data: Contradictory measurement importance for neural networks and random forests}, volume = {112}, year = {2025}, }
• (2025). Improving semi-device-independent randomness certification by entropy accumulation. PRA, 112(2), 022430. (www)

  @article{ , abstract = {Certified randomness guaranteed to be unpredictable by adversaries is central to information security. The fundamental randomness inherent in quantum physics makes certification possible from devices that are only weakly characterized, i.e., requiring little trust in their implementation. It was recently shown that the amount of certifiable randomness can be improved using the so-called entropy accumulation theorem generalized to prepare-and-measure settings. Furthermore, this approach allows a finite-size analysis which avoids assuming that all rounds are independent and identically distributed. Here, we demonstrate this improvement in semi-device-independent randomness certification from untrusted measurements.}, archive = {J_PRA}, author = {Carles Roch Carceller, I and Lucas Nunes Faria and Zheng-Hao Liu and Nicolò Sguerso and Ulrik Lund Andersen and Jonas Schou Neergaard-Nielsen and Jonatan Bohr Brask}, doi = {10.1103/dwdv-89bj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022430}, shortjournal = {Phys. Rev. A}, title = {Improving semi-device-independent randomness certification by entropy accumulation}, volume = {112}, year = {2025}, }
• (2025). Assessing quantum and classical approaches to combinatorial optimization: Testing quadratic speed-ups for heuristic algorithms. PRA, 112(2), 022429. (www)

  @article{ , abstract = {Many recent investigations have concluded, based on asymptotic complexity analyses, that quantum computers could accelerate combinatorial optimization (CO) tasks relative to a purely classical computer. However, asymptotic analysis alone cannot support a credible claim of quantum advantage. Here, we highlight the challenges involved in benchmarking quantum and classical heuristics for CO, with a focus on the Sherrington-Kirkpatrick problem. Whereas hope remains that a quadratic quantum advantage is possible, our numerical analysis casts doubt on the idea that current methods exhibit any quantum advantage at all. This doubt arises because even a simple classical approach can match with quantum methods we investigated. We conclude that more careful numerical investigations are needed to evaluate the potential for quantum advantage in CO, and we give some possible future directions for such investigations.}, archive = {J_PRA}, author = {Pedro C. S. Costa and Mauro E. S. Morales and Dong An and Yuval R. Sanders}, doi = {10.1103/hm1z-z9p2}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022429}, shortjournal = {Phys. Rev. A}, title = {Assessing quantum and classical approaches to combinatorial optimization: Testing quadratic speed-ups for heuristic algorithms}, volume = {112}, year = {2025}, }
• (2025). Quantum computing quantum monte carlo algorithm. PRA, 112(2), 022428. (www)

  @article{ , abstract = {Quantum computing (QC) and quantum Monte Carlo (QMC) represent state-of-the-art quantum and classical computing methods, respectively, for understanding many-body quantum systems. However, straightforward integration of the two methods may encounter significant challenges, such as exponential sampling cost and inefficient walker propagation. Here, we propose an efficient hybrid quantum-classical algorithm that integrates the two methods, overcoming these limitations while leveraging their strengths in representing and manipulating quantum states. To measure the effectiveness of the hybrid approach, we first introduce nonstoquasticity indicators (NSIs) and their theoretical upper bounds, which quantify the severity of the sign problem, a major limitation of QMC. Next, we present a hybrid QC-QMC method where the walkers are represented by quantum states prepared by a shallow quantum circuit. Although the Hamiltonian in the quantum state walker basis is not sparse, we offer an efficient and scalable approach to implement walker propagation using a quantum computer. From the QMC perspective, our algorithm significantly mitigates the sign problem in the quantum state walker basis. From the QC perspective, integrating QMC increases the expressivity of shallow quantum circuits, enabling more accurate computations that are traditionally achievable only with much deeper quantum circuits. Our method has immediate applications in tackling complex quantum many-body problems. We numerically test and verify it for the molecule (12 qubits) and the Hubbard model (16 qubits), observing a significant suppression of the sign problem (which exponentially decreases with circuit depth) and a notable improvement in calculation accuracy (which is about two to three orders compared to variational quantum algorithms). Our work paves the way to solving practical problems with intermediate-scale and early fault-tolerant quantum computers, with broad applications in chemistry, condensed matter physics, and materials.}, archive = {J_PRA}, author = {Yukun Zhang and Yifei Huang and Jinzhao Sun and Dingshun Lv and Xiao Yuan}, doi = {10.1103/jt8s-hzhd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022428}, shortjournal = {Phys. Rev. A}, title = {Quantum computing quantum monte carlo algorithm}, volume = {112}, year = {2025}, }
• (2025). Universal quantum control with dynamical correction. PRA, 112(2), 022427. (www)

  @article{ , abstract = {Error correction is generally demanded in large-scale quantum information processing and quantum computation. We provide here a universal and real-time control strategy to dynamically correct the arbitrary type of errors in the system Hamiltonian. It yields multiple error-resilient paths for the interested system which are activated by the von Neumann equation for ancillary projection operators. With no extra control fields and precise designs, the path-dependent global phase alone suffices to mitigate the error-induced transitions among distinct paths as long as it varies faster than the other parameters. The corrected paths can also be regarded as the approximate solutions to the time-dependent Schrödinger equation perturbed by errors. Our dynamical-correction strategy is practiced with the cyclic transfer of populations in a three-level system, showing a superior error resilience to the parallel-transport condition. It provides a promising idea for advancing control methodologies in imprecise quantum systems.}, archive = {J_PRA}, author = {Zhu-yao Jin and Jun Jing}, doi = {10.1103/vfrs-fyzw}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022427}, shortjournal = {Phys. Rev. A}, title = {Universal quantum control with dynamical correction}, volume = {112}, year = {2025}, }
• (2025). Higher-order corrections to the quantum cramér-rao bound. PRA, 112(2), 022426. (www)

  @article{ , abstract = {Quantum Fisher information and the associated quantum Cramér-Rao bound (QCRB) are fundamental tools in frequentist quantum metrology, offering both analytical simplicity and practical precision limits for parameter estimation. The QCRB sets a lower bound on the mean square error (MSE) in the idealized limit of infinite measurement trials ( ). Here we perform a systematic expansion in powers of to refine MSE estimates in realistic, finite-resource scenarios. These corrections reveal differences between measurements that appear equally optimal under the QCRB. They also help to distinguish among multiple optimal state families for estimating an unknown unitary transformation. Additionally, we explore the Bhattacharyya bound and its quantum counterpart, which constrain these corrections. Our results are relevant for preasymptotic metrology, enabling optimized protocols with limited resources without reliance on numerical simulations.}, archive = {J_PRA}, author = {J. R. Hervas and A. Z. Goldberg and A. S. Sanz and Z. Hradil and J. Řeháček and L. L. Sánchez-Soto}, doi = {10.1103/ltz3-163t}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022426}, shortjournal = {Phys. Rev. A}, title = {Higher-order corrections to the quantum cramér-rao bound}, volume = {112}, year = {2025}, }
• (2025). Simulating quantum collision models with hamiltonian simulations using early fault-tolerant quantum computers. PRA, 112(2), 022425. (www)

  @article{ , abstract = {We develop randomized quantum algorithms to simulate quantum collision models, also known as repeated interaction schemes, which provide a rich framework to model various open-system dynamics. The underlying technique involves composing time evolutions of the total (system, bath, and interaction) Hamiltonian and intermittent tracing out the environment degrees of freedom. This results in a unified framework where any near-term Hamiltonian simulation algorithm can be incorporated to implement an arbitrary number of such collisions on early fault-tolerant quantum computers: we do not assume access to specialized oracles such as block encodings and minimize the number of ancilla qubits needed. In particular, using the correspondence between Lindbladian evolution and completely positive trace-preserving maps arising out of memoryless collisions, we provide an end-to-end quantum algorithm for simulating Lindbladian dynamics. For a system of -qubits, we exhaustively compare the circuit depth needed to estimate the expectation value of an observable with respect to the reduced state of the system after time while employing different near-term Hamiltonian simulation techniques, requiring at most qubits in all. We compare the cnot gate counts of the various approaches for estimating the transverse field magnetization of a 10-qubit XX -Heisenberg spin chain under amplitude damping. Finally, we also develop a framework to efficiently simulate an arbitrary number of memory-retaining collisions, i.e., where environments interact, leading to non-Markovian dynamics. Overall, our methods can leverage quantum collision models for both Markovian and non-Markovian dynamics on early fault-tolerant quantum computers, shedding light on the advantages and limitations of simulating open systems dynamics using this framework.}, archive = {J_PRA}, author = {Kushagra Garg and Zeeshan Ahmed and Subhadip Mitra and Shantanav Chakraborty}, doi = {10.1103/3trk-smbh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022425}, shortjournal = {Phys. Rev. A}, title = {Simulating quantum collision models with hamiltonian simulations using early fault-tolerant quantum computers}, volume = {112}, year = {2025}, }
• (2025). Quantum natural gradient with thermal-state initialization. PRA, 112(2), 022424. (www)

  @article{ , abstract = {Parametrized quantum circuits (PQCs) are central to variational quantum algorithms (VQAs), yet their performance is hindered by complex loss landscapes that make their trainability challenging. Quantum natural gradient descent, which leverages the geometry of the parametrized space through quantum generalizations of the Fisher information matrix, offers a promising solution but has been largely limited to pure-state scenarios, with only approximate methods available for mixed-state settings. This paper addresses this question, originally posed by Stokes et al. , Quantum 4 , 269 (2020) , by providing exact methods to compute three quantum generalizations of the Fisher information matrix—the Fisher-Bures, Wigner-Yanase, and Kubo-Mori information matrices—for PQCs initialized with thermal states. We prove that these matrix elements can be estimated using quantum algorithms combining the Hadamard test, classical random sampling, and Hamiltonian simulation. By broadening the set of quantum generalizations of Fisher information and realizing their unbiased estimation, our results enable the implementation of quantum natural gradient descent algorithms for mixed-state PQCs, thereby enhancing the flexibility of optimization when using VQAs. Another immediate consequence of our findings is to establish fundamental limitations on the ability to estimate the parameters of a state generated by an unknown PQC, when given sample access to such a state.}, archive = {J_PRA}, author = {Michele Minervini and Dhrumil Patel and Mark M. Wilde}, doi = {10.1103/49b1-fbc3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022424}, shortjournal = {Phys. Rev. A}, title = {Quantum natural gradient with thermal-state initialization}, volume = {112}, year = {2025}, }
• (2025). Structure of the majorana clifford group. PRA, 112(2), 022423. (www)

  @article{ , abstract = {In quantum information science, Clifford operators and stabilizer codes play a central role for systems of qubits (or qudits). In this paper, we study their analogs for systems composed of Majorana fermions. In this case, a crucial role is played by fermion parity symmetry, which is an unbreakable symmetry present in any system with fundamentally fermionic degrees of freedom. We prove that the subgroup of parity-preserving Majorana Cliffords can be represented by the orthogonal group over the binary field , and we show how it can be generated by braiding operators and used to construct any (even-parity) Majorana stabilizer code. We also analyze the frame potential for this so-called p-Clifford group when acting on a fixed-parity sector of the Hilbert space, proving that it is equivalent to the frame potential of the ordinary Clifford group acting on the same sector.}, archive = {J_PRA}, author = {Valérie Bettaque and Brian Swingle}, doi = {10.1103/9gk9-yw3w}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022423}, shortjournal = {Phys. Rev. A}, title = {Structure of the majorana clifford group}, volume = {112}, year = {2025}, }
• (2025). Effect of correlated errors on quantum memory. PRA, 112(2), 022422. (www)

  @article{ , abstract = {Recent results on constant overhead LDPC code-based fault-tolerance against i.i.d. errors naturally lead to the question of fault-tolerance against errors with long-range correlations. Ideally, any correlation can be captured by a joint (system and bath) Hamiltonian. However, an arbitrary joint Hamiltonian is often intractable, and hence, the joint Hamiltonian model with pairwise terms was introduced and developed in a seminal series of papers by Terhal and Burkard [ Phys. Rev. A 71 , 012336 (2005) ], Aliferis, Gottesman, and Preskill [ Quantum Inf. Comput. 6 , 97 (2005) ], and Aharonov, Kitaev, and Preskill [ Phys. Rev. Lett. 96 , 050504 (2006) ]. However, the analysis of the new constant overhead codes in that error model appears to be quite challenging. In this paper, to model correlated errors in quantum memory, we introduce a correlation model which is a generalization of the well-known hidden random fields. This proposed model, which includes stationary and ergodic (and possibly non-Markov) error distributions, is shown to capture correlations not captured by the joint Hamiltonian model with pairwise terms. On the other hand, building on non-i.i.d. measure concentration, we show that for a broad class of (possibly) non-Markov and nonstationary error distributions, quantum Tanner codes ensure an exponential retention time (in the number of physical qubits), when the error rate is below a threshold. An implication of this work is that the rate of decay of the correlation with distance does not necessarily differentiate between good and bad correlations.}, archive = {J_PRA}, author = {Smita Bagewadi and Avhishek Chatterjee}, doi = {10.1103/hg2r-py13}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022422}, shortjournal = {Phys. Rev. A}, title = {Effect of correlated errors on quantum memory}, volume = {112}, year = {2025}, }
• (2025). Topological quantum compilation of metaplectic anyons based on the genetic optimized algorithms. PRA, 112(2), 022421. (www)

  @article{ , abstract = {Topological quantum computing holding global anti-interference ability is realized by braiding some anyons, such as well-known Fibonacci anyons. Here, based on theory we obtain a total of six anyon models utilizing matrices, symbols, and fusion rules of metaplectic anyon. We obtain the elementary braiding matrices (EBMs) by means of unconventional encoding. After braiding and , we insert a pair of anyons into them to ensure that the initial order of anyons remains unchanged. In this process only fusion is required, and measurement is not necessary. Three of them are studied in detail. We study systematically the compilation of these three models through EBMs obtained analytically. For the one-qubit case, the classical and gate can be well constructed using the Genetic Algorithm-enhanced Solovay-Kitaev Algorithm (GA-enhanced SKA) by . The obtained accuracy of the and gates by is slightly inferior to the corresponding gates of the Fibonacci anyon model, but it also can meet the requirements of fault-tolerant quantum computing,with giving the best performance of these four models. For the two-qubit case, we use the exhaustive method for short lengths and the GA for long lengths to obtain a braidword for models. The resulting matrices can well approximate the local equivalence class of the controlled- not ( cnot ) gate, while demonstrating a much smaller error than the Fibonacci model, especially for the . The braiding processes of conventional encoding (using identical anyons) and unconventional encoding (using distinct anyons) are compared. Finally, we attempt to generalize the model to the -qubit case.}, archive = {J_PRA}, author = {Jiangwei Long and Jianxin Zhong and Lijun Meng}, doi = {10.1103/js85-r2m7}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022421}, shortjournal = {Phys. Rev. A}, title = {Topological quantum compilation of metaplectic anyons based on the genetic optimized algorithms}, volume = {112}, year = {2025}, }
• (2025). Image current detection of electrons in a room-temperature paul trap. PRA, 112(2), 022420. (www)

  @article{ , abstract = {We report the image current detection of electrons in a room-temperature Paul trap at microwave frequencies. By selectively leveraging distinct cavity modes for trapping and detection, our approach efficiently extracts electron signals otherwise buried in the microwave drive used for pseudopotential formation. When the trapped electrons resonate with the cavity mode, we observe a mode excitation and its exponential decay attributed to resistive cooling. Detuning electrons from the cavity resonance halts this decay, and sweeping electrons' secular frequency reveals their oscillatory spectrum. Implementing this experiment at cryogenic temperatures could enable the image current detection and ground-state cooling of a single electron in Paul traps.}, archive = {J_PRA}, author = {Kento Taniguchi and Atsushi Noguchi}, doi = {10.1103/6mpr-5s2h}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022420}, shortjournal = {Phys. Rev. A}, title = {Image current detection of electrons in a room-temperature paul trap}, volume = {112}, year = {2025}, }
• (2025). Shadow measurements for feedback-based quantum optimization. PRA, 112(2), 022419. (www)

  @article{ , abstract = {Improving the performance of quantum algorithms is a fundamental task to achieve quantum advantage. In many cases, extracting information from quantum systems poses an important challenge for practical implementations of real-world quantum computers, given the high resource cost of performing state tomography. In this scenario, randomized measurements have emerged as a promising tool. In particular, the classical shadow protocol allows one to retrieve expected values of low-weight Pauli observables by performing only local measurements. In this paper, we present an implementation of the recently introduced feedback-based algorithm for quantum optimization using the Ket quantum programming platform to solve the MaxCut optimization problem. We employ classical shadows for the feedback routine of parameter estimation and compare this approach with the direct estimation of observables. Our results show that depending on the graph geometry of the MaxCut problem, the number of measurements required to estimate expected values of observables with classical shadows can be up to 16 times lower than with direct-observable estimation. Furthermore, by analyzing complete graphs, we numerically confirm logarithmic growth in the required number of measurements relative to the number of observables, reinforcing that classical shadows can be a useful tool for estimating low-locality Pauli observables in quantum algorithms.}, archive = {J_PRA}, author = {Letícia Bertuzzi and João P. Engster and Evandro C. R. da Rosa and Eduardo I. Duzzioni}, doi = {10.1103/snht-7jsf}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022419}, shortjournal = {Phys. Rev. A}, title = {Shadow measurements for feedback-based quantum optimization}, volume = {112}, year = {2025}, }
• (2025). Designing quantum error correction codes for practical spin qudit systems. PRA, 112(2), 022418. (www)

  @article{ , abstract = {The implementation of practical error correction protocols is essential for deployment of quantum information technologies. Ways of exploiting high-spin nuclei, which have multilevel quantum resources, have attracted interest in this context because they offer additional Hilbert space dimensions in a spatially compact and theoretically efficient structure. We present a quantitative analysis of the performance of a spin-qudit-based error-correctable quantum memory, with reference to the actual Hamiltonians of several potential candidate systems. First, the ideal code-word implemented on a spin-7/2 nucleus, which provides first-order Pauli- and error correction, has intrinsic infidelity due to mixed eigenstates under realistic conditions. We confirm that expansion to a spin-9/2 system with tailored code words can compensate for this infidelity. Second, we claim that electric field fluctuations, which are inevitable in real systems, should also be considered as a noise source, and we illustrate an encoding and decoding scheme for a multi-spin-qudit-based error correction code that can simultaneously compensate for both electric- and magnetic-field perturbations. Such strategies are important as we move beyond the current noisy-intermediate quantum era, and fidelities above two or three nines become crucial for the implementation of quantum technologies.}, archive = {J_PRA}, author = {Sumin Lim and Arzhang Ardavan}, doi = {10.1103/7q6l-d4qh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022418}, shortjournal = {Phys. Rev. A}, title = {Designing quantum error correction codes for practical spin qudit systems}, volume = {112}, year = {2025}, }
• (2025). Quantum lock-in amplification with spin-oscillator hybrid interferometers for weak-signal detection. PRA, 112(2), 022417. (www)

  @article{ , abstract = {Achieving high-precision detection of weak alternating signals in noisy environments is a fundamental challenge in metrology. Given that the lock-in amplification technique has been successfully applied to facilitate sensitive detection of various unknown weak signals, in this study, we investigate the extension of this technique, termed quantum lock-in amplification, for precise detection of an unknown alternating signal. With a generalized spin-oscillator hybrid quantum system, we show that the target signal driving the oscillator can be precisely locked in by modulating the pulses that drive the spin, while the amplification of the signal is simultaneously achieved by alternatively driving the probe (i.e., oscillator), similar to its classical counterpart. Unlike previous methods that utilize pulses solely for signal accumulation and amplification, the quantum lock-in amplification scheme proposed here simultaneously harnesses both the spin-oscillator entanglement resources and the quantum squeezing of the oscillator. Notably, the simultaneous use of entanglement and squeezing can achieve greater noise compression compared to the case using entanglement only. Consequently, the spin state, characterized by large phase accumulation, can be measured with significantly high sensitivity even under the noisy environment, allowing for precise locking and amplification of the unknown weak signal.}, archive = {J_PRA}, author = {Y. Zhao and X. N. Feng and L. F. Wei}, doi = {10.1103/n13k-tw4p}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022417}, shortjournal = {Phys. Rev. A}, title = {Quantum lock-in amplification with spin-oscillator hybrid interferometers for weak-signal detection}, volume = {112}, year = {2025}, }
• (2025). Magnetic noise in macroscopic quantum spatial superpositions. PRA, 112(2), 022416. (www)

  @article{ , abstract = {In this paper, we show how random fluctuations in the magnetic field gradient jitter the paths of a matter-wave interferometer randomly, hence, decohere the quantum superposition. To create a large spatial superposition with nanoparticles, we envisage embedding a spin in a nanoparticle as a defect and applying an inhomogeneous magnetic field as in a Stern-Gerlach-type experiment to create a macroscopic quantum superposition. Such matter-wave interferometers are the cornerstone for many new fundamental advancements in physics; particularly, adjacent matter-wave interferometers can use entanglement features to test physics beyond the standard model, test the equivalence principle, improve quantum sensors, and test the quantum nature of space-time in a laboratory. In particular, we study how white and flicker noise induces decoherence for a setup involving superconducting wires embedded in a chip. We show that to obtain a tiny spatial superposition of a nanometer separation, and to minimize decoherence, where is the dephasing rate and is the frequency of the oscillator, we will need current fluctuations to be , which is not impossible to obtain in superconducting wire arrangements. For such tiny fluctuations, we demonstrate that the Humpty-Dumpty problem in a matter-wave interferometer arising from a mismatch in position and momentum does not cause a loss in contrast.}, archive = {J_PRA}, author = {Sneha Narasimha Moorthy and Andrew Geraci and Sougato Bose and Anupam Mazumdar}, doi = {10.1103/9n6y-cc7r}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022416}, shortjournal = {Phys. Rev. A}, title = {Magnetic noise in macroscopic quantum spatial superpositions}, volume = {112}, year = {2025}, }
• (2025). Detection power of real entanglement witnesses under local unitary equivalence. PRA, 112(2), 022415. (www)

  @article{ , abstract = {The imaginary unit has recently been experimentally proven to be indispensable for quantum mechanics. We study the differences in detection power between real and complex entanglement witnesses (EWs) distinguished by whether their matrix expressions incorporate imaginary parts. We show that a real EW (REW), denoted by a real Hermitian matrix, must detect one entangled state of a real density matrix, and conversely an entangled state of a real density matrix must be detected by one REW. We present a necessary and sufficient condition for the entangled states detected by REWs and give a specific example implying the detection limitations of REWs. From an operational perspective, we investigate whether all entangled states are detected by the EWs locally equivalent to some REWs. We prove the validity for all nonpositive partial transpose states. We also derive a necessary and sufficient condition of the validity for the positive partial transpose (PPT) entangled states of complex density matrices. By this condition we show the validity for a family of two-qutrit PPT entangled states of rank four. Another way to figure out the problem is to check whether a counterexample exists. We propose a method to examine the existence from a set-theoretic perspective and provide some supporting evidence of nonexistence. Finally, we derive some results on local projections of EWs with product projectors.}, archive = {J_PRA}, author = {Yi Shen and Lin Chen and Zhihao Bian}, doi = {10.1103/py8r-jklj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022415}, shortjournal = {Phys. Rev. A}, title = {Detection power of real entanglement witnesses under local unitary equivalence}, volume = {112}, year = {2025}, }
• (2025). Viewing protected superconducting qubits through the lens of the cat qubit. PRA, 112(2), 022414. (www)

  @article{ , abstract = {We draw analogies between protected superconducting qubits and bosonic qubits by studying the fluxonium Hamiltonian in its Fock basis. The mean-field phase diagram of fluxonium (at the sweet spot) is identified, with a region in parameter space that is characterized by -symmetry-broken ground states. In the heavy fluxonium limit, these ground states are well approximated by squeezed coherent states in a Fock basis (corresponding to persistent current states with definite flux but indefinite charge) and simple expressions are provided for them in terms of the circuit parameters. We study the noise bias in fluxonium via a universal Lindblad master equation and find that the bit-flip rate is exponentially small in , while the phase-flip rate does not get worse with this ratio. Analogous behavior is found in qubits. We describe cat-qubit-inspired bias-preserving and gates for fluxonium. We discuss first steps towards generating an Ising interaction between protected superconducting qubits on a two-dimensional lattice, with the aim of achieving a passive quantum memory by coupling a static Hamiltonian to a generic thermal bath.}, archive = {J_PRA}, author = {Simon Lieu and Emma L. Rosenfeld and Kyungjoo Noh and Connor T. Hann}, doi = {10.1103/p8fy-qdc8}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022414}, shortjournal = {Phys. Rev. A}, title = {Viewing protected superconducting qubits through the lens of the cat qubit}, volume = {112}, year = {2025}, }
• (2025). Bounding entanglement entropy with clifford double cosets. PRA, 112(2), 022413. (www)

  @article{ , abstract = {Following on our previous work studying the orbits of quantum states under Clifford circuits via reachability graphs, we introduce contracted graphs whose vertices represent classes of quantum states with the same entropy vector. These contracted graphs represent the double cosets of the Clifford group, where the left cosets are built from the stabilizer subgroup of the starting state and the right cosets are built from the entropy-preserving operators. We study contracted graphs for stabilizer states, as well as states and Dicke states, discussing how the diameter of a state's contracted graph constrains the entropic diversity of its two-qubit Clifford orbit. We derive an upper bound on the number of entropy vectors that can be generated using any -qubit Clifford circuit, for any quantum state. We speculate on the holographic implications for the relative proximity of gravitational duals of states within the same Clifford orbit. Although we concentrate on how entropy evolves under the Clifford group, our double-coset formalism, and thus the contracted graph picture, is extendable to generic gate sets and generic state properties.}, archive = {J_PRA}, author = {Cynthia Keeler and William Munizzi and Jason Pollack}, doi = {10.1103/hfhg-2z68}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022413}, shortjournal = {Phys. Rev. A}, title = {Bounding entanglement entropy with clifford double cosets}, volume = {112}, year = {2025}, }
• (2025). Variational quantum algorithms on cat-state qubits. PRA, 112(2), 022412. (www)

  @article{ , abstract = {Variational quantum algorithms (VQA) have emerged with a wide variety of applications. One question to ask is either they can efficiently be implemented and executed on existing architectures. Current hardware suffers from uncontrolled noise that can alter the expected results of one calculation. The nature of this noise is different from one technology to another. In this work, we choose to investigate a technology that is intrinsically resilient to bit-flips: cat-state qubits. To this end, we implement two noise models. The first one is uniformly depolarizing in the sense that it is used in the literature to cover different hardware types. The second one is specific to cat-state qubits. We perform simulations on two types of problems that can be formulated with VQAs [the quantum approximate optimization algorithm (QAOA) and the variational quantum linear solver (VQLS)], study the impact of noise on the evolution of the cost function, and extract noise-level thresholds from which a noise-resilient regime can be considered. By tackling compilation issues, we discuss the need for implementing hardware-specific noise models as uniformly depolarizing ones can lead to misleading conclusions regarding the regime of noise that is acceptable for an algorithm to run.}, archive = {J_PRA}, author = {Anne-Solène Bornens and Michel Nowak}, doi = {10.1103/l7lq-tmfd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022412}, shortjournal = {Phys. Rev. A}, title = {Variational quantum algorithms on cat-state qubits}, volume = {112}, year = {2025}, }
• (2025). Inequivalent ways to apply semiclassical smoothing to a quantum system. PRA, 112(2), 022411. (www)

  @article{ , abstract = {In this paper, we correct a mistake we made in [ Phys. Rev. Lett. 122 , 190402 (2019) ] and [ Phys. Rev. A 103 , 012213 (2021) ] regarding the Wigner function of the so-called smoothed Weak-Valued state (SWV state). Here smoothing refers to estimation of properties at time using information obtained in measurements both before and after . The SWV state is a pseudostate (Hermitian but not necessarily positive) that gives, by the usual trace formula, the correct value for a weak measurement preformed at time , i.e., its weak value. The Wigner function is a pseudo probability distribution (real but not necessarily positive) over phase space. A smoothed (in this estimation sense) Wigner distribution at time can also be defined by applying classical smoothing for probability distributions to the Wigner functions. The smoothed Wigner distribution gives identical means for the canonical phase-space variables as does the SWV state. However, contrary to the assumption in the above references, the Wigner function of the SWV state is not the smoothed Wigner distribution.}, archive = {J_PRA}, author = {Kiarn T. Laverick and Areeya Chantasri and Howard M. Wiseman}, doi = {10.1103/j71g-pnmb}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022411}, shortjournal = {Phys. Rev. A}, title = {Inequivalent ways to apply semiclassical smoothing to a quantum system}, volume = {112}, year = {2025}, }
• (2025). Geometrical scheduling of adiabatic control without information of energy spectra. PRA, 112(2), 022410. (www)

  @article{ , abstract = {Adiabatic control is a fundamental technique for manipulating quantum systems, guided by the quantum adiabatic theorem, which ensures suppressed nonadiabatic transitions under slow parameter variations. Quantum annealing, a heuristic algorithm leveraging adiabatic control, seeks the ground states of Ising spin-glass models and has drawn attention for addressing combinatorial optimization problems. However, exponentially small energy gaps in such models often necessitate impractically long runtime to satisfy the adiabatic condition. Despite this limitation, improving the quality of approximate solutions remains crucial for practical applications. The quantum adiabatic brachistochrone provides a method to enhance adiabaticity by minimizing an action representing nonadiabaticity via the variational principle. While effective, its implementation requires detailed energy spectra, complicating its use in quantum annealing. Shortcuts to adiabaticity by counterdiabatic driving offer alternative approaches for accelerating adiabatic processes. However, the theory of shortcuts to adiabaticity often faces challenges such as nonlocal control requirements, high computational cost, and trade-offs between speed and energy efficiency. In this work we propose a quantum adiabatic brachistochrone protocol tailored for quantum annealing that eliminates the need for energy spectrum information. Our approach builds on advancements in counterdiabatic driving to design efficient parameter schedules. We demonstrate the effectiveness of our method through numerical simulations on the transverse-field Ising chain and axial next-nearest-neighbor Ising models.}, archive = {J_PRA}, author = {Yuta Shingu and Takuya Hatomura}, doi = {10.1103/n5xj-phwv}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022410}, shortjournal = {Phys. Rev. A}, title = {Geometrical scheduling of adiabatic control without information of energy spectra}, volume = {112}, year = {2025}, }
• (2025). Extreme points of sets of absolutely separable and positive partial transpose states. PRA, 112(2), 022409. (www)

  @article{ , abstract = {The absolutely separable (resp. positive partial transpose) states remain separable (resp. PPT) under any global unitary operation. We present a compact form of the extreme points in the sets of absolutely separable states and PPT states in two-qubit and qubit-qudit systems. The results imply that each extreme point has at most three distinct eigenvalues. For a two-qubit system, we also quantify geometric probabilities of absolute separability. We establish a necessary and sufficient condition for determining extreme points of the set of absolutely PPT states in two-qutrit and qutrit-qudit systems, expressed as solvable linear equations. We also demonstrate that any extreme point in a qutrit-qudit system has at most seven distinct eigenvalues. We introduce the concept of robustness of nonabsolute separability. It quantifies the minimal amount by which a state needs to mix with other states such that the overall state is absolutely separable. We show that the robustness satisfies positivity, invariance under unitary transformation, monotonicity, and convexity, so it is a good measure within the resource theory of nonabsolute separability. Analytical expressions for this measure are given for pure states in an arbitrary system and rank-two mixed states in a two-qubit system. Furthermore, we extend the study of absolutely separable and PPT states to multipartite systems, proving that three-qubit absolutely separable states form a proper subset of three-qubit absolutely PPT states, with symmetry under subsystem permutations and stricter spectral constraints.}, archive = {J_PRA}, author = {Zhiwei Song and Lin Chen}, doi = {10.1103/7pnp-qgrq}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022409}, shortjournal = {Phys. Rev. A}, title = {Extreme points of sets of absolutely separable and positive partial transpose states}, volume = {112}, year = {2025}, }
• (2025). Constructions of multipartite entanglement resistant to particle loss. PRA, 112(2), 022408. (www)

  @article{ , abstract = {An entangled state is called m resistant if it remains entangled after losing an arbitrary subset of m particles but becomes fully separable after losing any number of particles larger than m . Quinta et al. [ Phys. Rev. A 100 , 062329 (2019) ] conjectured that for any N -particle systems, there always exists an m -resistant pure state of some local dimension d . In this paper, we give two general constructions of m -resistant pure states. One is from the mixtures of Dicke states, which provides strong ( N − k ) -resistant pure N -qubit states with k = 4 or 5. The other is from classical error-correcting codes, which provides new m -resistant pure qudit states for certain m < N / 2 .}, archive = {J_PRA}, author = {Wanchen Zhang and Zicheng Han and Fei Shi and Xiande Zhang}, doi = {10.1103/g4bk-gfhs}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022408}, shortjournal = {Phys. Rev. A}, title = {Constructions of multipartite entanglement resistant to particle loss}, volume = {112}, year = {2025}, }
• (2025). Self-testing of nonmaximal genuine entangled states using tripartite hardy relations. PRA, 112(2), 022407. (www)

  @article{ , abstract = {We demonstrate that, in the tripartite scenario with all parties' local events being space-like separated, Hardy-type nonlocality reveals a stronger nonlocal correlation than those captured by Mermin-type inequalities, an important distinction previously unrecognized. To substantiate this assertion, we develop a general framework for tripartite correlations by extending the notion of Settings Independence and Outcome Independence beyond their bipartite formulation. This framework highlights the pivotal role of Hardy-type reasoning in detecting genuine multipartite nonlocality. Furthermore, we show that the tripartite Hardy-nonlocality enables self-testing of a broad class of pure nonmaximally genuine entangled tripartite states, offering a key advantage over Bell inequality-based methods by allowing certification even under nonmaximal violations. Unlike Bell functionals, which typically self-test only a single extremal point, the Hardy relation self-tests a set of extremal correlations for any nonzero Hardy probability. This, in turn, facilitates the device-independent certification of randomness from Hardy-type correlations. We find that the maximum certifiable randomness is -bits, highlighting both the practical and foundational significance of Hardy-based techniques for quantum randomness generation.}, archive = {J_PRA}, author = {Ranendu Adhikary and Souradeep Sasmal and Arup Roy}, doi = {10.1103/yfsz-xt2f}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022407}, shortjournal = {Phys. Rev. A}, title = {Self-testing of nonmaximal genuine entangled states using tripartite hardy relations}, volume = {112}, year = {2025}, }
• (2025). Fast scrambling in classically simulable quantum circuits. PRA, 112(2), 022406. (www)

  @article{ , abstract = {We study operator scrambling in quantum circuits built from “super-Clifford” gates. For such circuits it was established by Blake and Linden [ Phys. Rev. Lett. 125 , 030502 (2020) ] that the time evolution of operator entanglement for a large class of many-body operators can be efficiently simulated on a classical computer, including for operators with volume-law entanglement. Here we extend the scope of this formalism in two key ways. First we provide evidence that these classically simulable circuits include examples of fast scramblers, by constructing a circuit for which operator entanglement is numerically found to saturate in a time (with the number of qubits). Second we demonstrate that, in addition to operator entanglement, certain out-of-time-ordered correlation functions (OTOCs) can be classically simulated within the same formalism. As a consequence such OTOCs can be computed numerically in super-Clifford circuits with thousands of qubits and we study several explicit examples in the aforementioned fast scrambling circuits.}, archive = {J_PRA}, author = {Mike Blake and Noah Linden and Anthony P. Thompson}, doi = {10.1103/yx7v-m2zz}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022406}, shortjournal = {Phys. Rev. A}, title = {Fast scrambling in classically simulable quantum circuits}, volume = {112}, year = {2025}, }
• (2025). How to use arbitrary measuring devices to perform almost-perfect measurements. PRA, 112(2), 022405. (www)

  @article{ , abstract = {We consider the problem of reproducing one quantum measurement given the ability to perform another. We give a general framework and specific protocols for this problem. For example, we show how to use available “imperfect” devices a small number of times to implement a target measurement with average error that drops off exponentially with the number of imperfect measurements used. We hope that could be useful in near-term applications as a type of lightweight error mitigation of the measuring devices. As well as the view to practical applications, we consider the question from a general theoretical perspective in the most general setting where both the available and target measurements are arbitrary generalized quantum measurements. We show that this general problem in fact reduces to the ability to reproduce the statistics of (complete) von Neumann measurements, and that in the asymptotic limit of infinitely many uses of the available measurement, a simple protocol based upon “classical cloning” can perfectly achieve this task. We show that asymptotically any nontrivial quantum measurement can reproduce any other. We also study optimal protocols for a fixed number of uses of the available measurement. This includes, but is not limited to, improving both noisy and lossy quantum measurements. Furthermore, we show that, in a setting where we perform multiple measurements in parallel, we can achieve finite-rate measurement reproduction, by using block-coding techniques from classical information theory. Finally, we show that advantages can also be gained by making use of probabilistic protocols.}, archive = {J_PRA}, author = {Noah Linden and Paul Skrzypczyk}, doi = {10.1103/8tph-mc2p}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022405}, shortjournal = {Phys. Rev. A}, title = {How to use arbitrary measuring devices to perform almost-perfect measurements}, volume = {112}, year = {2025}, }
• (2025). Variational-toolbox-based separability detection of multiqubit states. PRA, 112(2), 022404. (www)

  @article{ , abstract = {Parameterized quantum circuits (PQCs) play a crucial role in variational quantum algorithms. While it is commonly believed that the optimal PQC can be used to reproduce the target state, here we reveal that the optimal PQC can also provide valuable insights into the state's properties. We propose variational toolboxes to identify the -separability of pure states, with or without preparation noise, by checking the structure within the optimal PQCs. Additionally, we introduce adaptive optimization strategies to detect the -separability of mixed states. Compared to fixed PQCs, our approach controls fewer parameters for low-rank states. Finally, we validate our methods through numerical demonstrations for various states.}, archive = {J_PRA}, author = {Jin-Min Liang and Shao-Ming Fei and Qiongyi He}, doi = {10.1103/44wv-9qlf}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022404}, shortjournal = {Phys. Rev. A}, title = {Variational-toolbox-based separability detection of multiqubit states}, volume = {112}, year = {2025}, }
• (2025). Quantum many-body simulations from a reinforcement-learned exponential ansatz. PRA, 112(2), 022403. (www)

  @article{ , abstract = {Solving for the many-body wave function represents a significant challenge on both classical and quantum devices because of the exponential scaling of the Hilbert space with system size. While the complexity of the wave function can be reduced through conventional Ansätze (e.g., the coupled-cluster Ansatz ), it can still grow rapidly with system size even on quantum devices. An exact, universal two-body exponential Ansatz for the many-body wave function has been shown to be generated from the solution of the contracted Schrödinger equation (CSE), and recently this Ansatz has been implemented without classical approximation on quantum simulators and devices for the scalable simulation of many-body quantum systems. Here we combine the solution of the CSE with a form of artificial intelligence known as reinforcement learning to generate highly compact circuits that implement this Ansatz without sacrificing accuracy. As a natural extension of the CSE, we reformulate the wave-function update as a Markovian decision process and train the agent to select the optimal actions at each iteration based upon only the current CSE residual. Compact circuits with high accuracy are achieved for and molecules over a range of molecular geometries.}, archive = {J_PRA}, author = {Yuchen Wang and David A. Mazziotti}, doi = {10.1103/hrgr-klw3}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022403}, shortjournal = {Phys. Rev. A}, title = {Quantum many-body simulations from a reinforcement-learned exponential ansatz}, volume = {112}, year = {2025}, }
• (2025). Qudit noisy stabilizer formalism. PRA, 112(2), 022402. (www)

  @article{ , abstract = {We introduce the qudit noisy stabilizer formalism, a framework for efficiently describing the evolution of stabilizer states in prime-power dimensions subject to generalized Pauli-diagonal noise under Clifford operations and generalized Pauli measurements. For arbitrary dimensions, the formalism remains applicable, though restricted to a subset of stabilizer states and operations. The computational complexity scales linearly with the number of qudits in the initial state and exponentially with the number of qudits in the final state. This ensures that when noisy qudit stabilizer states evolve via generalized Pauli measurements and Clifford operations to generate multipartite entangled states of a few qudits, their description remains efficient. We demonstrate this by analyzing the generation of a generalized Bell pair from a noisy linear cluster state subject to two distinct noise sources acting on each of the qudits.}, archive = {J_PRA}, author = {Paul Aigner and Maria Flors Mor-Ruiz and Wolfgang Dür}, doi = {10.1103/gqfw-x72s}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022402}, shortjournal = {Phys. Rev. A}, title = {Qudit noisy stabilizer formalism}, volume = {112}, year = {2025}, }
• (2025). Thermal quantum correlations of a single electron in a double quantum dot with transverse magnetic field. PRA, 112(2), 022401. (www)

  @article{ , abstract = {In this paper we investigate the thermal quantum correlations in a semiconductor double-quantum-dot system. The device comprises a single electron in a double quantum dot subjected to a longitudinal-magnetic-field and a transverse-magnetic-field gradient. The thermal entanglement of the single electron is driven by the charge and spin qubits. Employing the density-matrix formalism, we derive analytical expressions for thermal concurrence and correlated coherence, providing a comprehensive analysis of how temperature and various system parameters influence quantum coherence. Our results demonstrate that the transverse magnetic field serves as a tunable parameter for controlling thermal entanglement and quantum coherence. We also highlight the roles of thermal entanglement and correlated coherence in generating quantum correlations, noting that thermal correlated coherence is consistently more robust than thermal entanglement. This suggests that quantum algorithms based solely on correlated coherence might be more resilient than those relying on entanglement.}, archive = {J_PRA}, author = {Vinicius Leitão and Onofre Rojas and Moises Rojas}, doi = {10.1103/gj3r-n25m}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022401}, shortjournal = {Phys. Rev. A}, title = {Thermal quantum correlations of a single electron in a double quantum dot with transverse magnetic field}, volume = {112}, year = {2025}, }
• (2025). Nonadiabatic non-abelian geometric phase in non-hermitian quantum systems. PRA, 112(2), 022222. (www)

  @article{ , abstract = {With the growing interest in non-Hermitian quantum systems, the concepts of geometric phase such as Berry phase, adiabatic non-Abelian geometric phase, and nonadiabatic Abelian geometric phase have been gradually extended from Hermitian to non-Hermitian quantum systems. However, extending the most general form, the nonadiabatic non-Abelian geometric phase, to non-Hermitian systems has remained an open problem. In this paper, we address this issue by proposing a formalism of the nonadiabatic non-Abelian geometric phase in non-Hermitian quantum systems. Our formalism is consistent with the previous extensions in non-Hermitian quantum systems, and can also naturally revert to the concepts of geometric phase in Hermitian quantum systems. It provides a general formulation of geometric phase for both Hermitian and non-Hermitian quantum systems.}, archive = {J_PRA}, author = {Xu-Ying Lou and Yu-Shi Cheng and P. Z. Zhao and D. M. Tong}, doi = {10.1103/kjpc-l778}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022222}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic non-abelian geometric phase in non-hermitian quantum systems}, volume = {112}, year = {2025}, }
• (2025). Local information flow in quantum quench dynamics. PRA, 112(2), 022221. (www)

  @article{ , abstract = {We investigate the out-of-equilibrium dynamics of quantum information in one-dimensional systems undergoing a quantum quench using a local perspective based on the information lattice. This framework provides a scale- and space-resolved decomposition of quantum correlations, enabling a hydrodynamic description of the information flow through well-defined local densities—termed local information—and currents. We apply this framework to three local quenches in noninteracting fermionic chains: (i) the release of a single particle into an empty tight-binding chain, (ii) the connection of two critical chains via the removal of a central barrier, and (iii) the coupling of a topological Kitaev chain to a critical chain. In each case, the information lattice reveals the local structure of correlation buildup and information interface effects, going beyond global measures such as the von Neumann entropy. In particular, through the information lattice, we uncover the signatures in the local information flow associated with topological edge modes and analytically explain the fractional von Neumann entropy values observed in Majorana quench protocols. Our approach is general and applicable to interacting, disordered, and open systems, providing a powerful tool for characterizing quantum information dynamics.}, archive = {J_PRA}, author = {Nicolas P. Bauer and Björn Trauzettel and Thomas Klein Kvorning and Jens H. Bardarson and Claudia Artiaco}, doi = {10.1103/v7gb-5gq8}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022221}, shortjournal = {Phys. Rev. A}, title = {Local information flow in quantum quench dynamics}, volume = {112}, year = {2025}, }
• (2025). Anomalous flow in correlated quantum systems: No-go result and multiple-charge scenario. PRA, 112(2), 022220. (www)

  @article{ , abstract = {Correlated quantum systems can exhibit thermodynamic behaviors that defy classical expectations, with anomalous energy flow (AEF) against temperature gradients serving as a paradigmatic example. While AEF has been shown to arise from the consumption of initial quantum correlations, little is known about whether AEF can occur without correlation depletion, or if analogous anomalous transport exists for conserved quantities—dubbed charges—other than energy. Here, we develop a general global-local thermodynamic approach to describe charge exchange between arbitrary correlated quantum systems. For energy-conserving systems, we analytically rule out AEF in initially uncorrelated states, even with the involvement of quantum catalysts, thereby complementing existing studies. In contrast, in systems with multiple conserved charges, we uncover a mechanism for AEF that requires no initial correlations but is instead induced by a drag effect from normal flows of nonenergy charges. Furthermore, by treating all conserved charges on equal footing, we generalize AEF to a broader concept of anomalous charge flow, applicable to any conserved charge. We confirm theoretical expectations with numerical examples. These findings deepen our understanding of nonequilibrium quantum thermodynamics and open new avenues for controlling transport phenomena in correlated quantum systems.}, archive = {J_PRA}, author = {Rui Guan and Junjie Liu}, doi = {10.1103/gy6n-5x26}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022220}, shortjournal = {Phys. Rev. A}, title = {Anomalous flow in correlated quantum systems: No-go result and multiple-charge scenario}, volume = {112}, year = {2025}, }
• (2025). Statistical characterization of entanglement degradation under markovian noise in composite quantum systems. PRA, 112(2), 022219. (www)

  @article{ , abstract = {Understanding how noise degrades entanglement is crucial for the development of reliable quantum technologies. While the Markovian approximation simplifies the analysis of noise, it remains computationally demanding, particularly for high-dimensional systems like quantum memories. In this paper, we present a statistical approach to study the impact of different noise models on entanglement in composite quantum systems. By comparing global and local noise scenarios, we quantify entanglement degradation using the positive partial transpose time (PPTT) metric, which measures how long entanglement persists under noise. When the sampling of different noise scenarios is performed under controlled and homogeneous conditions, our analysis reveals that systems subjected to global noise tend to exhibit longer PPTTs, whereas those influenced by independent local noise models display the shortest entanglement persistence. To carry out this analysis, we employ a computational method proposed by Cao and Lu, which accelerates the simulation of PPTT distributions and enables efficient analysis of systems with dimensions up to . Our results demonstrate the effectiveness of this approach for investigating the resilience of quantum systems under Markovian noise.}, archive = {J_PRA}, author = {Nunzia Cerrato and Sauro Succi and Giacomo De Palma and Vittorio Giovannetti}, doi = {10.1103/9dw1-y4bl}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022219}, shortjournal = {Phys. Rev. A}, title = {Statistical characterization of entanglement degradation under markovian noise in composite quantum systems}, volume = {112}, year = {2025}, }
• (2025). Benchmarks for quantum communication via gravity. PRA, 112(2), 022218. (www)

  @article{ , abstract = {We establish limitations and bounds on the transmission of quantum states between gravitationally interacting mechanical oscillators under different models of gravity. This provides benchmarks that can enable tests for quantum features of gravity. Our proposal does not require the measurement of gravitationally induced entanglement and only requires final measurements of a single subsystem. We discuss bounds for classical models based on local operations and classical communication when considering coherent-state alphabets, and we discuss the transfer of quantum squeezing for falsifying the Schrödinger-Newton model.}, archive = {J_PRA}, author = {Kristian Toccacelo and Ulrik Lund Andersen and Jonatan Bohr Brask}, doi = {10.1103/7tfb-k2xh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022218}, shortjournal = {Phys. Rev. A}, title = {Benchmarks for quantum communication via gravity}, volume = {112}, year = {2025}, }
• (2025). Switchable coherent quantum batteries with large ergotropy. PRA, 112(2), 022217. (www)

  @article{ , abstract = {The quantum battery (QB) is a conceptually new energy storage and conversion device, which consists usually of a quantum charger and an energy store (usually called the QB for simplicity). The demonstrated advantage of a QB, over its classical counterpart, is that its charging efficiency can be significantly enhanced by using quantum entanglement resources. In this paper, we investigate alternatively how to realize the switchable charging and the lossless power detection of the charged QB. With the proposed QB configuration we show that, by adjusting the eigenfrequency of the qubit-based charger, the cavity-based QB can be switched on between the charging and power-off states and its stored energy can be nondestructively monitored by probing the transmitted spectrum of the external electromagnetic waves scattered by the qubit-based charger. As the qubit-based charger has never been excited, the proposed cavity-based QB could directly store the coherent-state energy (rather than the single-photon one) and thus possess significantly large ergotropy. The physical realization of the proposed switchable QB configuration is demonstrated specifically with the experimental circuit quantum electrodynamical devices.}, archive = {J_PRA}, author = {Y. F. Li and S. R. He and P. H. Ouyang and X. N. Feng and L. F. Wei}, doi = {10.1103/jpcs-998q}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022217}, shortjournal = {Phys. Rev. A}, title = {Switchable coherent quantum batteries with large ergotropy}, volume = {112}, year = {2025}, }
• (2025). Statistical properties of photon emission from relativistic electrons in intense electromagnetic fields. PRA, 112(2), 022216. (www)

  @article{ , abstract = {Ultrahigh-intensity laser-matter interactions generate high-energy photons, which carry essential information about the dynamics in the interaction region. Several models are developed to describe the statistical properties of emitted photons and the total photon yield produced by an electron beam propagating through a static, homogeneous magnetic field. The accuracy of these models, as well as the Fokker-Planck approximation, is verified using first-principles Monte Carlo simulations. While these models are valid in the quasiclassical regime, it is demonstrated that a model can be constructed to describe photon statistics in both the quasiclassical and quantum regimes. The extension of the developed approach to the strong quantum regime is discussed. Finally, the results are generalized to the case of an electron beam interacting with an ultrashort, high-intensity laser pulse.}, archive = {J_PRA}, author = {I. I. Artemenko and I. Yu. Kostyukov}, doi = {10.1103/h2y2-d77y}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022216}, shortjournal = {Phys. Rev. A}, title = {Statistical properties of photon emission from relativistic electrons in intense electromagnetic fields}, volume = {112}, year = {2025}, }
• (2025). Exact analytic toolbox for quantum dynamics with tunable noise strength. PRA, 112(2), 022215. (www)

  @article{ , abstract = {We introduce a framework that allows for the exact analytic treatment of quantum dynamics subject to noise, captured by unitary evolution under a Hamiltonian drawn from a random-matrix ensemble. The unitary acts on a Hilbert space of arbitrary dimension , which may include ancillary (e.g., “bath”) degrees of freedom, and the “strength” of the noise is tunable . While the methods we develop apply to generic random-matrix ensembles with a notion of rotation invariance, we explicitly consider the Gaussian unitary ensemble (GUE). Averaging over the ensemble of “noisy” Hamiltonians produces an effective quantum channel, the properties of which are analytically calculable and determined by the spectral form factors of the relevant ensemble. We compute spectral form factors of the GUE exactly for any finite , along with the corresponding GUE quantum channel and its variance. Importantly, the GUE channel captures the effects of generic unitary sources of noise. Key advantages of our approach include the ability to access exact analytic results for any , the ability to tune to the noise-free limit (in contrast, e.g., to the Haar ensemble), and analytic access to moments beyond the variance. We also highlight some unusual features of the GUE channel, including the nonmonotonicity of the coefficients of various operators as a function of noise strength and the failure to saturate the Haar-random limit, even with infinite noise strength.}, archive = {J_PRA}, author = {Mert Okyay and Oliver Hart and Rahul Nandkishore and Aaron J. Friedman}, doi = {10.1103/qqb7-h7xf}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022215}, shortjournal = {Phys. Rev. A}, title = {Exact analytic toolbox for quantum dynamics with tunable noise strength}, volume = {112}, year = {2025}, }
• (2025). Enhanced charging in multibattery systems by nonreciprocity. PRA, 112(2), 022214. (www)

  @article{ , abstract = {Quantum batteries (QBs), harnessing quantum systems to transfer and store energy, have garnered substantial attention recently, enabling potentials in enhanced charging capacity, increased charging power, and device miniaturization. However, constrained by the weak interaction between the quantum nodes, the implementations of QB networks exhibit limited charging performance. In this work, we propose an efficient approach to improving charging in multibattery systems by capitalizing on nonreciprocity. By constructing non-Hermitian Aharonov-Bohm triangles to establish unidirectional energy transfer in both cascaded and parallel configurations, we can achieve a significant enhancement of the stored energy in QBs under weak interaction. Remarkably, the nonreciprocal cascaded setups display an exponentially increasing gain in the battery energy as the charging distance lengthens compared to the reciprocal counterparts. Furthermore, we demonstrate that nonreciprocity can also lead to the same enhancement in the charging power of QBs, accelerating the charging processes. Our findings provide a practical pathway for enhancing the charging performance of QBs and exhibit the potentials for constructing efficient QB networks.}, archive = {J_PRA}, author = {Hua-Wei Zhao and Yong Xie and Xinyao Huang and Guo-Feng Zhang}, doi = {10.1103/fbv7-m7sd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022214}, shortjournal = {Phys. Rev. A}, title = {Enhanced charging in multibattery systems by nonreciprocity}, volume = {112}, year = {2025}, }
• (2025). Simulating monitoring-induced topological phase transitions with small systems. PRA, 112(2), 022213. (www)

  @article{ , abstract = {The topological properties of open quantum lattice systems have attracted much attention, due to their fundamental significance and potential applications. However, experimental demonstrations with large-scale lattice models remain challenging. On top of that, formulations of topology in terms of quantum trajectories require monitoring along with the detection of quantum jumps. This is particularly the case for the dark-state-induced topology that relies on averaging quantum trajectories at their jump times. Here we propose two significant simplifications to ease the experimental burden to demonstrate dark state-induced topological phase transitions: First, we emulate the topology in the phase space of small systems, where the effective size of the system is reflected by the accessible parameter range. Second, we develop a method how to, by augmenting the system with an auxiliary system, access the jump-time-averaged state through standard wall-time averaging, which effectively substitutes the monitoring along with the counting of quantum jumps. While these simplifications are applicable to general lattice systems, we demonstrate them with a one-dimensional Su-Schrieeffer-Heeger model. In this case, the lattice system is emulated by a four-level system, while the jump-time-averaged state up to the second jump is accessed through a three-level auxiliary system.}, archive = {J_PRA}, author = {Rui Xie and Clemens Gneiting and Zheng-Yang Zhou and Ai-Xi Chen}, doi = {10.1103/yk7m-hcqr}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022213}, shortjournal = {Phys. Rev. A}, title = {Simulating monitoring-induced topological phase transitions with small systems}, volume = {112}, year = {2025}, }
• (2025). Extended wigner's friend paradoxes do not require nonlocal correlations. PRA, 112(2), 022212. (www)

  @article{ , abstract = {Extended Wigner's friend no-go theorems provide a modern lens for investigating the measurement problem, by making precise the challenges that arise when one attempts to model agents as dynamical quantum systems. Most such no-go theorems studied to date, such as the Frauchiger-Renner argument and the Local Friendliness argument, are explicitly constructed using quantum correlations that violate Bell inequalities. In this work, we show that such correlations are not necessary for having extended Wigner's friend paradoxes, by constructing a no-go theorem utilizing a proof of the failure of noncontextuality. The argument hinges on an alternative metaphysical assumption (which we term commutation irrelevance) that is a natural extension of a key assumption going into the Frauchiger and Renner's no-go theorem.}, archive = {J_PRA}, author = {Laurens Walleghem and Rafael Wagner and Yìlè Yīng and David Schmid}, doi = {10.1103/n4hv-rlgj}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022212}, shortjournal = {Phys. Rev. A}, title = {Extended wigner's friend paradoxes do not require nonlocal correlations}, volume = {112}, year = {2025}, }
• (2025). Efficacy of the information causality principle in ruling out beyond-quantum compositions. PRA, 112(2), 022211. (www)

  @article{ , abstract = {The composition of individual quantum system can mathematically be defined in various ways. However, the no-signaling principle alongside local tomography criteria delineates two possible extreme compositions, commonly referred to as the minimal and maximal compositions. The former (latter) allows for the effects (states) that are beyond-quantum composition. A recent work [ Phys. Rev. Lett. 130 , 110202 (2023) ] demonstrates that the information causality (IC) principle rules out extreme compositions. In this work, we introduce a communication game to show that there are states and effects within both extreme compositions for which the success probability of the game surpasses the maximum achievable quantum bound. However, the IC principle remains satisfied, meaning that it cannot rule out all beyond-quantum correlations resulting from the extreme compositions. This again opens up the question of the effectiveness of the IC principle in ruling out beyond-quantum correlation.}, archive = {J_PRA}, author = {Vishnu Purushothaman and Akarshit Baranwal and A. K. Pan}, doi = {10.1103/bbnp-6mhv}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022211}, shortjournal = {Phys. Rev. A}, title = {Efficacy of the information causality principle in ruling out beyond-quantum compositions}, volume = {112}, year = {2025}, }
• (2025). Local and global approaches to the thermodynamics of pure decoherence processes in open quantum systems. PRA, 112(2), 022210. (www)

  @article{ , abstract = {We study the nonequilibrium thermodynamics of pure decoherence processes in open quantum systems coupled to a thermal reservoir. We review various definitions of central quantities, such as internal energy, work, heat, and entropy production, developed within local and global approaches to quantum thermodynamics. Within local approaches, thermodynamic quantities only refer to the open system's degrees of freedom, while in the global approaches, certain quantities are defined by referring explicitly to the reservoir degrees of freedom. Employing a microscopic, analytically solvable model, we perform a comparison of these two perspectives, revealing substantial differences in the thermodynamic quantities and in the formulations of the first and second laws. The main reason for these discrepancies is the fact that the global approaches involve the system-reservoir interaction which exchanges a large amount of energy with the environment, while the average open system energy is constant in time because the dynamics represents pure decoherence and does not affect the open system populations.}, archive = {J_PRA}, author = {Irene Ada Picatoste and Alessandra Colla and Heinz-Peter Breuer}, doi = {10.1103/kbsf-x4bz}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022210}, shortjournal = {Phys. Rev. A}, title = {Local and global approaches to the thermodynamics of pure decoherence processes in open quantum systems}, volume = {112}, year = {2025}, }
• (2025). Suppression of decoherence dynamics by a dissipative bath at strong coupling. PRA, 112(2), 022209. (www)

  @article{ , abstract = {Control of decoherence in open quantum systems has become a topic of great interest due to the emergence of quantum technologies that depend on quantum coherence effects. In this work, we investigate the decoherence dynamics of systems coupled to multiple baths through noncommuting systems' operators and beyond the weak system-bath coupling limit. By building on cooperative effects between baths, we propose a strategy to mitigate rapid decoherence. Concretely, we study the dynamics of a qubit coupled to multiple environments with arbitrary interaction strengths and along different coordinates. Based on insights gained on the decoherence dynamics from the analytical effective Hamiltonian method, we carry out numerical simulations using the reaction coordinate quantum master equation method. We show that when the system strongly interacts with a decohering bath, increasing its coupling to a second, dissipative bath can slow down the decoherence dynamics in a certain parameter regime. Our work offers insights into the preservation of quantum coherence in open quantum systems based on frustration effects, by utilizing cooperative effects between different heat baths.}, archive = {J_PRA}, author = {Jitian Chen and Jakub Garwoła and Dvira Segal}, doi = {10.1103/3d9c-4x2q}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022209}, shortjournal = {Phys. Rev. A}, title = {Suppression of decoherence dynamics by a dissipative bath at strong coupling}, volume = {112}, year = {2025}, }
• (2025). Purely geometrical aharonov-bohm effect. PRA, 112(2), 022208. (www)

  @article{ , abstract = {We present an application of the affine covariant integral quantization (ACIQ) [ Adv. Oper. Theory 5 , 901 (2020) ; Adv. Oper. Theory 7 , 22 (2022) ] to quantum mechanics on the punctured plane. The associated four-dimensional phase space is identified with the similitude group SIM(2), which comprises translations, rotations, and dilations of the plane. Due to the topology of the punctured plane, our quantization procedure gives rise to an affine vector potential. This potential can be interpreted as the Aharonov-Bohm (AB) gauge field produced by an infinite solenoid. This observation supports a reinterpretation of the AB effect: it emerges from the topological constraint imposed by the impenetrable coil rather than from an externally applied classical gauge field. In addition to this gauge structure, ACIQ also generates a repulsive, centrifugal-like scalar potential, a feature already encountered when applying ACIQ to motion on the half-line, whose phase space is the open half-plane. These results provide a new perspective on the AB effect, highlighting the central roles of topology and symmetry in quantum mechanics.}, archive = {J_PRA}, author = {Jean-Pierre Gazeau and Tomoi Koide and Romain Murenzi and Aidan Zlotak}, doi = {10.1103/h5b1-97ds}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022208}, shortjournal = {Phys. Rev. A}, title = {Purely geometrical aharonov-bohm effect}, volume = {112}, year = {2025}, }
• (2025). Optimal protocol to increase the lifetime of a harmonic oscillator via a squeezing reservoir. PRA, 112(2), 022207. (www)

  @article{ , abstract = {Reservoir engineering makes it possible to adjust the dissipation of quantum systems by driving the reservoir. This inspires investigations on how to slow a system's damping via squeezing reservoirs. In this paper we characterize damping by the quantum reliability of quantum states. We analyze the reliability loss of the harmonic oscillators in a squeezed thermal reservoir, where the quantum states under consideration have garnered significant interest in recent experiments, such as the coherent state, the squeezed coherent state, and the cat state. We explore the optimal protocol to extend the lifetime of these quantum states by adjusting the squeezed parameters of the squeezed thermal reservoir in both the high-damping and low-damping regimes. In the low-damping regime, our findings suggest that the unique optimal protocol follows the phase-matching condition and is insensitive to the reservoir's temperature. We also evaluate the optimal condition for the large damping regime. Furthermore, we show that when the state parameters satisfy a specific condition, there exists an interval for the damping rate, within which a bifurcation of the optimal protocol occurs.}, archive = {J_PRA}, author = {Yong-Qi Liu and Y.-M. Du and Xiaoguang Wang}, doi = {10.1103/gz8l-8gp6}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022207}, shortjournal = {Phys. Rev. A}, title = {Optimal protocol to increase the lifetime of a harmonic oscillator via a squeezing reservoir}, volume = {112}, year = {2025}, }
• (2025). Global and local performance of a quantum battery under correlated noise channels. PRA, 112(2), 022206. (www)

  @article{ , abstract = {We investigate the global and local performances of a quantum battery exposed to the depolarizing and bit-flip channels, respectively, using the correlation matrix method. The battery is initially prepared as the highest-energy state of a two-qubit Ising model with open boundary conditions and is discharged via interaction with local noise channels. We show that compared to the independent noise channels, the correlated noise channels provide varying degrees of protection for the global and local performances of the Ising battery. The correlated depolarizing channel not only protects the global energy, ergotropy, and capacity of the Ising battery, but also protects the local ergotropy and capacity, whereas the correlated bit-flip channel provides protection only for the global ergotropy and capacity of the Ising battery. In both the correlated depolarizing and bit-flip channels, the greater the correlation strength, the greater the protective effect. Furthermore, we also use the same method to investigate the protective effect of correlated channels on the performances of the multiqubit battery and general Heisenberg battery in noise channels.}, archive = {J_PRA}, author = {Lu Wang and Shu-Qian Liu and Feng-lin Wu and Hao Fan and Na-Na Li and Si-Yuan Liu}, doi = {10.1103/stc3-xkp5}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022206}, shortjournal = {Phys. Rev. A}, title = {Global and local performance of a quantum battery under correlated noise channels}, volume = {112}, year = {2025}, }
• (2025). Physicality of evolution and statistical contractivity as equivalent notions of maps. PRA, 112(2), 022205. (www)

  @article{ , abstract = {Statistical quantifiers are generically required to contract under physical maps, following the intuition that information should be lost under noisy transformations. This principle is so important in statistics that it even allows one to derive uniqueness results based on it: the Chentsov-Petz theorem identifies the Fisher information metrics as the only family, on the space of probability distributions (or density matrices), that contracts under physical maps. This construction could suggest that statistical quantifiers are a derived concept, while the only fundamental objects are the physical evolutions. The aim of this work is to disprove this belief. To this end, we prove a statement dual to the Chentsov-Petz theorem, showing that among all possible linear maps, the only ones that contract the Fisher information (including, in the quantum case, any idle ancilla) are exactly the physical ones. This result proves that, contrary to the common opinion, there is no fundamental hierarchy between physical maps and canonical statistical quantifiers, as either of them can be defined in terms of the other.}, archive = {J_PRA}, author = {Matteo Scandi and Paolo Abiuso and Dario De Santis and Jacopo Surace}, doi = {10.1103/2wb3-9gsh}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022205}, shortjournal = {Phys. Rev. A}, title = {Physicality of evolution and statistical contractivity as equivalent notions of maps}, volume = {112}, year = {2025}, }
• (2025). Non-equilibrium dynamics of localization phase transition in the non-hermitian disorder-aubry-andré model. PRA, 112(2), 022204. (www)

  @article{ , abstract = {The driven dynamics of localization transitions in a non-Hermitian disorder-Aubry-André (DAA) model are examined under both open boundary conditions (OBC) and periodic boundary conditions (PBC). Through an analysis of the static properties of observables, including the localization length ( ), inverse participation ratio ( ), and energy gap ( ), we found that the critical exponents examined under PBC are also applicable under OBC. The Kibble-Zurek scaling (KZS) for the driven dynamics in the non-Hermitian DAA systems is formulated and numerically verified for different local-to-local quench directions. The hybrid KZS (HKZS) in the overlapping critical region of non-Hermitian DAA and Anderson localization is proposed and numerically confirms the validity across a local-to-skin quench direction. This study generalizes the application of the KZS to the dynamical localization transitions within systems featuring dual localization mechanisms.}, archive = {J_PRA}, author = {Yue-Mei Sun and Xin-Yu Wang and Liang-Jun Zhai}, doi = {10.1103/26fx-j27m}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022204}, shortjournal = {Phys. Rev. A}, title = {Non-equilibrium dynamics of localization phase transition in the non-hermitian disorder-aubry-andré model}, volume = {112}, year = {2025}, }
• (2025). Violation of the thermodynamic uncertainty relation in quantum collisional models. PRA, 112(2), 022203. (www)

  @article{ , abstract = {The thermodynamic uncertainty relation (TUR) is a fundamental principle in nonequilibrium thermodynamics that relates entropy production to fluctuations in a system, establishing a trade-off between the precision of an observable and the thermodynamic cost. Investigating TUR violations challenges classical thermodynamic limits, offering the potential for improved precision-entropy trade-offs, which is crucial for enhancing performance and optimization in quantum technologies. In this work, we investigate the thermodynamic uncertainty relation within a quantum collisional model, which offers the advantage of discretizing interactions into successive collisions with auxiliaries, allowing for precise tracking of dynamics and the incorporation of memory effects and non-Markovian behavior. We consider three types of dynamics in the collisional model: one is Markovian evolution, achieved by taking the continuous-time limit and imposing the stability condition, while the other two are non-Markovian dynamics—one arising from increasing the collision time between the system and the auxiliaries, and the other from incorporating interactions between the auxiliaries. For the Markovian dynamics, we examine the classical and quantum TUR bounds in the nonequilibrium steady-state regime, and also the finite-time TUR bound. We identify two distinct regimes of classical TUR violation: in some cases, the maximum violation occurs in the steady state, while in others, it is necessarily transient—appearing only at early times and vanishing with further evolution. For the two non-Markovian approaches, we find that both the degree and type of non-Markovianity crucially affect TUR violations. The second approach shows more pronounced violations during transient times, while the first approach has much stronger violations in the steady-state regime for a certain parameter window.}, archive = {J_PRA}, author = {Arghya Maity and Ahana Ghoshal}, doi = {10.1103/kjkg-ksjd}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022203}, shortjournal = {Phys. Rev. A}, title = {Violation of the thermodynamic uncertainty relation in quantum collisional models}, volume = {112}, year = {2025}, }
• (2025). Caldeira-leggett quantum time crystal: Periodic revival of quantum coherence by a sub-ohmic environment. PRA, 112(2), 022202. (www)

  @article{ , abstract = {We propose the Caldeira-Leggett quantum time crystal in which the interaction between a quantum system and a viscoelastic sub-Ohmic environment leads to periodic revivals of quantum coherence. Using the Caldeira-Leggett model of quantum decoherence with a sub-Ohmic environment characterized by the spectral function J ( ω ) ∝ ω s ( 0 ≤ s < 1 ), we discover that decreasing the sub-Ohmic parameter s enhances the coherence lifetime of Gaussian wave packets, with the purity (i.e. coherence) decaying as t − s / 2 throughout the regime 0 ≤ s < 1 . A revival oscillation of the purity with lifetime e 2 / s occurs in the deep sub-Ohmic regime ( s < 0.1 ), which we call the Caldeira-Leggett quantum time crystal. We reveal that such oscillations originate from the fact that an environment in the deep sub-Ohmic regime behaves as a gel-like fractal medium with viscosity and elasticity, suggesting the significance of fractal gel-like environments in vivo and in information processing.}, archive = {J_PRA}, author = {Keiji Nakatsugawa and Satoshi Tanda and Toshiyuki Fujii}, doi = {10.1103/k1q6-lr6x}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022202}, shortjournal = {Phys. Rev. A}, title = {Caldeira-leggett quantum time crystal: Periodic revival of quantum coherence by a sub-ohmic environment}, volume = {112}, year = {2025}, }
• (2025). Quantifying information flow in quantum processes. PRA, 112(2), 022201. (www)

  @article{ , abstract = {We present a framework for quantifying information flow within general quantum processes. For this purpose, we introduce the signaling power of quantum channels and discuss its relevant operational properties. This function supports extensions to higher-order maps, enabling the evaluation of information flow in general quantum causal networks and processes with indefinite causal order. Furthermore, our results offer a rigorous approach to information dynamics in open systems that applies also in the presence of initial system-environment correlations, and allows for the distinction between classical and quantum information backflow.}, archive = {J_PRA}, author = {Leonardo S. V. Santos and Zhen-Peng Xu and Jyrki Piilo and Otfried Gühne}, doi = {10.1103/5211-h7g2}, journal = {Physical Review a}, month = {8}, number = {2}, pages = {022201}, shortjournal = {Phys. Rev. A}, title = {Quantifying information flow in quantum processes}, volume = {112}, year = {2025}, }
• (2025). Tailoring indistinguishability of photons using longitudinal spatial coherence. PRA, 112(1), L011702. (www)

  @article{ , abstract = {Methods to generate photons with tailored indistinguishability are central to developing photonic quantum technologies and making fundamental tests of quantum physics. This study introduces a novel method for manipulating effective longitudinal spatial coherence (LSC) of biphotons, controlling their indistinguishability in a significant manner. The experimental results show that, instead of tailoring the frequency spectrum of the interfering photons, changing their LSC also leads to controlling the width of Hong-Ou-Mandel dip as validated by the theoretical calculations. This powerful approach not only modifies the conventional wisdom claiming only frequency width responsible for indistinguishability control of photons but also positions the LSC as a promising tool for fine-tuning the longitudinal coherence of photons, thereby expanding their potential use in quantum science and technologies.}, archive = {J_PRA}, author = {Preeti Sharma and Gaytri Arya and Bhaskar Kanseri}, doi = {10.1103/tbpt-jbmw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011702}, shortjournal = {Phys. Rev. A}, title = {Tailoring indistinguishability of photons using longitudinal spatial coherence}, volume = {112}, year = {2025}, }
• (2025). Magic-wavelength nanofiber-based two-color dipole trap with sub-λ/2 spacing. PRA, 112(1), L011701. (www)

  @article{ , abstract = {We report on the realization and characterization of a novel magic-wavelength nanofiber-based two-color optical dipole trap for cesium that allows us to generate two diametral periodic one-dimensional arrays of trapping sites with a spacing significantly smaller than half the resonant free-space wavelength of the cesium transition. This is achieved by launching a blue-detuned partial standing wave and two red-detuned light fields through the nanofiber. We trap and optically interface the atoms in the resulting periodic optical potential and characterize the trap by measuring the lifetime of the trapped atoms, the atom-light coupling strength, the filling factor, and the trap frequencies in the radial and axial directions. The implementation of this nanofiber-based optical interface with magic trapping wavelengths and sub- spacing is an important step towards the exploration of novel collective radiative effects, such as selective radiance.}, archive = {J_PRA}, author = {Lucas Pache and Martin Cordier and Hector Letellier and Max Schemmer and Philipp Schneeweiss and Jürgen Volz and Arno Rauschenbeutel}, doi = {10.1103/89l1-dys4}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011701}, shortjournal = {Phys. Rev. A}, title = {Magic-wavelength nanofiber-based two-color dipole trap with sub-λ/2 spacing}, volume = {112}, year = {2025}, }
• (2025). Correlated-hopping-induced topological order in an atomic mixture. PRA, 112(1), L011305. (www)

  @article{ , abstract = {The large majority of topological phases in one-dimensional many-body systems are known to be inherited from the corresponding single-particle Hamiltonian. In this work, we go beyond this assumption and find a new example of topological order induced through specific interaction couplings. Specifically, we consider a fermionic mixture where one component experiences a staggered on-site potential and it is coupled through density-dependent hopping interactions to the other fermionic component. Crucially, by varying the sign of the staggered potential, we show that this latter fermionic component can acquire topological properties. Due to matrix product state simulations, we prove this result both at equilibrium by extracting the behavior of correlation functions and in an out-of-equilibrium scheme by employing a Thouless charge pumping. Notably, we further discuss how our results can be probed in quantum simulators made up of ultracold atoms. Our results reveal an important and alternative mechanism that can give rise to topological order.}, archive = {J_PRA}, author = {Ashirbad Padhan and Luca Barbiero and Tapan Mishra}, doi = {10.1103/lw8k-7h6p}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011305}, shortjournal = {Phys. Rev. A}, title = {Correlated-hopping-induced topological order in an atomic mixture}, volume = {112}, year = {2025}, }
• (2025). Scattering resonances and pairing in a rabi-coupled fermi gas. PRA, 112(1), L011304. (www)

  @article{ , abstract = {We investigate the possibility of using a Rabi drive to tune the interactions in an atomic Fermi gas. Specifically, we consider the scenario where two fermion species (spins) are Rabi coupled and interacting with a third uncoupled species. Using an exact calculation within a minimal low-energy model, we derive analytical expressions for the effective scattering length and effective range that characterize the collisions between a Rabi-dressed atom and an atom from the third species. In particular, we find that new scattering resonances emerge in the Rabi-coupled system, which we demonstrate are linked to the existence of hybrid two-body bound states. Furthermore, we show via a generalized Thouless criterion that the scattering properties have a direct impact on the superfluid transitions in the Rabi-coupled Fermi gas. The presence of Rabi-induced resonances thus has implications for the investigation of many-body physics with driven atomic gases.}, archive = {J_PRA}, author = {Olivier Bleu and Brendan C. Mulkerin and Cesar R. Cabrera and Jesper Levinsen and Meera M. Parish}, doi = {10.1103/stvf-cn1b}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011304}, shortjournal = {Phys. Rev. A}, title = {Scattering resonances and pairing in a rabi-coupled fermi gas}, volume = {112}, year = {2025}, }
• (2025). Area laws and thermalization from classical entropies in a bose-einstein condensate. PRA, 112(1), L011303. (www)

  @article{ , abstract = {The scaling of local quantum entropies is of utmost interest for characterizing quantum fields, many-body systems, and gravity. Despite their importance, theoretically and experimentally accessing quantum entropies is challenging as they are nonlinear functionals of the underlying quantum state. Here, we show that suitably chosen classical entropies capture many features of their quantum analogs for an experimentally relevant setting. We describe the postquench dynamics of a multiwell spin-1 Bose-Einstein condensate from an initial product state via measurement distributions of spin observables and estimate the corresponding entropies using the asymptotically unbiased k -nearest-neighbor method. We observe the dynamical buildup of quantum correlations signaled by an area law, as well as local thermalization revealed by a transition to a volume law, both in regimes characterized by non-Gaussian distributions. We emphasize that all relevant features can be observed at small sample numbers without reconstructing the underlying state or measurement distributions, rendering our method directly applicable to a large variety of models and experimental platforms.}, archive = {J_PRA}, author = {Yannick Deller and Martin Gärttner and Tobias Haas and Markus K. Oberthaler and Moritz Reh and Helmut Strobel}, doi = {10.1103/7jzy-g3vd}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011303}, shortjournal = {Phys. Rev. A}, title = {Area laws and thermalization from classical entropies in a bose-einstein condensate}, volume = {112}, year = {2025}, }
• (2025). Engineering the bogoliubov modes through geometry and interaction: From collective edge modes to flat-band excitations. PRA, 112(1), L011302. (www)

  @article{ , abstract = {We propose a procedure to engineer solid-state lattice models with superlattices of interaction-coupled Bose-Einstein condensates. We show that the dynamical equation for the excitations of Bose-Einstein condensates at zero temperature can be expressed in an eigenvalue form that resembles the time-independent Schrödinger equation. The eigenvalues and eigenvectors of this equation correspond to the dispersions of the collective modes and the amplitudes of the density oscillations. This likeness opens the way for the simulation of different tight-binding models with arrays of condensates. We demonstrate, in particular, how we can model a one-dimensional Su-Schrieffer-Heeger lattice supporting topological edge modes and a two-dimensional Lieb lattice with flat-band excitations with superlattices of Bose-Einstein condensates.}, archive = {J_PRA}, author = {Maryam Darvishi and Fatemeh Pouresmaeeli and Saeed H. Abedinpour}, doi = {10.1103/6888-q2cd}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011302}, shortjournal = {Phys. Rev. A}, title = {Engineering the bogoliubov modes through geometry and interaction: From collective edge modes to flat-band excitations}, volume = {112}, year = {2025}, }
• (2025). Topological quantum floating phase of dipolar bosons in an optical ladder. PRA, 112(1), L011301. (www)

  @article{ , abstract = {Ultracold dipolar hard-core bosons in optical ladders provide exciting possibilities for the quantum simulation of anisotropic spin ladders. We show that introducing a tilt along the rungs results in a rich phase diagram at unit rung filling. In particular, for a sufficiently strong dipolar strength, the interplay between the long-range tail of the dipolar interactions and the tilting leads to the emergence of a quantum floating phase, a critical phase with incommensurate density-density correlations. Interestingly, the floating phase is topological, constituting an intermediate gapless stage in the melting of a crystal into a gapped topological Haldane phase. This novel scenario for topological floating phases in dipolar spin ladders can be investigated in ongoing experiments.}, archive = {J_PRA}, author = {Henning Korbmacher and Gustavo A. Domínguez-Castro and Mateusz Łącki and Jakub Zakrzewski and Luis Santos}, doi = {10.1103/lhfx-c4xr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011301}, shortjournal = {Phys. Rev. A}, title = {Topological quantum floating phase of dipolar bosons in an optical ladder}, volume = {112}, year = {2025}, }
• (2025). Attosecond pulse synthesis from high-order harmonic generation in intense squeezed light. PRA, 112(1), L011102. (www)

  @article{ , abstract = {High-order harmonic generation (HHG) of an atom in a strong laser field provides a broad spectral bandwidth for attosecond pulse synthesis. However, due to complex electron dynamics in the atom, usually only a part of the HHG can be used for the synthesis of the attosecond pulse, which significantly limits the attosecond pulse width. In this work we theoretically study the synthesis of attosecond pulses from high-order harmonics generated by intense squeezed light. It is found that, unlike the coherent light, the whole HHG spectrum can be effectively used to synthesize attosecond pulses. By developing strong-field approximation theory in squeezed light, this is attributed to substantial suppression of long and multireturn electron trajectories at the single-atom level. Based on this novel scheme using intense squeezed light, we show that an isolated attosecond pulse can be synthesized from the entire HHG spectrum, and the pulse width is much shorter than that from the coherent light with the same laser parameters.}, archive = {J_PRA}, author = {ShiJun Wang and XuanYang Lai and XiaoJun Liu}, doi = {10.1103/4x11-phs2}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011102}, shortjournal = {Phys. Rev. A}, title = {Attosecond pulse synthesis from high-order harmonic generation in intense squeezed light}, volume = {112}, year = {2025}, }
• (2025). Tuning the terahertz response of liquids by creating polar many-body excitations. PRA, 112(1), L011101. (www)

  @article{ , abstract = {A surprising result from the theory of quantum control is the degree to which the properties of a physical system can be manipulated. Both atomic and many-body solid-state models admit the possibility of creating a “driven imposter” in which the optical response of one material mimics that of a dynamically distinct system. Here we apply these techniques to polarons in polar liquids. Such quasiparticles describe solvated electrons interacting with many-body degrees of freedom of their environment. The polaron frequency, which depends on the electron concentration in the liquid, is controlled with a pump field. Using this field as a control, we demonstrate the aforementioned dynamical mimicry experimentally, rendering the polaron frequency of three different liquids identical.}, archive = {J_PRA}, author = {Gerard McCaul and Matthias Runge and Michael Woerner and Diyar Talbayev and Thomas Elsaesser and Denys I. Bondar}, doi = {10.1103/qbqx-zcsx}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L011101}, shortjournal = {Phys. Rev. A}, title = {Tuning the terahertz response of liquids by creating polar many-body excitations}, volume = {112}, year = {2025}, }
• (2025). Direct extraction of nuclear structure information using precision lithium-ion spectroscopy. PRA, 112(1), L010801. (www)

  @article{ , abstract = {Accurately describing nuclear interactions within atomic nuclei remains a challenge, which hinders our exploration of new physics beyond the Standard Model. However, these nuclear interactions can be characterized by nuclear parameters such as the Zemach radius and the electric quadrupole moment, which are reflected in atomic spectra. Our work achieves high-precision measurements of lithium-ion hyperfine splittings at the level of 10 kHz, and directly extracts these important nuclear structure parameters. We observe significant discrepancies between our results and both nuclear theory and molecular spectra regarding the electric quadrupole moment. The result for deviates by from the currently recommended value, whereas the result for deviates by up to from the recommended value determined by molecular spectroscopy. We supplement the measurements with independent calculations based on nuclear structure theory. They provide support for the results obtained from the present ion spectroscopy measurements. Our results provide valuable information for characterizing nuclear forces, serve as sensitive benchmarks for testing nuclear structure theories, and enable critical comparisons with both electron-nuclear scattering and molecular spectroscopy.}, archive = {J_PRA}, author = {Hua Guan and Xiao-Qiu Qi and Jian-Guo Li and Peng-Peng Zhou and Wei Sun and Shao-Long Chen and Xu-Rui Chang and Yao Huang and Pei-Pei Zhang and Zong-Chao Yan and G. W. F. Drake and Ai-Xi Chen and Zhen-Xiang Zhong and Jia-Li Wang and Nicolas Michel and Ting-Yun Shi and Ke-Lin Gao}, doi = {10.1103/s61z-b1t5}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L010801}, shortjournal = {Phys. Rev. A}, title = {Direct extraction of nuclear structure information using precision lithium-ion spectroscopy}, volume = {112}, year = {2025}, }
• (2025). Extra cost of erasure due to quantum lifetime broadening. PRA, 112(1), L010601. (www)

  @article{ , abstract = {The energy cost of erasing a bit of information was fundamentally lower bounded by Landauer, in terms of the temperature of its environment, W ≥ k B T ln 2 . Energy consumption and heat generation in computers is now a pressing issue, but real electronic devices operate out of equilibrium and are subject to other noise sources besides temperature. Considering a quantum dot charge bit as a concrete model, we here derive a tighter bound, rigorously quantifying the dissipative impact of lifetime broadening and potential difference, in terms of a few experimentally measurable parameters. In practical contexts, these additional contributions may significantly outweigh the cost due to temperature alone. The results shed light not only on theoretical limits of erasure but also on constraints in realistic devices.}, archive = {J_PRA}, author = {Joe Dunlop and Federico Cerisola and Juliette Monsel and Sofia Sevitz and Jorge Tabanera-Bravo and Jonathan Dexter and Federico Fedele and Natalia Ares and Janet Anders}, doi = {10.1103/pc2t-ybtz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L010601}, shortjournal = {Phys. Rev. A}, title = {Extra cost of erasure due to quantum lifetime broadening}, volume = {112}, year = {2025}, }
• (2025). Local entanglement transfer from an entanglement source to multiple pairs of spatially separated observers. PRA, 112(1), L010402. (www)

  @article{ , abstract = {For an efficient usage and deployment of entanglement, we envisage the scenario where a pair of spatially separated observers, Charu and Debu, want to share entanglement without interacting with each other. As a way out, their systems can separately and locally interact with those of Alice and Bob, respectively, who already share an entangled state. We find joint unitaries which, when applied by Alice and a Charu, and by Bob and the corresponding Debu, can transfer entanglement from the Alice-Bob pair to an indefinite number of pairs of Charus and Debus. We also discuss the amount of entanglement that can be transferred to a fixed number of pairs using these unitaries. Moreover, by optimizing over all possible local unitaries, we analyze the maximum number of pairs to which entanglement can be transferred in such a way that each pair gets at least a fixed amount of entanglement. Given the valuable role played by the costly resource, entanglement, in quantum information processing and communication, we expect that our results will have significant impact in quantum technologies.}, archive = {J_PRA}, author = {Tanmoy Mondal and Kornikar Sen and Chirag Srivastava and Ujjwal Sen}, doi = {10.1103/17s4-rtdm}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L010402}, shortjournal = {Phys. Rev. A}, title = {Local entanglement transfer from an entanglement source to multiple pairs of spatially separated observers}, volume = {112}, year = {2025}, }
• (2025). Quantum algorithm for the advection-diffusion equation by direct block encoding of the time-marching operator. PRA, 112(1), L010401. (www)

  @article{ , abstract = {A quantum algorithm for simulating multidimensional scalar transport problems using a time-marching strategy is presented. A direct unitary block encoding of the explicit time-marching operator is constructed, resulting in the intrinsic success probability of the squared solution norm without the need for amplitude amplification, thereby retaining a linear dependence on the simulation time. The algorithm separates the explicit time-marching operator into an advection-like component and a corrective shift operator. The advection-like component is mapped to a Hamiltonian simulation and combined with the shift operator through the linear combination of unitaries algorithm. State-vector simulations of a scalar transported in a steady two-dimensional Taylor-Green vortex support the theoretical findings.}, archive = {J_PRA}, author = {Paul Over and Sergio Bengoechea and Peter Brearley and Sylvain Laizet and Thomas Rung}, doi = {10.1103/d8hb-fv93}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {L010401}, shortjournal = {Phys. Rev. A}, title = {Quantum algorithm for the advection-diffusion equation by direct block encoding of the time-marching operator}, volume = {112}, year = {2025}, }
• (2025). Erratum: Generic optical singularities in brewster-reflected postparaxial beam fields [Phys. rev. a 103, 013510 (2021)]. PRA, 112(1), 019906. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019906 (2025)}, archive = {J_PRA}, author = {Anirban Debnath and Nirmal K. Viswanathan}, doi = {10.1103/3bqb-14y3}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019906}, shortjournal = {Phys. Rev. A}, title = {Erratum: Generic optical singularities in brewster-reflected postparaxial beam fields [Phys. rev. a 103, 013510 (2021)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Two-dimensional non-hermitian fermionic superfluidity with spin imbalance [Phys. rev. a 109, 063306 (2024)]. PRA, 112(1), 019905. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019905 (2025)}, archive = {J_PRA}, author = {Tingting Shi and Siqi Wang and Zhiyue Zheng and Wei Zhang}, doi = {10.1103/7c6t-4bkb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019905}, shortjournal = {Phys. Rev. A}, title = {Erratum: Two-dimensional non-hermitian fermionic superfluidity with spin imbalance [Phys. rev. a 109, 063306 (2024)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Forces on alkali rydberg atoms due to nonlinearly polarized light [Phys. rev. a 111, 053120 (2025)]. PRA, 112(1), 019904. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019904 (2025)}, archive = {J_PRA}, author = {A. Bhowmik and D. Blume}, doi = {10.1103/p2s4-12yy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019904}, shortjournal = {Phys. Rev. A}, title = {Erratum: Forces on alkali rydberg atoms due to nonlinearly polarized light [Phys. rev. a 111, 053120 (2025)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Low-depth phase oracle using a parallel piecewise circuit [Phys. rev. a 111, 062420 (2025)]. PRA, 112(1), 019903. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019903 (2025)}, archive = {J_PRA}, author = {Zhu Sun and Gregory Boyd and Zhenyu Cai and Hamza Jnane and Bálint Koczor and Richard Meister and Romy Minko and Benjamin Pring and Simon C. Benjamin and Nikitas Stamatopoulos}, doi = {10.1103/8tng-x9nj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019903}, shortjournal = {Phys. Rev. A}, title = {Erratum: Low-depth phase oracle using a parallel piecewise circuit [Phys. rev. a 111, 062420 (2025)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Superradiance-driven optomechanical entanglement [Phys. rev. a 111, 053713 (2025)]. PRA, 112(1), 019902. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019902 (2025)}, archive = {J_PRA}, author = {Kai-Wei Huang and Xin Wang and Yi Ren and Hao Xiong}, doi = {10.1103/yv1s-9g6b}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Superradiance-driven optomechanical entanglement [Phys. rev. a 111, 053713 (2025)]}, volume = {112}, year = {2025}, }
• (2025). Erratum: Quantum langevin theory for two coupled phase-conjugated electromagnetic waves [Phys. rev. a 107, 053703 (2023)]. PRA, 112(1), 019901. (www)

  @article{ , abstract = {Phys. Rev. A 112, 019901 (2025)}, archive = {J_PRA}, author = {Yue Jiang and Yefeng Mei and Shengwang Du}, doi = {10.1103/3cml-r2sv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {019901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Quantum langevin theory for two coupled phase-conjugated electromagnetic waves [Phys. rev. a 107, 053703 (2023)]}, volume = {112}, year = {2025}, }
• (2025). Reply to “Comment on ‘Hermitian stochastic methodology for x-ray superfluorescence’ ”. PRA, 112(1), 017702. (www)

  @article{ , abstract = {This Reply addresses the Comment by Park, Kim, and Lindberg on our article, “Hermitian stochastic methodology for x-ray superfluorescence” [ Phys. Rev. A 109 , 063705 (2024) ]. The Comment presents criticism, primarily claiming that our derivations involve “a redefinition of physical variables without a clear rationale.” Additionally, it asserts that our methodology closely resembles the stochastic Maxwell-Bloch equations (SMBEs) introduced by Park et al. We disagree with these observations. In this Reply, we further elaborate on the rationale behind our derivations, building on the explanation already provided in the original article. Furthermore, we demonstrate that the “redefinition of physical variables” is an example of stochastic gauge freedom, a well-established concept in methodologies based on positive- stochastic equations (PPSEs), which underscores the consistency of our derivations with the PPSE formalism. Additionally, we highlight the fundamental differences between our methodology and the SMBEs.}, archive = {J_PRA}, author = {Stasis Chuchurka and Vladislav Sukharnikov and Nina Rohringer}, doi = {10.1103/tz1g-ttn9}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {017702}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Hermitian stochastic methodology for x-ray superfluorescence’ ”}, volume = {112}, year = {2025}, }
• (2025). Comment on “Hermitian stochastic methodology for x-ray superfluorescence”. PRA, 112(1), 017701. (www)

  @article{ , abstract = {This comment critically examines the paper “Hermitian stochastic methodology for x-ray superfluorescence” by Chuchurka, Sukharnikov, and Rohringer [ Phys. Rev. A 109 , 063705 (2024) ]. The paper proposes a Hermitian framework based on the positive- stochastic equations (PPSEs), claimed to be derived “from first principles,” through a redefinition of physical variables without a clear rationale. However, because the original PPSEs cannot satisfy Hermiticity under any stochastic-diffusion-gauge transformation, the framework necessarily employs representations beyond this gauge freedom, thereby contradicting the original PPSEs and their ensemble-average predictions. The resulting equations have close structural similarities with the previously established Hermitian formalism of stochastic Maxwell-Bloch equations [ arXiv:2305.04653 and Phys. Rev. A 110 , 023724 (2024) ].}, archive = {J_PRA}, author = {Jeong-Wan Park and Kwang-Je Kim and Ryan Lindberg}, doi = {10.1103/1n7g-rnmy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {017701}, shortjournal = {Phys. Rev. A}, title = {Comment on “Hermitian stochastic methodology for x-ray superfluorescence”}, volume = {112}, year = {2025}, }
• (2025). Heralded generation of entangled states based on N-bundle emission in a waveguide magnonics system. PRA, 112(1), 013723. (www)

  @article{ , abstract = {We propose a scheme for the heralded generation of entangled states, such as Bell states, between two magnetic spheres individually coupled to a common waveguide. By deriving the quantum trajectory equation, we describe the system's dynamics under continuous monitoring and reveal how the waveguide output influences its internal evolution. Based on this formalism, we analyze the two- and three-magnon resonance conditions and demonstrate the two- and three-photon bundles reflected from the waveguide when it is driven from one side. Under these conditions, the detection outcomes allow us to infer the internal magnon states, namely the detection of the first photon in a bundle heralds the successful generation of an entangled state. We further examine abnormal photon emission events and potential experimental imperfections, highlighting the crucial role of detector efficiency in achieving high-fidelity entanglement. Our work provides a robust method for entanglement generation in waveguide magnonics systems.}, archive = {J_PRA}, author = {Chengsong Zhao and Wenlin Li and Biao Xiong and Jia-Xin Peng and Ling Zhou and Wei-jiang Gong}, doi = {10.1103/nqkp-ykf7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013723}, shortjournal = {Phys. Rev. A}, title = {Heralded generation of entangled states based on N-bundle emission in a waveguide magnonics system}, volume = {112}, year = {2025}, }
• (2025). Many-body quantum dimerization in two-dimensional atomic arrays. PRA, 112(1), 013722. (www)

  @article{ , abstract = {We consider a two-dimensional (2D) atomic array coupled to different photonic environments, focusing on the half-filled excitation subspace, where strong photon interactions can give rise to complex many-body states. In particular, we demonstrate that the least radiant state in this sector is well described by a coherent superposition of all possible quantum dimer coverings: a resonating valence bond liquid state. We discuss possible strategies to probe this exotic state, along with their limitations and challenges. Finally, we show that such a quantum dimer covering can also emerge as the ground state of the coherent Hamiltonian describing a 2D atomic array coupled to a photonic band-gap material.}, archive = {J_PRA}, author = {Giuseppe Calajó and Matija Tečer and Simone Montangero and Pietro Silvi and Marco Di Liberto}, doi = {10.1103/1r6c-6ftv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013722}, shortjournal = {Phys. Rev. A}, title = {Many-body quantum dimerization in two-dimensional atomic arrays}, volume = {112}, year = {2025}, }
• (2025). Efficient tensor-network simulation of multiemitter non-markovian systems. PRA, 112(1), 013721. (www)

  @article{ , abstract = {We present a numerical method to simulate a system of multiple emitters coupled to a noninteracting bath in any parameter regime. Our method relies on a Block Lanczos transformation that maps the whole system onto a strip geometry whose width is given by the number of emitters. Utilizing the spatial symmetries of the problem and identifying the relevant range of energies of the bath, we achieve a more efficient simulation, which we perform using tensor network techniques. As a demonstration, we study the collective emission from multiple emitters coupled to a square lattice of bosons and observe how the departure from Markovianity as coupling strength and emitter number is increased prevents collective radiation. We also simulate the dynamic preparation of an excitation in a bound state from a multiexcitation initial state. Our work opens possibilities for the systematic exploration of non-Markovian effects in the dynamics and equilibrium properties of multiemitter systems. Furthermore, it can easily be extended to other setups, including finite bath temperature or impurities coupled to fermionic environments.}, archive = {J_PRA}, author = {Irene Papaefstathiou and Daniel Malz and J. Ignacio Cirac and Mari Carmen Bañuls}, doi = {10.1103/hmbj-lg7p}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013721}, shortjournal = {Phys. Rev. A}, title = {Efficient tensor-network simulation of multiemitter non-markovian systems}, volume = {112}, year = {2025}, }
• (2025). Stark-induced tunable phase transition in the two-photon dicke-stark model. PRA, 112(1), 013720. (www)

  @article{ , abstract = {We theoretically investigate the superradiant phase transition (SPT) in the two-photon Dicke-Stark model, which incorporates both Rabi and Stark coupling. By introducing a Stark coupling term, we significantly reduce the critical Rabi coupling strength required to achieve the SPT, enabling it to occur even in non-ultrastrong-coupling regimes. Using mean-field theory, we derive the conditions for the SPT and show that it exhibits a second-order phase transition. Surprisingly, we demonstrate that the transition point can be widely tuned by the Stark coupling strength. The signatures of these Stark-tunable SPT points manifest through atomic pseudospin mean values. When quantum fluctuations are included, the spin-squeezing distributions also reveal the effects of Stark-tunable SPT points. In addition, we propose an experimentally feasible realization using an ion-trap system driven by three lasers. Our scheme enables optical switching between normal and superradiant phases through pump field intensity modulation, where the Stark coupling coefficient serves as the optically tunable parameter. Our results offer an alternative approach to engineer the SPT, extending superradiance-based quantum technologies beyond the ultrastrong-coupling regime.}, archive = {J_PRA}, author = {Cui-Lu Zhai and Wei Wu and Chun-Wang Wu and Ping-Xing Chen}, doi = {10.1103/vqnf-zd5w}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013720}, shortjournal = {Phys. Rev. A}, title = {Stark-induced tunable phase transition in the two-photon dicke-stark model}, volume = {112}, year = {2025}, }
• (2025). Quantum beat of two single photons in the transverse momentum space. PRA, 112(1), 013719. (www)

  @article{ , abstract = {Two-photon Hong-Ou-Mandel (HOM) interference is a pivotal quantum optical phenomenon, with broad applications in quantum information and metrology. Although conventional HOM interferometry loses sensitivity for transverse spatial separations beyond the photons' coherence length, we reveal experimentally that momentum-space measurements preserve this information through phase-sensitive two-photon interference fringes. Notably, we achieve micrometer-scale precision in determining transverse spatial separations an order of magnitude larger than the coherence length with only hundreds of photons. Our work establishes momentum-space interferometry as an important platform for quantum-enhanced metrology and information processing, overcoming the constraints of standard HOM techniques while providing new insights into quantum interference.}, archive = {J_PRA}, author = {Bixiang Guo and Ziye Chen and Luca Maggio and Wenbo Wu and Shiting Liu and Vincenzo Tamma and Jingyun Fan}, doi = {10.1103/wv2d-5z4g}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013719}, shortjournal = {Phys. Rev. A}, title = {Quantum beat of two single photons in the transverse momentum space}, volume = {112}, year = {2025}, }
• (2025). Vacuum-induced goos-hänchen shift. PRA, 112(1), 013718. (www)

  @article{ , abstract = {We present a theoretical investigation of the Goos-Hänchen shift in an optical cavity containing a three-level atomic medium. Unlike conventional approaches that require external control or pump fields, transparency in our system is induced by the vacuum field itself through a phenomenon known as vacuum-induced transparency, distinguishing it from the traditional electromagnetically induced transparency. Inspired by this mechanism, we introduce the concept of the vacuum-induced Goos-Hänchen (VIGH) shift, where the lateral displacement of the reflected beam is governed by vacuum field interactions. Additionally, we explore the influence of a microwave field on the atomic medium, demonstrating its ability to modulate both the magnitude and direction of the VIGH shift. Notably, we establish a tunable control over positive and negative VIGH shifts through the microwave field, with the shifts in magnitude further influenced by the photon number inside the cavity. Moreover, we examine the impact of Doppler broadening, revealing a unique deviation in VIGH shift behavior. In contrast to the Doppler-free case, where the microwave field can transition the VIGH shift between positive and negative regimes, Doppler broadening suppresses this transition, enhancing only the magnitude of the negative VIGH shift as microwave strength increases. Our findings provide deeper insights into light-matter interactions at the quantum level and open pathways for precision control of optical shifts in cavity-based quantum systems.}, archive = {J_PRA}, author = {Zareen A. Khan and Anwar Ali Khan and Zeeshan Ali and Rahmatullah and Ziauddin and Shi-Hai Dong}, doi = {10.1103/mqz2-8n2q}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013718}, shortjournal = {Phys. Rev. A}, title = {Vacuum-induced goos-hänchen shift}, volume = {112}, year = {2025}, }
• (2025). Many-body enhancement of energy storage in a waveguide QED quantum battery. PRA, 112(1), 013717. (www)

  @article{ , abstract = {Quantum batteries have demonstrated remarkable charging properties, showing that a quantum advantage is possible in the realm of quantum thermodynamics. However, finding an effective strategy to store energy for long periods remains crucial in these systems. Here, we investigate different configurations of a waveguide QED system acting as a quantum battery and show that, in this context, collective effects can slow down the self-discharging time of the battery, thus improving the storage time. Specifically, when the artificial atoms of the array are arranged randomly, the energy and ergotropy of the optical system are shown to decay at a subexponential rate over long periods, in contrast to the energy decay of a single atom in a waveguide. In the case of atoms arranged in an ordered lattice, collective effects slow down dissipative discharging only for a specific lattice spacing. Thus, in both configurations, collective effects can be used to boost the energy-protection properties of optical systems.}, archive = {J_PRA}, author = {Salvatore Tirone and Gian Marcello Andolina and Giuseppe Calajò and Vittorio Giovannetti and Davide Rossini}, doi = {10.1103/c4hd-8vfj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013717}, shortjournal = {Phys. Rev. A}, title = {Many-body enhancement of energy storage in a waveguide QED quantum battery}, volume = {112}, year = {2025}, }
• (2025). Optimizing the brightness of a spontaneous parametric down-conversion source in laguerre-gaussian modes using a type-0 periodically poled nonlinear crystal. PRA, 112(1), 013716. (www)

  @article{ , abstract = {Photon pairs generated via spontaneous parametric down-conversion (SPDC) can exhibit entanglement in the Laguerre-Gaussian (LG) mode basis, which enables high-dimensional free-space quantum communication by exploiting the high-dimensional space spanned by the LG modes. For such free-space quantum communication, the brightness of the quantum light source plays an important role due to the atmospheric turbulence and photon loss. A variety of studies have analyzed the SPDC brightness by decomposing biphoton states into LG modes, but they have often relied on a degenerate state, a narrow-spectral-bandwidth approximation, or a thin-crystal approximation. However, these approaches are unsuitable for nondegenerate type-0 SPDC with a periodically poled nonlinear crystal, which offers higher brightness due to its superior nonlinear coefficients. In this study, we examine the spectrum of photon pairs in specific LG modes generated by a type-0 periodically poled potassium titanyl phosphate crystal while avoiding the constraints imposed by the aforementioned assumptions. In addition, we investigate the optimal focal parameters of the pump, signal, and idler to maximize the brightness for a given LG mode. Our findings show that it is not feasible to simultaneously optimize the brightness for different LG modes with a single pump focal parameter. The results of this study provide a comprehensive framework for developing high-brightness quantum light sources and contribute to the advancement of high-dimensional free-space quantum communication.}, archive = {J_PRA}, author = {Jungmo Lee and Kyungdeuk Park and Dongkyu Kim and Yonggi Jo and Dong-Gil Im and Yong Sup Ihn}, doi = {10.1103/l6mg-szxj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013716}, shortjournal = {Phys. Rev. A}, title = {Optimizing the brightness of a spontaneous parametric down-conversion source in laguerre-gaussian modes using a type-0 periodically poled nonlinear crystal}, volume = {112}, year = {2025}, }
• (2025). Wigner-negative states in the steady-state emission of a two-level system driven by squeezed light. PRA, 112(1), 013715. (www)

  @article{ , abstract = {Propagating modes of light with Wigner distributions exhibiting negativity are of fundamental interest in quantum optics and represent a key resource in the pursuit of optics-based quantum information technologies. Most schemes proposed or implemented for the generation of such modes are probabilistic in nature and rely on heralding by detection of a photon or on conditional methods where photons are separated from the original field mode by a beam splitter. We demonstrate theoretically, using a cascaded-quantum-system model, the possibility of deterministic generation of Wigner negativity in temporal modes of the steady-state emission of a two-level system driven by finite-bandwidth quadrature-squeezed light. Optimal negativity is obtained for a squeezing bandwidth similar to the linewidth of the transition of the two-level system. While the Wigner distribution associated with the incident squeezed light is Gaussian and everywhere positive, the Wigner functions of the outgoing temporal modes show distinct similarities and overlap with a superposition of displaced squeezed states.}, archive = {J_PRA}, author = {Miriam J. Leonhardt and Scott Parkins}, doi = {10.1103/1kbt-kqjd}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013715}, shortjournal = {Phys. Rev. A}, title = {Wigner-negative states in the steady-state emission of a two-level system driven by squeezed light}, volume = {112}, year = {2025}, }
• (2025). Persistent quantum advantage with definite photon-number states in lossy multiple-phase estimation. PRA, 112(1), 013714. (www)

  @article{ , abstract = {Multiple-phase estimation exploiting quantum states has broad applications in novel sensing and imaging technologies. However, the unavoidable presence of lossy environments in practical settings often diminishes the precision of phase estimations. To address this challenge, we propose an optimal multiple-phase estimation scheme that is inherently robust against photon loss, ensuring a persistent quantum advantage across all levels of photon loss. The scheme employs a multimode definite photon-number (DPN) state with weights optimized for given levels of photon loss. We theoretically demonstrate that the DPN state can sustain quantum enhancement in estimation precision under all levels of photon loss, compared to the classical benchmark that employs a coherent state input. The proposed scheme using DPN states generalizes earlier studies employing NOON states, which are only optimal when photon loss is small. We believe that our study, demonstrating persistent robustness to photon loss, paves the way for significant advancements in quantum-enhanced sensing technologies, enabling practical applications and quantum advantages in real-world scenarios.}, archive = {J_PRA}, author = {Min Namkung and Dong-Hyun Kim and Seongjin Hong and Changhyoup Lee and Hyang-Tag Lim}, doi = {10.1103/l44c-d76x}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013714}, shortjournal = {Phys. Rev. A}, title = {Persistent quantum advantage with definite photon-number states in lossy multiple-phase estimation}, volume = {112}, year = {2025}, }
• (2025). Stochastic-chebyshev-expansion approach for the simulation of linear polariton spectroscopy in the collective-coupling regime. PRA, 112(1), 013713. (www)

  @article{ , abstract = {Molecular polaritons are becoming one of the leading directions to control a multitude of chemical and physical processes, such as charge transfer, selective bond breaking, and excited-state dynamics. Accurately and efficiently simulating polariton properties under the collective-coupling regimes (between molecules and the cavity mode) remains a central theoretical challenge. In this work, we use a stochastic resolution of the identity approach coupled with a Chebyshev expansion to compute various polariton photophysical properties, with a substantially reduced computational effort than would be needed for a direct diagonalization of the same Hamiltonian, which is often the bottleneck for such large dimensionality. Such quantities of interest are the total density of states (the eigenspectrum of the Hamiltonian) and the transmission spectrum (a probe of the photonic degrees of freedom), the latter of which is a direct observable in the experiment. We simulate the linear spectroscopy of molecule-cavity hybrid systems, specifically exploring the effects of the distribution and magnitude of molecular disorder for one, few, and many coupled molecules. We compare our numerical results to recent work, which formulated analytic expressions in the large- limit for the spectroscopic signals. We find that our results match those of the analytic results when , at which point we find that the collective effects for linear spectroscopy are converged.}, archive = {J_PRA}, author = {Braden M. Weight and Pengfei Huo}, doi = {10.1103/x5q3-tm1q}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013713}, shortjournal = {Phys. Rev. A}, title = {Stochastic-chebyshev-expansion approach for the simulation of linear polariton spectroscopy in the collective-coupling regime}, volume = {112}, year = {2025}, }
• (2025). Magnon blockade in spin-magnon systems with frequency detuning. PRA, 112(1), 013712. (www)

  @article{ , abstract = {Magnon blockade is a physical mechanism for the preparation of a single-magnon source, which has important applications in quantum information processing. Here we propose a scheme for generating an optimal magnon blockade in the spin-magnon quantum system. By introducing frequency detuning between the magnon and spin qubit of nitrogen-vacancy center, the conventional magnon blockade and the unconventional magnon blockade can be obtained under both strong and weak coupling, relaxing the requirements for coupling strength. Moreover, the conventional and unconventional magnon blockade can occur simultaneously when both the magnon and the spin qubit are driven. This allows the equal-time second-order correlation function to reach , about five orders of magnitude lower than that of the single conventional or unconventional magnon blockade. Additionally, the time-delayed second-order correlation function avoids oscillation. Our study demonstrates the impact of frequency detuning on the magnon blockade and proposes methods to enhance the magnon blockade and relax the requirements for coupling strength through frequency detuning.}, archive = {J_PRA}, author = {Sheng Zhao and Ya-Long Ren and Xin-Lei Hei and Xue-Feng Pan and Peng-Bo Li}, doi = {10.1103/8jy6-fp5x}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013712}, shortjournal = {Phys. Rev. A}, title = {Magnon blockade in spin-magnon systems with frequency detuning}, volume = {112}, year = {2025}, }
• (2025). Excitation of narrow x-ray transitions in thin-film cavities by focused pulses. PRA, 112(1), 013711. (www)

  @article{ , abstract = {A method to compute the excitation of narrow transitions at hard-x-ray energies by short focused x-ray pulses is developed. In particular, the effect of thin-film cavities on the pulse propagation is incorporated via a semianalytical algorithm requiring the numerical evaluation of only one two-dimensional Fourier transform. We investigate various limiting cases to confirm the reliability of the algorithm. As an application, we show how a focused x-ray pulse propagates in cavity structures utilized in previous theoretical studies and experiments with collimated beams.}, archive = {J_PRA}, author = {Dominik Lentrodt and Christoph H. Keitel and Jörg Evers}, doi = {10.1103/PhysRevA.112.013711}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013711}, shortjournal = {Phys. Rev. A}, title = {Excitation of narrow x-ray transitions in thin-film cavities by focused pulses}, volume = {112}, year = {2025}, }
• (2025). Modeling and optimization of pulsed-squeezed-state generation in a ring-resonator system. PRA, 112(1), 013710. (www)

  @article{ , abstract = {We present a semianalytic formalism for calculating the squeezing and antisqueezing spectrum in a channel waveguide side-coupled to a lossy ring resonator. Our approach first uses the semianalytic evolution of the density matrix inside the ring up to the time where the squeezing is maximized. Then noting that a conservative approximate result for the squeezing can be obtained by ignoring the effect of the pump at later times, we calculate the free evolution of the field operators in the channel waveguide at all later times. We then calculate the quadrature squeezing spectrum in the waveguide, assuming that the measurement starts at the time when the squeezing in the ring is maximized. Using these results, we determine the optimum values for the pump pulse duration and amplitude and the ring-channel coupling for the pump and signal. We find that squeezing above 10 dB can be easily achieved in the channel for antisqueezing levels of less than 22 dB.}, archive = {J_PRA}, author = {Marc M. Dignam and Marco Liscidini}, doi = {10.1103/f2y1-scgw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013710}, shortjournal = {Phys. Rev. A}, title = {Modeling and optimization of pulsed-squeezed-state generation in a ring-resonator system}, volume = {112}, year = {2025}, }
• (2025). High-efficiency telecom frequency conversion via a diamond-type atomic ensemble. PRA, 112(1), 013709. (www)

  @article{ , abstract = {Efficient telecom frequency conversion (TFC) in atomic systems is crucial for integrating atom-based quantum nodes into low-loss fiber-optic quantum networks. Here, we demonstrate high-efficiency TFC from 795 to 1367 nm in a cold ensemble via diamond-type four-wave mixing (FWM), achieving conversion efficiencies of 66 and 80% at optical depths of 75 and 110, respectively, using a weak coherent probe field. These results surpass all previously reported values in atomic systems, enabled by a systematic investigation of the built-in V-type and cascade-type electromagnetically induced transparency spectra that guided the optimization of FWM conditions. Although this work employs coherent fields, our previous theoretical study has shown that quantum states can be preserved with high fidelity during the conversion process, highlighting the promise of diamond-type atomic FWM as a robust interface for long-distance quantum communication.}, archive = {J_PRA}, author = {Ling-Chun Chen and Meng-Yi Lin and Jiun-Shiuan Shiu and Xuan-Qing Zhong and Po-Han Tseng and Yong-Fan Chen}, doi = {10.1103/mp7d-87nw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013709}, shortjournal = {Phys. Rev. A}, title = {High-efficiency telecom frequency conversion via a diamond-type atomic ensemble}, volume = {112}, year = {2025}, }
• (2025). Robustness of entanglement in a non-hermitian cavity-optomechanical system even away from exceptional points. PRA, 112(1), 013708. (www)

  @article{ , abstract = {Quantum physics can be extended into the complex domain by considering non-Hermitian Hamiltonians that are parity-time ( ) symmetric. These exhibit exceptional points (EPs) where the eigenspectrum changes from purely real to purely imaginary values and have useful properties enabling applications such as accelerated entanglement generation and the delay of the sudden death of entanglement in noisy systems. An interesting question is whether similar beneficial effects can be achieved away from EPs, since this would extend the available parameter space and make experiments more accessible. We investigate this by considering a -symmetric optomechanical system but also consider what happens when two-mode squeezing interactions are included, taking us into the pseudo-Hermitian regime. The addition of squeezing is motivated by an attempt to extend the lifetime of the system's entanglement. While this does not prove to be the case, rich dynamics are nonetheless observed in both the pseudo-Hermitian and -symmetric systems, including the sudden death and revival of entanglement under certain conditions. In both cases, we find that the sudden disappearance of entanglement can be mitigated at EPs and also show that the revival of entanglement is quite robust to thermal noise in a group of parameters away from the EPs. This investigation extends our understanding of non-Hermitian systems and opens a new perspective for the development of quantum devices in non-Hermitian systems even away from EPs.}, archive = {J_PRA}, author = {Jia-Jia Wang and Yu-Hong He and Chang-Geng Liao and Rong-Xin Chen and Jacob A. Dunningham}, doi = {10.1103/f8pm-7z7r}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013708}, shortjournal = {Phys. Rev. A}, title = {Robustness of entanglement in a non-hermitian cavity-optomechanical system even away from exceptional points}, volume = {112}, year = {2025}, }
• (2025). Non-hermitian optical scattering in cold atoms via four-wave mixing. PRA, 112(1), 013707. (www)

  @article{ , abstract = {Nonlinear effects may play a crucial role in addressing optical nonreciprocal behaviors in scattering media. Such behaviors are however typically observed within a single transmission channel and predominantly in media with fixed optical structures, which inherently restrict the tunability of a nonreciprocal response. We suggest to combine the (intrinsic) nonlinearities of a coherent multilevel medium with a tailored driving geometry that relies on two phase-mismatched standing-wave (SW) beams. This combination is essential for creating extra scattering channels over which, in addition, fully tunable optical nonreciprocal reflection can be attained. Our general approach is adapted here to four-level double- Λ atoms that are found to exhibit distinct forms of nonreciprocal multichannel scattering and to be quite sensitive to easily tunable parameters of two SW driving beams. The numerical results we present offer valuable insights into the field of non-Hermitian optical scattering and arise indeed from the interplay of interference among scattering processes and Bragg reflection.}, archive = {J_PRA}, author = {Xiao Liu and M. Artoni and G. C. La Rocca and Jin-Hui Wu}, doi = {10.1103/fcs4-99zl}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013707}, shortjournal = {Phys. Rev. A}, title = {Non-hermitian optical scattering in cold atoms via four-wave mixing}, volume = {112}, year = {2025}, }
• (2025). Triphoton generation and heralded biphotons via spontaneous six-wave mixing in coherently driven cold atoms. PRA, 112(1), 013706. (www)

  @article{ , abstract = {We investigate the generation of a triphoton state based on spontaneous six-wave mixing in cold atoms coherently driven by pumping, dressing, and coupling fields upon separate transitions. The designed energy-level structure largely suppresses linear absorption (Raman gain) of generated triphotons due to destructive interference (negligible excitation) and avoids stray biphotons arising from spontaneous four-wave mixing with appropriate atomic states and driving schemes. Numerical results show that two Stokes and one anti-Stokes photon, traveling respectively at the vacuum light speed and a reduced group velocity, can be simultaneously generated in a joint spectral region of two detunings exhibiting four resonances. Original third-order and reduced second-order time correlations of these photons suggest that one is an excellent messenger for heralding the existence of the other two, exhibiting a considerable generation rate and an obvious nonclassical feature.}, archive = {J_PRA}, author = {Xin-Yi Ling and Hui-Min Zhao and Xiao-Jun Zhang and Jin-Hui Wu}, doi = {10.1103/5c5q-1tk8}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013706}, shortjournal = {Phys. Rev. A}, title = {Triphoton generation and heralded biphotons via spontaneous six-wave mixing in coherently driven cold atoms}, volume = {112}, year = {2025}, }
• (2025). Coupled states of cold yb174 atoms in a high-finesse cavity. PRA, 112(1), 013705. (www)

  @article{ , abstract = {We experimentally and theoretically study the formation of dressed states emerging from strong collective coupling of the narrow intercombination line of Yb atoms to a single mode of a high-finesse optical cavity. By permanently trapping and cooling the Yb atoms during their interaction with the cavity, we gain continuous experimental access to the dressed states. This allows us to detect both their field and their atomic properties, by simultaneously measuring the steady-state cavity transmission and free-space fluorescence. By varying the cavity and probe frequencies, we observe coupled atom-cavity states with atom-number-dependent splitting, the hallmark of collective strong coupling of the atoms with the single cavity mode. We find additional fluorescence output at atomic resonance, which we explain by the effects of dephasing and inhomogeneous broadening. We compare our experimental results with a theoretical model and find good qualitative agreement.}, archive = {J_PRA}, author = {Saran Shaju and Dmitriy Sholokhov and Simon B. Jäger and Jürgen Eschner}, doi = {10.1103/8k18-9mvn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013705}, shortjournal = {Phys. Rev. A}, title = {Coupled states of cold yb174 atoms in a high-finesse cavity}, volume = {112}, year = {2025}, }
• (2025). Quantum-optical scattering by macroscopic lossy objects: A general approach. PRA, 112(1), 013704. (www)

  @article{ , abstract = {We develop a general approach to describe the scattering of quantum light by a lossy macroscopic object placed in vacuum with no restrictions on both its dispersive optical response and its spatially inhomogeneous composition. Our analysis is based on the modified Langevin noise formalism, a recently introduced version of macroscopic quantum electrodynamics where scattering modes are explicitly separated from electric and magnetic medium excitations; accordingly the formalism involves three kinds of noninteracting boson polaritons such that, in the lossless limit, polaritons reduce to standard photons whereas and polaritons disappear. We analytically derive the input-output unitary relation joining the boson operators of the ingoing and outgoing polaritons, a nontrivial result hinging upon original relations which comprehensively describe the transmission-emission-absorption interplay pertaining the classical radiation scattering, relations we here deduce by resorting to properties of the dyadic Green's function. Besides we exploit the input-output relation to connect the output state of the field to the input one, this unveiling the role played by various classical electromagnetic dyadics in quantum optical scattering. We specialize the discussion to the most common situation where the object is initially not electromagnetically excited, with the ingoing electromagnetic state only containing polaritons, and we analyze the impact of the classical transmission and absorption dyadics on the transitions from ingoing to outgoing polaritons and on the creation of outgoing and polaritons, respectively. Since the scattered radiation is collected in the far-field and the object is usually left unmeasured, we analytically derive the reduced density operator of the outgoing polaritons revealing, in particular, how object losses both produce quantum decoherence of the scattered radiation and enable to exploit the possible entanglement among ingoing polaritons to dramatically manipulate the statistical mixture of the quantum states pertaining to the scattered radiation.}, archive = {J_PRA}, author = {A. Ciattoni}, doi = {10.1103/9mpv-thdp}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013704}, shortjournal = {Phys. Rev. A}, title = {Quantum-optical scattering by macroscopic lossy objects: A general approach}, volume = {112}, year = {2025}, }
• (2025). Analytic solution to degenerate biphoton states generated in arrays of nonlinear waveguides. PRA, 112(1), 013703. (www)

  @article{ , abstract = {Arrays of nonlinear waveguides are a powerful integrated photonics platform for studying and manipulating quantum states of light. Also, they are a valuable resource for various quantum technologies. In this work, we employed a supermode approach to obtain an analytic solution to the evolution of degenerate biphoton states in arrays of nonlinear waveguides. The solution accounts for arrays of an arbitrary number of waveguides and coupling profiles. In addition, it provides an explicit analytic expression without the need of computationally expensive steps. Actually, it only relies on the calculation of the eigenvalues and eigenvectors of the coupling matrix. In general, this needs to be performed numerically, but there are relevant instances in which analytic expressions are available. Thus, in certain cases, the procedure proposed here does not require the use of any numerical method. We analyze the general properties of the solution and show some application examples. Particularly, simple solutions that can be obtained by special symmetric injection profiles, the results for small arrays, and the properties of the propagation when only the center waveguide is pumped in a symmetric odd array. In addition, we present a proof-of-principle example on how to use the analytic solution to tackle inversion problems. That is, obtaining the initial conditions required to achieve a desired quantum state—which is a valuable technological application. A relevant aspect of the method presented here is its scalability for large arrays due to the lack of resource-intensive steps—both for the direct and inverse problems.}, archive = {J_PRA}, author = {Jefferson Delgado-Quesada and David Barral and Kamel Bencheikh and Edgar A. Rojas-González}, doi = {10.1103/n9yc-kz52}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013703}, shortjournal = {Phys. Rev. A}, title = {Analytic solution to degenerate biphoton states generated in arrays of nonlinear waveguides}, volume = {112}, year = {2025}, }
• (2025). Single-atom optical gate and single-photon source based on magneto-optical effects in a waveguide. PRA, 112(1), 013702. (www)

  @article{ , abstract = {We have discovered the abnormally strong influence of the magnetic field on the optical properties of an atomic ensemble confined in a waveguide. We demonstrate qualitative changes in the character of spontaneous emission and single-atom susceptibility. Based on the revealed effects, we propose a scheme of a true single-photon source. Furthermore, we propose the highly efficient optical gate using just one atom.}, archive = {J_PRA}, author = {A. S. Kuraptsev and I. M. Sokolov}, doi = {10.1103/s85r-vx8t}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013702}, shortjournal = {Phys. Rev. A}, title = {Single-atom optical gate and single-photon source based on magneto-optical effects in a waveguide}, volume = {112}, year = {2025}, }
• (2025). Controlling the polarization of superfluorescence in a degenerate system using a continuous resonant laser field. PRA, 112(1), 013701. (www)

  @article{ , abstract = {We investigate superfluorescence (SF) in a degenerate system, where two polarization modes of SF were emitted in competition with each other. A circularly polarized femtosecond laser pulse is used to excite Rb atoms in a heated gas cell from the ground to state, followed by the SF decay process . Because the and levels degenerate into two and four states, respectively, four degenerate transitions are optically allowed between the two levels. Therefore, the left- or right-circularly polarized SF is emitted with a relative intensity determined by the Clebsch-Gordan coefficients of all degenerate transitions. We investigate the polarization characteristics of all SF fields emitted during the decay process. Furthermore, we demonstrate the possibility of switching the dominant polarization component of the SF on the transition by seeding it with a weak resonant circularly polarized continuous laser field.}, archive = {J_PRA}, author = {K. Kitano and T. Kobayashi and H. Maeda}, doi = {10.1103/1446-5fjj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013701}, shortjournal = {Phys. Rev. A}, title = {Controlling the polarization of superfluorescence in a degenerate system using a continuous resonant laser field}, volume = {112}, year = {2025}, }
• (2025). Self-phase-modulation of non-gaussian pulses in multiple quantum wells by a tunneling mechanism. PRA, 112(1), 013537. (www)

  @article{ , abstract = {In this article, we investigate the spectral broadening of cosh-Gaussian pulses which is induced by self-phase modulation (SPM) within the tunneling-induced transparency (TIT) window in an asymmetric multiple-quantum-well system. The study demonstrates how a single laser field, combined with a steady static electric field, enables dynamic control of absorption and dispersion profiles of the system, offering precise control of the group velocity of the applied field. The multiple-quantum-well system exhibits a large Kerr nonlinearity (approximately ), which enhances the SPM effect under the TIT window. Our exploration of SPM using cosh-Gaussian pulses demonstrates that higher probe laser powers result in broader spectral widths and increased internal oscillations, especially under strong tunneling strengths. These results suggest promising applications for fine-tuning light propagation in quantum-well systems and offer a more economical approach for optical light-matter interaction experiments, minimizing the need for extensive optics and optomechanical components.}, archive = {J_PRA}, author = {Rohit Mukherjee and Nitu Borgohain and Rohit Hazra and Kingshuk Bose and Arindam Kumar Chatterjee}, doi = {10.1103/8vqj-rvsh}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013537}, shortjournal = {Phys. Rev. A}, title = {Self-phase-modulation of non-gaussian pulses in multiple quantum wells by a tunneling mechanism}, volume = {112}, year = {2025}, }
• (2025). Single solitons and intermode breathing solitons in MgF2 microresonators. PRA, 112(1), 013536. (www)

  @article{ , abstract = {Intermode breathers can be triggered by the avoided mode crossings in microresonators. Here, we numerically and experimentally explore the breather and single soliton regimes as the pump-power and pump-cavity detuning vary. Below a pump-power threshold, a single soliton regime is obtained within a detuning range. Above this threshold, an intermode breather section emerges, resulting in a soliton-breather-soliton pattern in which the system transits from a stable soliton to a breathing soliton and back to a stable soliton as the detuning increases.}, archive = {J_PRA}, author = {Alioune Niang and Logan Courtright and Gary Carter and Curtis R. Menyuk}, doi = {10.1103/bkzf-65qy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013536}, shortjournal = {Phys. Rev. A}, title = {Single solitons and intermode breathing solitons in MgF2 microresonators}, volume = {112}, year = {2025}, }
• (2025). Phase-controlled robust tripartite quantum entanglement in cavity-magnon optomechanics. PRA, 112(1), 013535. (www)

  @article{ , abstract = {The preparation of highly entangled states involving multiparticle systems is of crucial importance in quantum physics, playing a fundamental role in exploring the nature of quantum mechanics and offering essential quantum resources for nascent quantum technologies that surpass classical limits. Here we present how to generate and manipulate a tripartite entangled state of photons, phonons, and magnons within a hybrid cavity magnomechanical system. It is shown that simultaneously applying two coherent driving fields to this system in opposite input directions enables a coherent and effective way to regulate the magnomechanical interaction by tuning the phase difference of the driving fields. Based on this feature, it is found that the tripartite entanglement also becomes phase dependent and can be enhanced for certain phase differences. More interestingly, it is shown that the robustness of tripartite entanglement against environmental thermal noises can also be improved by choosing a proper phase difference of the driving fields. Our findings offer a promising way to manipulate and protect fragile tripartite entanglement, which is applicable to a wide range of quantum protocols that require multipartite entangled resources such as quantum communication and quantum metrology.}, archive = {J_PRA}, author = {Jing-Xue Liu and Ya-Feng Jiao and Bin Yin and Hong-Yun Yu and Ruo-Chen Wang and Hui Jing}, doi = {10.1103/cr9z-n6ry}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013535}, shortjournal = {Phys. Rev. A}, title = {Phase-controlled robust tripartite quantum entanglement in cavity-magnon optomechanics}, volume = {112}, year = {2025}, }
• (2025). Cross-kerr nonlinearity and four-wave mixing in an N-type four-level coherent system. PRA, 112(1), 013534. (www)

  @article{ , abstract = {We present a theoretical investigation of cross-Kerr nonlinearities and associated four-wave mixing (FWM) in an N -type four-level coherent system. By pairing the probe field with another field, the system involves Λ and V types of electromagnetically induced transparency (EIT) which correspond to two cross-Kerr nonlinearities. Our analysis reveals that both the cross-Kerr nonlinearities and associated FWMs exhibit significant enhancement accompanied by compressed linewidths with increasing the detuning of the third field, though their enhancement behaviors differ remarkably. For the cross-Kerr nonlinearity and the associated FWM arising from the probe-coupling Λ -type EIT, the positions of the enhanced nonlinearities remain essentially unchanged with increasing signal detuning, and their magnitudes grow monotonically with the signal detuning. In contrast, for those from the probe-signal V -type EIT, the positions of the nonlinearities shift with the increasing coupling detuning, forming a two-photon resonance between the probe and coupling fields, while their magnitudes first increase and then decrease with the coupling detuning.}, archive = {J_PRA}, author = {Jiaxin Ou and Yupeng Duan and Yingjie Du}, doi = {10.1103/zmjv-fdtd}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013534}, shortjournal = {Phys. Rev. A}, title = {Cross-kerr nonlinearity and four-wave mixing in an N-type four-level coherent system}, volume = {112}, year = {2025}, }
• (2025). Increased output of superradiant light-emitting diodes due to population fluctuations. PRA, 112(1), 013533. (www)

  @article{ , abstract = {The quantum nonlinear Maxwell-Bloch equations for a single-mode laser with a two-level active medium are solved in the LED regime without adiabatic elimination of the medium polarization, when the population fluctuation spectrum is much narrower than the radiation and polarization spectra. It is shown that population fluctuations significantly increase the output power and collective Rabi splitting of a superradiant LED.}, archive = {J_PRA}, author = {Igor E. Protsenko and Alexander V. Uskov}, doi = {10.1103/ytkr-hd9h}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013533}, shortjournal = {Phys. Rev. A}, title = {Increased output of superradiant light-emitting diodes due to population fluctuations}, volume = {112}, year = {2025}, }
• (2025). Gain-modified emission dynamics between two quantum emitters in a plasmonic gain cavity system. PRA, 112(1), 013532. (www)

  @article{ , abstract = {We present a general theory of gain-modified emission dynamics between two quantum emitters (two level systems) in a linear gain medium, demonstrating how gain modifies the usual radiative decay rates and interemitter coupling and decay rates, from purely lossy systems. We derive a Born-Markov master equation that shows explicitly how gain modifies the usual rates appearing for two emitters in a loss-only medium and introduces new gain terms. We then present Bloch equations in the bare state basis as well as a dressed-state basis (using superradiant and subradiant states). As an application of the theory, we show calculations for a fully three-dimensional metal dimer in a gain-compensated medium containing two quantum emitters and show explicit solutions in terms of the quasinormal modes, which easily allows one to obtain all the relevant decay rates. We study the modified decay dynamics, gain excited pumping, as well as the entanglement entropy and spectral emission. We also demonstrate how a breakdown of the weak excitation approximation in the presence of gain requires a careful treatment beyond a linear response, which yields nontrivial incoherent coupling terms that typically are not included in dipole-dipole coupling models and heuristic gain pumping models.}, archive = {J_PRA}, author = {Becca VanDrunen and Juanjuan Ren and Sebastian Franke and Stephen Hughes}, doi = {10.1103/rrwd-47xr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013532}, shortjournal = {Phys. Rev. A}, title = {Gain-modified emission dynamics between two quantum emitters in a plasmonic gain cavity system}, volume = {112}, year = {2025}, }
• (2025). Coupled two-dye gain-medium-based photonic nanolasers for short-pulse generation. PRA, 112(1), 013531. (www)

  @article{ , abstract = {Nanoscale lasers that generate short pulses at high repetition rates have exciting applications in various fields. However, creating short pulses as well as broad frequency combs in nanoscale lasers is complex and remains a relatively unexplored area. Research has focused on materials with two or more types of resonantly coupled dyes for applications in energy harvesting, biocentered uses, and expanding the tuning range of lasers. We propose that a gain medium composed of two types of coupled dye molecules can produce the saturable gain and absorption necessary for short-pulse generation. We present a mathematical model for this proposed two-dye gain material and integrate it with a finite-difference time-domain method. This developed model is used to assess the effectiveness of the two-dye material for pulse shortening in miniature lasers and to explore the role of a simple one-dimensional photonic cavity in pulsed laser operation. Additionally, we investigate various possible modes of laser operation by varying key design parameters of the dye molecules and the cavity. The findings indicate that the proposed laser can emit a train of short pulses and frequency combs with appropriate tuning of both the laser medium and the cavity. When the parameters of the material and cavity are optimally adjusted, the two-dye gain-medium-based laser is capable of emitting subpicosecond pulses at repetition rates in the hundreds of gigahertz.}, archive = {J_PRA}, author = {Shadman Shahid and Muhammad Anisuzzaman Talukder}, doi = {10.1103/6472-9sky}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013531}, shortjournal = {Phys. Rev. A}, title = {Coupled two-dye gain-medium-based photonic nanolasers for short-pulse generation}, volume = {112}, year = {2025}, }
• (2025). Electromagnetic helicity in twisted cavity resonators. PRA, 112(1), 013530. (www)

  @article{ , abstract = {Through left- or right-handed twisting, we investigate the impact of mirror-asymmetry (chirality) of the conducting boundary conditions of an equilaterial triangular cross section electromagnetic resonator. We observe the generation of eigenmodes with nonzero electromagnetic helicity as a result of the coupling of near degenerate and modes. This can be interpreted as an emergence of magnetoelectric coupling, which in turn produces a measurable shift in resonant mode frequency as a function of twist angle. We show that this coupling mechanism is equivalent to introducing a nonzero chirality material parameter or axion field to the medium. Our findings demonstrate the potential for real-time, macroscopic manipulation of electromagnetic helicity.}, archive = {J_PRA}, author = {E. C. I. Paterson and J. Bourhill and M. E. Tobar and M. Goryachev}, doi = {10.1103/6gp4-76td}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013530}, shortjournal = {Phys. Rev. A}, title = {Electromagnetic helicity in twisted cavity resonators}, volume = {112}, year = {2025}, }
• (2025). Chiral solitons in quadratic quasi-phase-matched photonic crystals. PRA, 112(1), 013529. (www)

  @article{ , abstract = {We introduce a quasi-phase-matched technique in quadratic nonlinear crystals, constructing an artificial gauge field by changing the inclination angle of stripes, which is realized by the positive- and negative-polarization directions of nonlinear susceptibility along the crystal. Unlike the artificial gauge field constructed through linear coupling in other settings, the gauge field in this system is realized by nonlinear coupling. We demonstrate that this gauge field can generate stable chiral solitons with chiral energy flow rotating around the solitons. In contrast to conventional chiral currents generated with the same species or frequency, the chiral currents in the present system are formed by mutual coupling between fundamental-frequency and second-harmonic components. We derive the semianalytical solution for the chiral energy flow in this system. It is found that an optimal inclination angle that can maximize the chiral energy flow under different parameters exists, and this optimal inclination shows a positive correlation with the power and detuning. The mobility and collisions of the chiral solitons are also discussed. The results show that chiral solitons move in response to kicking and undergo fully elastic collisions with each other. In addition, the possibility of experimentally generating chiral solitons and chiral currents is outlined.}, archive = {J_PRA}, author = {Yuxin Guo and Xuening Wang and Zhiwei Fan and Zhaopin Chen and Qiuyi Ning and Hexiang He and Wei Pang and Li Zhang and Yongyao Li}, doi = {10.1103/83j9-cy92}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013529}, shortjournal = {Phys. Rev. A}, title = {Chiral solitons in quadratic quasi-phase-matched photonic crystals}, volume = {112}, year = {2025}, }
• (2025). Supercorrelated decay in a quasiperiodic nonlinear waveguide: From markovian to non-markovian transitions. PRA, 112(1), 013528. (www)

  @article{ , abstract = {Mobility edges (MEs) are critical boundaries in disordered quantum systems that separate localized from extended states, significantly affecting transport properties and phase transitions. Although MEs are well-understood in single-photon systems, their manifestation in many-body contexts remains an active area of research. In this work, we investigate a one-dimensional Bose-Hubbard chain with a quasiperiodic potential modulating photon-photon interactions, effectively creating a mosaic lattice. We identify MEs for doublon states (i.e, bound photon pairs resulting from strong interactions) within the two-photon subspace. Our analytical solutions and numerical simulations confirm the existence of these MEs, extending single-photon MEs theories to the two-photon regime. Additionally, we analyze the dynamics of two emitters coupled to the waveguide, enabling the emission of supercorrelated photon pairs into the waveguide. Our findings reveal that coupling to extended states results in Markovian dynamics, characterized by exponentially supercorrelated decay, while coupling to localized states gives rise to non-Markovian dynamics, marked by suppressed decay and persistent oscillations. Here, a transition from Markovian to non-Markovian behavior occurs around the MEs of the doublons. Finally, we propose a feasible experimental implementation using superconducting circuits, providing a platform to observe the interplay between interactions and disorder in quantum systems.}, archive = {J_PRA}, author = {Jia-Qi Li and Tian-Yu Zhou and Xin Wang}, doi = {10.1103/4mql-32sg}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013528}, shortjournal = {Phys. Rev. A}, title = {Supercorrelated decay in a quasiperiodic nonlinear waveguide: From markovian to non-markovian transitions}, volume = {112}, year = {2025}, }
• (2025). Local perfect chirality at reflection zeros away from exceptional points in optical whispering-gallery microcavities. PRA, 112(1), 013527. (www)

  @article{ , abstract = {Recently, a local and imperfect chirality of the resonant eigenmode at the exceptional point (EP) has been reported in the optical whispering gallery microcavity system perturbed by two strong nanoscatterers [ Phys. Rev. A 108 , L041501 (2023) ]. Here we discover a local perfect chirality of the resonant eigenmode away from the EP in the parameter space of the strongly perturbed microcavity system. By considering the multiple scattering process of the azimuthally propagating modes (APMs) at the nanoscatterers with a first-principles-based model, the local perfect chirality is predicted to result from the unidirectional reflectionlessness, i.e., the reflection-zero ( -zero) of the APMs at the two nanoscatterers. Numerical results and model predictions consistently show that the structural parameters of the -zero typically deviate from those of the EP, which means that the pair of split resonant eigenmodes at the -zero have different complex resonance frequencies and electromagnetic fields. In general, only one of the pair of split eigenmodes exhibits a local perfect chirality within the local azimuthal range divided by the two nanoscatterers. With the decrease of the two nanoscatterers' sizes or their relative azimuthal angle, the -zero tends to coincide with the EP.}, archive = {J_PRA}, author = {Junda Zhu and Haitao Liu and Fang Bo and Can Tao and Guoquan Zhang and Jingjun Xu}, doi = {10.1103/mcyj-gn1h}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013527}, shortjournal = {Phys. Rev. A}, title = {Local perfect chirality at reflection zeros away from exceptional points in optical whispering-gallery microcavities}, volume = {112}, year = {2025}, }
• (2025). Noise avalanche and its quantum quenching in bosonic chains with random off-diagonal disorder. PRA, 112(1), 013526. (www)

  @article{ , abstract = {Here we discuss a phenomenon of sharp increase in the photon number noise at initial stages of propagation in tight-binding bosonic chains with off-diagonal disorder. Such a “noise avalanche” occurs under classical coherent excitation of waveguides and leads to high superthermal photon bunching. Additional classical excitation slows but cannot quench this noise avalanche. However, an additional single-photon excitation stops the avalanche.}, archive = {J_PRA}, author = {Vladislav Stefanov and Andre Stefanov and Lea Sirota and Gregory Slepyan and Dmitri Mogilevtsev}, doi = {10.1103/4mdy-5x95}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013526}, shortjournal = {Phys. Rev. A}, title = {Noise avalanche and its quantum quenching in bosonic chains with random off-diagonal disorder}, volume = {112}, year = {2025}, }
• (2025). Nanomechanical squeezing: Toward quantum imaging with atomic force microscopy. PRA, 112(1), 013525. (www)

  @article{ , abstract = {Leveraging quantum effects in mechanical oscillators promises major advancements in nanometrology, including sensing and imaging. Microscopic cantilevers serve as versatile force sensors with broad applications in nanoscience, nanotechnology, and, increasingly, quantum sensing. We theoretically model and investigate the quantum mechanics of cantilever probes in atomic force microscopy under conditions of reduced thermal noise. Specifically, our model captures the cantilever interaction with a surface via long-range attractive van der Waals forces and short-range repulsive-adhesive interactions described by the Derjaguin-Muller-Toporov model. We find that when the probe resides within the attractive interaction regime, a coherent state emerges, whereas, in the repulsive regime, a squeezed state forms for the cantilever's deformation state. Our calculations explain the functional role of interaction potentials in the quantum dynamics of macroscopic mechanical systems, which are proving useful in quantum sensing and information processing. The presented calculations can be extended to investigate other interaction forces relevant to atomic force microscopy.}, archive = {J_PRA}, author = {Wael M. Al-Sawai and Ali Passian}, doi = {10.1103/1nnx-xc4r}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013525}, shortjournal = {Phys. Rev. A}, title = {Nanomechanical squeezing: Toward quantum imaging with atomic force microscopy}, volume = {112}, year = {2025}, }
• (2025). Diffraction-resistant arbitrary-trajectory plasmon with multitunability. PRA, 112(1), 013524. (www)

  @article{ , abstract = {In this paper, a diffraction-resistant arbitrary-trajectory plasmon with multitunability is introduced. The initial field of the plasmon is designed by us and superimposed with the composition of the Airy wave packet. Based on caustic phase modulation, arbitrary trajectories such as a parabola, hyperbola, and hyperbolic secant are achieved, by encoding the geometric functions into the wave front. The propagation trajectory can not only be accelerated by adjusting the geometric function parameters but also have its inclination angle adjusted. The migration of the energy center along the trajectory propagation direction is also found. The utilization of diffraction-resistant arbitrary trajectory plasmon also facilitates the control of plasmonic focus, enabling more on-chip manipulation possibilities. Also, we further illustrate the diffraction-resistant properties of the plasmon from the self-healing phenomenon. A scheme to generate the plasmon is proposed, and it is validated by the finite-difference time-domain numerical simulations.}, archive = {J_PRA}, author = {Zhang Ruan and Junxi Zhang and Yanru Chen and Shibin Wen and Meixia Ma and Dongmei Deng}, doi = {10.1103/dqgj-wrn7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013524}, shortjournal = {Phys. Rev. A}, title = {Diffraction-resistant arbitrary-trajectory plasmon with multitunability}, volume = {112}, year = {2025}, }
• (2025). Time-reversed landau-zener tunneling in synthetic temporal lattices. PRA, 112(1), 013523. (www)

  @article{ , abstract = {As the flow of time governs all evolutions, the reversal of time evolution has garnered intense research in many fields. The phenomenon of Landau-Zener (LZ) tunneling is one of the most remarkable time evolution processes in quantum mechanics. In this work, we study LZ tunneling with time-reversal operation in a Floquet system of synthetic temporal lattices, which is formed by the evolution of optical pulses in coupled fiber loops. With an abrupt change of gauge potential and the splitting parameter imposed on the lattices, the two eigenstates of the system are exchanged so that the time-reversal operation is realized. In the experiment, we demonstrate that time-reversal operations eliminate path degeneracy through propagation path reconstruction. The measurement of the dynamics of LZ tunneling and that with time-reversal operation is shown by applying the quenching dynamics. The study provides an effective approach to perform the LZ tunneling with time-reversal operation and expands our capability of measuring various tunneling processes. These methods can also be applied to optical interferometers, fiber communications, and quantum control.}, archive = {J_PRA}, author = {Lange Zhao and Shulin Wang and Chengzhi Qin and Zhuoxiong Liu and Lingzhi Zheng and Bing Wang and Peixiang Lu}, doi = {10.1103/jv83-xgvs}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013523}, shortjournal = {Phys. Rev. A}, title = {Time-reversed landau-zener tunneling in synthetic temporal lattices}, volume = {112}, year = {2025}, }
• (2025). Cooperative absorption model for photon avalanche upconversion. PRA, 112(1), 013522. (www)

  @article{ , abstract = {Photon avalanche (PA) is a nonlinear process that presents a large growth of the upconversion fluorescence intensity signal and a strong absorption of the excitation light source occurring in lanthanide-doped systems. Conventional excitation schemes may introduce unwanted detrimental effects such as linear transmission losses and thermal effects. Here, a model is proposed in which the triggering mechanism for the PA effect is the absorption of a single photon by a pair of neighboring ions. The proposed model was studied using a rate equation system that describes the population dynamics of the electronic states of praseodymium ions in a silica fiber. The theoretical simulations confirm the presence of transmission attenuation and PA upconversion fluorescence when the lanthanide ions are at a short distance (a few angstroms), which guarantees the necessary PA positive feedback condition: a large cross-relaxation energy transfer rate among the lanthanide ions.}, archive = {J_PRA}, author = {Glauco S. Maciel and Anderson S. L. Gomes and Cid B. de Araújo}, doi = {10.1103/96n8-6hk6}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013522}, shortjournal = {Phys. Rev. A}, title = {Cooperative absorption model for photon avalanche upconversion}, volume = {112}, year = {2025}, }
• (2025). Plasmon hybridization and the charge-transfer plasmon in a nanoparticle complex: An equivalent circuit model approach. PRA, 112(1), 013521. (www)

  @article{ , abstract = {The coupling among plasmonic excitations of the nanoparticle complex plays an important role in the responses of optical nanocircuits with multifunction in signal processing. We develop an equivalent circuit model based on the loop matrix method to explore the coupling effects in the complex of nanorods. Our analytical results supported by finite-difference time-domain simulations not only give the resonance characters of (screening) bonding mode, antibonding mode, and charge-transfer plasmon (CTP) mode simultaneously, but also reveal the physics picture of the screening bonding dipole plasmon (BDP) and CTP with common origin (the remnants of multipole plasmonic modes). It is found that the resonance wavelength of the CTP depends sensitively on the length of the conductive bridge connecting the nanorods, showing factor 10 enhancement of measurement (of the interparticle gap size) sensitivity as a nanoruler compared with that based on the BDP, while with changing the bridge width there is a switch of the mode nature with associated change of far-field scattering patterns. In addition, interparticle coupling induced Rabi splitting, Fano effect, and dual CTPs have been found. Our studies provide a new analytical perspective on the electromagnetic coupling mechanism of nanocomposites and establish a foundation for the design of nanocircuits and micro-nano-optical devices.}, archive = {J_PRA}, author = {Yifan Zhi and Wei Zhang}, doi = {10.1103/p6pq-lhw1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013521}, shortjournal = {Phys. Rev. A}, title = {Plasmon hybridization and the charge-transfer plasmon in a nanoparticle complex: An equivalent circuit model approach}, volume = {112}, year = {2025}, }
• (2025). Band structures of generalized eigenvalue equations and conic sections. PRA, 112(1), 013520. (www)

  @article{ , abstract = {Generalized eigenvalue equations describe the band structures of various metamaterials, where complex bands can emerge even if the involved matrices are Hermitian. In this paper, we provide a geometrical understanding of the real-complex transition of the band structures. Specifically, our analysis, based on auxiliary eigenvalues, clarifies the correspondence between the real-complex transition of the generalized eigenvalue equations and the Lifshitz transition in electron systems. Furthermore, we demonstrate that real (complex) bands of a photonic system correspond to the Fermi surfaces of type-II (type-I) Dirac cones in electron systems when the permittivity ɛ and the permeability μ are independent of frequency. In addition, our analysis reveals that exceptional points are induced by the frequency dependence of permittivity ɛ and permeability μ in our photonic system.}, archive = {J_PRA}, author = {Takuma Isobe and Tsuneya Yoshida and Yasuhiro Hatsugai}, doi = {10.1103/m6qm-2bll}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013520}, shortjournal = {Phys. Rev. A}, title = {Band structures of generalized eigenvalue equations and conic sections}, volume = {112}, year = {2025}, }
• (2025). Nonreciprocal optical metasurface based on spinning cylinders. PRA, 112(1), 013519. (www)

  @article{ , abstract = {Optical systems breaking Lorentz reciprocity have attracted broad attention due to their intriguing physics and applications. Nonreciprocal metasurfaces can enable one-way light transmission and reflection with essential applications in optical communication. Conventional nonreciprocal metasurfaces rely on using magneto-optic or nonlinear materials to induce nonreciprocal optical properties. Here we propose and demonstrate an alternative mechanism for realizing nonreciprocal metasurfaces based on the relativistic effect of a moving medium. The metasurface is composed of periodic spinning dielectric cylinders located above a dielectric substrate. The spinning motion breaks the time-reversal symmetry and induces bi-anisotropic Tellegen-type response of the meta-atoms. We show that the metasurface can realize both asymmetric and nonreciprocal manipulations of the incident plane wave. The underlying mechanism is attributed to the Sagnac effect associated with the chiral multipole modes of the coupled spinning cylinders. By introducing dielectric pillars to modulate the phase profile, the metasurface can enable nonreciprocal wavefront manipulations. Our work offers a mechanism for realizing nonreciprocal light manipulation in free space. The proposed metasurface can serve as a platform to explore the interesting physics of nonreciprocal optics, non-Hermitian optics, and topological photonics.}, archive = {J_PRA}, author = {Zheng Yang and Wanyue Xiao and Hengzhi Li and Hao Pan and Shubo Wang}, doi = {10.1103/w18x-xdyd}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013519}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal optical metasurface based on spinning cylinders}, volume = {112}, year = {2025}, }
• (2025). Scalar product for the radiation of resonant modes. PRA, 112(1), 013518. (www)

  @article{ , abstract = {We introduce the conformally invariant scalar product, originally devised for radiation fields, to the study of the modes of optical resonators. This scalar product allows one to normalize and compare resonant modes using their corresponding radiation fields. Such fields are polychromatic fields free of divergences, which are determined from the complex frequencies and the modal fields on the surface of the resonator. The scalar product is expressed as surface integrals involving the modal fields, multiplied by closed-form factors incorporating the complex frequencies. In a practical application, we study the modes of disk-shaped whispering gallery resonators and show that the proposed scalar product accurately predicts the geometry-dependent anticrossings between modes.}, archive = {J_PRA}, author = {Maria Paszkiewicz-Idzik and Lukas Rebholz and Carsten Rockstuhl and Ivan Fernandez-Corbaton}, doi = {10.1103/1rhp-ts2q}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013518}, shortjournal = {Phys. Rev. A}, title = {Scalar product for the radiation of resonant modes}, volume = {112}, year = {2025}, }
• (2025). Transverse momentum exchange in optical vector beam propagation: Theory and experiment. PRA, 112(1), 013517. (www)

  @article{ , abstract = {In this work we present a model for the paraxial propagation of linearly polarized vector beams. Of particular importance is the appearance of a transverse momentum term proportional to the linear polarization angle gradient imparted to the beam during the beam preparation process. The model predicts that during propagation, this momentum will be exchanged for classical transverse momentum, thereby causing the beam to accelerate. We observe the momentum exchange in experiment by designing the polarization profile in such a way to cause the beam centroid to follow a parabolic path through free space.}, archive = {J_PRA}, author = {J. M. Nichols and D. V. Nickel and F. Bucholtz}, doi = {10.1103/83pz-mm61}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013517}, shortjournal = {Phys. Rev. A}, title = {Transverse momentum exchange in optical vector beam propagation: Theory and experiment}, volume = {112}, year = {2025}, }
• (2025). Programmable interferometer: An application in quantum channels. PRA, 112(1), 013516. (www)

  @article{ , abstract = {Quantum optics plays a crucial role in developing quantum computers on different platforms. In photonics, precise control over light's degrees of freedom—including discrete variables (polarization, photon number, orbital angular momentum) and continuous variables (phase, amplitude quadratures, frequency)—is fundamental. Our model manipulates photonic systems to encode and process quantum information via the photon's spatial degree of freedom, employing polarization as an auxiliary qubit. We propose a programmable photonic circuit that simulates quantum channels, including phase-damping, amplitude-damping, and bit-flip channels, through adjustable interferometric parameters. Furthermore, the interferometer extends to more complex channels, such as the squeezed generalized amplitude damping. This work contributes to advancing quantum simulation techniques and serves as a foundation for exploring quantum computing applications, while highlighting pathways for their practical implementation.}, archive = {J_PRA}, author = {J. S. Araújo and K. Khan and A. S. Coelho}, doi = {10.1103/x2px-wvcr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013516}, shortjournal = {Phys. Rev. A}, title = {Programmable interferometer: An application in quantum channels}, volume = {112}, year = {2025}, }
• (2025). Induced berry connection and photonic spin hall effect in optical dirac theory. PRA, 112(1), 013515. (www)

  @article{ , abstract = {Within the framework of optical Dirac theory, we present a field-theoretical model of spin-orbit interaction and photonic spin and orbital Hall effects. Our approach reformulates light propagation along helical paths as solving the Maxwell equations in a ray-based curvilinear coordinate system. This system can alternatively be interpreted as a spin-degenerate medium with antisymmetric elements in the dielectric tensor, corresponding to the spin-1 excitation mode characterized by a rotational dipole vector. We show that, at leading order, the resulting effective Hamiltonian is equivalent to the Maxwell theory in a uniformly rotating frame, incorporating both spin-rotation and orbit-rotation coupling. This rotation arises from the torsion of helical paths, manifesting as extrinsic orbital angular momentum (EOAM) of photons. Notably, the spin angular momentum of the photon and its intrinsic orbital angular momentum contribute jointly to the geometric phase. In the Heisenberg picture, the spin and orbital Hall effects naturally emerge from interaction terms in the ray equations. Furthermore, we find that the transverse spin of evanescent waves couples with EOAM, revealing that the geometric phase of elliptically polarized light differs from that of circularly polarized light. This distinction underscores the role of spin-orbit coupling in modifying phase accumulation.}, archive = {J_PRA}, author = {Lili Yang and Longlong Feng}, doi = {10.1103/b3ls-krx1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013515}, shortjournal = {Phys. Rev. A}, title = {Induced berry connection and photonic spin hall effect in optical dirac theory}, volume = {112}, year = {2025}, }
• (2025). Light propagation in magnetoelectric materials: The role of optical coefficients in refractive index modulation. PRA, 112(1), 013514. (www)

  @article{ , abstract = {Investigations into optical phenomena associated with nonlinear magnetoelectric effects are attracting growing attention within the scientific community. Technologies constantly demand new materials capable of exhibiting precise and controllable responses to external electromagnetic fields. In this context, the optics of such materials is of remarkable importance. Here, working in a lossless and nondispersive regime, electromagnetic wave propagation in materials presenting linear and nonlinear optical coefficients is investigated. We expand the discussion of the roles of nonlinear coefficients by examining special cases in which the contribution of the magnetoelectric optical coefficients , and to birefringence and nonreciprocal phenomena is elucidated. Notably, expressions that directly connect the magnetoelectric coefficients to the refractive indices of the medium are fully derived. These expressions enable the direct measurement of all components of each nonlinear magnetoelectric coefficient, providing an advancement over previous works. This development bridges theoretical models with experimental applications, offering possibilities for the optical characterization of magnetoelectric effects.}, archive = {J_PRA}, author = {Vitorio A. De Lorenci and Lucas T. de Paula}, doi = {10.1103/w2y7-gfc8}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013514}, shortjournal = {Phys. Rev. A}, title = {Light propagation in magnetoelectric materials: The role of optical coefficients in refractive index modulation}, volume = {112}, year = {2025}, }
• (2025). Topologically enabled high-Q chiral electromagnetically induced transparency in all-dielectric metasurfaces. PRA, 112(1), 013513. (www)

  @article{ , abstract = {Bound states in the continuum (BICs) represent a unique class of physical phenomena characterized by resonant or leaky modes that remain perfectly confined, despite residing within the continuum. The high-quality -factor guided-mode resonances associated with BICs have garnered considerable attention in photonics research. In this study, we achieve electromagnetically induced transparency (EIT) with perfect chirality by coupling a high- chiral quasi-BIC with a broad achiral resonance. We demonstrate the utilization of the topological properties of BICs to realize a high- transparent band with maximum chirality in an all-dielectric planar metasurface. Additionally, we observe a spin-dependent slow-light effect, where the group delay difference between the two circularly polarized states exceeds 150 ps. These results reveal a straightforward mechanism for engineering ultranarrow spin-dependent EIT, which holds broad applicability across the electromagnetic spectrum, particularly in filtering and sensing.}, archive = {J_PRA}, author = {Yingfang Zhang and Tao Hu and Penglai Guo and Jianqing Li}, doi = {10.1103/j191-sfpz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013513}, shortjournal = {Phys. Rev. A}, title = {Topologically enabled high-Q chiral electromagnetically induced transparency in all-dielectric metasurfaces}, volume = {112}, year = {2025}, }
• (2025). Probing the topological anderson transition in quasiperiodic photonic lattices via chiral displacement and wavelength tuning. PRA, 112(1), 013512. (www)

  @article{ , abstract = {The interplay of topology and disorder in quantum dynamics has recently attracted significant attention across diverse platforms, including solid-state devices, ultracold atoms, and photonic systems. Here, we report on a topological Anderson transition caused by quasiperiodic modulation of the stronger intracell couplings in photonic Su-Schrieffer-Heeger lattices. As the quasiperiodic strength is varied, the system exhibits a reentrant transition from a trivial phase to a topological phase and back to a trivial phase, accompanied by the closing and reopening of the band gap around zero energy. Unlike the traditional detection of photonic topological edge modes, we measure the mean chiral displacement from the transport of light in the bulk of the lattices. In our photonic lattices with a fixed length, the propagation dynamics is retrieved by varying the wavelength of light, which tunes the interwaveguide couplings.}, archive = {J_PRA}, author = {Abhinav Sinha and Trideb Shit and Avinash Tetarwal and Diptiman Sen and Sebabrata Mukherjee}, doi = {10.1103/9jjd-vbp1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013512}, shortjournal = {Phys. Rev. A}, title = {Probing the topological anderson transition in quasiperiodic photonic lattices via chiral displacement and wavelength tuning}, volume = {112}, year = {2025}, }
• (2025). Mechanical squeezed kerr oscillator based on a tapered ion trap. PRA, 112(1), 013511. (www)

  @article{ , abstract = {We propose a theoretical description of a mechanically squeezed Kerr oscillator with a single ion in a tapered trap. We show that the motion coupling between the axial and radial modes caused by the trap geometry leads to Kerr nonlinearity of the radial mode with magnitude controlled by the trap frequencies. This allows the realization of non-Gaussian quantum gates, which play a significant role in the universal set of continuous variable quantum gates. Furthermore, we show that, because of the nonlinearity of the ion trap, applying an off-resonant time-varying electric field along the trap axis causes a motion squeezing of the radial mode. Finally, we discuss the motion mode frequency spectrum of an ion crystal in a tapered trap. We show that the frequency gap between the motion modes increases with trap nonlinearity, which benefits the realization of faster quantum gates.}, archive = {J_PRA}, author = {Bogomila S. Nikolova and Moritz Göb and Kilian Singer and Peter A. Ivanov}, doi = {10.1103/ybm3-72hs}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013511}, shortjournal = {Phys. Rev. A}, title = {Mechanical squeezed kerr oscillator based on a tapered ion trap}, volume = {112}, year = {2025}, }
• (2025). Deep-sub-cycle ultrafast optical pulses. PRA, 112(1), 013510. (www)

  @article{ , abstract = {Subcycle optical pulse is of great importance for ultrafast science and technology. While a narrower pulse can offer a higher temporal resolution, so far the pulse width has not reached the limit of half an optical cycle. Here we propose to generate deep-sub-cycle (i.e., less than half a cycle, sub-half-cycle) ultrafast optical pulses that break the half-cycle limit via inverse Compton scattering of a deep-subwavelength-confined THz optical driving field by relativistic electrons. Quantitatively, based on a deep-subwavelength-confined 0.4-THz 1-ps pulsed driving field, we obtain a 0.095-cycle 3.6-fs-width mid-infrared femtosecond pulse with a peak frequency of ∼26 THz (∼38 fs in optical cycle) by using a 3-MeV 1-fs electron bunch, and a 0.091-cycle 180-as-width visible attosecond pulse with a peak frequency of ∼0.49 PHz (∼2.0 fs in optical cycle) by using a 15-MeV 50-as electron bunch, respectively. Below the optical damage threshold of the sapphire prisms used for field confinement, the single-pulse photon number can exceed 10 5 . Such pulses may open opportunities for studying light-matter interaction on the deep-sub-cycle level, and pave a way to unprecedented optical technology ranging from temporal super-resolution optical microscopy and spectroscopy to unconventional atom/molecule polarization and manipulation.}, archive = {J_PRA}, author = {Hongliang Dang and Jiaxin Gao and Hao Wu and Yudong Zhang and Xin Guo and Limin Tong}, doi = {10.1103/s269-kl9z}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013510}, shortjournal = {Phys. Rev. A}, title = {Deep-sub-cycle ultrafast optical pulses}, volume = {112}, year = {2025}, }
• (2025). Room-temperature exciton-vibration-photon entanglement in polariton optomechanics. PRA, 112(1), 013509. (www)

  @article{ , abstract = {Room-temperature quantum entanglement not only is significant for the advancement of quantum physics but also has broad application prospects in quantum technology. Here we investigate the generation of room-temperature quantum entanglement in a polariton optomechanical system consisting of an optical mode, a molecular vibrational mode, and excitonic modes. The excitons and vibration are coupled via conditional displacement interactions, while the photon-exciton couplings occur via electric dipole interactions. We find that, mediated by exciton-vibration interaction, strong entanglement is established between the photon and the exciton, as well as between the photon and the vibration. Notably, the photon-vibration entanglement exhibits an astonishing enhancement with an increasing number of excitons, even far surpassing the entanglement generated from direct coupling between the exciton and vibration. Moreover, we demonstrate that these entanglements not only can be generated in a room-temperature environment ( K) but also exhibit considerable robustness against thermal noise. Furthermore, we achieve tripartite entanglement in this system under both room- and ultrahigh-temperature conditions. The increase in the number of excitons can significantly improve the tolerance of tripartite entanglement to thermal noise and optical dissipation. Our results indicate that polariton optomechanical systems could provide a promising platform for generating room-temperature and high-temperature-resistant entangled quantum resources, which are crucial for practical quantum technologies.}, archive = {J_PRA}, author = {Jian Huang and Zhedong Zhang}, doi = {10.1103/2dfx-23qp}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013509}, shortjournal = {Phys. Rev. A}, title = {Room-temperature exciton-vibration-photon entanglement in polariton optomechanics}, volume = {112}, year = {2025}, }
• (2025). Goos-hänchen shift and photonic spin hall effect in semi-dirac material heterostructures. PRA, 112(1), 013508. (www)

  @article{ , abstract = {We investigate the photonic spin Hall effect (PSHE) and the Goos-Hänchen shift (GH shift) in semi-Dirac materials. Through theoretical modeling, we demonstrate that the anisotropic dielectric function in semi-Dirac materials plays a critical role in determining the magnitude and polarity of these optical displacements. Furthermore, by utilizing the unidirectional drift of massless Dirac electrons in semi-Dirac materials, we systematically reveal how the drift velocity and direction modulate the behavior of optical displacements. The results indicate that the unique electronic properties of semi-Dirac materials—particularly their anisotropic dielectric response and carrier drift dynamics—establish mechanisms for controlling optical displacements and polarization-dependent phenomena. This work opens a new avenue for designing advanced photonic devices with tunable optical responses, particularly with significant application potential in quantum information processing and topological photonics.}, archive = {J_PRA}, author = {Hong-Liang Cheng and Yong-Mei Zhang}, doi = {10.1103/q8qc-46jv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013508}, shortjournal = {Phys. Rev. A}, title = {Goos-hänchen shift and photonic spin hall effect in semi-dirac material heterostructures}, volume = {112}, year = {2025}, }
• (2025). Crossed ponderomotive lenses for spherical aberration correction in electron optics. PRA, 112(1), 013507. (www)

  @article{ , abstract = {This article evaluates the lens characteristics of a nonrotationally symmetric electron lens based on a ponderomotive potential, i.e., a ponderomotive lens, formed by intersecting one or more optical beams perpendicular to an electron beam. Based on geometric optics, design formulas are derived for the focal length and general spherical aberration coefficients of specifically crossed ponderomotive lenses. Numerical calculations demonstrate that a pair of these crossed ponderomotive lenses can effectively correct spherical aberration in the objective lens of an electron microscope. Unlike rotationally symmetric ponderomotive lenses, which require the optical beam to be coaxially aligned with the electron beam, the crossed ponderomotive lens avoids the need to place optical mirrors and lenses directly on the beam axis. Thus, it offers practical advantages in designing and building electron optical instruments and contributes to system miniaturization. With lens properties similar to multipole lenses, the proposed crossed ponderomotive lens is expected to facilitate diverse developments in electron optical systems incorporating ponderomotive potentials.}, archive = {J_PRA}, author = {Yuuki Uesugi and Yuichi Kozawa}, doi = {10.1103/jk8d-dn5z}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013507}, shortjournal = {Phys. Rev. A}, title = {Crossed ponderomotive lenses for spherical aberration correction in electron optics}, volume = {112}, year = {2025}, }
• (2025). Observation of distinct first-order and second-order topological insulators in photonic martini lattices. PRA, 112(1), 013506. (www)

  @article{ , abstract = {Topological insulators are unique physical structures that exhibit insulating properties in their interior while being conductive on their surface. Here, we present an observation of distinct first-order and second-order topological insulators in photonic martini lattices fabricated by femtosecond laser writing technology. By using direct femtosecond laser writing techniques, we experimentally construct two types of photonic nontrivial martini lattices with tailored boundary conditions (i.e., the martini-up lattice and the martini-down lattice), enabling direct experimental observation of topological edge states and corner states with distinct phase structures. Remarkably, these lattices support different second-order topological phases, each giving rise to distinct classes of topological corner states under varying phase transition conditions. Furthermore, we uncover striking differences in their edge state behavior: while the martini-down lattice sustains only in-phase topological edge states, the martini-up lattice hosts both in-phase and out-of-phase configurations. This work not only introduces a novel framework for exploring higher-order topology, but also provides the possibility for innovative approaches to light manipulation and the development of advanced photonic devices.}, archive = {J_PRA}, author = {Weizhao Cheng and Ruichang Chen and Haixiang Wu and Weijie Liu and Menghan Zhang and Bin Zhang and Wenchao Yan and Feng Chen}, doi = {10.1103/84h8-tt5y}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013506}, shortjournal = {Phys. Rev. A}, title = {Observation of distinct first-order and second-order topological insulators in photonic martini lattices}, volume = {112}, year = {2025}, }
• (2025). High-order harmonic generation with radially chirped annular beams in the overdriven regime: Spectral extension and coherent high-flux radiation. PRA, 112(1), 013505. (www)

  @article{ , abstract = {High-order harmonic generation (HHG) with simultaneously high energy and high photon flux remains a fundamental challenge in strong-field physics. In this study, we introduce a method employing radially chirped annular (RCA) beams to significantly enhance HHG efficiency and coherence. RCA beams, which enable symmetric simultaneous spatio-temporal focusing with precise control, satisfy the essential requirements for efficient HHG: they can maximize laser intensity at the target while spatially separating the driving field from the harmonics in the far field. The 2D 1 carrier-resolved pulse propagation simulations demonstrate that, in the presence of plasma-induced defocusing, the RCA beam resists lateral spreading and maintains a more consistent phase front across the beam due to its spatio-spectral structure. Interestingly, the beam profile also exhibits dual chirp behavior, with positive chirping observed on axis and negative chirping off axis. RCA-driven harmonics demonstrate position-independent yield stability relative to the focal point, while remaining highly structured, broader in spectrum, more intense, and less divergent than those generated with conventional Gaussian beams. Moreover, harmonics achieve more spectral extension in the cutoff region and can generate attosecond pulses with durations nearly twice as short and intensities 1.5 times higher than conventional methods, along with enhanced phase stability across the generated harmonics. These findings suggest RCA beams hold strong potential for applications requiring high-flux coherent extreme ultraviolet and soft-x-ray radiation, opening transformative possibilities for advancing attosecond science and ultrafast spectroscopy.}, archive = {J_PRA}, author = {Mohamad Dashcasan and Atamalek Ghorbanzadeh}, doi = {10.1103/95xh-351z}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013505}, shortjournal = {Phys. Rev. A}, title = {High-order harmonic generation with radially chirped annular beams in the overdriven regime: Spectral extension and coherent high-flux radiation}, volume = {112}, year = {2025}, }
• (2025). Engineering polariton states through liquid-crystal-induced anisotropy and topology optimization. PRA, 112(1), 013504. (www)

  @article{ , abstract = {We propose a liquid-crystal-filled microcavity system that enables polarization-selective control of exciton-polariton condensates. The structure consists of a microcavity with embedded perovskite layers, which are positioned to couple independently with orthogonally polarized cavity modes. This configuration allows for the engineering of independent stationary potentials for different polarization components. Using topology optimization, we design these potentials to shape the spatial distribution of polariton condensates, enabling smooth intensity gradation encoding in the emission profile. Our approach provides a versatile platform for polarization-sensitive optical processing and spatial light modulation.}, archive = {J_PRA}, author = {E. Sedov and A. Kavokin}, doi = {10.1103/gj31-3wnr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013504}, shortjournal = {Phys. Rev. A}, title = {Engineering polariton states through liquid-crystal-induced anisotropy and topology optimization}, volume = {112}, year = {2025}, }
• (2025). Directional intense terahertz emission by abruptly autofocusing lasers. PRA, 112(1), 013503. (www)

  @article{ , abstract = {Two-color laser induced plasma filamentation in air could serve as tabletop sources of broadband terahertz (THz) pulses. Ubiquitous air in the earth facilitates its widespread utilities, particularly, in wireless communication and remote sensing, exploiting the unique advantage of the air-based scheme that the THz sources can be delivered over standoff distances via the pump laser propagation in air. However, the THz emission pattern inevitably has a conical angular profile with a dip in the propagation axis. Therefore, THz energy concentration, propagation directionality, and accuracy of signal demodulation are significantly impaired, greatly limiting its direct applications. Here, we successfully eliminate the unfavorable conical profile by experiments and meanwhile enhance THz directionality and intensity by 17 folds at the focus by use of abruptly autofocusing laser beams. Our simulations with a far-field model well reproduce the experimental observations, when the air filament length is read from the experimentally recorded fluorescence images. More importantly, we find that because the Gouy phase of Gaussian beam is ignored, the widely adopted dephasing length is significantly overestimated by 30 folds, which cannot explain the observed conical THz emission even when the filament length is shorter than the dephasing length. While the abruptly autofocusing beams are employed, the dephasing length is increased by five folds and the dephasing effect can be well overcome, which causes elimination of the unfavorable conical profile and enhancement of the THz intensity. This scheme is easily accessible since the abruptly autofocusing beam can be achieved by imposing a spatial light modulator on the input Gaussian beam.}, archive = {J_PRA}, author = {Xiao-Ran Zheng and Nan Li and Wei-Min Wang and Rui Zhang and Cun-Lin Zhang and Liang-Liang Zhang}, doi = {10.1103/b57m-txqz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013503}, shortjournal = {Phys. Rev. A}, title = {Directional intense terahertz emission by abruptly autofocusing lasers}, volume = {112}, year = {2025}, }
• (2025). Extreme electrodynamics in time-varying media. PRA, 112(1), 013502. (www)

  @article{ , abstract = {Abrupt time variations of the properties of optical materials have been at the center of intense research efforts in recent years, with the prospect of enabling extreme wave transformations and of leveraging time as a degree of freedom for wave control. While the most viable approach to yield ultrafast variations of the optical material response is through optical pumping of nonlinear media, the complex dynamics in these systems are not yet fully understood. Here, as a relevant case study of recent experimental observations, we rigorously investigate the pump-probe dynamics in a 310-nm-thick transparent conductive oxide etalon, using a weak 40-fs probe and a pump that displays peak power densities in the range with a duration of a few femtoseconds. We examine the pump-probe interaction using a hydrodynamic Maxwell approach that accounts for diffraction, self-focusing and self-defocusing, self- and cross-phase modulation, probe gain, and linear and nonlinear material dispersion expanded in the perturbative regime up to ninth order for both pump and probe. By allowing the intricacies of the pump-probe interaction to proceed in time, we can also define an effective spatiotemporal permittivity for a more direct evaluation of the material ultrabroadband optical behavior. The reported results challenge the conventional modeling of this kind of problem, which has so far overlooked pump dynamics, simplistically assigning a local time-dependent refractive index to the probe that may be designed to fit the experimental data but has no physical connection to the complex pump-probe interaction. Our approach unveils new dynamics, pointing toward the possibility to achieve extreme pulse compression into the attosecond range and nonlinear diffraction over deeply subwavelength propagation distances, thus opening a possible new path toward novel and cost-effective tools for integrated photonics and attosecond science.}, archive = {J_PRA}, author = {M. Scalora and M. A. Vincenti and D. de Ceglia and N. Akozbek and M. Ferrera and C. Rizza and A. Alù and N. Litchinitser and C. Cojocaru and J. Trull}, doi = {10.1103/5cjl-ltvg}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013502}, shortjournal = {Phys. Rev. A}, title = {Extreme electrodynamics in time-varying media}, volume = {112}, year = {2025}, }
• (2025). Dissipative structures in one- and two-dimensional kerr cavities with a spatially periodic pump. PRA, 112(1), 013501. (www)

  @article{ , abstract = {The interplay of periodic driving and dissipation is a fundamental feature of nonequilibrium physics. We elaborate a scenario for the formation of dissipative multispot excitations (MSEs) in Kerr cavities, modeled by the one- and two-dimensional (1D and 2D) Lugiato-Lefever (LL) equations, which include a spatially periodic pump (SPP). First, we demonstrate that the SPP produces three alternative exact periodic solutions of the LL equation, expressed in terms of the , and elliptic functions. By means of numerical methods, we explore the modulational instability (MI) and transverse instability (TI) of the periodic states in 1D and 2D settings, respectively. In the case of the defocusing nonlinearity, the 1D MI breaks the periodic states into an array of spatiotemporal crescents. In the case of self-focusing, the 1D MI, initiated by small random perturbations, leads to the establishment of a chaotic state, with the amplitude statistics featuring a long-tail probability distribution, that represents the presence of dissipative rogue waves. On the other hand, spatially periodic perturbations initiate the formation of breather chains, which periodically disappear and reappear, resembling the Fermi-Pasta-Ulam-Tsingou recurrence. In the 2D regime, the TI results in the formation of an array of 2D lumps. For a given SPP strength, the exact solutions for the periodic structures are stable if the loss constant exceeds a critical value. The findings reported here provide a contribution to nonequilibrium physics in general and may find direct applications in laser physics.}, archive = {J_PRA}, author = {Wen-Rong Sun and Wei-Chao Ma and Boris A. Malomed}, doi = {10.1103/8by5-1lsf}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013501}, shortjournal = {Phys. Rev. A}, title = {Dissipative structures in one- and two-dimensional kerr cavities with a spatially periodic pump}, volume = {112}, year = {2025}, }
• (2025). Mobility rings in a non-hermitian non-abelian quasiperiodic lattice. PRA, 112(1), 013320. (www)

  @article{ , abstract = {We study localization and topological properties in spin-1/2 nonreciprocal Aubry-André chain with SU(2) non-Abelian artificial gauge fields. The results reveal that, different from the Abelian case, mobility rings will emerge in the non-Abelian case accompanied by the non-Hermitian topological phase transition. As the non-Hermitian extension of mobility edges, such mobility rings separate Anderson-localized eigenstates from extended eigenstates in the complex energy plane under the periodic boundary condition. Based on the topological properties, we obtain the exact expression of the mobility rings. Furthermore, the corresponding indicators such as inverse participation rate, normalized participation ratio, winding number, non-Hermitian spectral structures, and wave functions are numerically studied. The numerical results are in good agreement with the analytical expression, which confirms the emergence of mobility rings.}, archive = {J_PRA}, author = {Rui-Jie Chen and Guo-Qing Zhang and Zhi Li and Dan-Wei Zhang}, doi = {10.1103/zfrn-53lz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013320}, shortjournal = {Phys. Rev. A}, title = {Mobility rings in a non-hermitian non-abelian quasiperiodic lattice}, volume = {112}, year = {2025}, }
• (2025). Bound-like states in a one-dimensional self-similar δ-barrier array. PRA, 112(1), 013319. (www)

  @article{ , abstract = {We investigate a one-dimensional quantum system with a self-similar arrangement of -function potential barriers, exhibiting discrete scale invariance. The singular potential induces kinematically enforced symmetry breaking at , decoupling the positive and negative spatial regions and leading to nonsymmetric zero-energy states. We demonstrate that the system supports a unique zero-energy wave function, which, although it is not square integrable, decays to zero at infinity and acts as a bound-like state with self-similar properties under discrete scaling transformations, akin to Efimov physics but limited to a single state. In momentum space, this wave function exhibits a threshold singularity at low momenta, with behavior depending on the scaling exponent : power-law divergence and log-periodic modulations for , logarithmic divergence for , and a finite limit for , which may be observable through time-of-flight or spectroscopic measurements in cold-atom experiments. The system's continuous spectrum, starting at zero energy, lacks discrete bound states. These findings highlight the role of singular potentials in generating scale-invariant quantum phenomena and provide a minimal framework for studying discrete scale symmetry and its potential experimental signatures.}, archive = {J_PRA}, author = {Jia-Chen Tang and Xu-Yang Hou and Yan He and Hao Guo}, doi = {10.1103/kbty-mxxb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013319}, shortjournal = {Phys. Rev. A}, title = {Bound-like states in a one-dimensional self-similar δ-barrier array}, volume = {112}, year = {2025}, }
• (2025). Elongated vortex quantum droplets in binary bose-einstein condensates. PRA, 112(1), 013318. (www)

  @article{ , abstract = {Stability of elongated (“slender”) quantum droplets (QDs) with embedded unitary and multiple vorticity is a problem that was not solved previously. In this work, we propose a solution which relies upon the use of the spatial modulation of the interspecies scattering length in the binary Bose-Einstein condensates, in the form of a two-dimensional axisymmetric Gaussian, shaped by means of the optical Feshbach resonance. The corresponding effective nonlinear trapping potential supports completely stable elongated QDs with vorticity and partly stable families of elongated QDs with (other nonlinear systems do not maintain stability of vortex droplets with ). We systematically analyze effects of the amplitude and width of the Gaussian modulation, as well as the total number of atoms, on the shape and stability of the QDs, some effects being explained analytically. Collisions between identical QDs with moving in opposite directions along the central axis leads to their merger into still more elongated breathing QDs with the same vorticity, while collisions between QDs with are quasielastic. Moving modulation profiles are able to adiabatically rotate the trapped elongated QDs. Application of a torque to the vector QD sets in the gyroscopic regime of robust precession, which realizes a macroscopic spin-orbit-coupling effect.}, archive = {J_PRA}, author = {Guilong Li and Zibin Zhao and Rui Zhang and Zhaopin Chen and Bin Liu and Boris A. Malomed and Yongyao Li}, doi = {10.1103/771t-rkdj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013318}, shortjournal = {Phys. Rev. A}, title = {Elongated vortex quantum droplets in binary bose-einstein condensates}, volume = {112}, year = {2025}, }
• (2025). Shortcuts to adiabatic topological pumping. PRA, 112(1), 013317. (www)

  @article{ , abstract = {Topological effects, known for their robustness against considerable perturbation, disorder, and defects, are believed to promote emerging quantum technologies. However, topological enhancement and protection could play a crucial role within coherence time, out of which decoherence mostly washes out the quantum feature. It motivates us to accelerate topological effects to achieve effective protection and optimal control of quantum information. Taking the prototypical Thouless pumping as an example, quantized transport of particles in a cyclic adiabatic evolution faces a challenge: slow driving may exceed the coherent time, while fast driving may break quantization. To address this dilemma, we propose to add a control Hamiltonian to speed up Thouless pumping using shortcuts to adiabaticity. Compared to traditional Thouless pumping, our fast quantum pumping scheme not only enables a substantial reduction of pumping time, but also effectively suppresses wave-packet diffusion. Furthermore, we demonstrate the resilience of our protocol to moderate noise levels in both momentum and real space. Our study settles the notoriously critical problem of practical quantum pumping.}, archive = {J_PRA}, author = {Wenjie Liu and Yongguan Ke and Chaohong Lee}, doi = {10.1103/pl6r-xmbq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013317}, shortjournal = {Phys. Rev. A}, title = {Shortcuts to adiabatic topological pumping}, volume = {112}, year = {2025}, }
• (2025). Narrowline cooling of dysprosium atoms in an optical tweezer array. PRA, 112(1), 013316. (www)

  @article{ , abstract = {We perform narrowline cooling of single dysprosium atoms trapped in a one-dimensional optical tweezer array, employing the narrow single-photon transition at 741 nm. At the trapping wavelength of 532 nm, the excited state is less trapped than the ground state. To obtain efficient cooling performances, we chirp the frequency of the cooling beam to subsequently address the red sidebands of different motional states. We demonstrate the effectiveness of the cooling protocol through Raman thermometry, which we characterize for our experimental conditions. We obtain an array of 75 atoms close to the motional ground state in the radial direction of the tweezers. Our results demonstrate the possibility to manipulate the motional degree of freedom of dysprosium in optical tweezer arrays, a key ingredient to exploit the potential of lanthanide-based tweezer platforms for quantum science.}, archive = {J_PRA}, author = {Giulio Biagioni and Britton Hofer and Nathan Bonvalet and Damien Bloch and Antoine Browaeys and Igor Ferrier-Barbut}, doi = {10.1103/k4vn-y7mb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013316}, shortjournal = {Phys. Rev. A}, title = {Narrowline cooling of dysprosium atoms in an optical tweezer array}, volume = {112}, year = {2025}, }
• (2025). Gyroscopic stability for nanoparticles in stern-gerlach interferometry and spin contrast. PRA, 112(1), 013315. (www)

  @article{ , abstract = {There is a severe impediment in Stern-Gerlach interferometry with a spin-embedded nanoparticle. This is because particle rotation creates a significant mismatch of the wave function of angular degrees of freedom during the creation and recombination of the spatial superposition, resulting in an inferior visibility contrast. We show that imparting angular momentum along the direction of a defect, such as the nitrogen-vacancy (NV) center, during the Stern-Gerlach interferometry provides excellent gyroscopic quantum stability to a nanodiamond, which opens up a way to maintain significant visibility in the quantum interference. The spin contrast improves by many folds for a wide-ranging value of the initial angular momentum, e.g., Hz for a mass of order -kg nanodiamond. Our scheme is independent of the material and is pertinent to any nanoparticle that can be used to create massive and large spatial superpositions with an embedded spin defect.}, archive = {J_PRA}, author = {Tian Zhou and Sougato Bose and Anupam Mazumdar}, doi = {10.1103/4xvz-gnk7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013315}, shortjournal = {Phys. Rev. A}, title = {Gyroscopic stability for nanoparticles in stern-gerlach interferometry and spin contrast}, volume = {112}, year = {2025}, }
• (2025). Hybrid-pair superfluidity in a strongly driven fermi gas. PRA, 112(1), 013314. (www)

  @article{ , abstract = {We explore the paired superfluid phases of a Fermi gas in the presence of a continuous Rabi drive. We focus on the case where two components are Rabi coupled strongly enough that they form hybrid superpositions, which in turn interact with an uncoupled third component. Using a generalized Bardeen-Cooper-Schrieffer (BCS) ansatz, we show that there are two coupled superfluid order parameters, and we obtain the associated free energy and quasiparticle excitation spectrum. We find that we can drive BCS-BCS, BCS-Bose-Einstein condensate (BEC), and BEC-BEC crossovers purely by varying the detuning of the Rabi drive from the bare transition, with the precise crossover depending on the sign of the underlying interactions between the coupled and uncoupled components. We furthermore identify an exotic excited branch which features both normal to BCS superfluid transitions, as well as a BCS-BEC-BCS crossover. Introducing a generalized Thouless criterion, we show that this behavior is reflected in the critical temperature for superfluidity. Our Rabi-coupled scenario also possesses additional thermodynamic properties related to the pseudospin of the coupled components, which provide novel signatures of the state of the many-body system. The Rabi-driven Fermi gas thus emerges as a unique platform for engineering and probing a rich array of multiband superfluid phases.}, archive = {J_PRA}, author = {Brendan C. Mulkerin and Olivier Bleu and Cesar R. Cabrera and Meera M. Parish and Jesper Levinsen}, doi = {10.1103/xtfy-8nrt}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013314}, shortjournal = {Phys. Rev. A}, title = {Hybrid-pair superfluidity in a strongly driven fermi gas}, volume = {112}, year = {2025}, }
• (2025). Out-of-equilibrium behavior of quantum vortices: A comparison of point vortex dynamics and fokker-planck evolution. PRA, 112(1), 013313. (www)

  @article{ , abstract = {An out-of-equilibrium two-dimensional superfluid relaxes towards equilibrium via a process of coarsening, driven by the annihilation of vortices with antivortices. Here we present a comparison of two different numerical models of this process, a dissipative point vortex model and Fokker-Planck evolution, across a wide range of initial configurations and levels of dissipation. We find that our dissipative point vortex model is well approximated by Fokker-Planck evolution only for very low initial energies per vortex, when almost all vortices and antivortices are closely bound into dipoles. We observe that the dynamical critical exponent in the dissipative point vortex model undergoes a crossover, from a roughly constant value close to 2 for , to a value which depends explicitly on the initial conditions for .}, archive = {J_PRA}, author = {R. J. Tattersall and A. W. Baggaley and T. P. Billam}, doi = {10.1103/l8yk-kk5c}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013313}, shortjournal = {Phys. Rev. A}, title = {Out-of-equilibrium behavior of quantum vortices: A comparison of point vortex dynamics and fokker-planck evolution}, volume = {112}, year = {2025}, }
• (2025). Microwave spectroscopy of ultracold-sodium least-bound molecular states. PRA, 112(1), 013312. (www)

  @article{ , abstract = {We have performed microwave spectroscopy of sodium least-bound molecular states, improving the precision of the knowledge of their energies at zero magnetic field by almost three orders of magnitude. Our experimental observations give us access also to states submitted to predissociation, a phenomenon where a bound molecular state can naturally decay into the continuum. Our findings are compared to numerical calculations based on the latest interpolation of sodium interaction potentials and show good agreement, with slight discrepancies in the zero-field energy of the molecular states, suggesting a need for small adjustment of the interaction potentials.}, archive = {J_PRA}, author = {M. Ballu and Z. Yao and B. Mirmand and D. J. Papoular and H. Perrin and A. Perrin}, doi = {10.1103/qv5s-71ll}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013312}, shortjournal = {Phys. Rev. A}, title = {Microwave spectroscopy of ultracold-sodium least-bound molecular states}, volume = {112}, year = {2025}, }
• (2025). Condensation of composite bosonic trions in interacting bose-fermi mixtures. PRA, 112(1), 013311. (www)

  @article{ , abstract = {We reveal a quantum coherent state characterized by composite bosonic trions, wherein paired fermions further bind with bosons, in one-dimensional Bose-Fermi mixtures. This phase emerges in two separate models, both featuring onsite boson-fermion attraction that induces negative binding energy for the composite trions. The first is the pair-hopping model, in which spinless fermions undergo pair hopping to form preformed pairs. The second is the extended Bose-Fermi-Hubbard model, describing dipolar bosons and fermions with density-density interactions. Notably, the formation of composite trions is independent of the specific pairing interactions of fermions. Extensive density-matrix renormalization-group calculations demonstrate the quasicondensation of the composite trions, evidenced by algebraically decaying correlations of trions, gapped single-particle excitations, and suppressed fermion pair correlations. Our findings provide valuable insights into the three-body pairing mechanism in mixed-particle systems.}, archive = {J_PRA}, author = {Qi Song and Jie Lou and Yan Chen}, doi = {10.1103/1mvs-7c86}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013311}, shortjournal = {Phys. Rev. A}, title = {Condensation of composite bosonic trions in interacting bose-fermi mixtures}, volume = {112}, year = {2025}, }
• (2025). Rotational decoherence dynamics in ultracold molecules induced by a tunable spin environment: The central rotor model. PRA, 112(1), 013310. (www)

  @article{ , abstract = {We show that quantum rotational wavepacket dynamics in molecules can be rigorously described by a system-environment model, which consists of a rotational subsystem coupled to a magnetically tunable spin bath formed by the nuclear spins within the molecule. The central rotor model shares similarities with the paradigmatic central spin model but features much richer rotational dynamics that is sensitive to the molecule's environment, which can be initiated and probed with short laser pulses used to control molecular orientation and alignment. We present numerical simulations of the nuclear-spin-bath-induced rotational decoherence dynamics of KRb molecules, which exhibit remarkable sensitivity to an external magnetic field. Our results show that ultracold molecular gases provide a natural platform for the experimental realization of the CRM.}, archive = {J_PRA}, author = {Timur V. Tscherbul and Lincoln D. Carr}, doi = {10.1103/7ncd-wm4p}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013310}, shortjournal = {Phys. Rev. A}, title = {Rotational decoherence dynamics in ultracold molecules induced by a tunable spin environment: The central rotor model}, volume = {112}, year = {2025}, }
• (2025). Droplets of bosons at a narrow resonance. PRA, 112(1), 013309. (www)

  @article{ , abstract = {We consider bosons interacting through a narrow s -wave resonance. Such a resonance is characterized by an infinite scattering length and a large and negative effective range r 0 . We argue that any number N ≥ 3 of bosons can form a self-bound cluster with the binding energy per particle increasing as N 2 for 1 ≪ N ≪ ( − r 0 / a bg ) 1 / 2 , where a bg is the background scattering length (between atoms and molecules). In the opposite limit N ≫ ( − r 0 / a bg ) 1 / 2 , bosons form droplets with binding energy per particle saturating to a constant value independent of the particle number. The stability of clusters and droplets when the interaction is detuned from the resonance is also studied.}, archive = {J_PRA}, author = {Ke Wang and Thimo Preis and Dam Thanh Son}, doi = {10.1103/zx28-gxlt}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013309}, shortjournal = {Phys. Rev. A}, title = {Droplets of bosons at a narrow resonance}, volume = {112}, year = {2025}, }
• (2025). Topological phases in two-dimensional rydberg lattices. PRA, 112(1), 013308. (www)

  @article{ , abstract = {We propose theoretically a simple two-dimensional system consisting of two square lattices of Rydberg atoms for the exploration of topological phenomena. In particular, we exploit the strong dipole-dipole interactions between Rydberg atoms to simulate a two-dimensional Su-Schrieffer-Heeger model. This model reveals a plethora of topological phases, which can be reached by varying the lattice geometry. We predict not only the emergence of edge and corner states, which characterize topological insulators, but also the appearance of pairs of topologically charged Dirac points and cones in gapless semimetallic phases. Moreover, the position, tilt, and degree of anisotropy of the cones, which may determine the transport properties in the system, are tunable via the lattice parameters. This establishes Rydberg lattice gases, which are already at the forefront of quantum simulation platforms, as the ideal setup for the exploration of topological phenomena.}, archive = {J_PRA}, author = {Mathias B. M. Svendsen and Beatriz Olmos}, doi = {10.1103/lf2c-h1kk}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013308}, shortjournal = {Phys. Rev. A}, title = {Topological phases in two-dimensional rydberg lattices}, volume = {112}, year = {2025}, }
• (2025). Competing bosonic reactions: Insight from exactly solvable time-dependent models. PRA, 112(1), 013307. (www)

  @article{ , abstract = {We discuss the progress on exactly solvable multistate Landau-Zener models from a perspective of their application to competing reactions of particle creation from a false vacuum. Such models generally predict that, even with identical initial conditions, and for nearly the same other particle parameters, a quantum coherent evolution results in a final particle distribution with significant asymmetry. We use an exact solution of the driven bosonic Tavis-Cummings model for two reaction pathways in order to quantify this effect, reveal a corresponding phase transition, and identify its universality class.}, archive = {J_PRA}, author = {Fumika Suzuki and Rajesh K. Malla and Nikolai A. Sinitsyn}, doi = {10.1103/68zs-gv5y}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013307}, shortjournal = {Phys. Rev. A}, title = {Competing bosonic reactions: Insight from exactly solvable time-dependent models}, volume = {112}, year = {2025}, }
• (2025). Beyond mean-field effects in dynamics of bose-einstein condensate in two-core trap. PRA, 112(1), 013306. (www)

  @article{ , abstract = {The nonlinear dynamics of quantum droplets in a quasi-one-dimensional BEC loaded in a two-core trap potential are investigated. The cases of standing and moving quantum droplets are considered. The frequencies of the Josephson oscillations and the condition for self-trapping are found. An analytical description is based on the variational approach to a system of coupled extended Gross-Pitaevskii (EGP) equations, including Lee-Huang-Yang correction terms. In the case of moving droplets, the system of equations describing the coupling of the relative motion of droplets in two cores with the dynamics of the relative phase and population imbalance (Josephson currents) is derived. Different regimes of droplet dynamics are found, including attraction and repulsion in dependence on the relative phase evolution. These phenomena are the realization of the Andreev-Bashkin effect for superfluids in a two-core trap potential. Analytical predictions of the model are confirmed by full numerical simulations of the coupled extended Gross-Pitaevskii equations.}, archive = {J_PRA}, author = {Fatkhulla Kh. Abdullaev and Ravil M. Galimzyanov and Akbar M. Shermakhmatov}, doi = {10.1103/hr45-tcyb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013306}, shortjournal = {Phys. Rev. A}, title = {Beyond mean-field effects in dynamics of bose-einstein condensate in two-core trap}, volume = {112}, year = {2025}, }
• (2025). Quantum tomography of the superfluid-insulator transition for a mesoscopic atomtronic ring. PRA, 112(1), 013305. (www)

  @article{ , abstract = {We provide a phase-space perspective for the analysis of the superfluid-insulator transition for finite-size Bose-Hubbard circuits. We explore how the eigenstates parametrically evolve as the interparticle interaction is varied, paying attention to the fingerprints of chaos at the quantum phase transition. Consequently, we demonstrate that the tomographic spectrum reflects the existence of mixed regions of chaos and quasiregular motion in phase space. This tomographic semiclassical approach is much more efficient and informative compared to the traditional level statistics inspection. Of particular interest is the characterization of the fluctuations that are exhibited by the many-body eigenstates. In this context, we associate with each eigenstate a Higgs measure for the identification of amplitude modes of the order parameter. Finally, we focus on the formation of the lowest Goldstone and Higgs bands.}, archive = {J_PRA}, author = {Yehoshua Winsten and Doron Cohen}, doi = {10.1103/tq97-7mjp}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013305}, shortjournal = {Phys. Rev. A}, title = {Quantum tomography of the superfluid-insulator transition for a mesoscopic atomtronic ring}, volume = {112}, year = {2025}, }
• (2025). Condensation of vanishing photon emission rates in random atomic clouds. PRA, 112(1), 013304. (www)

  @article{ , abstract = {In the collective photon emission from atomic clouds both the atomic transition frequency and the decay rate are modified compared to a single isolated atom, leading to the effects of superradiance and subradiance. In this article, we analyze the properties of the Euclidean random matrix associated with the radiative dynamics of a cold atomic cloud, previously investigated in the contexts of photon localization and Dicke super- and subradiance. We present evidence of a phase transition, surprisingly controlled by the cooperativeness parameter, rather than the spatial density or the diagonal disorder. The numerical results corroborate the occurrence of such a phase transition at a critical value of the cooperativeness parameter, above which the lower edge of the spectrum vanishes, exhibiting a macroscopic accumulation of eigenvalues. Independent evaluations based on the two phenomena provide the same value for the critical cooperativeness parameter.}, archive = {J_PRA}, author = {Viviana Viggiano and Romain Bachelard and Fabio Deelan Cunden and Paolo Facchi and Robin Kaiser and Saverio Pascazio and Francesco V. Pepe and Antonello Scardicchio}, doi = {10.1103/v4vy-wn4p}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013304}, shortjournal = {Phys. Rev. A}, title = {Condensation of vanishing photon emission rates in random atomic clouds}, volume = {112}, year = {2025}, }
• (2025). Nonintegrability of driven-dissipative one-dimensional hard-core bosons. PRA, 112(1), 013303. (www)

  @article{ , abstract = {We address the question whether hard-core bosons, equivalent to the XX model, remain integrable once the system is no longer closed. We consider the lattice version under incoherent local pump and loss and show, using random matrix theory, that the statistics of the complex spacial ratios indicate that the system is chaotic. Further, we show that the model belongs in the AI † universality class of random matrices. In addition to this analysis, we investigate an emergent stripe pattern in the Lindbladian spectrum and relate it to the dissipative parameters of the model.}, archive = {J_PRA}, author = {M. Zündel}, doi = {10.1103/2qxk-xk88}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013303}, shortjournal = {Phys. Rev. A}, title = {Nonintegrability of driven-dissipative one-dimensional hard-core bosons}, volume = {112}, year = {2025}, }
• (2025). Tunneling control of dipolar bosons in triple-well circuits via dipole polarization orientation and quantum sensing application. PRA, 112(1), 013302. (www)

  @article{ , abstract = {Precise control of the transport of ultracold atoms in optical lattices is essential for the exploration of quantum phenomena and the development of advanced quantum technologies. Harnessing the distinctive characteristics of the system near integrability, we investigate the tunneling control of dipolar bosons confined within a triple-well circuit via dipole polarization orientation. Based on this control mechanism, we propose a quantum magnetic compass. Remarkably, this device achieves high sensitivity to small changes in magnetic-field orientation, using a nonentangled initial state, making it a promising candidate for sensing applications.}, archive = {J_PRA}, author = {Leandro H. Ymai and Arlei P. Tonel}, doi = {10.1103/pcyp-d3gg}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013302}, shortjournal = {Phys. Rev. A}, title = {Tunneling control of dipolar bosons in triple-well circuits via dipole polarization orientation and quantum sensing application}, volume = {112}, year = {2025}, }
• (2025). Strongly repulsive one-dimensional gases at higher branches: Spin-charge correlation and coupled spin-chain model. PRA, 112(1), 013301. (www)

  @article{ , abstract = {We investigate the higher repulsive branches of one-dimensional (1D) bosonic and fermionic quantum gases beyond the super-Tonks-Girardeau regime, utilizing the Bethe-Ansatz method and exact diagonalization of small trapped clusters. In contrast to the well-studied lowest branches that are characterized by spin-charge separation, we demonstrate the emergence of strong spin-charge correlation in all higher branches with hard-core interactions. This manifests in distinct quasimomentum distributions and energy spectra for bosons and spin-1/2 fermions, despite their fermionization. Furthermore, trapped fermions in higher branches exhibit novel spin textures, intricately linked to charge excitations, necessitating a coupled multichain description beyond single effective spin-chain models. Our findings unveil a rich interplay between spin and charge degrees of freedom in highly excited 1D systems, opening avenues for exploring novel quantum phenomena beyond the conventional paradigm of low-lying states.}, archive = {J_PRA}, author = {Yu Chen and Xiaoling Cui}, doi = {10.1103/slxg-7dnm}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013301}, shortjournal = {Phys. Rev. A}, title = {Strongly repulsive one-dimensional gases at higher branches: Spin-charge correlation and coupled spin-chain model}, volume = {112}, year = {2025}, }
• (2025). Anomalous suppression of spin-exchange relaxation in alignment signals in cesium in ultraweak magnetic fields. PRA, 112(1), 013123. (www)

  @article{ , abstract = {The results of a study of the dynamics of atomic moments alignment in cesium under optical pumping by linearly polarized resonant light in ultraweak magnetic field are presented. It is shown that there are alignment components whose relaxation does not depend on spin-exchange broadening. The effect of suppression of spin-exchange relaxation in zero magnetic fields is detected, which is similar in its manifestations to the SERF (spin-exchange relaxation free) effect observed in orientation signals. This observation is interesting from the standpoint of general theory since the law of conservation of angular momentum responsible for maintaining orientation in the SERF mode should not guarantee the preservation of alignment under the same conditions. A comparison with theoretically calculated parameters of SERF resonances in orientation is given. A qualitative explanation of the observed effect is presented.}, archive = {J_PRA}, author = {M. V. Petrenko and A. K. Vershovskii}, doi = {10.1103/rmyw-8zny}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013123}, shortjournal = {Phys. Rev. A}, title = {Anomalous suppression of spin-exchange relaxation in alignment signals in cesium in ultraweak magnetic fields}, volume = {112}, year = {2025}, }
• (2025). Long-range electron correlation in dissociative double ionization of argon dimers. PRA, 112(1), 013122. (www)

  @article{ , abstract = {We experimentally investigate long-range electron-electron correlation across the two atomic sites of an argon dimer in its dissociative double ionization induced by a linearly polarized 400-nm femtosecond laser field. The correlation between the two electrons, ionized at two atomic sites, is revealed through analysis of the joint kinetic energy spectra and the momentum distributions. Notably, one of the two electrons exhibits a pronounced redshift in the low-kinetic-energy region, in contrast to the electron energy spectrum observed in single ionization of argon dimers. This distinctive spectral feature is corroborated by theoretical simulations, which attribute the redshift to the differing intensity dependence of the kinetic energy distributions of the two electrons, as well as to the influence of electron-electron correlation during the ionization process.}, archive = {J_PRA}, author = {Hao Huang and Hongcheng Ni and Jian Wu and Yan Yang and Junyang Ma and Zhenrong Sun}, doi = {10.1103/vm2r-127c}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013122}, shortjournal = {Phys. Rev. A}, title = {Long-range electron correlation in dissociative double ionization of argon dimers}, volume = {112}, year = {2025}, }
• (2025). Role of mechanical effects on the excitation spectra of microwave-dressed rydberg states in a cold atomic cloud. PRA, 112(1), 013121. (www)

  @article{ , abstract = {We explore the excitation spectra of cold atoms to the Rydberg state in the presence of microwave (MW) radiation as a function of MW frequency. The spectra reveal several features around the transition frequencies between adjacent Rydberg states. We argue that some of these features are indicative of variations in the Rydberg excitation probability while others result from the removal of atoms from the cold cloud as a consequence of a MW-induced strong dipole-dipole interatomic force. Our claim is supported by experimental observations and theoretical modeling.}, archive = {J_PRA}, author = {H. Failache and J. A. Muniz and L. Velazco and D. Talento and A. Lezama}, doi = {10.1103/fqjy-fhm2}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013121}, shortjournal = {Phys. Rev. A}, title = {Role of mechanical effects on the excitation spectra of microwave-dressed rydberg states in a cold atomic cloud}, volume = {112}, year = {2025}, }
• (2025). Coherent and incoherent control of ionization-fragmentation dynamics in h2 driven by a two-color laser field. PRA, 112(1), 013120. (www)

  @article{ , abstract = {We utilize the time-dependent wave-packet propagation method to simulate the complete fragmentation dynamics of molecules subjected to the two-color field. The study focuses on elucidating the influence of the carrier-envelope phase (CEP) difference between the two laser beams on key dynamical properties, including the alignment of neutral molecules, ionization probability, dissociation probability, proton angular distribution, and kinetic energy release (KER). Our study shows that two-color fields can simultaneously provide coherent and incoherent modulations of molecular dynamics. For neutral molecular alignment, two-color modulation proves ineffective as it depends quadratically on intensity rather than wave properties. However, strong-field ionization's inherent nonlinearity enables coherent control through intensity-dependent angular distributions and ionization probabilities. Examining fragmentation dynamics, we observe coexisting first-, second-, and third-order processes under two-color irradiation. First-order transitions exhibit incoherent modulation via laser component competition, altering vibrational distributions and KER spectra phase independently. The second-order process repopulates bound states but minimally affects fragmentation. Crucially, at high intensities, the dominant third-order process enables phase-dependent coherent control through reexcitation of second-order-created bound states, revealing fundamental insights into multiorder process interplay in strong-field molecular dynamics.}, archive = {J_PRA}, author = {JinPeng Ma and CongCong Jia and Ting Xu and SiQi Pei and YinSong Tang and HaoDong Ju and XiaoQing Hu and Yong Wu and JianGuo Wang}, doi = {10.1103/6xf5-b3t7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013120}, shortjournal = {Phys. Rev. A}, title = {Coherent and incoherent control of ionization-fragmentation dynamics in h2 driven by a two-color laser field}, volume = {112}, year = {2025}, }
• (2025). Photodissociation dynamics of XH+ (X = na, k, rb, cs): Rovibrationally resolved shape resonances driven by potential barriers in the ultraviolet spectrum. PRA, 112(1), 013119. (www)

  @article{ , abstract = {Alkali-metal hydride cations ( , K, Rb, Cs) are potentially important in interstellar chemistry and early cosmological environments, yet their photodissociation properties remain poorly characterized. We present a systematic study of their photodissociation cross sections based on high-accuracy ab initio electronic structure calculations. The cross sections are computed under the assumption of local thermodynamic equilibrium, covering photon wavelengths from 50 nm up to the dissociation threshold, and include transitions from most rovibrational levels in the ground electronic state . Prominent shape resonances are identified near the Lyman line, significantly modulating the photodissociation behavior. In particular, for , strong contributions from the and states are found in the spectral region between the Lyman line and the Lyman limit. These results provide critical theoretical data for the spectral characterization of alkali-metal hydride cations and offer valuable input for astrophysical modeling of UV-driven processes and early-universe chemistry.}, archive = {J_PRA}, author = {Kun Wang and Xing Guang Su and Dong Liu and Yu Wang and Yongjun Cheng and Yong Wu and Jian Guo Wang and Yi Zhi Qu and Ke Dong Wang and Song Bin Zhang and Yu Kun Yang}, doi = {10.1103/ny9t-wqp1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013119}, shortjournal = {Phys. Rev. A}, title = {Photodissociation dynamics of XH+ (X = na, k, rb, cs): Rovibrationally resolved shape resonances driven by potential barriers in the ultraviolet spectrum}, volume = {112}, year = {2025}, }
• (2025). Reconstruction of attosecond beating by interference of two-photon transitions with higher-order processes. PRA, 112(1), 013118. (www)

  @article{ , abstract = {The reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) method is a leading technique for time-resolved investigation of photoionization processes. Interpretation of RABBITT spectra is limited to a lowest-order description, while new variants of the technique necessitate higher intensity infrared fields where this description breaks down. Here, we present an extension of RABBITT theory which can account for higher-order processes (RABBITT-HOP), and demonstrate RABBITT-HOP's ability to predict and describe higher-order processes through ab initio simulation of a RABBITT experiment targeting the high-lying Rydberg series of helium. We demonstrate that the signature line shape imparted by the resonances in the phase of the lowest sideband can also be observed in the phase of the next mainband, as well as in the phases of the next sideband and mainband—each with additional phase shifts predicted under RABBITT-HOP. Repeating this analysis for a range of infrared intensities, we determine the lower limits of intensities required for these higher-order processes to become observable and upper limits beyond which nonperturbative effects begin to dominate. This new theoretical framework forms a much-needed basis for accurate interpretation of RABBITT spectra in experiments involving more intense fields, and paves the way for the development of new RABBITT-like techniques which take advantage of this new understanding of how atomic resonance effects may be propagated beyond their nearest sideband.}, archive = {J_PRA}, author = {L. Roantree and H. W. van der Hart and A. C. Brown}, doi = {10.1103/bksn-wgkm}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013118}, shortjournal = {Phys. Rev. A}, title = {Reconstruction of attosecond beating by interference of two-photon transitions with higher-order processes}, volume = {112}, year = {2025}, }
• (2025). Formation of a schrödinger cat state of a strong circularly polarized laser field due to thomson scattering by free electrons. PRA, 112(1), 013117. (www)

  @article{ , abstract = {Ionization of a target gas by a strong laser field, which is the first step for many processes studied in strong-field physics, results in the appearance of free electrons. Recently, we showed that the interaction of the laser field with these electrons affects the quantum state of the field, leading to the formation of nonclassical and non-Gaussian field states [ Phys. Rev. A 110 , 023115 (2024) ]. In this paper we generalize our model to the multimode case, which allows us to consider Thomson scattering (TS) of the laser field by the electrons. We show that for sufficiently long pulses under typical experimental conditions TS causes coherent transfer of photons from the strong laser mode to weak modes with close frequencies and wave vectors. This results in a displacement of the initial coherent state of the laser field similar to that recently discovered and caused by the high-order harmonic generation (HHG) process [M. Lewenstein et al. , Nat. Phys. 17 , 1104 (2021) ]. The similarity with HHG suggests that, by conditioning on TS, multiphoton Schrödinger cat states of the laser field can be generated. The TS mechanism has a different dependence on the pulse parameters compared with the HHG mechanism, which may facilitate more efficient and robust generation of cat states. In particular, it also works for circularly polarized fields, in which case HHG does not occur.}, archive = {J_PRA}, author = {Evgeny S. Andrianov and Oleg I. Tolstikhin}, doi = {10.1103/3gjp-f7br}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013117}, shortjournal = {Phys. Rev. A}, title = {Formation of a schrödinger cat state of a strong circularly polarized laser field due to thomson scattering by free electrons}, volume = {112}, year = {2025}, }
• (2025). Dissipation-induced transition between optical reciprocity and nonreciprocity. PRA, 112(1), 013116. (www)

  @article{ , abstract = {Optical nonreciprocity, violating Lorentz reciprocity, is pivotal for advanced classical optics and quantum networks. Despite significant progress in its realization across diverse systems, intricate interconnection and transition between reciprocity and nonreciprocity remain elusive, which poses a limitation on the development of controllable nonreciprocal devices. Here, we demonstrate that inherent atomic dissipation, traditionally detrimental, serves as a flexible tool for nonreciprocity control. It is shown that the dissipation-dependent atomic population and coherence effects exhibit competitive yet distinct characteristics in breaking Lorentz reciprocity, enabling the coexistence and interconversion of reciprocal and nonreciprocal states within a V-type atomic system. By implementing a dissipation-engineered switching framework, a nontrivial transition between reciprocity and nonreciprocity is achieved. These findings establish the direct link between microscopic dissipation and dynamic nonreciprocity control, paving a way for all-optical reconfigurable nonreciprocity.}, archive = {J_PRA}, author = {Lifan Chen and Jiale Li and Zhan Zheng and Jin Yan and Feng Li and Yanpeng Zhang and Yin Cai}, doi = {10.1103/298n-q3tq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013116}, shortjournal = {Phys. Rev. A}, title = {Dissipation-induced transition between optical reciprocity and nonreciprocity}, volume = {112}, year = {2025}, }
• (2025). Radio-frequency pseudonull induced by light in an ion trap. PRA, 112(1), 013115. (www)

  @article{ , abstract = {In a linear radio-frequency (rf) ion trap, the rf null is the point of zero electric field in the dynamic trapping potential where the ion motion is approximately harmonic. When displaced from the rf null, the ion is superimposed by fast oscillations known as micromotion, which can be probed through motion-sensitive light-atom interactions. In this work, we report on the emergence of the rf pseudonull, a locus of points where the ion responds to light as if it were at the true rf null, despite being displaced from it. The phenomenon is fully explained by accounting for the general two-dimensional structure of micromotion and is experimentally verified under various potential configurations, with observations in great agreement with numerical simulations. The rf pseudonull manifests as a line in a two-dimensional parameter space, determined by the geometry of the incident light and its overlap with the motional structure of the ion. The true rf null occurs uniquely at the concurrent point of the pseudonull lines induced by different light sources.}, archive = {J_PRA}, author = {Daun Chung and Yonghwan Cha and Hosung Shon and Jeonghyun Park and Woojun Lee and Kyungmin Lee and Beomgeun Cho and Kwangyeul Choi and Chiyoon Kim and Seungwoo Yu and Suhan Kim and Uihwan Jeong and Jiyong Kang and Jaehun You and Taehyun Kim}, doi = {10.1103/3dsq-47n7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013115}, shortjournal = {Phys. Rev. A}, title = {Radio-frequency pseudonull induced by light in an ion trap}, volume = {112}, year = {2025}, }
• (2025). Generation of bessel vortex electrons via atomic photoionization. PRA, 112(1), 013114. (www)

  @article{ , abstract = {We investigate the transfer of longitudinal orbital angular momentum (OAM) from a twisted light beam to an electron through the photoionization of a hydrogen atom. Our theoretical analysis employs an asymptotic Laguerre-Gaussian (LG) beam, a form of LG beam with a higher radial index, whose spatial complex field amplitude closely resembles that of an ideal Bessel beam. We show that the outgoing electron acquires a well-defined OAM projection when the hydrogen atom is located along the propagation axis of the twisted photon. Additionally, we find that the transverse spatial structure of the outgoing electron mirrors the higher-order Bessel profile, characterized by an intensity null at the center and multiple off-axis rings. Our findings offer a practical and experimentally feasible approach for generating Bessel electron vortex beams, providing a significant advancement in this area of research.}, archive = {J_PRA}, author = {B. Kumar Das and C. Granados and L. Wang and M. F. Ciappina}, doi = {10.1103/jtxw-363p}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013114}, shortjournal = {Phys. Rev. A}, title = {Generation of bessel vortex electrons via atomic photoionization}, volume = {112}, year = {2025}, }
• (2025). Semiclassical floquet-markov master equation for monte carlo spin integration. PRA, 112(1), 013113. (www)

  @article{ , abstract = {In conducting an experiment to measure a neutron electric dipole moment (nEDM), it is often necessary to determine the behavior of an ensemble of spins under time-dependent and randomly fluctuating magnetic fields. This is particularly relevant for experiments which utilize dressing magnetic fields to modify the effective Larmor frequency of the neutrons under study. In this work, we investigate a new technique to calculate the frequency shifts arising from magnetic field inhomogeneities and motional magnetic fields, particularly in the case where the spins in question are subjected to a time-periodic magnetic field. The method is based on Floquet theory, a general framework for analyzing periodic linear differential equations, and Redfield theory, which governs the time evolution of the density matrix in the presence of weak couplings to an environment. We benchmark this method against the analytical results derived both with and without dressing field, as well as against the results of a conventional Runge-Kutta integrator, and find agreement in all cases. We further study the performance of the method, and find order-of-magnitude improvements in runtime over the conventional integrator.}, archive = {J_PRA}, author = {Raymond Tat}, doi = {10.1103/2bp2-hs9d}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013113}, shortjournal = {Phys. Rev. A}, title = {Semiclassical floquet-markov master equation for monte carlo spin integration}, volume = {112}, year = {2025}, }
• (2025). Phase-dependent coulomb focusing effect in orthogonally polarized two-color laser fields. PRA, 112(1), 013112. (www)

  @article{ , abstract = {We theoretically investigate the Coulomb focusing effect in an orthogonally polarized two-color (OTC) laser field by numerically solving the time-dependent Schrödinger equation. Based on the photoelectron momentum distribution along the light-propagation direction, the strength of the Coulomb focusing effect across all relative phases in the OTC field is quantified using a unified standard, revealing a phase dependence. Employing a semiclassical model, we conduct a comprehensive study of the underlying mechanism and find that both the unique electron looplike dynamic behavior and the electron birth time distribution play crucial roles. Their respective influences are manifested in two different aspects, i.e., altering the effective interaction time with the ionic potential and changing the proportion of rescattering electrons. We further investigate the phase-modulated Coulomb focusing effect for different atoms in the OTC field. Distinct modulation trends are observed, which arise from the differences in the proportion of rescattering electrons.}, archive = {J_PRA}, author = {Peng Qin and Yidian Tian and Long Xu and Min Gong and Kunlong Liu and Lingling Zheng and Xufei Sun and Zhanghai Chen}, doi = {10.1103/hfr3-dsqx}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013112}, shortjournal = {Phys. Rev. A}, title = {Phase-dependent coulomb focusing effect in orthogonally polarized two-color laser fields}, volume = {112}, year = {2025}, }
• (2025). Quantum versus semiclassical signatures of correlated triple ionization in dalitz plots. PRA, 112(1), 013111. (www)

  @article{ , abstract = {We investigate correlated three-electron escape in Ne when driven by an intense, infrared laser field. We do so by employing a reduced-dimensionality quantum-mechanical model and two three-dimensional semiclassical models. One semiclassical model is a recently developed one that accounts with effective Coulomb potentials for the interaction between two bound electrons (ECBB) while it fully accounts for all other interactions. The other semiclassical model is the Heisenberg one, which effectively accounts for the interaction of each electron with the core via a soft-core potential. We identify and compare the signatures of correlated three-electron escape for both quantum and semiclassical models on Dalitz plots and find a better agreement between the quantum and the ECBB model. We also show that a central “spot” on the Dalitz plots is reproduced by all models. Using the ECBB model we associate this spot with the direct triple ionization pathway and argue this to be the case also for the quantum model. Devising a simple classical model that accounts for the direct pathway of triple ionization, we show that the width of this spot in the Dalitz plots solely depends on the time of tunnel ionization.}, archive = {J_PRA}, author = {Dmitry K. Efimov and Georgios P. Katsoulis and Tymoteusz Rozpętkowski and Sergiusz Chwałowski and Agapi Emmanouilidou and Jakub S. Prauzner-Bechcicki}, doi = {10.1103/43wt-x129}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013111}, shortjournal = {Phys. Rev. A}, title = {Quantum versus semiclassical signatures of correlated triple ionization in dalitz plots}, volume = {112}, year = {2025}, }
• (2025). Quantum state engineering of light using intensity measurements and postselection. PRA, 112(1), 013110. (www)

  @article{ , abstract = {Quantum state engineering of light is of great interest for quantum technologies, particularly for generating nonclassical states of light, and is often studied through conditioning approaches. Recently, we demonstrated that state engineering approaches can be applied in intense laser-atom interactions to obtain measurement statistics which resemble optical “cat” states by using intensity measurements and classical postselection of the measurement data. Postprocessing of a finite-size sampled data set allows one to select specific events, here the processes that are energy conserving, corresponding to measurement statistics of nonclassical states of light. However, to fully realize the potential of this method for quantum state engineering, it is crucial to thoroughly investigate the role of the involved measurements and the finite-size nature of the postselection scheme. We illustrate this by analyzing the postselection approach recently developed for high harmonic generation, which enables the generation of optical cat states bright enough to induce nonlinear phenomena. These findings provide significant guidance for quantum light engineering and the generation of intense optical cat states with potential applications in nonlinear optics and quantum science.}, archive = {J_PRA}, author = {J. Rivera-Dean and Th. Lamprou and E. Pisanty and M. F. Ciappina and P. Tzallas and M. Lewenstein and P. Stammer}, doi = {10.1103/11vz-9gcz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013110}, shortjournal = {Phys. Rev. A}, title = {Quantum state engineering of light using intensity measurements and postselection}, volume = {112}, year = {2025}, }
• (2025). Purcell effect in chiral environments: A macroscopic QED perspective. PRA, 112(1), 013109. (www)

  @article{ , abstract = {The Purcell effect describes the modification of the spontaneous decay rate in the presence of electromagnetic media and bodies. In this work, we shed light on the dependencies and magnitude of this effect for chiral materials. Using the framework of macroscopic quantum electrodynamics and Fermi's Golden Rule, we study a chiral bulk medium with and without local-field corrections, an idealized chiral mirror and a chiral surface. The results imply that the chiral effect is greatest for large transition frequencies, molecules with large optical rotatory strength and media with a strong cross-susceptibility. In the case of a half space, short distances from the molecule to the interface additionally enhance the effect.}, archive = {J_PRA}, author = {C. S. Rapp and Janine C. Franz and Stefan Yoshi Buhmann and O. J. Franca}, doi = {10.1103/9k2w-rvcm}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013109}, shortjournal = {Phys. Rev. A}, title = {Purcell effect in chiral environments: A macroscopic QED perspective}, volume = {112}, year = {2025}, }
• (2025). All-optical raman control of ultracold atomic hyperfine states using the pulsed jump protocol. PRA, 112(1), 013108. (www)

  @article{ , abstract = {We develop a pulse-driven jump protocol to achieve all-optical Raman control of ultracold atomic hyperfine states. By establishing general conditions for adiabatic evolution between quantum states in parameter space, we derive the essential pulse area and phase conditions necessary for quantum state transfer in a resonant single- three-level system. We extend this approach to a double- four-level system by incorporating a neighboring intermediate state, which leads to a single-photon detuned three-level system. Through numerical simulations of the ultracold atomic system, we demonstrate that high-fidelity and robust control of quantum state transfer can be achieved in the single- three-level system using stimulated Raman adiabatic passage and the pulsed jump protocol. Furthermore, we show that the destructive quantum interference effects between resonant and detuned Raman pathways in the double- four-level system can be mitigated by optimizing the pulse area and two-photon detuning parameters within the pulsed jump protocol. This work presents a promising approach for achieving all-optical Raman control of quantum state transfer in ultracold atomic hyperfine states.}, archive = {J_PRA}, author = {Xin-Xia Jian and Zhi-Jian Zheng and Jun-Jie Jiang and Lin Zhou and Chuan-Cun Shu and Jun He}, doi = {10.1103/j86x-bpp5}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013108}, shortjournal = {Phys. Rev. A}, title = {All-optical raman control of ultracold atomic hyperfine states using the pulsed jump protocol}, volume = {112}, year = {2025}, }
• (2025). Nonperturbative effects in attosecond four-wave-mixing spectra. PRA, 112(1), 013107. (www)

  @article{ , abstract = {We study the nonlinear optical response of argon to a four-wave-mixing pulse sequence consisting of an extreme-ultraviolet pulse, a collinear IR dressing pulse, and a delayed noncollinear IR probe pulse. Sequential absorption of an extreme ultraviolet photon and an IR photon from the collinear beams excites the bright state and the dark states. The subsequent absorption of an IR photon from the noncollinear beam then leads to an angled extreme ultraviolet emission, whose variation with delay encodes the coupling between autoionizing states, the lifetimes of dark states, and nonperturbative effects. Both our measurements and ab initio simulations of the angled four-wave-mixing signal reveal a double-peak structure in the delay dependence, in good agreement with each other. We attribute the central minimum between the two peaks to rapid Rabi cycling, driven by the collinear IR dressing pulse, between the dark states and the resonance, which leads to destructive interference in the final transition amplitude.}, archive = {J_PRA}, author = {Sergio Yanez-Pagans and Nathan Harkema and Arvinder Sandhu and Coleman Cariker and Luca Argenti}, doi = {10.1103/jtcp-yt14}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013107}, shortjournal = {Phys. Rev. A}, title = {Nonperturbative effects in attosecond four-wave-mixing spectra}, volume = {112}, year = {2025}, }
• (2025). Origin of entanglement in an h(2p) atom pair produced through the photodissociation of an h2 molecule. PRA, 112(1), 013106. (www)

  @article{ , abstract = {In this paper, as a continuation of our recent article demonstrating that the atom pair is entangled in the photodissociation [ Phys. Rev. A 111 , 023116 (2025) ], we have discovered the origins of the entanglement for the atom-pair state and obtained the entanglement entropies by origins. The same investigation has been carried out for the precursor molecular state of the atom pair. The reason for the increase of the entanglement entropy during the dissociation from the precursor molecule into the atom pair has been made clear.}, archive = {J_PRA}, author = {Kouichi Hosaka and Yutaro Torizuka and Philipp Schmidt and Takeshi Odagiri and Arno Ehresmann and Masashi Kitajima and Noriyuki Kouchi}, doi = {10.1103/g7tj-mkqt}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013106}, shortjournal = {Phys. Rev. A}, title = {Origin of entanglement in an h(2p) atom pair produced through the photodissociation of an h2 molecule}, volume = {112}, year = {2025}, }
• (2025). Orientation-dependent enhanced ionization in acetylene revealed by ultrafast cross-polarized pulse pairs. PRA, 112(1), 013105. (www)

  @article{ , abstract = {We investigate the orientation dependence of enhanced ionization (EI) during strong-field-driven nuclear motion in acetylene ( ). Here, we both initiate and probe molecular dynamics in acetylene with intense 6-fs cross-polarized pulse pairs, separated by a variable delay. Following multiple ionization by the first pulse, acetylene undergoes simultaneous elongation of the carbon-carbon and carbon-hydrogen bonds, enabling further ionization by the second pulse and the formation of a very highly charged state, [ . At small interpulse delays ( fs), this enhancement occurs when the molecule is aligned to the probe pulse. Conversely, at large delays ( fs), formation of [ occurs when the molecule is aligned to the pump pulse. By analyzing the polarization and time dependence of sequentially ionized [ , we resolve two transient alignments that both contribute to a large increase in the multiple ionization yield. This cross-polarized pulse pair scheme uniquely enables selective probing of deeply bound orbitals, providing new insights on orientation-dependent EI in highly charged hydrocarbons.}, archive = {J_PRA}, author = {S. A. Mohideen and A. J. Howard and C. Cheng and I. Gabalski and A. M. Ghrist and E. Weckwerth and P. H. Bucksbaum}, doi = {10.1103/8grj-cmzv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013105}, shortjournal = {Phys. Rev. A}, title = {Orientation-dependent enhanced ionization in acetylene revealed by ultrafast cross-polarized pulse pairs}, volume = {112}, year = {2025}, }
• (2025). Algorithmic cooling based on quantum measurement. PRA, 112(1), 013104. (www)

  @article{ , abstract = {We propose a method to improve the purity of interacting systems through quantum measurement. We find that the previous quantum-energy-teleportation-based cooling scheme is a special case of our method and the local operations are not necessary for purification [N. A. Rodríguez-Briones et al. , Phys. Rev. Lett. 119 , 050502 (2017) ]. We give the analytical results of measurement-based cooling for two-qubit systems and numerical examples in Gibbs states. Our method can exceed the partner pairing algorithm without multiple iterations and additional auxiliary systems. This shows that the measurement-based cooling scheme may be an effective cooling scheme for strongly interacting systems and shows the important role of quantum correlations in algorithmic cooling.}, archive = {J_PRA}, author = {Hao Fan and Feng-Lin Wu and Lu Wang and Shu-Qian Liu and Si-Yuan Liu}, doi = {10.1103/yrlx-82zx}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013104}, shortjournal = {Phys. Rev. A}, title = {Algorithmic cooling based on quantum measurement}, volume = {112}, year = {2025}, }
• (2025). Polarizability of one-dimensional soft-core atoms. PRA, 112(1), 013103. (www)

  @article{ , abstract = {Simulation of nonperturbative interactions between electric fields and real three-dimensional atoms is demanding. For this reason, many proof-of-principle and method studies replace three-dimensional atoms by suitable one-dimensional soft-core models. Soft-core potentials may be classified by their curvature at the nucleus that can be either infinite, finite, or vanishing. Within each class, models with analytical ground states and correct binding energy exist. In this work we examine if the agreement with real atoms extends to perturbations by electric fields for such models. We demonstrate that the static polarizability is generally overestimated. Accordingly, we construct an improved soft-core potential, for which both binding energy and polarizability agree with three-dimensional values. Additionally, the hyperpolarizability of this model deviates by as little as 3% from three-dimensional hydrogen, and field-induced ionization is correctly captured. Finally, we show that the new potential leads to significantly improved response to time-dependent fields.}, archive = {J_PRA}, author = {Thomas Garm Pedersen}, doi = {10.1103/l926-m81s}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013103}, shortjournal = {Phys. Rev. A}, title = {Polarizability of one-dimensional soft-core atoms}, volume = {112}, year = {2025}, }
• (2025). Atom transporting and routing by crossed waveguides on a chip. PRA, 112(1), 013102. (www)

  @article{ , abstract = {The development of hybrid photonic-atomic chips (PACs) for trapping, guiding, and controlling single atoms on a chip has been limited by the lack of efficient methods for routing atoms between different optical waveguides. Here we propose an approach for extending single-waveguide atom trapping techniques to multiple-waveguide structures, enabling the realization of multiport hybrid PAC devices. We introduce inverted-rib waveguides to mitigate the scattering and interference of dipole trap lasers at waveguide crossings and utilize high-order optical waveguide modes for atom manipulation. Numerical simulations demonstrate stable atom transporting and routing using copropagating dipole trap lasers with tens of milliwatt power, providing a trap depth of 0.51 mK. This work contributes to the development of scalable PACs, opening avenues for advanced matter-wave manipulation and precision measurements.}, archive = {J_PRA}, author = {Aiping Liu and Tong Wang and Xiaofeng Jian and Pengfei Zhang and Mingkai Chen and Xifeng Ren and Chang-Ling Zou and Qin Wang}, doi = {10.1103/pdcw-c346}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013102}, shortjournal = {Phys. Rev. A}, title = {Atom transporting and routing by crossed waveguides on a chip}, volume = {112}, year = {2025}, }
• (2025). Machine-learning-constructed molecular potential and its application for exploring deep-lying-orbital effects in high-order harmonic generation. PRA, 112(1), 013101. (www)

  @article{ , abstract = {Creating a soft-Coulomb-type (SC) molecular potential within single-active-electron approximation (SAE) is essential since it allows solving the time-dependent Schrödinger equations with fewer computational resources compared to other multielectron methods. The current available SC potentials can accurately reproduce the energy of the highest occupied molecular orbital (HOMO), which is sufficient for analyzing nonlinear effects in laser-molecule interactions like high-order harmonic generation (HHG). However, recent discoveries of significant effects of deep-lying molecular orbitals call for more precise potentials to analyze them. In this study, we present a fast and accurate method based on machine learning to construct SC potentials that simultaneously reproduce various molecular features, including energies, symmetries, and dipole moments of HOMO, HOMO-1, and HOMO-2. We use this ML model to create SC SAE potentials of the HCN molecule and then comprehensively analyze the fingerprints of lower-lying orbitals in HHG spectra emitted while varying the H-CN distance. Our findings reveal that HOMO-1 plays a role in forming the second HHG plateau. Additionally, as the H-C distance increases, the plateau structure and the smoothness of HHG spectra are altered due to the redistribution of orbital electron density. These results are in line with other theoretical and experimental studies. Lastly, the machine learning approach using deconvolution and convolution neural networks in the present study is so general that it can be applied to construct a molecular potential for other molecules and molecular dynamic processes.}, archive = {J_PRA}, author = {Duong D. Hoang-Trong and Khang Tran and Doan-An Trieu and Quan-Hao Truong and Ngoc-Hung Phan and Ngoc-Loan Phan and Van-Hoang Le}, doi = {10.1103/mckv-yrg1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {013101}, shortjournal = {Phys. Rev. A}, title = {Machine-learning-constructed molecular potential and its application for exploring deep-lying-orbital effects in high-order harmonic generation}, volume = {112}, year = {2025}, }
• (2025). Time-dependent coupled-cluster theory of multireference systems. PRA, 112(1), 012825. (www)

  @article{ , abstract = {In this work we present a coupled-cluster theory for the propagation of multireference electronic systems initiating at general quantum mechanical states. Our formalism is based on the infinitesimal analysis of modified cluster operators, from which we extract a set of additional operators and their equations of motion. These cluster operators then can be used to compute electronic properties of interest in a size-extensive manner. The equations derived herein are also studied for the free propagation of linear superpositions. In this regime, we derive asymmetric matrix elements for observables, and a resymmetrization factor so they become consistent with their quantum mechanical counterparts. Our formalism is applied to a four-electron/four-level model with a Hubbard-like Hamiltonian, where we show that it reproduces the numerically exact results for observables, populations, and coherences.}, archive = {J_PRA}, author = {Martín A. Mosquera}, doi = {10.1103/y9y8-vjrv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012825}, shortjournal = {Phys. Rev. A}, title = {Time-dependent coupled-cluster theory of multireference systems}, volume = {112}, year = {2025}, }
• (2025). Bayesian approach for strong-field QED tests with he-like ions. PRA, 112(1), 012824. (www)

  @article{ , abstract = {Detailed comparisons between theory and experiment for quantum electrodynamics (QED) effects in He-like ions have been performed in the literature to search for hints of new physics. Different frequentist statistical analyses of the existing atomic transition energy data have shown contradictory conclusions as to the presence of possible deviations from the theory predictions. We present here an approach using Bayesian statistics to assign quantitative probabilities to the different deviation models from theory for He-like ions for . Potential deviations beyond the standard model or higher-order QED effects are modeled with functions. Considering the currently available data, no significant difference between theory and experiment is found, and we show that recent experiments have reduced the possible deviations previously observed in the literature. Using past measurements and a weighted average on the different deviation models, we estimate the accuracy required for future measurements to investigate possible anomalies.}, archive = {J_PRA}, author = {César Godinho and Jorge Machado and Nancy Paul and Mauro Guerra and Paul Indelicato and Martino Trassinelli}, doi = {10.1103/g5pg-85v3}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012824}, shortjournal = {Phys. Rev. A}, title = {Bayesian approach for strong-field QED tests with he-like ions}, volume = {112}, year = {2025}, }
• (2025). Role of the deposited charge in the transmission of low-energy electrons through insulating nanocapillaries. PRA, 112(1), 012823. (www)

  @article{ , abstract = {The transmission of low-energy electrons through polyethylene terephthalate nanocapillaries is studied both by experiments and simulations. It is found that the transmission of electrons with incident energy occurs mostly within the geometrically allowed angle and they exit along the incident direction. The rate of the directly transmitted electrons decreases with time and their angular distributions broaden as the incident charge increases. A tentative simulation is performed to explain the experimental results by taking into account the deposited charges on the capillary walls, the image force, and electron scattering processes. The blocking of the transmission of the electrons with the incident energy is explained to be from the formation of the attractive Coulomb field, from the opposite (positive) charge to the incident electron inside the capillaries due to the impact of the projectiles and the production of secondary electrons. The broadening of the full angular distribution for the directly transmitted electrons is attributed to the charging of the bulk of the capillary membrane. This provides evidence for the controversial issue of the production of charge patches and their role in transmitting electrons through insulating nanocapillaries.}, archive = {J_PRA}, author = {Shuai Ha and Pengfei Li and Wenming Zhang and Bo Jin and Ben Niu and Zidong Chen and Hua Yuan and Chengliang Wan and Ying Cui and Ke Yao and Yue Ma and Zhihu Yang and Reinhold Schuch and Hongqiang Zhang and Ximeng Chen}, doi = {10.1103/m1fy-8ntn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012823}, shortjournal = {Phys. Rev. A}, title = {Role of the deposited charge in the transmission of low-energy electrons through insulating nanocapillaries}, volume = {112}, year = {2025}, }
• (2025). Electronic structure calculation for superheavy elements livermorium (Lv, z=116) and tennessine (Ts, z=117) and their lighter analogs te, i, po, and at. PRA, 112(1), 012822. (www)

  @article{ , abstract = {Advanced theoretical techniques that combine the linearized coupled-cluster method, configuration-interaction method, and perturbation theory are used to calculate energy levels, ionization potentials, electron affinities, field isotope shifts, and static dipole polarizabilities of the superheavy elements Lv and Ts, along with their lighter analogs Te, I, Po, and At. Calculations for the heavy elements, Po, At, Lv, and Ts, are used to address the gaps in the experimental data. Calculations for the lighter elements, Te and I (and partly Po and At), are used to demonstrate the accuracy of the calculations.}, archive = {J_PRA}, author = {V. A. Dzuba and V. V. Flambaum and G. K. Vong}, doi = {10.1103/7nqz-3ddv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012822}, shortjournal = {Phys. Rev. A}, title = {Electronic structure calculation for superheavy elements livermorium (Lv, z=116) and tennessine (Ts, z=117) and their lighter analogs te, i, po, and at}, volume = {112}, year = {2025}, }
• (2025). Laser-fluence-dependent production of molecular thorium ions in different charge states for trapped-ion experiments. PRA, 112(1), 012821. (www)

  @article{ , abstract = {Thorium ions and molecules, recognized for their distinctive nuclear and atomic attributes, are central to numerous trapped-ion experiments globally. Our study introduces an effective, compact source of thorium atomic and molecular ions produced via laser ablation of microgram-scale, salt-based samples. We thoroughly analyze the variety of ion species and charge states generated at varying laser fluences. Utilizing 10 µ g of thorium fluoride crystals and laser fluences between 1.00(5) and 6.75(35) J/ cm 2 , we produce thorium molecular ions ThF x 232 n + (with x = 0 – 3 and charge states up to n = 3 ), including ThF 2 + and ThF 3 + . These species are particularly relevant for spectroscopy; ThF 3 + is valuable due to its stable closed-shell configuration, while ThF 2 + , which is isoelectronic to RaF, offers a unique probe for studying nuclear structure and fundamental symmetries due to its simple electronic structure with a single unpaired electron. Density-functional-theory-based calculations of the electric charge distribution aid in understanding the formation of the observed species. Positive charges are found to be mainly located on the thorium atom, which points to an inhibition of immediate Coulomb explosion, thus supporting the existence of the observed ion species. The simplicity of the method and similarities among the actinide elements suggest that our approach will also be applicable to other actinide species.}, archive = {J_PRA}, author = {TACTICa Collaboration and Jonas Stricker and Jean Velten and Valerii Andriushkov and Lennard M. Arndt and Dmitry Budker and Konstantin Gaul and Dennis Renisch and Ferdinand Schmidt-Kaler and Azer Trimeche and Lars von der Wense and Christoph E. Düllmann}, doi = {10.1103/ztxz-dwhk}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012821}, shortjournal = {Phys. Rev. A}, title = {Laser-fluence-dependent production of molecular thorium ions in different charge states for trapped-ion experiments}, volume = {112}, year = {2025}, }
• (2025). Atom-field-medium interactions. II. covariance matrix dynamics for n harmonic atoms in a dielectric-altered quantum field and effects of dielectric on atom-field entanglement. PRA, 112(1), 012820. (www)

  @article{ , abstract = {We continue our investigation of multipartite open quantum systems comprising layers of structure using the atom-field-medium interactions as a familiarly important example. Same as in Paper I [J.-T. Hsiang and B. L. Hu, Phys. Rev. A 110 , 062807 (2024) ] we consider a system of N harmonic oscillators, modeling the internal degrees of freedom (idf) of N neutral atoms interacting with a scalar quantum field altered by the presence of a dielectric medium. Different from Paper I, which uses the graded influence action formalism, here, taking advantage of the Gaussian nature of our extended system's interactions, we use the quantum Langevin equation method to calculate the time evolution of the covariance matrix elements of the quantum correlation functions of the idfs of the N system atoms in a dielectric-altered quantum field. The covariance matrix is particularly useful for extracting quantum informational properties of a Gaussian system related to quantum correlations, such as quantum entanglement. As an illustration of the method we calculate the entanglement between one system atom and the ambient quantum field outside the dielectric half-space, measured by the purity function and the von Neumann entropy. We highlight one somewhat peculiar feature in our results and one important technical issue: The special feature refers to the nonmonotonic behavior of the purity function when the atom is positioned very close to the dielectric surface. By deriving the Robertson-Schrödinger function and displaying a similar qualitative behavior under these conditions we attribute this novelty to a manifestation of the uncertainty relation. The technical issue refers to the order-reduction scheme to remove the third time derivative term in the Langevin equation for the idfs of the atom. We point out the inconsistencies in the traditional treatments and propose a new consistent scheme of order reduction for Gaussian open systems.}, archive = {J_PRA}, author = {Jen-Tsung Hsiang and Bei-Lok Hu}, doi = {10.1103/2fxz-bqq2}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012820}, shortjournal = {Phys. Rev. A}, title = {Atom-field-medium interactions. II. covariance matrix dynamics for n harmonic atoms in a dielectric-altered quantum field and effects of dielectric on atom-field entanglement}, volume = {112}, year = {2025}, }
• (2025). High-precision measurement of the 2s2pP1o1 center of gravity in neutral be9 at the parts-per-billion level. PRA, 112(1), 012819. (www)

  @article{ , abstract = {We use saturated absorption spectroscopy to study neutral atoms produced in a dc discharge lamp. Previous measurements of the state energy were limited in precision due to overlapping hyperfine structure. In this work, we apply a 400 G magnetic field, which splits the magnetic sublevels creating a spectral feature near the center-of-gravity energy of the state. We determine the transition frequency from the ground state to be , corresponding to a center-of-gravity energy of . This result is a factor of 30 more precise than the previous best measurement and constitutes the most precise determination of an excited-state energy in a four-electron system to date. As theoretical methods advance, this result will enable stringent tests of quantum electrodynamics in four-electron systems.}, archive = {J_PRA}, author = {K. J. Ahrendsen and E. M. Kay and W. D. Williams}, doi = {10.1103/8b1f-fpgq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012819}, shortjournal = {Phys. Rev. A}, title = {High-precision measurement of the 2s2pP1o1 center of gravity in neutral be9 at the parts-per-billion level}, volume = {112}, year = {2025}, }
• (2025). Momentum imaging and kinetic-energy-release measurements for various fragmentation pathways in MeV-energy proton collisions with an SO2 molecule. PRA, 112(1), 012818. (www)

  @article{ , abstract = {We have studied the ionization and fragmentation of molecular target in collision with a 1 MeV proton beam using the technique of recoil ion momentum spectroscopy. Two- and three-body fragmentation channels were observed in the Coulomb break-up of molecular ions. Kinetic-energy-release distributions were measured and compared with the available experimental and theoretical data. Dissociation pathways for three-body fragmentation of a ion resulting in ( O) and (S ) were studied in detail using Dalitz plots and Newton diagrams. We also obtained the three-dimensional momentum distribution of all fragment particles, including the neutral atom. Correlated angular distributions of the particle momenta were used to infer the geometry of the molecular ion during the fragmentation process.}, archive = {J_PRA}, author = {Sandeep Bajrangi Bari and Ranojit Das and R. Tyagi and A. H. Kelkar}, doi = {10.1103/1hy6-mczn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012818}, shortjournal = {Phys. Rev. A}, title = {Momentum imaging and kinetic-energy-release measurements for various fragmentation pathways in MeV-energy proton collisions with an SO2 molecule}, volume = {112}, year = {2025}, }
• (2025). Applications of maximum likelihood estimations for analyzing photon counts in few-atom experiments. PRA, 112(1), 012817. (www)

  @article{ , abstract = {We present a method for determining the atom number distribution of few atoms in a tight optical tweezer from their fluorescence distributions. In the tight tweezer regime, the detection light causes rapid atom loss due to light-assisted collisions. This in turn leads to non-Poissonian and overlapping fluorescence distributions for different initial atom numbers, and commonly used threshold techniques fail. We use maximum likelihood estimation algorithms to fit model distributions that account for the atom loss. This gives accurate atom number distributions for relatively few experimental runs (about 600 is sufficient) to sample a photon number distribution. We show that the method can be extended to situations when the photon number distributions for known initial atom numbers cannot be modeled, at the cost of requiring a higher number of experimental runs.}, archive = {J_PRA}, author = {M. Weyland and L. Sanchez and P. Ruksasakchai and M. F. Andersen}, doi = {10.1103/l616-hrf7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012817}, shortjournal = {Phys. Rev. A}, title = {Applications of maximum likelihood estimations for analyzing photon counts in few-atom experiments}, volume = {112}, year = {2025}, }
• (2025). Radiative corrections to the nuclear size and polarizability effects in atomic systems. PRA, 112(1), 012816. (www)

  @article{ , abstract = {We perform a complete calculation of radiative corrections to the finite nuclear size, the recoil finite size, and the nuclear polarizability effects in atomic systems. Results confirm very good agreement for the mean square charge radii difference between the deuteron and the proton, as measured in electronic and muonic isotope shifts.}, archive = {J_PRA}, author = {Krzysztof Pachucki}, doi = {10.1103/mc55-lfhj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012816}, shortjournal = {Phys. Rev. A}, title = {Radiative corrections to the nuclear size and polarizability effects in atomic systems}, volume = {112}, year = {2025}, }
• (2025). Selective reflection casimir-polder spectroscopy in vapor cells: The influence of the thermal velocity distribution. PRA, 112(1), 012815. (www)

  @article{ , abstract = {Selective reflection is a high-resolution spectroscopic method that allows the probing of atomic and molecular gases in the near field of dielectric cell windows. It is a sensitive technique for measuring interactions between excited atoms and surfaces, thus providing a unique tool to probe resonant effects in Casimir-Polder physics. The theoretical modeling of selective reflection spectra has thus far employed the infinite Doppler approximation which assumes that the Doppler shift dominates over the atom-surface interactions as well as the homogeneous transition linewidth. Here we extend the theoretical treatment of selective reflection spectra to include the effects of finite Doppler width. This allows us to analyze the regime of very large Casimir-Polder interactions, relevant for Rydberg atom spectroscopy, and revisit previous analyses of experiments with low-lying excited states. Further, this will aid in determining the signatures of quantum friction in vapor cell spectroscopy.}, archive = {J_PRA}, author = {B. Dutta and C. Boldt and G. Garcia-Arellano and M. Ducloy and P. Pedri and S. Scheel and A. Laliotis}, doi = {10.1103/pygs-cvr9}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012815}, shortjournal = {Phys. Rev. A}, title = {Selective reflection casimir-polder spectroscopy in vapor cells: The influence of the thermal velocity distribution}, volume = {112}, year = {2025}, }
• (2025). Resonance strengths and linear polarization of higher-order electronic recombination from li-like to N-like ions. PRA, 112(1), 012814. (www)

  @article{ , abstract = {A systematic investigation of resonance strengths of higher-order (HO) electronic recombination for Li-like to N-like highly charged ions with atomic numbers ranging from to 60 is carried out based on the relativistic configuration-interaction method. The calculated results are compared with the previous work of Beilmann et al. [ Phys. Rev. Lett. 107 , 143201 (2011) ], revealing significantly lower HO recombination resonance strengths for low- ions. In the present work, the correction to the HO resonance strength results from the inclusion of configuration interaction in the initial state of electronic recombination. Furthermore, the angular correction and linear polarization of HO electronic recombination are investigated to facilitate the comparison of the calculated resonance strengths with the electron-beam ion-trap measurements. An unexpected polarization behavior of dielectronic and trielectronic recombination has been shown, suggesting a promising opportunity for further study of the HO electronic recombination process.}, archive = {J_PRA}, author = {Tianluo Luo and Zhencen He and Zhihao Yang and Zhimin Hu}, doi = {10.1103/7r4g-jsx8}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012814}, shortjournal = {Phys. Rev. A}, title = {Resonance strengths and linear polarization of higher-order electronic recombination from li-like to N-like ions}, volume = {112}, year = {2025}, }
• (2025). Fast calculation of diffraction patterns from an ensemble of aligned molecules. PRA, 112(1), 012813. (www)

  @article{ , abstract = {We report an algorithm to calculate electron diffraction patterns for molecules with anisotropic angular distribution, which is significantly faster than existing methods. The algorithm uses a transform to convert the molecular orientation distribution, which is a function of three Euler angles, to the atom-pair distribution functions which depend on the polar and azimuthal angles. The diffraction signal can then be calculated from the atom-pair distributions. We demonstrate the computation method numerically by calculating electron diffraction patterns for a symmetric top molecule (trifluoroiodomethane) and an asymmetric top molecule (formaldehyde) and show that it reduces the calculation time by approximately two orders of magnitude compared to the standard brute-force method. The method can also be applied to the calculation of x-ray diffraction patterns.}, archive = {J_PRA}, author = {Yanwei Xiong and Martin Centurion}, doi = {10.1103/bz9z-btdv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012813}, shortjournal = {Phys. Rev. A}, title = {Fast calculation of diffraction patterns from an ensemble of aligned molecules}, volume = {112}, year = {2025}, }
• (2025). State-selective single- and double-electron capture in slow n4+-he collisions. PRA, 112(1), 012812. (www)

  @article{ , abstract = {State-selective single- and double-electron capture in collisions of ions with He atoms have been studied at projectile energies in the range of 20–80 keV. The state-selective single- and double-electron capture cross sections and projectile scattering angle distributions were obtained using cold-target recoil-ion momentum spectroscopy. For single-electron capture, the experimentally obtained state-selective cross sections show an obvious discrepancy with the calculated results by molecular orbital close-coupling methods and are in good agreement at a projectile energy of 20 keV with other experiments. The angular distributions are compared with calculations from the multichannel Landau-Zener model. For double-electron capture, electrons captured into states of the projectile are dominant. The angular distributions are explained by a two-step model combining the classical deflection function.}, archive = {J_PRA}, author = {Dadi Xing and Shucheng Cui and Xiaoxia Wang and Denghong Zhang and Xubin Zhu and Kaizhao Lin and Yong Gao and Dalong Guo and Dongmei Zhao and Shaofeng Zhang and Xiaolong Zhu and X. Ma}, doi = {10.1103/lgyj-yzrk}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012812}, shortjournal = {Phys. Rev. A}, title = {State-selective single- and double-electron capture in slow n4+-he collisions}, volume = {112}, year = {2025}, }
• (2025). One- and two-photon spectroscopy with a test of the kennard-stepanov relation in high-pressure two-species xenon–noble-gas mixtures. PRA, 112(1), 012811. (www)

  @article{ , abstract = {Between the absorption and the emission spectral line shapes of dense atomic and molecular media, such as dye solutions and alkali-noble buffer gas mixtures at high pressure, in many cases there exists a universal scaling, the Kennard-Stepanov relation, which is a manifestation of detailed balance. This relation plays a crucial role in recent Bose-Einstein condensation experiments of visible-spectral photons in, e.g., dye-solution-filled optical microcavities. It has recently been proposed to use high-pressure xenon–noble-gas mixtures as a thermalization medium for vacuum-ultraviolet regime photons, so as to extend the achievable wavelength range of such Bose-Einstein-condensed optical sources from the visible to the vacuum-ultraviolet regime. In this work, we report two-photon excitation spectroscopy measurements of ground-state ( ) xenon atoms subject to up to of helium or krypton buffer gas pressure, respectively, in the 220–260 nm wavelength range. The study of such two-photon spectra is of interest, e.g., for the exploration of possible pumping schemes of a future vacuum-ultraviolet photon Bose-Einstein condensate. We have also recorded absorption and emission spectra of the single-photon transition near 147 nm wavelength of xenon atoms subject to of krypton buffer gas pressure. We find that the ratio of absorption and emission shows a Kennard-Stepanov scaling, which suggests that such gas mixtures are promising candidates as a thermalization medium for a Bose-Einstein condensate of vacuum-ultraviolet photons.}, archive = {J_PRA}, author = {Eric Boltersdorf and Thilo vom Hövel and Jeremy Andrew Morín Nenoff and Frank Vewinger and Martin Weitz}, doi = {10.1103/m77f-7r1j}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012811}, shortjournal = {Phys. Rev. A}, title = {One- and two-photon spectroscopy with a test of the kennard-stepanov relation in high-pressure two-species xenon–noble-gas mixtures}, volume = {112}, year = {2025}, }
• (2025). Positronium formation and threshold behavior in positron-sodium collisions at low energies. PRA, 112(1), 012810. (www)

  @article{ , abstract = {We investigate the elastic and inelastic scattering of positrons by sodium atoms in both the ground state, and excited states, using the hyperspherical coordinate method with a model potential to represent the atomic core. The threshold behavior of positronium (Ps) formation cross sections is analyzed as the positron impact energy approaches zero. Within this framework, we derive a generalized expression for partial-wave Ps-formation cross sections at low positron energies, which applies to both ground-state and excited-state sodium targets. Our results confirm that the total threshold behavior follows the expected power-law dependence: for exothermic reactions and for endothermic reactions, where . Furthermore, we find that Ps-formation cross sections for positron scattering from excited Na states are significantly larger than those from the ground state in the low-energy region. A notable enhancement of Gailitis-Damburg oscillations is observed above the threshold, which may account for the increase observed in experimental data. Incorporating contributions from excited sodium targets improves agreement with experimental results and may help resolve discrepancies between theoretical predictions and measurements.}, archive = {J_PRA}, author = {Ning-Ning Gao and Hui-Li Han and Ting-Yun Shi}, doi = {10.1103/gc63-s6rw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012810}, shortjournal = {Phys. Rev. A}, title = {Positronium formation and threshold behavior in positron-sodium collisions at low energies}, volume = {112}, year = {2025}, }
• (2025). Comparative analysis of mg+ properties using multiconfiguration dirac-hartree-fock and relativistic coupled-cluster methods. PRA, 112(1), 012809. (www)

  @article{ , abstract = {We demonstrate behaviors of correlation effects in the calculations of atomic properties through two commonly employed many-body methods, namely the multiconfiguration Dirac-Hartree-Fock (MCDHF) and the relativistic coupled-cluster (RCC) methods. Particularly, we have benchmarked excitation energies, electric dipole (E1) matrix elements, magnetic dipole hyperfine structure constants ( ), and isotope shift (IS) constants in the singly ionized magnesium ( ) systematically at different levels of approximation of both methods. We have also estimated the E1 polarizability of the ground state and lifetimes of the excited states using the E1 matrix elements from both methods. All these results are compared with the experimental values wherever available. We find that the computed results agree well with each other with a few exceptions; in particular, the and IS constants from the RCC method are found to agree with the measurements better. This comparison analysis would be useful in evaluating the above-discussed properties in other atomic systems using the MCDHF and RCC methods more reliably.}, archive = {J_PRA}, author = {B. K. Sahoo and Per Jönsson and Gediminas Gaigalas}, doi = {10.1103/bpg7-wm48}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012809}, shortjournal = {Phys. Rev. A}, title = {Comparative analysis of mg+ properties using multiconfiguration dirac-hartree-fock and relativistic coupled-cluster methods}, volume = {112}, year = {2025}, }
• (2025). Spins extracted from fermionic states and their entanglement properties. PRA, 112(1), 012808. (www)

  @article{ , abstract = {We investigate the spin states obtained by extracting electrons from closed-shell fermionic states. A partition of the system is defined through the introduction of the extraction modes. We derive the expression of the -body reduced density matrices, which represent the extracted spin states. We show that these states exhibit different forms of spin entanglement, whose detection is discussed in terms of the spin-squeezing inequalities.}, archive = {J_PRA}, author = {Filippo Troiani and Andrea Secchi and Stefano Pittalis}, doi = {10.1103/ktdz-rsjm}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012808}, shortjournal = {Phys. Rev. A}, title = {Spins extracted from fermionic states and their entanglement properties}, volume = {112}, year = {2025}, }
• (2025). Measurement of D-line energies in sodiumlike ir. PRA, 112(1), 012807. (www)

  @article{ , abstract = {We report measurements of the and transition energies in Na-like Ir ( ). The transition energy, measured in the extreme ultraviolet (EUV) region at eV with a relative uncertainty of 29 ppm, represents one of the most precise -line energy measurements to date for high atomic numbers . The transition energy, measured in the x-ray region, is eV. Therefore, there is a fine-structure separation of eV for the Na-like Ir levels. We present theoretical calculations of these energies using quantum electrodynamic-extended relativistic many-body perturbation theory and multiple-configuration Dirac-Hartree-Fock methods, and discuss the discrepancies between experimental and theoretical values. The prospect of determining the absolute nuclear charge radii of heavy elements, including rare isotopes, from these measurements is explored.}, archive = {J_PRA}, author = {H. Staiger and G. Mondeel and S. A. Blundell and Dipti and G. O'Neil and R. Silwal and A. Lapierre and G. Gwinner and J. N. Tan and J. D. Gillaspy and Yu. Ralchenko and E. Takacs}, doi = {10.1103/xf52-d6s6}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012807}, shortjournal = {Phys. Rev. A}, title = {Measurement of D-line energies in sodiumlike ir}, volume = {112}, year = {2025}, }
• (2025). Ionization and state-selective electron capture in collisions of fully stripped and hydrogenlike oxygen ions with hydrogen atoms. PRA, 112(1), 012806. (www)

  @article{ , abstract = {The wave-packet convergent close-coupling approach has been used to model electron-capture and ionization processes occurring in collisions of and ions with atomic hydrogen. We use a model potential approach to represent the interactions with the hydrogenlike oxygen ion. We outline a method to obtain model potential parameters which provide significantly more accurate ground- and excited-state energies for the projectiles formed through electron capture than what is currently available in the literature. For both collision systems, our results for the total electron-capture cross section agree very well with one set of experimental measurements, but disagree with the other set. For the total ionization cross section, our results disagree with the classical trajectory Monte Carlo calculations. This difference is likely due to the choice of distribution used to describe the initial electron cloud in the classical calculations. We also calculate state-selective electron-capture cross sections, important for fusion plasma diagnostics and astrophysical research, resolved in terms of the final-state principal and orbital angular momentum quantum numbers. For the projectile, slight differences are observed in some of the partial cross sections when compared with other theoretical calculations, but the present results are generally in good agreement with the existing literature. At energies relevant to fusion plasma modeling, there is no state-selective data available in the literature for the collision system. The presented results fill this gap.}, archive = {J_PRA}, author = {A. M. Kotian and N. W. Antonio and A. S. Kadyrov}, doi = {10.1103/7sjx-5hrj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012806}, shortjournal = {Phys. Rev. A}, title = {Ionization and state-selective electron capture in collisions of fully stripped and hydrogenlike oxygen ions with hydrogen atoms}, volume = {112}, year = {2025}, }
• (2025). Charge-exchange dynamics in he+ and he2+ collisions with ne and ar at 0.63–1.41-a.u. velocities. PRA, 112(1), 012805. (www)

  @article{ , abstract = {We report a comprehensive study of charge-exchange dynamics in collisions of and ions with Ne and Ar targets at velocities ranging from 0.63 to 1.41 a.u. (atomic units). Using a high-voltage cylindrical mirror analyzer, we analyzed scattered ions at a fixed large scattering angle of 14°, achieving sub- -shell penetration where projectile-target separations fall below the -shell radius of the target atoms. This work bridges the gap between low-velocity quasimolecular-orbital models and high-velocity perturbative approaches. The measured ratios exhibit a strong dependence on both velocity and target species, which are quantitatively reproduced by a modified classical overbarrier model incorporating empirical corrections for screening effects. Our analysis reveals that -shell electrons dominate charge exchange at intermediate velocities due to their ultrashort orbital periods, particularly in heavy targets like Ar. Our study advances the understanding of electron dynamics in deeply penetrating ion-atom collisions and provides a valuable reference for modeling charge transfer in asymmetric systems.}, archive = {J_PRA}, author = {Xinfei Hui and Baowei Ding and Deyang Yu and Tao Guo and Xiaoxun Song and Tongmin Zhang and Long Kang and Jinyu Li and Xiaolong Zhu and Ximeng Chen}, doi = {10.1103/fvdw-jkjj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012805}, shortjournal = {Phys. Rev. A}, title = {Charge-exchange dynamics in he+ and he2+ collisions with ne and ar at 0.63–1.41-a.u. velocities}, volume = {112}, year = {2025}, }
• (2025). Doubly differential cross sections for ionization in He2++He collisions. PRA, 112(1), 012804. (www)

  @article{ , abstract = {We study the differential ionization problem using the two-electron wave-packet convergent close-coupling (WP-CCC) method. We present the results for doubly differential cross sections for ionization in terms of the angle and energy of the emitted electrons at intermediate collision energies. In this energy region, coupling between all reaction channels and electron-electron correlation effects are of considerable importance. These are fully accounted for in the WP-CCC approach. Overall, our results are in good agreement with the available experimental data and other theoretical calculations. We also discuss the saddle-point ionization mechanism for this collision system. It is concluded that this mechanism is not justified in the intermediate-energy region.}, archive = {J_PRA}, author = {Sh. U. Alladustov and K. H. Spicer and N. W. Antonio and A. M. Kotian and A. S. Kadyrov}, doi = {10.1103/g9bl-vzqv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012804}, shortjournal = {Phys. Rev. A}, title = {Doubly differential cross sections for ionization in He2++He collisions}, volume = {112}, year = {2025}, }
• (2025). Spectroscopic footprints of quantum friction in nonreciprocal and chiral media. PRA, 112(1), 012803. (www)

  @article{ , abstract = {We investigate how the quantum friction experienced by a polarizable atom moving with constant velocity parallel to a planar interface is modified when the latter consists of chiral or nonreciprocal media, with special focus on topological insulators. Macroscopic quantum electrodynamics is used to obtain the velocity-dependent Casimir-Polder frequency shift and decay rate. These results are a generalization to matter with time-reversal symmetry breaking. Our findings are illustrated by examining the nonretarded and retarded limits for five examples: a perfectly conducting mirror, a perfectly reflecting nonreciprocal mirror, a three-dimensional topological insulator, a perfectly reflecting chiral mirror, and an isotropic chiral medium. Different asymptotic power laws are found for all these materials. Interestingly, two bridges exist between chirality and nonreciprocity through the frequency shift, which arise as a consequence of the magnetoelectric coupling. Specifically, the position-dependent Casimir-Polder frequency shift for the nonreciprocal case depends on a geometric magnetic field associated with photoionization of chiral molecules, while the Casimir-Polder frequency shift depending on the velocity for the chiral case has the optical rotatory strength as the atomic response, and those for the nonreciprocal case depend on an analog of the optical rotatory strength.}, archive = {J_PRA}, author = {O. J. Franca and Fabian Spallek and Steffen M. Giesen and Robert Berger and Kilian Singer and Stefan Aull and Stefan Yoshi Buhmann}, doi = {10.1103/jhnk-tpcf}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012803}, shortjournal = {Phys. Rev. A}, title = {Spectroscopic footprints of quantum friction in nonreciprocal and chiral media}, volume = {112}, year = {2025}, }
• (2025). Systematic bayesian optimization for atomic structure calculations of heavy elements. PRA, 112(1), 012802. (www)

  @article{ , abstract = {This study presents an optimization technique for atomic structure calculations using the Flexible Atomic Code, focusing on complex multielectron systems relevant to -process nucleosynthesis and kilonova modeling. We introduce a method to optimize the fictitious mean configuration used in the Flexible Atomic Code, significantly improving the accuracy of calculated energy levels and transition properties for lanthanide and actinide ions. Our approach employs a sequential model-based optimization algorithm to refine the fictitious mean configuration, iteratively minimizing the discrepancy between calculated and experimentally determined energy levels. We demonstrate the efficacy of this method through detailed analyses of Au ii , Pt ii , Pr ii , Pr iii , Er ii , and Er iii , representing a broad range of atomic configurations. The results show substantial improvements in the accuracy of the calculated energy levels, with average relative differences to the NIST data reduced from 20–60% to 10% or less for the studied ions. Transition wavelength calculations exhibit good agreement with experimental data, with about 90% of the calculated values falling within 10% of measurements for Pr and Er ions. While improvements in the transition probability calculations are observed, the calculated radiative transition probabilities. ) values] still show significant discrepancies compared to the experimental data, with root-mean-square deviations of approximately 1.1–1.4 dex for Pr and Er ions. We extend our optimization technique to systematic calculations of singly and doubly ionised lanthanides, achieving accuracies comparable to or surpassing those of ab initio atomic structure codes. The method's broad applicability across the lanthanide series demonstrates its potential for enhancing opacity calculations and spectral modeling in astrophysical contexts.}, archive = {J_PRA}, author = {Ricardo Ferreira da Silva and Andreas Flörs and Luís Leitão and José P. Marques and Gabriel Martínez-Pinedo and Jorge M. Sampaio}, doi = {10.1103/PhysRevA.112.012802}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012802}, shortjournal = {Phys. Rev. A}, title = {Systematic bayesian optimization for atomic structure calculations of heavy elements}, volume = {112}, year = {2025}, }
• (2025). Spin manipulation and nuclear polarization enhancement in particle beams with static magnetic fields. PRA, 112(1), 012801. (www)

  @article{ , abstract = {A theoretical study of spin dynamics in nonrelativistic particle beams with interacting angular momenta traversing static, spatially varying magnetic fields is presented. The computational framework evaluates sinusoidal magnetic field configurations, calculating key observables such as average spin projections and state populations during the interaction. It is demonstrated that such fields can effectively enhance nuclear polarization in partially, incoherently polarized hydrogen and deuterium atomic beams, as well as coherently rotationally state-selected hydrogen deuteride molecular beams. This enhancement is attributed to transitions induced within the hyperfine regime of these systems. The study spans frequency ranges from gigahertz scales for atoms to hundreds of kilohertz for molecules, corresponding to magnetic field variations on spatial scales from submillimeters to meters.}, archive = {J_PRA}, author = {C. S. Kannis and R. Engels and T. El-Kordy and N. Faatz and S. J. Pütz and V. Verhoeven and T. P. Rakitzis and M. Büscher}, doi = {10.1103/4nr6-xt7m}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012801}, shortjournal = {Phys. Rev. A}, title = {Spin manipulation and nuclear polarization enhancement in particle beams with static magnetic fields}, volume = {112}, year = {2025}, }
• (2025). Spin-squeezed vector atomic magnetometry. PRA, 112(1), 012626. (www)

  @article{ , abstract = {Atomic magnetometers based on Zeeman shift measurement have the potential for high sensitivity and long-term stability. Like other atomic sensors, including atomic clocks and atom interferometers, the atomic magnetometer could, in principle, be augmented with spin squeezing for further sensitivity enhancement. However, existing atomic magnetometers are not compatible with spin squeezing because the atoms can hardly be in a pure quantum state during operation. Moreover, a natural challenge faced by an atomic magnetometer is the arbitrary direction of the magnetic field. In this paper, we propose a cold-atom-based magnetometer with spin squeezing that can measure both the magnitude and the direction of an arbitrary magnetic field. For experimentally accessible parameters, we show that the technique described above could potentially achieve a sensitivity nearly two orders of magnitude higher than that of the best existing magnetometers.}, archive = {J_PRA}, author = {Jinyang Li and Gour Pati and Renu Tripathi and Selim M. Shahriar}, doi = {10.1103/qpff-4fvz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012626}, shortjournal = {Phys. Rev. A}, title = {Spin-squeezed vector atomic magnetometry}, volume = {112}, year = {2025}, }
• (2025). Classical postprocessing approach for quantum amplitude estimation. PRA, 112(1), 012625. (www)

  @article{ , abstract = {We propose an approach for quantum amplitude estimation (QAE) designed to enhance computational efficiency while minimizing the reliance on quantum resources. Our method leverages quantum computers to generate a sequence of signals, from which the quantum amplitude is inferred through classical postprocessing techniques. Unlike traditional methods that use quantum phase estimation, which requires numerous controlled unitary operations and the quantum Fourier transform, our method avoids these complex and resource-demanding steps. By integrating quantum computing with classical postprocessing techniques, our method significantly reduces the need for quantum gates and qubits, thus optimizing the utilization of quantum hardware. We present numerical simulations to validate the effectiveness of our method and provide a comprehensive analysis of its computational complexity and error. This hybrid strategy not only improves the practicality of QAE but also broadens its applicability in quantum computing.}, archive = {J_PRA}, author = {Yongdan Yang and Ruyu Yang}, doi = {10.1103/z9hk-f37h}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012625}, shortjournal = {Phys. Rev. A}, title = {Classical postprocessing approach for quantum amplitude estimation}, volume = {112}, year = {2025}, }
• (2025). Nondemolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering. PRA, 112(1), 012624. (www)

  @article{ , abstract = {Nondemolition readout and high-fidelity unconditional reset of qubits are key requirements for practical quantum computation. For superconducting qubits, readout and reset are typically realized using resonators based on dispersive approximation. However, violations of the approximation often lead to detrimental effects on the qubit. In this work, we demonstrate nondemolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering without employing a resonator. We design and implement a planar filter to protect the qubit from energy relaxation while enhancing the relaxation of the readout transition. By appropriately selecting the readout transition, we achieve fluorescence readout with enhanced quantum nondemolitionness. We also realize fast, high-fidelity, and all-microwave unconditional reset of the fluxonium qubit. These results highlight the potential of superconducting quantum computing architectures without relying on dispersive interaction between qubits and resonators.}, archive = {J_PRA}, author = {Shu Watanabe and Kotaro Hida and Kohei Matsuura and Yasunobu Nakamura}, doi = {10.1103/gcgj-srgy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012624}, shortjournal = {Phys. Rev. A}, title = {Nondemolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering}, volume = {112}, year = {2025}, }
• (2025). Analog quantum simulation of dirac hamiltonians in circuit QED using rabi-driven qubits. PRA, 112(1), 012623. (www)

  @article{ , abstract = {Quantum simulators hold promise for solving many intractable problems. However, a major challenge in quantum simulation, and quantum computation in general, is to solve problems with limited physical hardware. Currently, this challenge is tackled by designing dedicated devices for specific models, thereby allowing one to reduce control requirements and simplify the construction. Here we suggest a method for quantum simulation in circuit QED that provides versatility in model design and complete control over its parameters with minimal hardware requirements. We show how these features manifest through examples of quantum simulation of Dirac dynamics, which is relevant to the study of both high-energy physics and two-dimensional materials. We conclude by discussing the advantages and limitations of the proposed method.}, archive = {J_PRA}, author = {Gal Gumpel and Jiwon Kang and Eliya Blumenthal and Aron Klevansky and Eunseong Kim and Shay Hacohen-Gourgy}, doi = {10.1103/wn7t-pyrq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012623}, shortjournal = {Phys. Rev. A}, title = {Analog quantum simulation of dirac hamiltonians in circuit QED using rabi-driven qubits}, volume = {112}, year = {2025}, }
• (2025). Quantum reservoir computing on random regular graphs. PRA, 112(1), 012622. (www)

  @article{ , abstract = {Quantum reservoir computing (QRC) is a low-complexity learning paradigm that combines the inherent dynamics of input-driven many-body quantum systems with classical learning techniques for nonlinear temporal data processing. Optimizing the QRC process and computing device is a complex task due to the dependence of many-body quantum systems on various factors. To explore this, we introduce a strongly interacting spin model on random regular graphs as the quantum component and investigate the interplay between static disorder, interactions, and graph connectivity, revealing their critical impact on quantum memory capacity and learnability accuracy. We tackle linear quantum and nonlinear classical tasks, and identify optimal learning and memory regimes through studying information localization, dynamical quantum correlations, and the many-body structure of the disordered Hamiltonian. In particular, we uncover the role of previously overlooked network connectivity and demonstrate how the presence of quantum correlations can significantly enhance the learning performance. Our findings thus provide guidelines for the optimal design of disordered analog quantum learning platforms.}, archive = {J_PRA}, author = {Moein N. Ivaki and Achilleas Lazarides and Tapio Ala-Nissila}, doi = {10.1103/gq9r-d5q8}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012622}, shortjournal = {Phys. Rev. A}, title = {Quantum reservoir computing on random regular graphs}, volume = {112}, year = {2025}, }
• (2025). Deterministic carving of quantum states with grover's algorithm. PRA, 112(1), 012621. (www)

  @article{ , abstract = {We show that iteration of a few ( ∼ N 1 / 4 ) unitary steps of Grover's algorithm suffices to perfectly prepare a Dicke state of N atoms in a cavity. We also show that a few subsequent Grover steps can be employed to generate GHZ and Cat states. The Grover iteration is physically realized by global qubit rotations and by the phase shift of single photons reflected on the cavity. Our protocols are deterministic and require no individual addressing of the atoms. A detailed error analysis accounting for spatial mode matching of the photon to the cavity, spontaneous emission, mirror scattering, and the finite bandwidth of the photon mode is used to predict the fidelity of the prepared states as a function of system parameters and atom-cavity cooperativity. The fidelity can be increased by heralding on detection of the reflected photon.}, archive = {J_PRA}, author = {Omar Nagib and M. Saffman and K. Mølmer}, doi = {10.1103/s3vs-xz7w}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012621}, shortjournal = {Phys. Rev. A}, title = {Deterministic carving of quantum states with grover's algorithm}, volume = {112}, year = {2025}, }
• (2025). Hybrid quantum simulations with qubits and qumodes on trapped-ion platforms. PRA, 112(1), 012620. (www)

  @article{ , abstract = {We explore the feasibility of gate-based hybrid quantum computing using both discrete (qubit) and continuous (qumode) variables on trapped-ion platforms. Trapped-ion systems have demonstrated record one- and two-qubit gate fidelities and long qubit coherence times, while qumodes, which can be represented by the collective vibrational modes of the ion chain, have remained relatively unexplored for their use in computing. Using numerical simulations, we show that high-fidelity hybrid gates and measurement operations can be achieved for existing trapped-ion quantum platforms. As an exemplary application, we consider quantum simulations of the Jaynes-Cummings-Hubbard model, which is given by a one-dimensional chain of interacting spin and boson degrees of freedom. Using classical simulations, we study its real-time evolution and develop a suitable variational quantum algorithm for ground-state preparation. Our results should motivate further studies of hybrid quantum computing in this context, which may lead to direct applications in condensed-matter and fundamental particle and nuclear physics.}, archive = {J_PRA}, author = {Jack Y. Araz and Matt Grau and Jake Montgomery and Felix Ringer}, doi = {10.1103/kbv4-jj51}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012620}, shortjournal = {Phys. Rev. A}, title = {Hybrid quantum simulations with qubits and qumodes on trapped-ion platforms}, volume = {112}, year = {2025}, }
• (2025). Boson sampling validation approach by examining the sample space filling. PRA, 112(1), 012619. (www)

  @article{ , abstract = {Achieving a quantum computational advantage regime, and thus providing evidence against the extended Church-Turing thesis, remains one of the key challenges in modern science. Boson sampling seems to be a very promising platform in this regard, but to be confident of attaining the advantage regime, one must provide evidence of operating with the correct boson sampling distribution, and not with any of the distributions that admit efficient classical simulation. This problem is often called the validation problem, and it poses a major challenge to demonstrating unambiguous quantum advantage. In this work, using the recently proposed wave-function network approach, we study the sample space filling behavior with increasing the number of collected samples. We show that this allows for black-box data to exclude several undesired hypotheses, especially the distinguishable particles sampling. At this point, reference values corresponding to the true distribution are still required for the presented approach to be considered a complete validation protocol. Nevertheless, we show that it can instead be used for simple and efficient validation against a trusted sampling device. We also study the scaling of our approach with system size and under imperfections such as losses. These results highlight the potential of sample space filling analysis for addressing the validation problem.}, archive = {J_PRA}, author = {A. A. Mazanik and A. N. Rubtsov}, doi = {10.1103/s467-pqyf}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012619}, shortjournal = {Phys. Rev. A}, title = {Boson sampling validation approach by examining the sample space filling}, volume = {112}, year = {2025}, }
• (2025). Entanglement-assisted private communication over a classical-quantum multiple-access channel. PRA, 112(1), 012618. (www)

  @article{ , abstract = {We consider entanglement-assisted private communication over a classical-quantum multiple-access channel with two senders and a single receiver. We initially determine the capacity region where senders and receiver share unlimited entanglement resources. In this setting, each sender performs an encoding measurement on their share of the entangled state to transmit a measurement outcome via the classical-quantum multiple-access channel. Meanwhile, the receiver applies a decoding operation to both the channel's output state and their share of the entangled state. We further derive the private capacity. Moreover, we consider the capacity region and private capacity when entanglement is shared between only the two senders. This corresponds to a quantum extension of the classical multiple-access channel with entanglement. Significantly, we show that the capacity region when both senders share entanglement with the receiver is strictly larger than when only the two senders share the entanglement.}, archive = {J_PRA}, author = {Xiaomin Liu and Fangyuan Chen and Zhengjun Xi}, doi = {10.1103/2gbl-yb3v}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012618}, shortjournal = {Phys. Rev. A}, title = {Entanglement-assisted private communication over a classical-quantum multiple-access channel}, volume = {112}, year = {2025}, }
• (2025). Dissipation-assisted steady-state entanglement engineering based on electron transfer models. PRA, 112(1), 012617. (www)

  @article{ , abstract = {We propose a series of dissipation-assisted entanglement generation protocols that can be implemented on a trapped-ion quantum simulator. Our approach builds on the single-site molecular electron transfer (ET) model recently realized in experiment [So et al. , Sci. Adv. 10 , eads8011 (2024) ]. This model leverages spin-dependent boson displacement and dissipation controlled by sympathetic cooling. We show that, when coupled to external degrees of freedom, the ET model can be used as a dissipative quantum control mechanism, enabling the precise tailoring of both spin and boson steady states of a target subsystem. We derive simplified analytical formalisms that offer intuitive insights into the dissipative dynamics. Using realistic interactions in a trapped-ion system, we develop a protocol for generating N -qubit and N -boson W states. Additionally, we generalize this protocol to realize generic N -qubit Dicke states with tunable excitation numbers. Finally, we outline a realistic experimental setup to implement our schemes in the presence of noise sources.}, archive = {J_PRA}, author = {Mingjian Zhu and Visal So and Guido Pagano and Han Pu}, doi = {10.1103/9sr4-3jz2}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012617}, shortjournal = {Phys. Rev. A}, title = {Dissipation-assisted steady-state entanglement engineering based on electron transfer models}, volume = {112}, year = {2025}, }
• (2025). Finite-key analysis of high-dimensional quantum key distribution utilizing a subset of the monitoring states. PRA, 112(1), 012616. (www)

  @article{ , abstract = {High-dimensional quantum key distribution (HD-QKD) offers high photon information efficiency and robust noise tolerance. Furthermore, Islam et al. [ Phys. Rev. A 97 , 042347 (2018) ] proposed a variant of the HD-QKD protocol that can generate secret keys using any subset of monitoring states. However, there is a gap in the analysis of this protocol under finite-key scenarios, which is crucial for the practicality of any QKD protocol. In this work, we conduct a finite-key analysis of this protocol within the universally composable framework. Additionally, we analyze the performance of this protocol in actual experimental scenarios. The simulation results demonstrate that the protocol remains practical even with finite resources.}, archive = {J_PRA}, author = {Zhengeng Zhao and Yongqiang Du and Wei Li and Kejin Wei}, doi = {10.1103/hrk5-zbzy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012616}, shortjournal = {Phys. Rev. A}, title = {Finite-key analysis of high-dimensional quantum key distribution utilizing a subset of the monitoring states}, volume = {112}, year = {2025}, }
• (2025). Nonlinear protocol for high-dimensional quantum teleportation. PRA, 112(1), 012615. (www)

  @article{ , abstract = {Bell measurements, which allow entanglement between uncorrelated distant particles, play a central role in quantum communication. Indeed, sharing, measuring, and creating entanglement lie at the core of various protocols, such as entanglement swapping and quantum teleportation. While for optical qubit systems a Bell measurement can be implemented using only linear components, the same result is no longer true for high-dimensional states, where one has to consider either auxiliary photons or nonlinear processes. Here, inspired by the latter approach, we propose a protocol for high-dimensional quantum teleportation based on nonlinear techniques. Moreover, we discuss the practical implementation of our proposed setup in the case of path-encoded qutrits, where nonlinear effects arise from sum-frequency generation. Finally, we compute the fidelity between quantum states to benchmark the validity of our model under the presence of crosstalk noise. Our approach is deterministic, versatile, and does not rely on the use of auxiliary photons, thus paving the way towards the practical implementation of quantum networks based on nonlinear effects.}, archive = {J_PRA}, author = {Luca Bianchi and Carlo Marconi and Giulia Guarda and Davide Bacco}, doi = {10.1103/3x44-664w}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012615}, shortjournal = {Phys. Rev. A}, title = {Nonlinear protocol for high-dimensional quantum teleportation}, volume = {112}, year = {2025}, }
• (2025). Real-time scattering processes with continuous-variable quantum computers. PRA, 112(1), 012614. (www)

  @article{ , abstract = {We propose a framework for simulating the real-time dynamics of quantum field theories using continuous-variable quantum computing (CVQC). Focusing on ( 1 + 1 )-dimensional φ 4 scalar field theory, the approach employs the Hamiltonian formalism to map the theory onto a spatial lattice, with fields represented as quantum harmonic oscillators. Using measurement-based quantum computing, we implement non-Gaussian operations for CQVC platforms. The study introduces methods for preparing initial states with specific momenta and simulating their evolution under the φ 4 Hamiltonian. Key quantum objects, such as two-point correlation functions, validate the framework against analytical solutions. Scattering simulations further illustrate how mass and coupling strength influence field dynamics and energy redistribution. Thus, we demonstrate CVQC's scalability for larger lattice systems and its potential for simulating more complex field theories.}, archive = {J_PRA}, author = {Steven Abel and Michael Spannowsky and Simon Williams}, doi = {10.1103/q36d-w649}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012614}, shortjournal = {Phys. Rev. A}, title = {Real-time scattering processes with continuous-variable quantum computers}, volume = {112}, year = {2025}, }
• (2025). Spin contrast, finite temperature, and noise in matter-wave interferometers. PRA, 112(1), 012613. (www)

  @article{ , abstract = {In this paper, we will show how finite-temperature corrections and spin-dependent/independent noise will affect the contrast in a matter-wave interferometer, especially with massive objects and large spatial superposition sizes. Typically, spin is embedded in a nanoparticle as a defect, which can be manipulated by the external magnetic field to create a macroscopic quantum superposition. These massive matter-wave interferometers are the cornerstone for many new fundamental advancements in physics; particularly, macroscopic quantum superposition can use entanglement features to, e.g., test physics beyond the Standard Model, test the equivalence principle, improve quantum sensors, and test the quantum nature of spacetime in a laboratory. We will consider a Stern-Gerlach-type apparatus to create macroscopic quantum superposition in a harmonic oscillator trap, and figure out the spin contrast loss due to linear spin-independent and spin-dependent noise in a single interferometer. We will show that spin contrast loss due to spin-independent noise does not depend on the initial thermal state of the matter wave function. However, spin contrast loss due to spin-dependent fluctuations is dependent on the initial thermal occupation of the quantum state. We will keep our discussion general as far as the noise parameters are concerned.}, archive = {J_PRA}, author = {Tian Zhou and Ryan Rizaldy and Martine Schut and Anupam Mazumdar}, doi = {10.1103/dbrs-wn92}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012613}, shortjournal = {Phys. Rev. A}, title = {Spin contrast, finite temperature, and noise in matter-wave interferometers}, volume = {112}, year = {2025}, }
• (2025). Generalized numerical framework for improved finite-sized key rates with rényi entropy. PRA, 112(1), 012612. (www)

  @article{ , abstract = {Quantum key distribution requires tight and reliable bounds on the secret key rate to ensure robust security. This is particularly so for the regime of finite block sizes, where the optimization of generalized Rényi entropic quantities is known to provide tighter bounds on the key rate. However, such an optimization is often nontrivial. In this work, we present an analytical bound on the Rényi entropy in terms of the Rényi divergence and derive the analytical gradient of the Rényi divergence. This enables us to generalize existing state-of-the-art numerical frameworks for the optimization of key rates. With this generalized framework, we show improvements in regimes of high loss and low block sizes, which are particularly relevant for long-distance satellite-based protocols.}, archive = {J_PRA}, author = {Rebecca R. B. Chung and Nelly H. Y. Ng and Yu Cai}, doi = {10.1103/tyts-8v8j}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012612}, shortjournal = {Phys. Rev. A}, title = {Generalized numerical framework for improved finite-sized key rates with rényi entropy}, volume = {112}, year = {2025}, }
• (2025). Continuous-variable quantum teleportation, u(2)-invariant squeezing, and non-gaussian resource states. PRA, 112(1), 012611. (www)

  @article{ , abstract = {We investigate the role of quadrature squeezing in the quantum teleportation protocol for coherent states using non-Gaussian resource states. For two-mode systems, the non-Gaussian resource states that we use are obtained with an experimentally realizable scheme of photon subtraction, photon addition, and photon catalysis on the two-mode squeezed vacuum and two-mode squeezed thermal states. We first analyze the nonclassical attribute of quadrature squeezing in these generated non-Gaussian states using the -invariant squeezing approach, which allows us to account for all possible quadratures. We then show that the presence of such nonclassicality in non-Gaussian resource states is not necessary for successful quantum teleportation, a finding which is at variance with an earlier proposition in this direction. This result is important since it demonstrates how nonclassicality other than quadrature squeezing present in the resource can be utilized for quantum teleportation.}, archive = {J_PRA}, author = {Mohak Sharma and Chandan Kumar and Shikhar Arora and Arvind}, doi = {10.1103/w71d-smt1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012611}, shortjournal = {Phys. Rev. A}, title = {Continuous-variable quantum teleportation, u(2)-invariant squeezing, and non-gaussian resource states}, volume = {112}, year = {2025}, }
• (2025). Binned-detector probability distributions for gaussian boson sampling validation. PRA, 112(1), 012610. (www)

  @article{ , abstract = {Gaussian boson sampling (GBS), a computational problem conjectured to be hard to simulate on a classical machine, has been at the forefront of recent years' experimental and theoretical efforts to demonstrate quantum advantage. The classical intractability of the sampling task makes validating these experiments a challenging and essential undertaking. In this paper, we propose binned-detector probability distributions as a suitable quantity to statistically validate GBS experiments employing photon-number-resolving detectors. We develop the theoretical framework to compute such distributions by leveraging their connection with their respective characteristic function. The latter may be efficiently and analytically computed for squeezed input states as well as for relevant classical hypothesis like squashed states. Our theoretical framework encompasses other validation methods based on marginal distributions and correlation functions. Additionally, it can analytically accommodate various sources of noise, such as losses and partial distinguishability, a feature that has received limited attention within the GBS framework so far. We also derive how binned-detector probability distributions behave when Haar averaged over all possible interferometric networks, extending known results for Fock boson sampling.}, archive = {J_PRA}, author = {Gabriele Bressanini and Benoit Seron and Leonardo Novo and Nicolas J. Cerf and M. S. Kim}, doi = {10.1103/jqvf-pm1r}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012610}, shortjournal = {Phys. Rev. A}, title = {Binned-detector probability distributions for gaussian boson sampling validation}, volume = {112}, year = {2025}, }
• (2025). Robust implicit quantum control of interacting spin chains. PRA, 112(1), 012609. (www)

  @article{ , abstract = {Robust quantum control can achieve noise resilience of quantum systems and quantum technological devices. While the need for noise resilience grows with the number of fluctuating quantities, and thus typically with the number of qubits, most numerically exact optimal control techniques are limited to systems of few interacting qubits. This paper exploits quantum control that avoids explicit reference to quantum states in exponentially large Hilbert space. Exemplary control protocols for spin chains are discussed in terms of noise-resilient preparation of highly entangled states.}, archive = {J_PRA}, author = {Luca Stefanescu and Louis Edwards-Pratt and Jeremy O'Connor and Ezra Tsegaye and Nguyen H. Le and Florian Mintert}, doi = {10.1103/zmcn-ddkj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012609}, shortjournal = {Phys. Rev. A}, title = {Robust implicit quantum control of interacting spin chains}, volume = {112}, year = {2025}, }
• (2025). Noise-resistant phonon operations in a hybrid superconducting circuit-mechanical resonator system. PRA, 112(1), 012608. (www)

  @article{ , abstract = {Hybrid systems consisting of superconducting circuits and mechanical resonators are a promising platform for quantum technologies. However, realizing high-performance preparation and manipulation of phonon states remains an outstanding challenge due to the complex energy levels and interactions of hybrid systems. Here, we propose a noise-resistant phonon manipulation scheme. Using engineered superconducting-resonator dispersive interactions, we tailor a control sequence combined with dynamical decoupling pulses, which forms the basis for a universal set of phonon gate operations. Using this gate design, we demonstrate the preparation of Schrödinger cat states of phonons, the creation of complex phonon superposition states, and the encoding and transfer of quantum information into phonon states. In addition, we show that the fidelity of the state preparation can reach 95% under realistic parameters and that these designs significantly reduce the error effects compared to existing schemes. These results provide a complete toolbox for superconducting-mechanics hybrid systems.}, archive = {J_PRA}, author = {Le-Tian Zhu and Xing-Yu Zhu and Guang-Can Guo and Tao Tu and Chuan-Feng Li}, doi = {10.1103/41jh-w6ft}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012608}, shortjournal = {Phys. Rev. A}, title = {Noise-resistant phonon operations in a hybrid superconducting circuit-mechanical resonator system}, volume = {112}, year = {2025}, }
• (2025). Efficient quantum circuit execution with continuous distribution of entanglement. PRA, 112(1), 012607. (www)

  @article{ , abstract = {In recent years, the rapid development of quantum networks and distributed quantum clusters has created new opportunities to implement large-scale quantum algorithms. However, this advancement also presents a significant challenge: efficiently executing quantum programs based on entanglement distribution protocols within quantum clusters. This paper analyzes existing entanglement distribution protocols in the context of distributed quantum circuit execution, focusing on the on-demand distribution of entanglement (on-demand protocols) and the continuous distribution of entanglement (CD protocols). We define the min-depth qubit mapping and scheduling problem within the CD protocols, and we propose a systematic solution that encompasses protocol analysis, circuit partitioning and mapping, and remote operation scheduling. Furthermore, we introduce a connectivity-first swapping (CFS) scheme that outperforms the single random swap (SRS) scheme in the execution of distributed quantum circuits in most cases. Extensive evaluations demonstrate the effectiveness of our algorithms, achieving significant reductions in circuit execution times of 52.4%, 49.9%, and 53.1% in clusters with average bandwidths of 1, 3, and 5, respectively. The CFS protocol further enhances performance, reducing execution time by 24.5%, 19.7%, and 17.8% compared to the SRS protocol. Our method also reduces entanglement costs, decreasing consumption by an average of 20.3% compared to the baseline method at an average bandwidth of 3, while the CFS protocol further reduces costs by 11.5% compared to the SRS protocol.}, archive = {J_PRA}, author = {Hao Fu and Fangzheng Chen and Mingzheng Zhu and Chi Zhang and Jun Wu and Wei Xie and Xiang-Yang Li}, doi = {10.1103/3xc7-j3mn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012607}, shortjournal = {Phys. Rev. A}, title = {Efficient quantum circuit execution with continuous distribution of entanglement}, volume = {112}, year = {2025}, }
• (2025). Self-testing supersinglets with perfect quantum strategies. PRA, 112(1), 012606. (www)

  @article{ , abstract = {Supersinglets are states of spin zero of particles of levels. They are invariant under unitary transformations of the form and have applications in metrology, error protection, and communication. They also violate some specific Bell inequalities. However, none any of these applications require supersinglets nor do any of these Bell inequality violations capture the unique properties of the supersinglets. This leads to two questions. Question 1 is whether there exists a task that can be solved only with supersinglets. Question 2 is whether supersinglets can produce a unique -partite, -dimensional nonlocal signature. We answer both questions affirmatively by presenting a protocol that self-test all supersinglets by producing -partite, -dimensional perfect quantum strategies for any .}, archive = {J_PRA}, author = {Debashis Saha and Adán Cabello}, doi = {10.1103/3ymw-sn2z}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012606}, shortjournal = {Phys. Rev. A}, title = {Self-testing supersinglets with perfect quantum strategies}, volume = {112}, year = {2025}, }
• (2025). Robust, fast, and high-fidelity composite single-qubit gates for superconducting transmon qubits. PRA, 112(1), 012605. (www)

  @article{ , abstract = {We introduce a quantum control method for superconducting transmon qubits that substantially outperforms conventional techniques in precision and robustness against coherent errors. Our approach leverages composite pulses (CPs) to effectively mitigate system-specific errors, such as qubit frequency and anharmonicity variations. By utilizing CPs, we demonstrate both complete and partial population transfers between qubit states, as well as the implementation of two essential single-qubit quantum gates. Simulations reveal substantial reductions in common error rates and gate durations. The effectiveness of our method is validated through four independent verification techniques, underscoring its potential for advancing quantum computing with superconducting qubits.}, archive = {J_PRA}, author = {Hristo G. Tonchev and Boyan T. Torosov and Nikolay V. Vitanov}, doi = {10.1103/s7h1-lqc1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012605}, shortjournal = {Phys. Rev. A}, title = {Robust, fast, and high-fidelity composite single-qubit gates for superconducting transmon qubits}, volume = {112}, year = {2025}, }
• (2025). Fluctuation as a probe of entanglement transition in a monitored free-fermion chain. PRA, 112(1), 012604. (www)

  @article{ , abstract = {We investigate the measurement-induced entanglement transition (MIET) in a free-fermion chain under continuous measurements, using fluctuation as a scalable and accessible probe. The bipartite fluctuation of particle number within the subsystem is demonstrated to exhibit behaviors analogous to that of entanglement entropy. It effectively captures the nonequilibrium entanglement dynamics, as well as the transition in steady states from the critical phase with subextensive growth law to the area-law phase. By performing finite-size scaling analysis, we identify the critical measurement strength and demonstrate that the fluctuation can serve as a reliable indicator of the MIET. The results are consistent with previous entanglement entropy studies and reveal that the MIET belongs to the Berezinskii-Kosterlitz-Thouless universality class. Even when there are long-range hoppings or disorders, the fluctuation still acts as a reliable probe for the MIET. This approach offers a practical alternative to directly measuring entanglement entropy in monitored free-fermion chains, particularly for larger systems.}, archive = {J_PRA}, author = {Wen-Jie Qiu and Yi-Cong Yu and Xiaoming Cai}, doi = {10.1103/ps1h-ftfw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012604}, shortjournal = {Phys. Rev. A}, title = {Fluctuation as a probe of entanglement transition in a monitored free-fermion chain}, volume = {112}, year = {2025}, }
• (2025). Quantum monte carlo methods and stabilizer states. PRA, 112(1), 012603. (www)

  @article{ , abstract = {The quantum Monte Carlo technique known as the stochastic series expansion (SSE) relies on a crucial no-branching condition: the SSE sampling is carried out in the computational basis, and the no-branching assumption ensures that superpositions of basis states do not appear when operators are applied. Without this proviso, the number of complex amplitudes would grow exponentially with the number of qubits and would eventually overwhelm the memory and processing power of a classical computer. However, the action of Clifford group elements on stabilizer states can be very efficiently described without resorting to an amplitude description. We explore how stabilizer states allow an extension of the SSE technique, and we give an example of a toy model that can be studied in this way. The method is also illustrated using the transverse-field Ising model.}, archive = {J_PRA}, author = {Bhilahari Jeevanesan}, doi = {10.1103/8jmy-sj3f}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012603}, shortjournal = {Phys. Rev. A}, title = {Quantum monte carlo methods and stabilizer states}, volume = {112}, year = {2025}, }
• (2025). Short-time simulation of quantum dynamics by pauli measurements. PRA, 112(1), 012602. (www)

  @article{ , abstract = {Simulating the dynamics of complex quantum systems is a central application of quantum devices. Here we propose leveraging the power of measurements to simulate short-time quantum dynamics of physically prepared quantum states in classical postprocessing using a truncated Taylor series approach. While limited to short simulation times, our hybrid quantum-classical method is equipped with rigorous error bounds. It is extendable to estimate low-order Taylor approximations of smooth time-dependent functions of tractable linear combinations of measurable operators. These insights can be made use of in the context of Hamiltonian learning and device verification, short-time imaginary-time evolution, or the application of intractable operations to subuniversal quantum simulators in classical postprocessing.}, archive = {J_PRA}, author = {Paul K. Faehrmann and Jens Eisert and Mária Kieferová and Richard Kueng}, doi = {10.1103/6ggs-y392}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012602}, shortjournal = {Phys. Rev. A}, title = {Short-time simulation of quantum dynamics by pauli measurements}, volume = {112}, year = {2025}, }
• (2025). Dephasing-induced leakage in multilevel superconducting quantum circuits. PRA, 112(1), 012601. (www)

  @article{ , abstract = {Superconducting quantum circuits, such as the transmon, have multiple quantum states beyond the computational subspace. These states can be populated during quantum logic operations; residual population in such states is known as leakage. While control methods can eliminate this error in ideal systems, in the presence of dephasing, transient population leads to leakage. This dephasing-induced leakage effect is analyzed, both analytically and numerically, for common single- and two-qubit operations used in transmon-based approaches to quantum information processing.}, archive = {J_PRA}, author = {Frederick W. Strauch}, doi = {10.1103/4kkq-x5km}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012601}, shortjournal = {Phys. Rev. A}, title = {Dephasing-induced leakage in multilevel superconducting quantum circuits}, volume = {112}, year = {2025}, }
• (2025). Transfer learning for a deep-unfolded combinatorial optimization solver with quantum annealer. PRA, 112(1), 012431. (www)

  @article{ , abstract = {Quantum annealing (QA) has attracted research interest as a sampler and combinatorial optimization problem (COP) solver. A recently proposed sampling-based solver for QA significantly reduces the required number of qubits, being capable of large COPs. In relation to this, a trainable sampling-based COP solver has been proposed that optimizes its internal parameters from a dataset by using a deep-learning technique called deep unfolding. Although learning the internal parameters accelerates the convergence speed, the sampler in the trainable solver is restricted to using a classical sampler owing to the training cost. In this study, to utilize QA in the trainable solver, we propose classical-quantum transfer learning, in which parameters are trained classically, and the learned parameters are used in the solver with QA. The results of numerical experiments demonstrate that the trainable quantum COP solver using classical-quantum transfer learning improves convergence speed and execution time compared with the original solver.}, archive = {J_PRA}, author = {Ryo Hagiwara and Shunta Arai and Satoshi Takabe}, doi = {10.1103/d3sc-3wkj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012431}, shortjournal = {Phys. Rev. A}, title = {Transfer learning for a deep-unfolded combinatorial optimization solver with quantum annealer}, volume = {112}, year = {2025}, }
• (2025). Detecting spacelike vacuum entanglement at all distances and promoting negativity to a necessary and sufficient entanglement measure in many-body regimes. PRA, 112(1), 012430. (www)

  @article{ , abstract = {Though known to be present, the accessibility of spacelike vacuum entanglement capable of being a fundamental resource for quantum information processing has remained in question at distances beyond the scale of vacuum fluctuations in massive fields. For a broad subclass of physical many-body mixed Gaussian states, including the free scalar field vacuum, the logarithmic negativity is here shown to be a necessary and sufficient measure of entanglement and to be entirely accessible by pairs of single-mode detectors in the continuum. By deriving exact and optimal detection profiles, entanglement resources in the massive field are demonstrated to be available at all distances.}, archive = {J_PRA}, author = {Boyu Gao and Natalie Klco}, doi = {10.1103/m9w1-ppqz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012430}, shortjournal = {Phys. Rev. A}, title = {Detecting spacelike vacuum entanglement at all distances and promoting negativity to a necessary and sufficient entanglement measure in many-body regimes}, volume = {112}, year = {2025}, }
• (2025). Nonreciprocal charging in a quantum battery via a mediator. PRA, 112(1), 012429. (www)

  @article{ , abstract = {Nonreciprocal quantum batteries, leveraging unidirectional energy transfer from charger to battery, demonstrate enhanced energy storage efficiency through their inherent directionality. We present an optimized nonreciprocal quantum battery architecture incorporating a quantum mediator between the battery and the charger to catalyze energy transfer. This mediator-enabled design significantly improves upon conventional direct-coupling configurations. Through comparative analysis of two distinct driving protocols (classical coherent driving versus quadratic temporal pulse excitation), we establish fundamental performance criteria for mediator-enhanced nonreciprocal quantum battery. Our results indicate that this proposed model expresses superior advantages over the previous conventional battery models without adding a mediator between the battery and the charger. Furthermore, we observe that under the classical driving, the decay rates of the charger and the battery could influence the relationship between the battery performance and the spectral width of the shared reservoir. Specifically, when the decay rates are weak, the battery performance and the spectral width of the shared reservoir would show a negative correlation. However, as the decay rates increase, this relationship would shift to a positive correlation. In contrast, under quadratic temporal pulse, the spectral width and the battery performance could represent a consistent positive correlation regardless of the decay rates of the charger and the battery.}, archive = {J_PRA}, author = {Cheng-Ze Sun and Zai-Kun Wang and Wei-Bin Yan and Ying-Jie Zhang and Zhong-Xiao Man and Qing-Yu Cai}, doi = {10.1103/p93y-jflt}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012429}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal charging in a quantum battery via a mediator}, volume = {112}, year = {2025}, }
• (2025). Experimental robust certification of the maximally entangled state via nonprojective measurements. PRA, 112(1), 012428. (www)

  @article{ , abstract = {Entanglement is fundamental to quantum mechanics, and accurate certification of entangled states in a device-independent manner is crucial to the functioning of secure quantum information processing. Previous research on entanglement certification primarily relies on projective measurements, while experimental certification of entangled states based on nonprojective measurements remains an unexplored area. In this work, we experimentally certify the two-qubit maximally entangled state using three-outcome nonprojective measurements in the one-sided device-independent scenario. Based on the maximal violation of steering inequality, we can experimentally self-test both the maximally entangled state and the nonprojective measurements performed by the untrusted party. Furthermore, we also experimentally demonstrate that this approach is highly robust when white noise is introduced into the states and measurements. Our work enables further insight into the quantum state certification with nonprojective measurements.}, archive = {J_PRA}, author = {Meng-Yun Ma and Chao-Jie Sun and Xu Xu and Kai-Mei Zheng and Han-Yu Cheng and Qi-Ping Su and Chui-Ping Yang and Yong-Nan Sun}, doi = {10.1103/qs8r-kjms}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012428}, shortjournal = {Phys. Rev. A}, title = {Experimental robust certification of the maximally entangled state via nonprojective measurements}, volume = {112}, year = {2025}, }
• (2025). Complementarity relations in a multipath interferometer with quantum memory. PRA, 112(1), 012427. (www)

  @article{ , abstract = {Complementarity relations impose constraints on different aspects of quantum states. We study the complementarity relation within a multipath interferometer that includes detectors and quantum memory. We consider mixed states as the input states. We establish a duality relation between the visibility and the path distinguishability. Based on this duality, two triality relations are derived, one related to visibility, path distinguishability, and mixedness and the other related to visibility, path distinguishability, and entanglement. Therefore, the role of entanglement in multipath interferometer is characterized quantitatively. These complementarity relations are all complete for the two-path interferometer.}, archive = {J_PRA}, author = {Yue Sun and Ming-Jing Zhao and Peng-Tong Li}, doi = {10.1103/ms72-2mzb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012427}, shortjournal = {Phys. Rev. A}, title = {Complementarity relations in a multipath interferometer with quantum memory}, volume = {112}, year = {2025}, }
• (2025). Separable ellipsoids around multipartite states. PRA, 112(1), 012426. (www)

  @article{ , abstract = {We show that in finite dimensions, around any -partite product state , there exists an ellipsoid of separable states centered around . This separable ellipsoid contains the separable ball proposed in previous works, and the volume of the ellipsoid is typically exponentially larger than that of the ball due to the hierarchy of eigenvalues in typical states. We further generalize this ellipsoidal criterion to a trace formula that yields separable region around all separable states, and further study biseparability. Our criteria not only help numerical procedures to rigorously detect separability, but they also lead to a nested hierarchy of stochastic local operations and classiccal communication (SLOCC)-stable subsets that cover the separable set. We apply the procedure for separability detection to three-qubit X states, genuinely entangled four-qubit states mixed with noise, and the one-dimensional transverse-field Ising model at finite temperature to illustrate the power of our procedure for understanding entanglement in physical systems.}, archive = {J_PRA}, author = {Robin Y. Wen and Gilles Parez and Liuke Lyu and William Witczak-Krempa and Achim Kempf}, doi = {10.1103/tyhj-1wlq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012426}, shortjournal = {Phys. Rev. A}, title = {Separable ellipsoids around multipartite states}, volume = {112}, year = {2025}, }
• (2025). Nonstabilizerness entanglement entropy: A measure of hardness in the classical simulation of quantum many-body systems with tensor network states. PRA, 112(1), 012425. (www)

  @article{ , abstract = {Classical and quantum states can be distinguished by entanglement entropy, which can be viewed as a measure of quantum resources. Entanglement entropy also plays a pivotal role in understanding computational complexity in simulating quantum systems, especially in tensor network states related methods. However, stabilizer states formed solely by Clifford gates can be efficiently simulated with the tableau algorithm according to the Gottesman-Knill theorem, although they can host large entanglement entropy. In this work, we introduce the concept of nonstabilizerness entanglement entropy which is basically the minimum residual entanglement entropy for a quantum state by excluding the contribution from Clifford circuits. It can serve as a new practical measure of difficulty in the classical simulation of quantum many-body systems, which takes both entanglement and nonstabilizerness into consideration. We discuss why it is a better criterion than previously proposed metrics such as stabilizer Rényi entropy when measuring the difficulty in the classical simulation with tensor network states related method. We also show numerical results of nonstabilizerness entanglement entropy with concrete quantum many-body models. The concept of nonstabilizerness entanglement entropy expands our understanding of the “hardness” in the classical simulation of quantum many-body systems.}, archive = {J_PRA}, author = {Jiale Huang and Xiangjian Qian and Mingpu Qin}, doi = {10.1103/gxdn-zwrw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012425}, shortjournal = {Phys. Rev. A}, title = {Nonstabilizerness entanglement entropy: A measure of hardness in the classical simulation of quantum many-body systems with tensor network states}, volume = {112}, year = {2025}, }
• (2025). Performance analysis of different photon-mediated entanglement generation schemes under optical dephasing and spectral diffusion. PRA, 112(1), 012424. (www)

  @article{ , abstract = {Solid-state quantum emitters, such as quantum dots, color centers, rare-earth dopants, and organic molecules, offer qubit systems that integrate well with chip-scale photonic and electronic devices. To fully harness their potential for quantum applications requires the generation of entanglement between two remote qubits with high fidelity and efficiency. In this article, we compare the performance of three common photon-mediated entanglement schemes under realistic noise for solid-state quantum emitters, including optical dephasing and spectral diffusion. We identify the optimal scheme across different noise regimes and calculate the measurement parameters needed to achieve the highest entanglement fidelity at a given rate. Additionally, we explore the effects of temporal and spectral filtering in enhancing entanglement fidelity. Our findings provide practical guidelines for selecting optimal entanglement schemes and outline the measurement strategies for achieving better entanglement fidelity.}, archive = {J_PRA}, author = {Kinfung Ngan and Shuo Sun}, doi = {10.1103/bpsj-16wq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012424}, shortjournal = {Phys. Rev. A}, title = {Performance analysis of different photon-mediated entanglement generation schemes under optical dephasing and spectral diffusion}, volume = {112}, year = {2025}, }
• (2025). Quantum nested search for the shortest vector problem. PRA, 112(1), 012423. (www)

  @article{ , abstract = {Quantum computers represent a significant threat to the security of current public-key cryptographic systems. Postquantum cryptographic schemes, which are conjectured to be resistant to quantum attacks, are being actively developed. Among these, lattice-based cryptography has emerged as a prominent candidate, relying on the computational hardness of problems such as the shortest vector problem (SVP) for its security. In this paper, we propose a quantum approach that translates lattice enumeration into a quantum computing framework, which utilizes amplitude amplification to speed up the search process and pruning constraints to reduce unnecessary search space. This approach significantly lowers time complexity and improves performance, especially when solving the SVP in two variations of lattice enumeration. The effectiveness and efficiency of our approach are validated through small-scale simulations, which demonstrate notable speed improvements.}, archive = {J_PRA}, author = {Runxi Cao and Baocang Wang and Juntao Gao}, doi = {10.1103/dw23-dvr1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012423}, shortjournal = {Phys. Rev. A}, title = {Quantum nested search for the shortest vector problem}, volume = {112}, year = {2025}, }
• (2025). Warm-start adaptive-bias quantum approximate optimization algorithm. PRA, 112(1), 012422. (www)

  @article{ , abstract = {In the search for quantum advantage in real-world problems, one promising avenue is to use a quantum algorithm to improve on the solution found using an efficient classical algorithm. The quantum approximate optimization algorithm (QAOA) is particularly well adapted for such a “warm start” approach and can be combined with the powerful classical Goemans-Williamson (GW) algorithms based on semidefinite programing. Nonetheless, the best way to leverage the power of the QAOA remains an open question. Here we propose a general model that describes a class of QAOA variants and use it to explore routes to quantum advantages in a canonical optimization problem, MaxCut. For these algorithms we derive analytic expectation values of the cost Hamiltonian for the MaxCut problem in the level-1 case. Using these analytic results we obtain reliable averages over many instances for fairly large numbers of qubits. We find that the warm start adaptive-bias QAOA (WS-ab-QAOA) initialized by the GW algorithm outperforms previously proposed warm start variants on problems with 40 to 180 qubits. To assess whether a quantum advantage exists with this algorithm, we did numerical simulations with up to 1000 qubits to see whether the level-1 WS-ab-QAOA can improve the GW solution for three-regular graphs. In fact the improvement in the 1000-qubit case even in level 1 can only be matched by the GW algorithm after about random projections performed after the semidefinite program stage. Thus this work gives numerical evidence that the final stage of optimization after an efficient classical algorithm has produced an approximate solution may be a place where quantum advantages can be realized.}, archive = {J_PRA}, author = {Yunlong Yu and Xiang-Bin Wang and Nic Shannon and Robert Joynt}, doi = {10.1103/nt3w-j4mj}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012422}, shortjournal = {Phys. Rev. A}, title = {Warm-start adaptive-bias quantum approximate optimization algorithm}, volume = {112}, year = {2025}, }
• (2025). Phase-selective tripartite entanglement and asymmetric einstein-podolsky-rosen steering in squeezed optomechanics. PRA, 112(1), 012421. (www)

  @article{ , abstract = {The generation and manipulation of multipartite entanglement and Einstein-Podolsky-Rosen (EPR) steering in macroscopic systems not only play a fundamental role in exploring the nature of quantum mechanics, but are also at the core of current developments of various nascent quantum technologies. Here we report a theoretical method using squeezing-phase-controlled quantum noise flows to selectively generate and manipulate quantum entanglement and asymmetric EPR steering in a nonlinear whispering-gallery-mode (WGM) optomechanical resonator. We show that by pumping the nonlinear medium with two-photon optical fields and broadband squeezed lights, a pair of counterpropagating squeezed optical modes could be introduced to the WGM resonator, each coupled with an independent squeezed vacuum reservoir. This configuration could enable squeezing-phase-controlled light-reservoir interaction for each squeezed optical mode, providing a flexible tool for tailoring asymmetric optical noise flows in the counterpropagating modes. Based on this unique feature, it is found that with the injection of asymmetric noise flows, the generation of various types of bipartite and tripartite entanglement become phase-dependent, and thus they can be produced in an asymmetric way. More excitingly, it is also found that by further properly adjusting the squeezing parameters, the overall asymmetry of EPR steering can also be stepwise driven from a no-way regime, to a one-way regime, to a two-way regime. These findings, holding promise for preparing rich types of entangled quantum resources with asymmetric features, may have potential applications in the area of secure quantum information processing such as quantum secure direct communication and one-way quantum computing.}, archive = {J_PRA}, author = {Ya-Feng Jiao and Jie Wang and Dong-Yang Wang and Lei Tang and Yan Wang and Yun-Lan Zuo and Wan-Su Bao and Le-Man Kuang and Hui Jing}, doi = {10.1103/m28c-8ggl}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012421}, shortjournal = {Phys. Rev. A}, title = {Phase-selective tripartite entanglement and asymmetric einstein-podolsky-rosen steering in squeezed optomechanics}, volume = {112}, year = {2025}, }
• (2025). Virtual cloning of quantum states. PRA, 112(1), 012420. (www)

  @article{ , abstract = {The inherent limitations of physical processes prevent the copying of arbitrary quantum states. Furthermore, even if we only aim to clone two distinct quantum states, it remains impossible unless they are mutually orthogonal. To overcome this limitation, we propose a virtual-cloning protocol that bypasses the restrictions imposed by the quantum no-cloning theorem. Specifically, we begin by outlining the general framework for virtual cloning and deriving a necessary and sufficient criterion for the existence of a virtual operation capable of simultaneously cloning a set of states. Subsequently, through an analysis of the simulation cost of the virtual-cloning process, we demonstrate that the problem of identifying an optimal virtual-cloning protocol can be cast as a semidefinite programming problem. Finally, we establish a connection between virtual cloning and state discrimination, from which universal bounds on the optimal cloning cost are derived.}, archive = {J_PRA}, author = {Zhi-Hao Bi and Jing-Tao Qiu and Xiao-Dong Yu}, doi = {10.1103/4y3n-p641}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012420}, shortjournal = {Phys. Rev. A}, title = {Virtual cloning of quantum states}, volume = {112}, year = {2025}, }
• (2025). Entanglement witnesses for fermionic lattices. PRA, 112(1), 012419. (www)

  @article{ , abstract = {The fermionic partial transpose introduced by Shapourian et al . [ Phys. Rev. B 95 , 165101 (2017) ] has received widespread attention. A fundamental application of the partial transpose lies in the construction of entanglement witnesses. However, it is a notable characteristic that the fermionic partial transpose does not preserve Hermiticity. Instead, the fermionic partial transpose of a fermionic state yields a pseudo-Hermitian operator with respect to the local parity operators. This suggests that the suitable version of entanglement witness criterion for fermions is pseudo-Hermitian. Inspired by this, we systematically investigate whether the pseudo-Hermitian operators with respect to the local parity operators can serve as valid entanglement witnesses for fermions. These contents encompass completeness, comparison, intersection, and optimal conditions. Our answer is positive. We have provided some reasons why such pseudo-Hermitian operators are more suitable as entanglement witnesses than the Hermitian ones. As a byproduct, we observe that pseudo-Hermitian witnesses can reveal more information about entanglement contained in fermionic states.}, archive = {J_PRA}, author = {Bing Xu and Yangyang Wang and Xiaofei Qi and Jinchuan Hou}, doi = {10.1103/j4pd-xrs1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012419}, shortjournal = {Phys. Rev. A}, title = {Entanglement witnesses for fermionic lattices}, volume = {112}, year = {2025}, }
• (2025). Overcoming the superposition-state limitation for directed graph centrality ranking with ancilla assistance. PRA, 112(1), 012418. (www)

  @article{ , abstract = {We propose an algorithm for directed graph centrality ranking, called the ancilla-assisted pseudo-Hermitian continuous-time quantum walk algorithm (AA-PHCTQW). AA-PHCTQW overcomes a common limitation for existing CTQW-based centrality ranking algorithms, both for undirected and directed graphs, which is the requirement of an initial state in a uniform superposition over all vertices. Leveraging an ancilla vertex, we enable the use of a single-vertex basis state as the initial system state, thereby significantly improving the algorithm's experimental feasibility and robustness against noise. We prove the correctness of AA-PHCTQW and analyze centrality measures from PHCTQW and AA-PHCTQW on random graphs. Furthermore, we experimentally validate the algorithm on a silicon-based reconfigurable photonic chip with heralded single-photon source and multiphoton sources, complete the AA-PHCTQW of three-node and nine-node directed graphs. Here we provide an on-chip experimental demonstration of a quantum walk algorithm for directed graph centrality ranking.}, archive = {J_PRA}, author = {Miaomiao Yu and Pingyu Zhu and Yang Wang and Yan Wang and Yuxing Du and Kun Wang and Ping Xu}, doi = {10.1103/sv7q-gknn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012418}, shortjournal = {Phys. Rev. A}, title = {Overcoming the superposition-state limitation for directed graph centrality ranking with ancilla assistance}, volume = {112}, year = {2025}, }
• (2025). Imperfect entangling power of quantum gates. PRA, 112(1), 012417. (www)

  @article{ , abstract = {Achieving perfect control over the parameters defining a quantum gate is, in general, a very challenging task, and at the same time, environmental interactions can introduce disturbances to the initial states as well. Here we address the problem of how the imperfections in unitaries and noise present in the input states affect the entanglement-generating power of a given quantum gate—we refer to it as imperfect (noisy) entangling power. We observe that, when the parameters of a given unitary are chosen randomly from a Gaussian distribution centered around the desired mean, the quenched average entangling power—averaged across multiple random samplings—exhibits intriguing behavior like it may increase or show nonmonotonic behavior with the increase of disorder strength for certain classes of diagonal unitary operators. For arbitrary unitary operators, the quenched average power tends to stabilize, showing almost constant behavior with variation in the parameters instead of oscillating. Our observations also reveal that, in the presence of a local noise model, the input states that maximize the entangling power of a given unitary operator differ considerably from the noiseless scenario. Additionally, we report that the rankings among unitary operators according to their entangling power in the noiseless case change depending on the noise model and noise strength.}, archive = {J_PRA}, author = {Sudipta Mondal and Samir Kumar Hazra and Aditi Sen(De}, doi = {10.1103/jl2b-bxfn}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012417}, shortjournal = {Phys. Rev. A}, title = {Imperfect entangling power of quantum gates}, volume = {112}, year = {2025}, }
• (2025). Higher-dimensional-entanglement detection and quantum-channel characterization using moments of generalized positive maps. PRA, 112(1), 012416. (www)

  @article{ , abstract = {Higher-dimensional entanglement is a valuable resource for several quantum information processing tasks, and is often characterized by the Schmidt number and specific classes of entangled states beyond qubit-qubit and qubit-qutrit systems. We propose a criterion to detect higher-dimensional entanglement, focusing on determining the Schmidt number of quantum states and identifying significant classes of positive partial transposition and negative partial transposition entangled states. Our approach relies on evaluating moments of generalized positive maps which can be efficiently simulated in real experiments without the requirement of full-state tomography. We demonstrate the effectiveness of our detection scheme through various illustrative examples. As a direct application, we explore the implications of our moment-based detection schemes in identifying useful quantum-channels such as non-Schmidt-number breaking channels and nonentanglement breaking channels. Finally, we present an operational implication of our proposed moment criterion through its manifestation in channel discrimination tasks.}, archive = {J_PRA}, author = {Bivas Mallick and Ananda G. Maity and Nirman Ganguly and A. S. Majumdar}, doi = {10.1103/nzrc-8yrt}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012416}, shortjournal = {Phys. Rev. A}, title = {Higher-dimensional-entanglement detection and quantum-channel characterization using moments of generalized positive maps}, volume = {112}, year = {2025}, }
• (2025). Complexity of entanglement embezzlement. PRA, 112(1), 012415. (www)

  @article{ , abstract = {Embezzlement of entanglement is the counterintuitive process in which entanglement is extracted from a resource system using local unitary operations, with almost no detectable change in the resource's state. It was recently argued that any state of a relativistic quantum field theory can serve as a resource for perfect embezzlement. We study the circuit complexity of embezzlement using sequences of states that enable arbitrary precision for the process, commonly called universal embezzling families. In addition, we argue that this approach provides a well-defined model for the complexity of embezzlement from quantum field theories. Under fairly general assumptions, we establish a generic lower bound on the complexity, which increases with the precision of the process or the amount of embezzled entanglement, and diverges as either becomes infinite. As an example, we consider a one-dimensional critical system as the resource and derive an exponentially growing lower bound on the complexity. Consequently, the findings imply that circuit complexity acts as a physical obstruction to perfect embezzlement. Supplementary to the main results, we derive lower bounds for common models of circuit complexity for state preparation based on the difference between the Schatten norms of the initial and final states.}, archive = {J_PRA}, author = {Tal Schwartzman}, doi = {10.1103/pfyl-hwf2}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012415}, shortjournal = {Phys. Rev. A}, title = {Complexity of entanglement embezzlement}, volume = {112}, year = {2025}, }
• (2025). Unraveling reverse annealing: A study of D-wave quantum annealers. PRA, 112(1), 012414. (www)

  @article{ , abstract = {D-Wave quantum annealers offer reverse annealing as a feature allowing them to refine solutions to optimization problems. This paper investigates the influence of key parameters, such as annealing times and reversal distance, on the behavior of reverse annealing by studying models containing up to 1000 qubits. Through the analysis of theoretical models and experimental data, we explore the interplay between quantum and classical processes in describing the empirical data. Our findings provide a deeper understanding that can better equip users to fully harness the potential of the D-Wave annealers.}, archive = {J_PRA}, author = {Vrinda Mehta and Hans De Raedt and Kristel Michielsen and Fengping Jin}, doi = {10.1103/vfxh-gjgy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012414}, shortjournal = {Phys. Rev. A}, title = {Unraveling reverse annealing: A study of D-wave quantum annealers}, volume = {112}, year = {2025}, }
• (2025). Reducing complexity of shadow process tomography with generalized measurements. PRA, 112(1), 012413. (www)

  @article{ , abstract = {Quantum process tomography (QPT) is crucial for advancing quantum technologies, including quantum computers, quantum networks, and quantum sensors. Shadow process tomography (SPT) utilizes the Choi isomorphism to map QPT to shadow state tomography (SST), significantly reducing the sample complexity for extracting information from quantum processes. However, SPT relies on random unitary operators and complicates the determination of the optimal unitary operator that minimizes the shadow norm, which is the key factor influencing the sample complexity. In this work, we propose a generalized SPT framework that minimizes the shadow norm by replacing unitary operators with generalized measurements [positive operator-valued measures (POVMs)]. This approach, termed shadow process tomography with POVMs (POVM-SPT), uses convex optimization to identify the optimal POVM for minimizing the shadow norm, thereby further reducing sample complexity. We demonstrate the identification of the optimal POVM through numerical simulations and provide the corresponding optimization algorithms. Our numerical experiments demonstrate that POVM-SPT achieves a substantial reduction in the shadow norm compared to conventional SPT, with an approximate sevenfold improvement for single-qubit input states and a remarkable -fold enhancement for 64-qubit input states. These results reveal that POVM-SPT offers significant advantages in simplifying SPT tasks, particularly for large-scale quantum systems.}, archive = {J_PRA}, author = {Haigang Wang and Kan He}, doi = {10.1103/13ct-8vtv}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012413}, shortjournal = {Phys. Rev. A}, title = {Reducing complexity of shadow process tomography with generalized measurements}, volume = {112}, year = {2025}, }
• (2025). Quasi-inverse of qubit channels for mixed states. PRA, 112(1), 012412. (www)

  @article{ , abstract = {We find the quasi-inverse of qubit channels as a unitary map E i by minimizing the average trace distance between the input state to the channel and the output of the quasi-inverse channel for an arbitrary qubit channel E and for arbitrary input states. The channel E is assumed to be completely positive and trace preserving. To find the quasi-inverse for mixed states, we propose an alternative definition of the quasi-inverse based on the mean-square trace distance (MSTD) of a channel. The definition based on the trace distance allows easy generalization of the quasi-inverse to mixed input states. The quasi-inverse of the Pauli, generalized amplitude damping, mixed unitary, and tetrahedron channels calculated based on the MSTD agrees with the one computed using average fidelity in the special case of input states being pure.}, archive = {J_PRA}, author = {Muhammad Faizan and Muhammad Faryad}, doi = {10.1103/qmjt-g6hy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012412}, shortjournal = {Phys. Rev. A}, title = {Quasi-inverse of qubit channels for mixed states}, volume = {112}, year = {2025}, }
• (2025). Multipartite entanglement structures in quantum stabilizer states. PRA, 112(1), 012411. (www)

  @article{ , abstract = {We develop a method for visualizing the internal structure of multipartite entanglement in pure stabilizer states. Our algorithm graphically organizes the many-body correlations in a hierarchical structure. This provides a rich taxonomy from which one can simultaneously extract many quantitative features of a state including some traditional quantities such as entanglement depth, -uniformity, and entanglement entropy. Our method also presents an alternative computational tool for extracting the exact entanglement depth and all separable partitions of a stabilizer state. Our construction is gauge invariant and goes beyond traditional entanglement measures by visually revealing how quantum information and entanglement is distributed. We use this tool to analyze the internal structures of prototypical stabilizer states (Greenberger-Horne-Zeilinger state, cluster state, stabilizer error correction codes) and are able to contrast the complexity of highly entangled volume law states generated by random unitary operators and random projective measurements.}, archive = {J_PRA}, author = {Vaibhav Sharma and Erich J. Mueller}, doi = {10.1103/1cqt-8rxf}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012411}, shortjournal = {Phys. Rev. A}, title = {Multipartite entanglement structures in quantum stabilizer states}, volume = {112}, year = {2025}, }
• (2025). Detecting high-dimensional time-bin entanglement in fiber-loop systems. PRA, 112(1), 012410. (www)

  @article{ , abstract = {Many quantum communication protocols rely on the distribution of entanglement between the different participating parties. One example is quantum key distribution (QKD), an application that has matured to commercial use in recent years. However, difficulties remain, especially with noise resilience and channel capacity in long-distance communication. One way to overcome these problems is to use high-dimensional entanglement, which has been shown to be more robust to noise and enables higher secret-key rates. It is therefore important to have access to certifiable high-dimensional entanglement sources to confidently implement these advanced QKD protocols. Here we develop a method for certifying high-dimensional time-bin entanglement in fiber-loop systems. In these systems, entanglement creation and detection can utilize the same physical components, and the number of time bins, and thus the entanglement dimension, can be adapted without making physical changes to the setup. Our certification method builds on previous proposals for the certification of angular-momentum entanglement in photon pairs. In particular, measurements in only two experimentally accessible bases are sufficient to obtain a lower bound on the entanglement dimension for both two- and multiphoton quantum states. Numerical simulations show that the method is robust against typical experimental noise effects and works well even with limited measurement statistics, thus establishing time-bin encoded photons as a promising platform for high-dimensional quantum-communication protocols.}, archive = {J_PRA}, author = {Niklas Euler and Monika Monika and Ulf Peschel and Martin Gärttner}, doi = {10.1103/bn8s-bqnp}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012410}, shortjournal = {Phys. Rev. A}, title = {Detecting high-dimensional time-bin entanglement in fiber-loop systems}, volume = {112}, year = {2025}, }
• (2025). Quantum active learning. PRA, 112(1), 012409. (www)

  @article{ , abstract = {Quantum machine learning (QML), as an extension of classical machine learning that harnesses quantum mechanics, facilitates efficient learning from data encoded in quantum states. Training a quantum neural network (QNN) typically demands a substantial labeled training set for supervised learning. Human annotators, often experts, provide labels for samples through additional experiments, adding to the training cost. To mitigate this expense, there is a quest for methods that maintain model performance over fully labeled data sets while requiring fewer labeled samples in practice, thereby extending few-shot learning to the quantum realm. Quantum active learning (QAL) estimates the uncertainty of quantum data to select the most informative samples from a pool for labeling. Consequently, a QML model is supposed to accumulate maximal knowledge as the training set comprises labeled samples selected via sampling strategies. Notably, the QML models trained within the QAL framework are not restricted to specific types, allowing performance enhancement from the model architecture's perspective towards few-shot learning. Recognizing symmetry as a fundamental concept in physics ubiquitous across various domains, we leverage the symmetry inherent in quantum states induced by the embedding of classical data for model design. We employ an equivariant QNN capable of generalizing from fewer data with geometric priors. We benchmark the performance of QAL on two classification problems, observing both positive and negative results. QAL effectively trains the model, achieving performance comparable to that on fully labeled data sets by labeling less than 7% of the samples in the pool with unbiased sampling behavior. Furthermore, we elucidate the negative result of QAL being overtaken by random sampling baseline through miscellaneous numerical experiments. Our work lays the groundwork for real-world applications of QML by addressing realistic experimental costs.}, archive = {J_PRA}, author = {Yongcheng Ding and Yue Ban and Mikel Sanz and José D. Martín-Guerrero and Xi Chen}, doi = {10.1103/c8q9-6vy7}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012409}, shortjournal = {Phys. Rev. A}, title = {Quantum active learning}, volume = {112}, year = {2025}, }
• (2025). Application of zero-noise-extrapolation-based quantum error mitigation to a silicon spin qubit. PRA, 112(1), 012408. (www)

  @article{ , abstract = {As quantum computing advances towards practical applications, reducing errors remains a crucial frontier for developing near-term devices. Errors in the quantum gates and quantum state readout result in noisy circuits, which would prevent the acquisition of the exact expectation values of the observables. Although ultimate robustness to errors is known to be achievable by quantum error correction-based fault-tolerant quantum computing, its successful implementation demands large-scale quantum processors with low average error rates that are not yet widely available. In contrast, quantum error mitigation offers more immediate and practical techniques, which do not require extensive resources and can be readily applied to existing quantum devices to improve the accuracy of the expectation values. Here, we report the implementation of a zero-noise extrapolation-based error mitigation technique on a silicon spin qubit platform. This technique has recently been successfully demonstrated for other platforms such as superconducting qubits, trapped-ion qubits, and photonic processors. We first explore three methods for amplifying noise on a silicon spin qubit: global folding, local folding, and pulse stretching, using a standard randomized benchmarking protocol. We then apply global folding-based zero-noise extrapolation to the state tomography and achieve a state fidelity of 99.96% (98.52%), compared to the unmitigated fidelity of 75.82% (82.16%) for different preparation states. These results show that the zero-noise extrapolation technique is a versatile approach that is generally adaptable to quantum computing platforms with different noise characteristics through appropriate noise amplification methods.}, archive = {J_PRA}, author = {Hanseo Sohn and Jaewon Jung and Jaemin Park and Hyeongyu Jang and Lucas E. A. Stehouwer and Davide Degli Esposti and Giordano Scappucci and Dohun Kim}, doi = {10.1103/925y-b4s1}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012408}, shortjournal = {Phys. Rev. A}, title = {Application of zero-noise-extrapolation-based quantum error mitigation to a silicon spin qubit}, volume = {112}, year = {2025}, }
• (2025). Quantum determinant estimation. PRA, 112(1), 012407. (www)

  @article{ , abstract = {A quantum algorithm for computing the determinant of a unitary matrix U ∈ U ( N ) is given. The algorithm requires no preparation of eigenstates of U and estimates the phase of the determinant to t -binary digits accuracy with O ( N log 2 N + t 2 ) operations and t N controlled applications of U 2 m with m = 0 , ... , t − 1 . For an orthogonal matrix O ∈ O ( N ) the algorithm can determine with certainty the sign of the determinant using O ( N log 2 N ) operations and N controlled applications of O . An extension of the algorithm to contractions is discussed.}, archive = {J_PRA}, author = {J. Agerskov and K. Splittorff}, doi = {10.1103/mr7q-3z8s}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012407}, shortjournal = {Phys. Rev. A}, title = {Quantum determinant estimation}, volume = {112}, year = {2025}, }
• (2025). Non-markovian noise mitigation: Practical implementation, error analysis, and the role of spectral properties of the environment. PRA, 112(1), 012406. (www)

  @article{ , abstract = {Quantum error mitigation (QEM), an error suppression strategy without the need for additional ancilla qubits for noisy intermediate-scale quantum (NISQ) devices, presents a promising avenue for realizing quantum speedups of quantum computing algorithms on current quantum devices. However, prior investigations have predominantly been focused on Markovian noise, which only occurs when the separation between the system and environment is sufficiently large. In this paper, we propose a non-Markovian noise mitigation (NMNM) method by extending the probabilistic error cancellation (PEC) method in the QEM framework to treat non-Markovian noise. We present the derivation of a time-local quantum master equation where the incoherent coefficients are directly obtained from bath correlation functions (BCFs), key properties of a non-Markovian environment that will make the error mitigation algorithms environment aware. We further establish a direct connection between the overall approximation error and sampling overhead of QEM and the spectral property of the environment. Numerical simulations performed on a spin-boson model further validate the efficacy of our approach.}, archive = {J_PRA}, author = {Ke Wang and Xiantao Li}, doi = {10.1103/db4q-8ny9}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012406}, shortjournal = {Phys. Rev. A}, title = {Non-markovian noise mitigation: Practical implementation, error analysis, and the role of spectral properties of the environment}, volume = {112}, year = {2025}, }
• (2025). Performance of quantum annealing for 2-satisfiability problems with multiple satisfying assignments. PRA, 112(1), 012405. (www)

  @article{ , abstract = {Using a specially constructed set of hard 2-satisfiability problems with four satisfying assignments, we study the scaling and sampling performance of numerical simulation of quantum annealing as well as that of the physical quantum annealers offered by D-Wave. To this end, we use both the standard quantum annealing and reverse annealing protocols in both our simulations and on the D-Wave quantum annealer. In the case of ideal quantum annealing the sampling behavior can be explained by perturbation theory and the scaling behavior of the time to solution depends on the scaling behavior of the minimum energy gap between the ground state and the first-excited state of the annealing Hamiltonian. The corresponding results from the D-Wave quantum annealers do not fit to this ideal picture, but suggest that the scaling of the time to solution from the quantum annealers matches those calculated from the equilibrium probability distribution.}, archive = {J_PRA}, author = {Vrinda Mehta and Hans De Raedt and Kristel Michielsen and Fengping Jin}, doi = {10.1103/n7r5-s63q}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012405}, shortjournal = {Phys. Rev. A}, title = {Performance of quantum annealing for 2-satisfiability problems with multiple satisfying assignments}, volume = {112}, year = {2025}, }
• (2025). Unconditionally superposition-robust entangled state in all multiparty quantum systems. PRA, 112(1), 012404. (www)

  @article{ , abstract = {We investigate the inseparability of states generated by superposition of a multipartite pure entangled state with a product state. In particular, we identify specific multipartite entangled states that will always produce inseparability after superposition with an arbitrary completely product state. Thus, these entangled states are unconditionally superposition robust, and we refer to this phenomenon as “unconditional inseparability of superposition” in multipartite quantum systems. In this way, we complete the picture of unconditional inseparability of superposition which was introduced earlier for bipartite systems. We also characterize the superposition of a multipartite pure entangled state with a pure biseparable state. However, the present analysis allows us to obtain a more general result, viz., there exists at least one pure entangled state in any multipartite Hilbert space such that its superposition with an arbitrary completely product state always yields an entangled state. On the other hand, for any bipartite pure entangled state, if at least one of the subsystems is a qubit, then it is always possible to find a suitable product state such that the superposition of the entangled state and the product state produces a product state. In this way, we find a feature of multipartite quantum systems which is in sharp contrast with that of bipartite ones. We then show how unconditional inseparability of superposition can be useful in exhibiting an indistinguishability property within the local unambiguous state discrimination problem.}, archive = {J_PRA}, author = {Swati Choudhary and Ujjwal Sen and Saronath Halder}, doi = {10.1103/84vb-lnhx}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012404}, shortjournal = {Phys. Rev. A}, title = {Unconditionally superposition-robust entangled state in all multiparty quantum systems}, volume = {112}, year = {2025}, }
• (2025). Revealing quantum operator scrambling via measuring holevo information on digital quantum simulators. PRA, 112(1), 012403. (www)

  @article{ , abstract = {Quantum operator scrambling describes the spreading of local operators into the whole system in the picture of Heisenberg evolution, which is often quantified by the operator size growth. Here we propose a measure of quantum operator scrambling via Holevo information of operators, by taking its capacity to distinguish operator information locally. We show that the operator size is closely related to a special kind of Holevo information of operators. Moreover, we propose a feasible protocol for measuring Holevo information of operators on digital quantum simulators based on random states. For the mixed-field Ising model, our numerical simulations show that the integrable system can be told apart from the chaotic system by measuring the spatial-temporal patterns of Holevo information. Furthermore, we find that error mitigation is required to restore the time-oscillation behavior of Holevo information for the integrable system, a crucial feature distinct from the chaotic one. Our work provides a new perspective to understand the information scrambling and quantum chaos from aspects of Holevo information of operators.}, archive = {J_PRA}, author = {Bin Sun and Geng-Bin Cao and Xi-Dan Hu and Dan-Bo Zhang}, doi = {10.1103/s1t6-6brz}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012403}, shortjournal = {Phys. Rev. A}, title = {Revealing quantum operator scrambling via measuring holevo information on digital quantum simulators}, volume = {112}, year = {2025}, }
• (2025). Quantum XYZ cyclic codes for biased noise. PRA, 112(1), 012402. (www)

  @article{ , abstract = {In some quantum computing architectures, Pauli noise is highly biased. Tailoring quantum error-correcting codes to the biased noise may benefit reducing the physical qubit overhead without reducing the logical error rate. In this paper, we propose a family of quantum cyclic codes, which is the only family of quantum cyclic codes with code distance increasing with code length to the best of our knowledge. We exploit fully decoupled belief propagation combined with ordered statistics decoding (FDBP-OSD) and Tesseract decoder (TD) to explore the error-correcting performance of the codes. Our simulation results show that the quantum cyclic codes have code-capacity thresholds for all three types of pure Pauli noise. Under depolarizing noise, we observe code-capacity threshold obtained by FDBP-OSD, while the results obtained by TD indicates that the optimal code-capacity threshold may be approximately . In the finite-bias regime, when the noise is biased towards Pauli errors with noise bias ratios , the results obtained by FDBP-OSD and TD both indicate the quantum cyclic codes have around code-capacity threshold. When and 100, TD indicates that the corresponding code-capacity thresholds may be around and , respectively. In addition, we show that to reach the same code distance, the physical qubit overhead of cyclic code is much less than that of the XZZX surface code.}, archive = {J_PRA}, author = {Zhipeng Liang and Fusheng Yang and Zhengzhong Yi and Xuan Wang}, doi = {10.1103/6qbg-xslr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012402}, shortjournal = {Phys. Rev. A}, title = {Quantum XYZ cyclic codes for biased noise}, volume = {112}, year = {2025}, }
• (2025). Interfacing gottesman-kitaev-preskill qubits to quantum memories. PRA, 112(1), 012401. (www)

  @article{ , abstract = {Gottesman-Kitaev-Preskill (GKP) states have been demonstrated to pose significant advantages when utilized for fault-tolerant all-optical continuous-variable quantum computing as well as for quantum communications links for entanglement distribution. However, interfacing these systems to long-lived solid-state quantum memories has remained an open problem. Here we propose an interface between quantum memories and GKP qubit states based on a cavity-mediated controlled displacement gate. We characterize the quality of memory-GKP entanglement as a function of cavity parameters suggesting optimal regimes of operation for high-quality state transfer between either qubit states. We further extend this protocol to demonstrate the creation of GKP cluster states by avoiding the requirement of ancillary optical quadrature-squeezed light. Utilizing postselected entanglement swapping operations for GKP qubits, we demonstrate the utility of our protocol for high-rate entanglement generation between quantum memories. Extensions and derivatives of our proposal could enable a wide variety of applications by utilizing the operational tradeoffs for qubits encoded in memory and in the GKP basis.}, archive = {J_PRA}, author = {Prajit Dhara and Liang Jiang and Saikat Guha}, doi = {10.1103/4glk-qyj3}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012401}, shortjournal = {Phys. Rev. A}, title = {Interfacing gottesman-kitaev-preskill qubits to quantum memories}, volume = {112}, year = {2025}, }
• (2025). Dissipative quantum phase transitions monitored by current fluctuations. PRA, 112(1), 012226. (www)

  @article{ , abstract = {Dissipative phase transitions (DPTs) are defined by sudden changes in the physical properties of nonequilibrium open quantum systems and they present characteristics that have no analog in closed and thermal systems. Several methods to detect and characterize DPTs have been suggested in the literature, the most famous of which, the Liouvillian gap, can be derived from a spectral analysis of the Liouvillian superoperator that governs the complex interplay between coherent and dissipative dynamics. Here we consider the output current, defined as the average total quantum jumps per unit time between the open quantum system and the environment. We propose that output current fluctuations and in particular their dynamical correlations, their power spectrum, and their characteristic timescale can provide valuable information about DPTs, confirming a dramatic change of behavior at the critical point. We validate our proposal using the dissipative model and the nonlinear driven-dissipative Kerr model, showing good agreement with previous estimates of the location of the critical point. Compared to previous approaches, our proposal could already be experimentally tested in optical systems, providing a practical method to detect criticality in quantum open systems.}, archive = {J_PRA}, author = {Masataka Matsumoto and Zi Cai and Matteo Baggioli}, doi = {10.1103/2fw8-bsjy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012226}, shortjournal = {Phys. Rev. A}, title = {Dissipative quantum phase transitions monitored by current fluctuations}, volume = {112}, year = {2025}, }
• (2025). Quantum walks on a network based on a dual sierpinski gasket and a dendrimer. PRA, 112(1), 012225. (www)

  @article{ , abstract = {We investigate the transport properties of quantum walks on a multihierarchical network which is built by a replication of the dual Sierpinski gasket in the form of a regular dendrimer. The efficiency of the transport is monitored through the exact and the average return probabilities, which are obtained by implementing a continuous-time quantum walk (CTQW) model. All these probabilities (classical and quantum) are determined by knowing the eigenvalues and eigenvectors of the connectivity matrix. For our networks the complete eigenvalue spectrum is determined iteratively, a process that facilitates the analysis of very large networks. The classical return probability can be separated into two distinct components which depend on the underlying topologies: the dual Sierpinski gasket and the dendrimer. The quantum walks show strong localization effects, which are more accentuated when the starting node is peripheral. The quantum long-time average probability is determined analytically, depending solely on the generation numbers of our fractal and dendrimer. For networks with generation number of dual Sierpinski gasket higher than 5 the long-time probability keeps the same and depends only on the spectral dimension of the fractal.}, archive = {J_PRA}, author = {Geyson Maquiné Batalha and Mircea Galiceanu}, doi = {10.1103/v78n-y49t}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012225}, shortjournal = {Phys. Rev. A}, title = {Quantum walks on a network based on a dual sierpinski gasket and a dendrimer}, volume = {112}, year = {2025}, }
• (2025). Riemannian approach to the lindbladian dynamics of a locally purified tensor network. PRA, 112(1), 012224. (www)

  @article{ , abstract = {Tensor networks offer a valuable framework for implementing Lindbladian dynamics in many-body open quantum systems with nearest-neighbor couplings. In particular, a tensor network Ansatz known as the locally purified density operator employs the local purification of the density matrix to guarantee the positivity of the state at all times. Within this framework, the dissipative evolution utilizes the Trotter-Suzuki splitting, yielding a second-order approximation error. However, due to the Lindbladian dynamics' nature, employing higher-order schemes results in nonphysical quantum channels. In this work, we leverage the gauge freedom inherent in the Kraus representation of quantum channels to improve the splitting error. To this end, we formulate an optimization problem on the Riemannian manifold of isometries and find a solution via the second-order trust-region algorithm. We validate our approach using two nearest-neighbor noise models and achieve an improvement of orders of magnitude compared to other positivity-preserving schemes. In addition, we demonstrate the usefulness of our method as a compression scheme, helping to control the exponential growth of computational resources, which thus far has limited the use of the locally purified Ansatz .}, archive = {J_PRA}, author = {Emiliano Godinez-Ramirez and Richard M. Milbradt and Christian B. Mendl}, doi = {10.1103/kztw-ywxr}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012224}, shortjournal = {Phys. Rev. A}, title = {Riemannian approach to the lindbladian dynamics of a locally purified tensor network}, volume = {112}, year = {2025}, }
• (2025). Quantum synchronization blockade induced by nonreciprocal coupling. PRA, 112(1), 012223. (www)

  @article{ , abstract = {Recently, the synchronization of coupled quantum oscillators has attracted a great deal of interest. Synchronization requires driven constituents, and in such systems, the coupling can be designed to be nonreciprocal. Nonreciprocally coupled oscillators exhibit a rich variety of behavior including active traveling-wave-type states. In this work, we study the interplay of three competing synchronization mechanisms in a setup of two nonreciprocally coupled quantum van der Pol oscillators. One of the oscillators is driven externally, which induces phase locking. A dissipative interaction leads to antiphase locking, whereas a coherent interaction nurtures bistable phase locking and active states. We approximate the phase diagram of the quantum case by evaluating the synchronization measure of a perturbation expansion of the steady state. Effective unidirectional interactions lead to synchronization blockades between the undriven oscillator and the external drive as well as between both oscillators. Furthermore, we study the phase diagrams of two and three oscillators in the mean-field limit and find highly nontrivial active states.}, archive = {J_PRA}, author = {Tobias Kehrer and Christoph Bruder}, doi = {10.1103/9y9w-lw92}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012223}, shortjournal = {Phys. Rev. A}, title = {Quantum synchronization blockade induced by nonreciprocal coupling}, volume = {112}, year = {2025}, }
• (2025). Wave-particle duality in multipath interferometers via quantum fisher information. PRA, 112(1), 012222. (www)

  @article{ , abstract = {Quantum Fisher information, which serves as a powerful tool for quantifying the sensitivity of quantum states to parameter variations, has profound implications for quantum metrology. In this work, we establish a general framework for characterizing both the wave and particle features in multipath interferometers using the quantum Fisher information. Furthermore, we derive a complete complementarity relation involving the interference (wave feature), the predictability (particle feature), and the quantum entropies. As an illustration, we calculate the relevant quantities for the two-path interferometers. Compared with two related characterizations about the complementarity relations, we emphasize that the quantum Fisher information serves as the unified figure of merit for both wave and particle properties. This work builds the connections between the quantum Fisher information and the foundational complementarity principles, offering a fresh and unified perspective for the wave-particle duality in multipath interferometers.}, archive = {J_PRA}, author = {Xue Wang and Shuangshuang Fu}, doi = {10.1103/wdxh-nwsw}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012222}, shortjournal = {Phys. Rev. A}, title = {Wave-particle duality in multipath interferometers via quantum fisher information}, volume = {112}, year = {2025}, }
• (2025). Adiabatic perturbation theory invariant under the unitary transformations. PRA, 112(1), 012221. (www)

  @article{ , abstract = {We propose a new formalism of the adiabatic perturbation theory that is invariant under the unitary transformations. A strict distinction is made between the Hamiltonian operator and the instantaneous energy operator. The state of the system is expanded in terms of the eigenstates of the instantaneous energy operator. The expansion coefficients, which represent the transition amplitudes among instantaneous energy eigenstates, are invariant under the unitary transformations. A perturbative series, whose zeroth-order term is the adiabatic approximation invariant under the unitary transformations, is generated up to second order for the state of the system. A diagrammatic representation of the perturbative series is developed. The first-order nonadiabatic correction yields two first-order adiabatic conditions, of which the first one is the unitary-invariant version of the traditional adiabatic condition. A simple physical interpretation is given for it in terms of the physical power operator. The second-order nonadiabatic correction yields two second-order adiabatic conditions. The second first-order condition and the first second-order condition are the unitary-invariant versions of the supplemented conditions derived by Tong et al. [ Phys. Rev. Lett. 98 , 150402 (2007) ]. The second second-order adiabatic condition provides an additional condition setting the bound on the total evolution time.}, archive = {J_PRA}, author = {Hsiang-Shun Chou}, doi = {10.1103/p677-hf5r}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012221}, shortjournal = {Phys. Rev. A}, title = {Adiabatic perturbation theory invariant under the unitary transformations}, volume = {112}, year = {2025}, }
• (2025). Enhanced frequency and temperature estimation by a PT-symmetric quantum oscillator. PRA, 112(1), 012220. (www)

  @article{ , abstract = {Quantum metrology employs quantum properties to enhance the precision of physical parameters, in order to characterize quantum states as well as channels. Frequency and temperature estimations are of fundamental importance for these tasks and have been extensively studied in quantum sensing strategies. Among the quantum features that can be exploited in quantum metrology, those related to non-Hermitian systems have received much attention in recent times. Here, we consider a paradigmatic non-Hermitian system, the quantum Swanson oscillator, as a probe system in order to investigate how the non-Hermitian contribution affects the frequency and temperature estimation. We use the quantum Fisher information to compute the main results. Furthermore, to perform a fair comparison, we define a gain function which is the ratio between the quantum Fisher information with the non-Hermitian contribution and the quantum Fisher information when this term becomes Hermitian. In addition, the quantum Fisher information is discussed in terms of the energetic cost to include the non-Hermitian contribution. Dissipative effects are also considered by interacting different probe systems with a Markovian thermal reservoir. Given that we obtain the Hermitian counterpart of the Hamiltonian by applying the Dyson map, we also study the estimation of the parameters characterizing this mapping. Our results indicate that the non-Hermitian contribution in the Swanson quantum oscillator can contribute to enhancing the frequency and temperature estimation.}, archive = {J_PRA}, author = {Jonas F. G. Santos}, doi = {10.1103/xdnc-tc2y}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012220}, shortjournal = {Phys. Rev. A}, title = {Enhanced frequency and temperature estimation by a PT-symmetric quantum oscillator}, volume = {112}, year = {2025}, }
• (2025). Unbounded sharing of network nonlocality in the two-forked tree-shaped scenario. PRA, 112(1), 012219. (www)

  @article{ , abstract = {Quantum network nonlocality plays a crucial role in long-distance quantum communication, and nonlocality sharing via sequential measurements provides a novel perspective for large-scale quantum network applications. In this paper, we investigate network nonlocality sharing in the two-forked tree-shaped network. For the two-input n -layer ( n ≥ 2 ) scenario, the number of sequential observers in existing schemes is constrained by the layer n and the number of sequential sides. Here we achieve unbounded sharing of network nonlocality for arbitrary n by introducing sharpness parameters into Bell state measurements and allowing sequential observers to perform measurements with different sharpness parameters. An unbounded number of independent observers on each of the m ( m = 1 , ⋯ , 2 n − 2 ) sequential sides can simultaneously share non- ( 2 n − 2 ) -locality by violating the two-input ( 2 n − 2 ) -local inequality with all other nonsequential observers. Furthermore, we extend the two-input scenario to a generalized d -input ( d ≥ 2 ) case, investigating how the input number d affects network nonlocality sharing. A general model for sequential measurement scenarios in d -input two-forked n -layer tree-shaped networks is established. Using the simplest case ( n = 3 ) as an example, we investigate non-six-locality sharing based on the d -input six-local inequality and establish the relationship between the number of sequential observers, the number of sequential sides, and the input d . Based on the results, we conjecture that the two-input configuration is optimal for nonlocality sharing in two-forked tree-shaped networks.}, archive = {J_PRA}, author = {Hao Sun and Fenzhuo Guo and Haifeng Dong and Sujuan Qin and Fei Gao}, doi = {10.1103/6r7f-2wqc}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012219}, shortjournal = {Phys. Rev. A}, title = {Unbounded sharing of network nonlocality in the two-forked tree-shaped scenario}, volume = {112}, year = {2025}, }
• (2025). Powering a quantum clock with a nonequilibrium steady state. PRA, 112(1), 012218. (www)

  @article{ , abstract = {We propose powering a quantum clock with the nonthermal resources offered by the stationary state of an integrable quantum spin chain, driven out of equilibrium by a sudden quench. We describe the dynamics of the clock as a “biased random walk.” The bias level is directly related to the negativity of the steady-state response function. Using experimentally relevant examples of quantum spin chains, we suggest that crossing a phase transition point is crucial for the clock's operation. The coupling takes place through a global observable and, in this case, the battery lifespan is found to be extensive in its size.}, archive = {J_PRA}, author = {Daniele Nello and Alessandro Silva}, doi = {10.1103/86m1-yxwq}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012218}, shortjournal = {Phys. Rev. A}, title = {Powering a quantum clock with a nonequilibrium steady state}, volume = {112}, year = {2025}, }
• (2025). Impact of a tunneling particle on the quantum state of a barrier: Two-particle wave-packet model. PRA, 112(1), 012217. (www)

  @article{ , abstract = {We investigate the scattering of two distinguishable particles with unequal masses and a mutual short-range interaction with the aim of quantifying the impact of a tunneling “projectile” particle on the quantum mechanical state of the “barrier” particle. We find that the states of the barrier particle after the tunneling or reflection of the projectile are shifted by a distance which consists of a classical uniform motion and an aditional displacement that is given by the derivative of the phase of the transmission or reflection amplitudes multiplied by factors dependent on particles' masses, respectively. We demonstrate these results on a numerical example with a resonant interaction between a projectile and barrier. Our work demonstrates physical implications of the concept of phase time delay in the form of displacements of particles that are, in principle, experimentally measurable.}, archive = {J_PRA}, author = {Roman Michelko and Peter Bokes}, doi = {10.1103/g7yp-nmvy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012217}, shortjournal = {Phys. Rev. A}, title = {Impact of a tunneling particle on the quantum state of a barrier: Two-particle wave-packet model}, volume = {112}, year = {2025}, }
• (2025). Real-time instanton approach to quantum activation. PRA, 112(1), 012216. (www)

  @article{ , abstract = {Driven-dissipative nonlinear systems exhibit rich critical behavior, related to bifurcation, bistability, and switching, which underlie key phenomena in areas ranging from physics, chemistry, and biology [T. Wilhelm, BMC Syst. Biol. 3 , 90 (2009) ] to social sciences and economics. The importance of rare fluctuations leading to a dramatic jump between two very distinct states, such as survival and extinction in population dynamics [A. Taitelbaum et al. , Phys. Rev. Lett. 125 , 048105 (2020) ; A. Kamenev and B. Meerson, Phys. Rev. E 77 , 061107 (2008) ], success and bankruptcy in economics [S. Ghashghaie et al. , Nature (London) 381 , 767 (1996) ], and the occurrence of earthquakes [L. Knopoff and Y. Kagan, J. Geophys. Res. 82 , 5647 (1977) ] or of epileptic seizures [K. Lehnertz, Extreme Events in Nature and Society (Springer, Berlin, Heidelberg, 2006), pp. 123–143], have been already established. In the quantum domain, switching is of importance in both chemical reactions and the devices used in quantum state detection and amplification [R. Vijay et al. , Rev. Sci. Instrum. 80 , 111101 (2009) ]. In particular, the simplest driven single oscillator model serves as an insightful starting point. Here we describe switching induced by quantum fluctuations and illustrate that an instanton approach within Keldysh field theory can provide a deep insight into such phenomena. We provide a practical recipe to compute the switching rates semi-analytically, which agrees remarkably well with exact solutions across a wide domain of drive amplitudes spanning many orders of magnitude. Being set up in the framework of Keldysh coherent states path integrals, our approach opens the possibility of studying quantum activation in many-body systems where other approaches are inapplicable.}, archive = {J_PRA}, author = {Chang-Woo Lee and Paul Brookes and Kee-Su Park and Marzena H. Szymańska and Eran Ginossar}, doi = {10.1103/5jtm-ht4n}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012216}, shortjournal = {Phys. Rev. A}, title = {Real-time instanton approach to quantum activation}, volume = {112}, year = {2025}, }
• (2025). Generation of the complete bell basis via hong-ou-mandel interference of vector modes. PRA, 112(1), 012215. (www)

  @article{ , abstract = {Optical vector modes (VMs), characterized by spatially varying polarization distributions, have become essential tools across microscopy, metrology, optical trapping, nanophotonics, and optical communications. Here, we investigate the Hong-Ou-Mandel (HOM) interference of VMs providing a full spatial characterization of the output state. We find that, by carefully selecting the input VMs, it is possible to simultaneously observe all four polarization Bell states and their superpositions in the spatially varying polarization pattern of the two photons. These results represent a significant step in advancing our understanding of HOM interference within structured photons, offering promising avenues for high-dimensional quantum information processing and, in particular, high-dimensional quantum communication, quantum sensing, and advanced photonic technologies reliant on tailored quantum states of light.}, archive = {J_PRA}, author = {Xiaoqin Gao and Dilip Paneru and Francesco Di Colandrea and Yingwen Zhang and Ebrahim Karimi}, doi = {10.1103/dcxb-ql1r}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012215}, shortjournal = {Phys. Rev. A}, title = {Generation of the complete bell basis via hong-ou-mandel interference of vector modes}, volume = {112}, year = {2025}, }
• (2025). Advantage of greenberger-horne-zeilinger correlation in communication complexity: A step beyond the conventional greenberger-horne-zeilinger paradox. PRA, 112(1), 012214. (www)

  @article{ , abstract = {We propose a randomized variant of the Greenberger-Horne-Zeilinger (GHZ) game where promise conditions for input distributions are selected uniform randomly from different possibilities, and disclosed to a single party only. Despite this asymmetry, the game is deterministically winnable using the GHZ correlation that yields perfect success in the original GHZ pseudotelepathy game. The introduced randomization, however, reveals a higher operational advantage in a class of multipartite communication complexity tasks, where inputs are distributed among distant parties and a designated function must be computed by one of them. Classical strategies require two bits of communication to the computing node from each of the other parties, while preshared GHZ states enable the same task with only one bit per party. This separation demonstrates a superior utility of GHZ correlations in multipartite protocols and showcases an enhanced operational power of genuine entanglement in multipartite quantum communication complexity tasks.}, archive = {J_PRA}, author = {Ananya Chakraborty and Kunika Agarwal and Sahil Gopalkrishna Naik and Manik Banik}, doi = {10.1103/hwgb-g93f}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012214}, shortjournal = {Phys. Rev. A}, title = {Advantage of greenberger-horne-zeilinger correlation in communication complexity: A step beyond the conventional greenberger-horne-zeilinger paradox}, volume = {112}, year = {2025}, }
• (2025). Quantum interference of force with entangled photons. PRA, 112(1), 012213. (www)

  @article{ , abstract = {In this work, we experimentally demonstrate the quantum interference of force effect using pairs of entangled photons. Although photons are massless particles, they have linear momentum, and our experiments show that the quantum superposition of a positive momentum transfer with a null momentum transfer may result in a negative momentum transfer to an ensemble of quantum particles (photons), a behavior with no classical analog. The momentum transfer to each photon is defined by the result of a polarization measurement performed in a second photon, initially entangled with it.}, archive = {J_PRA}, author = {Gabriela S. Militani and Artur Matoso and Denise F. Ávila and Raul Corrêa and Reinaldo O. Vianna and Pablo L. Saldanha and Sebastião Pádua}, doi = {10.1103/q93f-b32w}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012213}, shortjournal = {Phys. Rev. A}, title = {Quantum interference of force with entangled photons}, volume = {112}, year = {2025}, }
• (2025). Exploring the effects of mass dependence in spontaneous collapse models. PRA, 112(1), 012212. (www)

  @article{ , abstract = {Spontaneous collapse models aim to solve the long-standing measurement problem in quantum mechanics by modifying the theory's dynamics to include objective wave-function collapses. These collapses occur randomly in space, bridging the gap between quantum and classical behavior. A central feature of these models is their dependence on mass density, which directly influences how and when collapse events occur. In this work, we explore a generalized framework in which the collapse dynamics depend on arbitrary functions of the mass density, extending previous models. We analyze the theoretical consistency of these generalizations, investigate their predictions, and compare them with experimental data. Our findings show that only a limited range of mass-dependence functions are viable, with significant implications for the future development and empirical testability of collapse-based models. Importantly, they also indicate that a well-justified model denoted here as PSL shows much more resilience to experimental falsification than standard collapse models.}, archive = {J_PRA}, author = {Nicolò Piccione and Angelo Bassi}, doi = {10.1103/2yy5-tj85}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012212}, shortjournal = {Phys. Rev. A}, title = {Exploring the effects of mass dependence in spontaneous collapse models}, volume = {112}, year = {2025}, }
• (2025). Input-output hierarchical equations of motion. PRA, 112(1), 012211. (www)

  @article{ , abstract = {We derive an extended version of the hierarchical equations of motion (HEOM) to compute output physical properties of a bosonic environment, which is allowed to be initially prepared at an earlier time in a non-Gaussian input state and then nonperturbatively interact with a quantum system with a linear environmental operator. While spectral assumptions analogous to those used in the regular HEOM are imposed to compute dynamical output bath observables, they are not required to model input states or output observables at a fixed time, in this case leading to time-dependent contributions to the equations. In the Markovian limit, we use this formalism to derive an input-output Lindblad equation which can be used to extend the applicability of the regular version. For a given desired input state and output observable, the range of the indexes extending the regular HEOM is, by construction, bounded. Overall, the aim of this formalism is to take advantage of the efficiency and generality of the HEOM framework to model non-Gaussian input states and the dynamics of environmental observables in bosonic, non-Markovian open quantum systems.}, archive = {J_PRA}, author = {Mauro Cirio and Pengfei Liang and Neill Lambert}, doi = {10.1103/4q4p-z14x}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012211}, shortjournal = {Phys. Rev. A}, title = {Input-output hierarchical equations of motion}, volume = {112}, year = {2025}, }
• (2025). Role of non-markovian dissipation in quantum phase transitions: Tricriticality, spin squeezing, and directional symmetry breaking. PRA, 112(1), 012210. (www)

  @article{ , abstract = {Understanding how to control phase transitions in quantum systems is at the forefront of research for the development of new quantum materials and technologies. Here, we study how the coupling of a quantum system to a non-Markovian environment, i.e., an environment with a frequency-dependent spectral density inducing memory effects, can be used to generate and reshape phase transitions and squeezing in matter phases. Focusing on a Lipkin-Meshkov-Glick model, we demonstrate that non-Markovian dissipation can be leveraged to engineer tricriticality via the fusion of second-order and first-order critical points. We identify phases that arise from different ways of breaking the single weak symmetry of our model, which led us to examine an alternative concept of directional spontaneous symmetry breaking (DSSB) as a general framework to understand this phenomenon. We show that signatures of DSSB can be seen in the emergence of spin squeezing along different directions, and that the latter is controllable via non-Markovian effects, opening up possibilities for applications in quantum metrology. Finally, we propose an experimental implementation of our non-Markovian model in cavity QED. Our work features non-Markovianity as a resource for controlling phase transitions in general systems, and highlights shortcomings of the Markovian limit in this context.}, archive = {J_PRA}, author = {Baptiste Debecker and Lukas Pausch and Jonathan Louvet and Thierry Bastin and John Martin and François Damanet}, doi = {10.1103/4wq2-wyh4}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012210}, shortjournal = {Phys. Rev. A}, title = {Role of non-markovian dissipation in quantum phase transitions: Tricriticality, spin squeezing, and directional symmetry breaking}, volume = {112}, year = {2025}, }
• (2025). Random non-hermitian hamiltonian framework for symmetry-breaking dynamics. PRA, 112(1), 012209. (www)

  @article{ , abstract = {We propose random non-Hermitian Hamiltonians to model the generic stochastic nonlinear dynamics of a quantum state in Hilbert space. Our approach features an underlying linearity in the dynamical equations, ensuring the applicability of techniques used for solving linear systems. Additionally, it offers the advantage of easily incorporating statistical symmetry, a generalization of explicit symmetry to stochastic processes. To demonstrate the utility of our approach, we apply it to describe real-time dynamics, starting from an initial symmetry-preserving state and evolving into a randomly distributed, symmetry-breaking final state. Our model serves as a quantum framework for the transition process, from disordered states to ordered ones, where symmetry is spontaneously broken.}, archive = {J_PRA}, author = {Pei Wang}, doi = {10.1103/rkdn-j6hy}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012209}, shortjournal = {Phys. Rev. A}, title = {Random non-hermitian hamiltonian framework for symmetry-breaking dynamics}, volume = {112}, year = {2025}, }
• (2025). Nonsecular thermalization dynamics of multilevel quantum systems: Complete positivity and insights from kossakowski matrix spectra. PRA, 112(1), 012208. (www)

  @article{ , abstract = {We establish the complete positivity of a quantum dynamical map associated with the quantum optical master equation of the partial secular Bloch-Redfield type, which describes the generation of noise-induced Fano coherences in three-level and V systems driven by incoherent blackbody radiation. To this end, we calculate the equation's Kossakowski matrix by evaluating the action of the Liouvillian on the orthonormal ) basis matrices and then computing a sum of matrix-product traces [M. J. W. Hall et al. , Phys. Rev. A 89 , 042120 (2014) ]. We also show that the Kossakowski matrix can be calculated using an alternative approach based on the Moore-Penrose pseudo-inverse of a rectangular tensor composed of the structure constants of ). Using these approaches, we find that the eigenvalues of the Kossakowski matrix are identical for the and V systems, implying hitherto undetected similarities in their dissipative dynamics, further elucidated by examining the diagonal Lindblad operators constructed from Kossakowski matrix spectra. The approaches explored here enable the extraction of the Kossakowski matrix directly from the Liouvillian in the system eigenstate basis and do not require one to provide an operator form of the quantum master equation. They are expected to be particularly advantageous in situations where quantum master equations are defined only by their Liouvillians, facilitating valuable insights into dissipative processes in open multilevel quantum systems of prime importance in precision measurement, photosynthetic light harvesting, and quantum thermodynamics.}, archive = {J_PRA}, author = {Timur V. Tscherbul}, doi = {10.1103/vqmk-k771}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012208}, shortjournal = {Phys. Rev. A}, title = {Nonsecular thermalization dynamics of multilevel quantum systems: Complete positivity and insights from kossakowski matrix spectra}, volume = {112}, year = {2025}, }
• (2025). Open quantum systems with particle and bath driven by time-dependent fields. PRA, 112(1), 012207. (www)

  @article{ , abstract = {We derive a generalized quantum Langevin equation and its fluctuation-dissipation relation describing the quantum dynamics of a tagged particle interacting with a medium (environment), where both the particle and the environment are driven by an external time-dependent (e.g. oscillating) field. We specialize on the case of a charged tagged particle interacting with a bath of charged oscillators, under an external ac electric field, although the results are much more general and can be applied to any type of external time-dependent fields. We derive the corresponding quantum Langevin equation, which obeys a modified fluctuation-dissipation relation (FDR) where the ac field plays an explicit role. The modified FDR is non-Markovian even if the undriven particle-bath system is Markovian without the external field. We provide an illustration of the usefulness of these results and derive a new form of the quantum Nyquist noise for the voltage fluctuations in electrical circuits under ac conditions (finite frequency), which is the most general since it also accounts for the response of the heat bath (e.g. lattice ions) to the applied ac electric field in the GHz–THz region, of relevance for 5G/6G wireless technologies. This generalized quantum fluctuation-dissipation relation for driven systems can also find other applications ranging from quantum noise in quantum optics to quantum computing with trapped ions.}, archive = {J_PRA}, author = {Daniele Gamba and Bingyu Cui and Alessio Zaccone}, doi = {10.1103/w3vk-wx62}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012207}, shortjournal = {Phys. Rev. A}, title = {Open quantum systems with particle and bath driven by time-dependent fields}, volume = {112}, year = {2025}, }
• (2025). Accuracy of a time-dependent generalized gibbs ensemble approach under weak dissipation. PRA, 112(1), 012206. (www)

  @article{ , abstract = {Unitary integrable models typically relax to a stationary generalized Gibbs ensemble (GGE), but in experimental realizations dissipation often breaks integrability. In this work, we use the recently introduced time-dependent GGE (t-GGE) approach to describe the open dynamics of a gas of bosons subject to atom losses and gains. We employ tensor network methods to provide numerical evidence of the exactness of the t-GGE in the limit of adiabatic dissipation, and of its accuracy in the regime of weak but finite dissipation. That accuracy is tested for two-point functions via the rapidity distribution, and for more complicated correlations through a non-Gaussianity measure. We combine this description with generalized hydrodynamics and we show that it correctly captures transport at large scales. Our results demonstrate that the t-GGE approach is robust in both homogeneous and inhomogeneous settings.}, archive = {J_PRA}, author = {Luca Lumia and Gianni Aupetit-Diallo and Jérôme Dubail and Mario Collura}, doi = {10.1103/x9c1-hyxh}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012206}, shortjournal = {Phys. Rev. A}, title = {Accuracy of a time-dependent generalized gibbs ensemble approach under weak dissipation}, volume = {112}, year = {2025}, }
• (2025). Reliable quantum advantage in quantum battery charging. PRA, 112(1), 012205. (www)

  @article{ , abstract = {Quantum batteries represent one of the most promising applications of quantum thermodynamics, whose goal is not only to store energy inside small quantum systems but also to potentially leverage genuine quantum effects to outperform classical counterparts. In this context, however, energy fluctuations become extremely relevant and have a significant impact on the charging efficiency. In our work, we consider a simple yet paradigmatic model in which a flying qubit (the battery) coherently interacts with a single-mode optical cavity (the charger) through a number conserving Jaynes-Cummings interaction. By making use of full-counting statistics techniques, we fully characterize the average charging power, its fluctuations, and the associated charging efficiency for several different choices of initial states of the optical cavity, demonstrating that preparing the latter in a genuinely quantum non-Gaussian Fock state (rather than a classical or even nonclassical Gaussian state) leads to a definite and in principle measurable advantage in all these figures of merit.}, archive = {J_PRA}, author = {Davide Rinaldi and Radim Filip and Dario Gerace and Giacomo Guarnieri}, doi = {10.1103/6kwv-z6fx}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012205}, shortjournal = {Phys. Rev. A}, title = {Reliable quantum advantage in quantum battery charging}, volume = {112}, year = {2025}, }
• (2025). Dynamical non-hermitian systems: Fingerprints and pure-dephasing-induced protection effect. PRA, 112(1), 012204. (www)

  @article{ , abstract = {Non-Hermitian systems have shown promising potential for realizing quantum information tasks that lack counterparts in the Hermitian realm. Understanding the dynamical characteristics of non-Hermitian systems as reflected in information-theoretic quantities is essential for advancing their applications. Here we investigate the dynamics of the trace distance and concurrence, which quantify information flow and entanglement, respectively, in non-Hermitian qubit systems exhibiting either parity-time or anti-parity-time symmetry. We identify dynamical fingerprints from the system density matrix which provide a unified explanation to the common oscillation and relaxation dynamics shared by the trace distance and concurrence observed in existing studies. We further investigate the fate of dynamical fingerprints under the impact of pure dephasing. Surprisingly, we find that pure dephasing can slow down the inherent relaxation of information flow and entanglement in non-Hermitian systems with unbroken anti-parity-time symmetry, suggesting a passive environment-assisted information protection in this class of non-Hermitian systems. Our findings enhance our understanding of dynamical non-Hermitian systems and have specific relevance to their information-oriented applications.}, archive = {J_PRA}, author = {Wanchen Ma and Hao Zhang and Junjie Liu}, doi = {10.1103/5d73-nrtb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012204}, shortjournal = {Phys. Rev. A}, title = {Dynamical non-hermitian systems: Fingerprints and pure-dephasing-induced protection effect}, volume = {112}, year = {2025}, }
• (2025). Generalized entropic quantum speed limits. PRA, 112(1), 012203. (www)

  @article{ , abstract = {We present a class of generalized entropic quantum speed limits based on -Rényi relative entropy, a real-valued, contractive, two-parameter family of distinguishability measures. The quantum speed limit (QSL) falls into the class of Mandelstam-Tamm bounds, and it applies to finite-dimensional quantum systems that undergo a general physical process, i.e., their effective dynamics can be modeled by unitary or nonunitary evolutions. The results cover pure or mixed, separable, and entangled probe quantum states. The QSL time depends on the smallest and largest eigenvalues of the probe and instantaneous states of the system, and its evaluation requires low computational cost. In addition, it is inversely proportional to the time-average of the Schatten speed of the instantaneous state, which in turn is fully characterized by the considered dynamics. We specialize our results to the case of unitary and nonunitary evolutions. In the former case, the QSL scales with the inverse of the energy fluctuations, while the latter depends on the Schatten 1-norm of the rate of change of the quantum channel Kraus operators. We illustrate our findings for single-qubit and two-qubit states, and unitary and nonunitary evolutions. Our results may find applications in the study of entropic uncertainty relations, quantum metrology, and also entanglement entropies signaled by generalized entropies.}, archive = {J_PRA}, author = {Jucelino Ferreira de Sousa and Diego Paiva Pires}, doi = {10.1103/ghr4-d2vb}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012203}, shortjournal = {Phys. Rev. A}, title = {Generalized entropic quantum speed limits}, volume = {112}, year = {2025}, }
• (2025). Quantum schrödinger bridges: Large deviations and time-symmetric ensembles. PRA, 112(1), 012202. (www)

  @article{ , abstract = {Quantum counterparts of Schrödinger's classical bridge problem have been around for the better part of half a century. During that time, several quantum approaches to this multifaceted classical problem have been introduced. In the present work, we unify, extend, and interpret several such approaches through a classical large-deviations perspective. To this end, we consider time-symmetric ensembles that are pre- and postselected before and after a Markovian experiment is performed. Then, the Schrödinger bridge problem is that of finding the most likely joint distribution of initial and final outcomes that is consistent with obtained endpoint results. The derived distribution provides quantum Markovian dynamics that bridge the observed endpoint states in the form of density matrices. The solution retains its classical structure in that density matrices can be expressed as the product of forward-evolving and backward-evolving matrices. In addition, the quantum Schrödinger bridge allows inference of the most likely distribution of outcomes of an intervening measurement with unknown results. This distribution may be written as a product of forward- and backward-evolving expressions, in close analogy to the classical setting, and in a time-symmetric way. The derived results are illustrated through a two-level amplitude-damping example.}, archive = {J_PRA}, author = {Olga Movilla Miangolarra and Ralph Sabbagh and Tryphon T. Georgiou}, doi = {10.1103/k35b-rkct}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012202}, shortjournal = {Phys. Rev. A}, title = {Quantum schrödinger bridges: Large deviations and time-symmetric ensembles}, volume = {112}, year = {2025}, }
• (2025). Classical analog of entanglement for a kicked top. PRA, 112(1), 012201. (www)

  @article{ , abstract = {Classical chaos is usually characterized by the sensitive dependence of trajectories on initial conditions. However, in quantum mechanics, the unitarity of time evolution ensures that the distances between quantum states are preserved in time. It has, therefore, been a challenge in quantum chaos to reconcile the lack of sensitive dependence on initial conditions with classical chaos. Ballentine [Fundamental Problems in Quantum Physics, edited by M. Ferrero and A. van der Merwe (Springer Netherlands, Dordrecht, 1995), pp. 15–28] has suggested a way out by constructing a parallel argument in classical mechanics based on the preservation of the inner product of phase-space densities. He has argued that the exponential separation of nearby states is a good identifier of chaos only at the level of individual trajectories. For statistical states such as quantum states and classical phase-space densities, chaos must instead be identified by some fundamentally statistical signatures. The search for these signatures is the primary goal in quantum chaos research. However, this perspective also naturally motivates the search for classical analogs of these signatures to reveal the inner machinery of chaos in quantum systems. One widely recognized signature of chaos in quantum systems is the dynamical generation of entanglement. Chaos in the classical system is correlated with a greater entanglement production in the corresponding quantum system. One of the most well-studied examples of this is the kicked top model. In this paper, we construct a classical analog of bipartite entanglement in terms of the mutual information between phase-space distributions of subsystems and find completely analogous signatures of chaos as those found in entanglement for the kicked top Hamiltonian.}, archive = {J_PRA}, author = {Bilal Khalid and Sabre Kais}, doi = {10.1103/3ldj-zwfg}, journal = {Physical Review a}, month = {7}, number = {1}, pages = {012201}, shortjournal = {Phys. Rev. A}, title = {Classical analog of entanglement for a kicked top}, volume = {112}, year = {2025}, }
• (2025). Chiral-extended photon-emitter dressed states in non-hermitian topological baths. PRA, 111(6), L061701. (www)

  @article{ , abstract = {The interplay of quantum emitters and non-Hermitian structured baths has received increasing attention in recent years. Here we predict unconventional quantum optical behaviors of quantum emitters coupled to a non-Hermitian topological bath, which is realized in a 1D Su-Schrieffer-Heeger photonic chain subjected to nonlocal dissipation. In addition to the Hermitian-like chiral bound states in the middle line gap and skin-mode-like hidden bound states inside the point gap, we identify peculiar in-gap chiral and extended photon-emitter dressed states. This is due to the competition of topological-edge localization and non-Hermitian skin-mode localization in combination with the non-Bloch bulk-boundary correspondence. Strikingly, dissipation can shape the wave-function profile of the dressed state. Furthermore, when two emitters are coupled to the same bath, such in-gap dressed states can mediate the nonreciprocal long-range emitter-emitter interactions, with the interaction range limited only by the dissipation of the bath. Our work opens the door to further study rich quantum optical phenomena and exotic many-body physics utilizing quantum emitters coupled to non-Hermitian baths.}, archive = {J_PRA}, author = {Zhao-Fan Cai and Xin Wang and Zi-Xuan Liang and Tao Liu and Franco Nori}, doi = {10.1103/8qpx-68x6}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L061701}, shortjournal = {Phys. Rev. A}, title = {Chiral-extended photon-emitter dressed states in non-hermitian topological baths}, volume = {111}, year = {2025}, }
• (2025). Observation of transition radiation carrying orbital angular momentum. PRA, 111(6), L061501. (www)

  @article{ , abstract = {Twisted photons carrying orbital angular momentum, which have potential applications spanning diverse fields, have been extensively studied since the theoretical work of Allen et al. in 1992. Various methods for direct producing twisted photons have been explored, leveraging the rotational (spiral) motion of relativistic electrons in phenomena such as undulator radiation. In the present study, transition radiation carrying orbital angular momentum is observed. This radiation was generated by 220 MeV electrons incident on an Au-coated Si wafer. The orbital angular momentum was measured by analyzing the diffraction patterns produced as the radiation passed through a triangular aperture and a double slit. These results demonstrate that twisted photons can also be generated through the interaction of rectilinearly moving electrons with a solid target.}, archive = {J_PRA}, author = {Y. Takabayashi and H. Takeda and E. Magome and K. Sumitani and P. O. Kazinski and P. S. Korolev and O. V. Bogdanov and T. A. Tukhfatullin}, doi = {10.1103/gxwj-yvdj}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L061501}, shortjournal = {Phys. Rev. A}, title = {Observation of transition radiation carrying orbital angular momentum}, volume = {111}, year = {2025}, }
• (2025). Polaronic dressing of bound states. PRA, 111(6), L061302. (www)

  @article{ , abstract = {Polarons have emerged as a powerful concept across many fields in physics to study an impurity coupled to a quantum bath. The interplay between impurity physics and the formation of composite objects remains a relevant problem to understand how few- and many-body states are robust towards complex environments and polaron physics. In most cases, impurities are modeled as pointlike objects. The question we address here is how quasiparticle properties are affected when impurities possess an internal structure. The simplest yet fundamental structure for the impurity is a dimer state. Here, we investigate the polaronic properties of a dimer dressed by the elementary excitations of a bosonic bath. We solve the two-body impurity-impurity problem to determine the position and broadening of the bound state and consider the polaron dressing using a field-theory approach. We demonstrate the emergence of different dressed dimer regimes, where polaron dressing drives a dimer from a well-defined to an ill-defined bound state.}, archive = {J_PRA}, author = {L. A. Peña Ardila and A. Camacho-Guardian}, doi = {10.1103/lvtz-9lfp}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L061302}, shortjournal = {Phys. Rev. A}, title = {Polaronic dressing of bound states}, volume = {111}, year = {2025}, }
• (2025). All-optical production of bose-einstein condensates with a 2-hz repetition rate. PRA, 111(6), L061301. (www)

  @article{ , abstract = {Bose-Einstein condensates (BECs) of neutral atoms constitute an important quantum system for fundamental research and precision metrology. Many applications require short preparation times of BECs, for example, for optimized data acquisition rates in scientific applications, and reduced dead times and improved bandwidths for atomic quantum sensors. Here, we report on the generation of rubidium BECs with a repetition rate of more than . The system relies on forced evaporation in a dynamically adjusted optical potential, which is created by the spatial modulation of laser beams. Our system provides a versatile source of the ubiquitous rubidium BECs, and promotes their exploitation for high-precision atom interferometers.}, archive = {J_PRA}, author = {Mareike Hetzel and Martin Quensen and Jan Simon Haase and Carsten Klempt}, doi = {10.1103/PhysRevA.111.L061301}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L061301}, shortjournal = {Phys. Rev. A}, title = {All-optical production of bose-einstein condensates with a 2-hz repetition rate}, volume = {111}, year = {2025}, }
• (2025). Simultaneous imaging of vibrational, rotational, and electronic wave-packet dynamics in a triatomic molecule. PRA, 111(6), L061101. (www)

  @article{ , abstract = {Light-induced molecular dynamics often involve the excitation of several electronic, vibrational, and rotational states. Since the ensuing electronic and nuclear motion determines the pathways and outcomes of photoinduced reactions, our ability to monitor and understand these dynamics is crucial for molecular physics, physical chemistry, and photobiology. However, characterizing this complex motion represents a significant challenge when different degrees of freedom are strongly coupled. In this Letter, we demonstrate how the interplay between vibrational, rotational, and electronic degrees of freedom governs the evolution of molecular wave packets in the low-lying states of strong-field-ionized sulfur dioxide. Using time-resolved Coulomb explosion imaging (CEI) and quantum mechanical wave packet simulations, we directly map the bending vibrations of the molecule, show how the vibrational wave packet is influenced by molecular alignment, and elucidate the consequences of nuclear motion for the coupling between the two lowest electronic states of the cation. Our results demonstrate that multicoincident CEI can be an efficient experimental tool for characterizing coupled electronic and nuclear motion in polyatomic molecules.}, archive = {J_PRA}, author = {Huynh Van Sa Lam and Van-Hung Hoang and Anbu Selvam Venkatachalam and Surjendu Bhattacharyya and Keyu Chen and Sina Jacob and Sanduni Kudagama and Tu Thanh Nguyen and Daniel Rolles and Uwe Thumm and Artem Rudenko and Vinod Kumarappan}, doi = {10.1103/1yd8-786g}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L061101}, shortjournal = {Phys. Rev. A}, title = {Simultaneous imaging of vibrational, rotational, and electronic wave-packet dynamics in a triatomic molecule}, volume = {111}, year = {2025}, }
• (2025). Precise determination of electric quadrupole moments and isotope shift constants of yb+ in pursuance of probing fundamental physics and nuclear radii. PRA, 111(6), L060801. (www)

  @article{ , abstract = {In an effort to obtain the signature of a new vector boson unambiguously from the measured nonlinear isotope shift (IS) effects in three recent experiments [ Phys. Rev. X 12 , 021033 (2022) ; Phys. Rev. Lett. 128 , 163201 (2022) ; and Phys. Rev. Lett. 134 , 063002 (2025) ], very precise values of quadrupole moments and IS constants for the and clock transitions of are presented. This is accomplished by incorporating contributions from the computationally challenging triply excited configurations through the relativistic coupled-cluster (RCC) theory. Testament of quality atomic wave functions of states of the above transitions, obtained using the RCC theory, are gauged by comparing the calculated energies and magnetic dipole hyperfine structure constants with their measurements. The improved quadrupole moments from this work will be immensely useful to estimate quadrupole shifts of the clock transitions of . Complementary approaches are employed to ascertain accuracy and comprehend roles of orbital relaxation and correlation effects in evaluating the IS constants. Combining these constants with the IS measurements from Phys. Rev. Lett. 128 , 163201 (2022) , differential nuclear charge radii of the Yb isotopes are inferred that deviate by 6–7% from the literature data.}, archive = {J_PRA}, author = {B. K. Sahoo}, doi = {10.1103/PhysRevA.111.L060801}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L060801}, shortjournal = {Phys. Rev. A}, title = {Precise determination of electric quadrupole moments and isotope shift constants of yb+ in pursuance of probing fundamental physics and nuclear radii}, volume = {111}, year = {2025}, }
• (2025). Experimental virtual quantum broadcasting. PRA, 111(6), L060402. (www)

  @article{ , abstract = {The quantum no-broadcasting theorem states that it is fundamentally impossible to perfectly replicate an arbitrary quantum state, even if correlations between the copies are allowed. While quantum broadcasting cannot occur through any physical process, it can be achieved via postprocessing of experimental data using a process called virtual quantum broadcasting (VQB). In this work, we report an experimental implementation of a quantum circuit based on the linear combination of unitaries, integrated with a postprocessing protocol, to realize VQB in a nuclear magnetic resonance system. VQB can be expressed as a linear combination of two channels: the universal cloner, which broadcasts the target quantum state, and the universal antisymmetrizer, which reduces broadcasting error. We implement both channels within the same circuit and demonstrate that the universal cloner is the closest physical map to VQB. In addition, we show how the universal antisymmetrizer can be utilized to mitigate imperfections in the cloner, enabling near-ideal fidelity. Our method is applicable to broadcasting quantum systems of any dimension.}, archive = {J_PRA}, author = {Yuxuan Zheng and Xinfang Nie and Hongfeng Liu and Yutong Luo and Dawei Lu and Xiangjing Liu}, doi = {10.1103/8vrg-tvsd}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L060402}, shortjournal = {Phys. Rev. A}, title = {Experimental virtual quantum broadcasting}, volume = {111}, year = {2025}, }
• (2025). Multivariate bicycle codes. PRA, 111(6), L060401. (www)

  @article{ , abstract = {Quantum error correction suppresses noise in quantum systems to allow for high-precision computations. In this Letter, we introduce multivariate bicycle quantum low-density parity-check (QLDPC) codes, via an extension of the framework developed by Bravyi et al. [S. Bravyi, A. W. Cross, J. M. Gambetta, D. Maslov, P. Rall, and T. J. Yoder, Nature (London) 627 , 778 (2024) ], and particularly focus on trivariate bicycle (TB) codes. Unlike the weight-6 codes proposed in their study, we offer concrete examples of weight-5 TB-QLDPC codes which promise to be more amenable to near-term experimental setups. We show that TB-QLDPC codes up to weight 6 have a biplanar structure and often possess a two-dimensional toric layout. Under circuit level noise, we find substantially better encoding rates than comparable surface codes while offering similar error suppression capabilities. For example, we can encode four logical qubits with distance 5 into 60 physical qubits using weight-5 check measurements of circuit depth 7, while a surface code with these parameters requires 200 physical qubits. The high encoding rate and compact layout make our codes highly suitable candidates for near-term hardware implementations, paving the way for a realizable quantum error correction protocol.}, archive = {J_PRA}, author = {Lukas Voss and Sim Jian Xian and Tobias Haug and Kishor Bharti}, doi = {10.1103/ll5p-z88p}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L060401}, shortjournal = {Phys. Rev. A}, title = {Multivariate bicycle codes}, volume = {111}, year = {2025}, }
• (2025). Effects of superradiance on relativistic foldy-wouthuysen densities. PRA, 111(6), L060202. (www)

  @article{ , abstract = {Recent interest in the studies of structured states obtained in relativistic electron beams has highlighted the use of two alternative descriptions, each based on a different wave function and the related space-time density. Although both wave functions obey the Dirac equation (one directly and the other through a Foldy-Wouthuysen transformation), they lead to different dynamics and properties, such as the presence or absence of spin-orbit interactions. In this work we investigate wave-packet dynamics for the Klein-Gordon equation, which displays the same ambiguity regarding the choice of different densities, in a setting involving Klein tunneling across a series of supercritical potential barriers. Relying on the superradiant character of this setting, we obtain solutions to the wave-packet dynamics indicating that the density based on a Foldy-Wouthuysen transformation of the wave function can be locally amplified outside the light cone. In principle, the exponential increase of the charge due to the field inhomogeneities can lead to an arbitrarily large amplification over macroscopic distances. These results question the interpretation of the Foldy-Wouthuysen density as a fundamentally correct probability or charge density.}, archive = {J_PRA}, author = {F. Daem and A. Matzkin}, doi = {10.1103/d38q-h3qw}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L060202}, shortjournal = {Phys. Rev. A}, title = {Effects of superradiance on relativistic foldy-wouthuysen densities}, volume = {111}, year = {2025}, }
• (2025). Uncertainty relations relative to phase-space quantum reference frames. PRA, 111(6), L060201. (www)

  @article{ , abstract = {We study Heisenberg's uncertainty relation relative to a quantum reference frame (QRF). We introduce the QRF as a covariant phase space observable, show that when described relative to it, position and momentum appear compatible, and derive novel, frame-relative uncertainty relations. This is achieved by constructing a joint observable for position and momentum, and calculating the variances of its margins. We then verify that in the classical limit of the QRF, the standard uncertainty relations are recovered, fortifying claims that standard quantum theory must be understood relative to an external, classical frame. These results may open up new research directions at the interface between QRFs and incompatibility.}, archive = {J_PRA}, author = {Miguel Jorquera Riera and Leon Loveridge}, doi = {10.1103/PhysRevA.111.L060201}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {L060201}, shortjournal = {Phys. Rev. A}, title = {Uncertainty relations relative to phase-space quantum reference frames}, volume = {111}, year = {2025}, }
• (2025). Erratum: Compression, spectral broadening, and collimation in multiple, femtosecond pulse filamentation in atmosphere [Phys. rev. a 86, 033834 (2012)]. PRA, 111(6), 069901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 069901 (2025)}, archive = {J_PRA}, author = {J. P. Palastro and T. M. Antonsen, Jr and H. M. Milchberg}, doi = {10.1103/mshd-sjfv}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {069901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Compression, spectral broadening, and collimation in multiple, femtosecond pulse filamentation in atmosphere [Phys. rev. a 86, 033834 (2012)]}, volume = {111}, year = {2025}, }
• (2025). Reply to “Comment on ‘Energy-level shift of quantum systems via the scalar electric aharonov-bohm effect' ”. PRA, 111(6), 066204. (www)

  @article{ , abstract = {We respond to the points raised in the preceding Comment [ Phys. Rev. A 111 , 066203 (2025) ] on our recent work [ Phys. Rev. A 107 , 042209 (2023) ], which introduced a theoretical framework for the scalar electric Aharonov-Bohm effect. In this Reply, we take the opportunity to address specific criticisms, by referring to foundational aspects of gauge invariance and time-dependent quantum systems. We explain why the gauging procedure used in the Comment leads to inconsistencies and show that, when applied similarly to the well-established magnetic Aharonov-Bohm effect, it would yield demonstrably incorrect conclusions. Moreover, we highlight the consistency of our results with canonical treatments of the time-dependent Schrödinger equation, and we reaffirm the physicality of energy shifts in field-free regions, an effect observed in the magnetic and predicted in the electric Aharonov-Bohm contexts. We believe that this response contributes to a deeper understanding of the subtleties involved in gauge theory and quantum phase phenomena.}, archive = {J_PRA}, author = {R. Y. Chiao and H. Hart and M. Scheibner and J. Sharping and N. A. Inan and D. A. Singleton and M. E. Tobar}, doi = {10.1103/mtfh-m6tr}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {066204}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Energy-level shift of quantum systems via the scalar electric aharonov-bohm effect' ”}, volume = {111}, year = {2025}, }
• (2025). Comment on “Energy-level shift of quantum systems via the scalar electric aharonov-bohm effect”. PRA, 111(6), 066203. (www)

  @article{ , abstract = {Recently, Chiao et al. proposed a novel scalar electric Aharonov-Bohm (AB) effect [ Phys. Rev. A 107 , 042209 (2023) ]. They claimed that a quantum system inside a Faraday cage with a time-varying but spatially uniform scalar potential acquires an AB phase, resulting in observable energy-level shifts. This Comment argues that their analysis is flawed: A spatially uniform scalar potential inside the cage, despite external variations, can be gauged away without altering gauge-invariant observables, such as energy differences, thus invalidating their claim. A possible explanation of this seemingly puzzling result is also given.}, archive = {J_PRA}, author = {Shan Gao}, doi = {10.1103/c8t7-y8h2}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {066203}, shortjournal = {Phys. Rev. A}, title = {Comment on “Energy-level shift of quantum systems via the scalar electric aharonov-bohm effect”}, volume = {111}, year = {2025}, }
• (2025). Reply to “Comment on ‘Association between quantum paradoxes based on weak values and a realistic interpretation of quantum measurements' ”. PRA, 111(6), 066202. (www)

  @article{ , abstract = {Seoane et al. [preceding Comment, Phys. Rev. A 111 , 066201 (2025) ] criticized our work [ Phys. Rev. A 109 , 022238 (2024) ], saying that our argument that realistic interpretations of weak values lead to inconsistencies is not valid for all weak values and quantum theories. This is true. We never intended that the arguments we presented would be valid for all weak values. We believe it is clearly stated in our work that we were dealing only with the weak values related to the quantum paradoxes cited in our paper. Seoane et al. also said in their Comment that the “general argument” we present in our paper is formally incorrect. However, this criticism is related to the interpretation they give to the expression “equivalent,” which is different from the one we use. In this sense, the presented criticisms are a matter of semantics, not of physics.}, archive = {J_PRA}, author = {Alice M. Aredes and Pablo L. Saldanha}, doi = {10.1103/PhysRevA.111.066202}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {066202}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Association between quantum paradoxes based on weak values and a realistic interpretation of quantum measurements' ”}, volume = {111}, year = {2025}, }
• (2025). Comment on “Association between quantum paradoxes based on weak values and a realistic interpretation of quantum measurements”. PRA, 111(6), 066201. (www)

  @article{ , abstract = {In their paper [ Phys. Rev. A 109 , 022238 (2024) ], Aredes and Saldanha analyze several paradoxes related to weak values and present a “general argument” that aims to show that “realistic interpretations of weak values lead to inconsistencies.” Although we agree with the identified inconsistencies for the specific weak values analyzed there, in this Comment we demonstrate that the origin of these inconsistencies is not their general argument, which is formally incorrect. We use Bohmian mechanics as a counterexample to confirm that their conclusions are not valid for all weak values and quantum theories. In particular, we show that weak values postselected in position can in fact be interpreted within Bohmian mechanics as properties of quantum systems, detached from any measuring devices, in a consistent and meaningful way.}, archive = {J_PRA}, author = {Juan Jose Seoane and Xabier Oianguren-Asua and Albert Solé and Xavier Oriols}, doi = {10.1103/PhysRevA.111.066201}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {066201}, shortjournal = {Phys. Rev. A}, title = {Comment on “Association between quantum paradoxes based on weak values and a realistic interpretation of quantum measurements”}, volume = {111}, year = {2025}, }
• (2025). Realizing the optimal measurement scheme for an SU(1,1) interferometer in ab initio phase estimation. PRA, 111(6), 063711. (www)

  @article{ , abstract = {In phase estimation via quantum interferometry, measurement precision is governed by the quantum state and the measurement strategy. Nonlinear SU(1,1) interferometers prepare entangled states that have been shown to enable Heisenberg-limit precision. In previous work, we developed the optimal measurement scheme, which saturates the ultimate limit in ab initio phase estimation, avoiding the issue of ambiguity. However, realizing this scheme is highly nontrivial and involves measurements beyond the photon-number operator. In this study, we propose a probabilistic measurement scheme capable of realizing the optimal measurement scheme with a success rate of 50% through postselection. This method allows us to achieve Heisenberg-scaling precision but it is suboptimal with respect to saturation of the quantum Cramér-Rao bound. It utilizes projection synthesis by introducing an ancillary optical mode prepared in a superposition state, combined with standard photon-number-resolving detection. This approach provides insights into the physical realization of optimal measurement strategies in nonlinear interferometers, with implications for quantum precision measurement in general.}, archive = {J_PRA}, author = {Mingchen Liu and Haixing Miao and Lijian Zhang}, doi = {10.1103/rv9m-n7px}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063711}, shortjournal = {Phys. Rev. A}, title = {Realizing the optimal measurement scheme for an SU(1,1) interferometer in ab initio phase estimation}, volume = {111}, year = {2025}, }
• (2025). Theory of symmetry-protected two-photon coherence. PRA, 111(6), 063710. (www)

  @article{ , abstract = {In a recent article [X. Lai et al. , Phys. Rev. Lett. 133 , 033601 (2024) ], the coherence time of degenerate entangled photon pairs (biphotons) generated via backward spontaneous four-wave mixing in a cold atomic ensemble was shown to be immune to optical loss and dephasing. This finding is crucial for practical applications in quantum information processing, quantum communication, and networking, where loss is inevitable. However, in studying the underlying mechanism for this loss- and dephasing-insensitive biphoton coherence time, the previous article did not take quantum noise into account. In this work, we employ the Heisenberg-Langevin approach to study this effect and provide a rigorous theoretical proof of the symmetry-protected biphoton coherence by taking quantum noise into consideration, as compared to the perturbation theory in the interaction picture.}, archive = {J_PRA}, author = {Xuanying Lai and Shengwang Du and Yue Jiang}, doi = {10.1103/gqpg-1nv3}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063710}, shortjournal = {Phys. Rev. A}, title = {Theory of symmetry-protected two-photon coherence}, volume = {111}, year = {2025}, }
• (2025). Geometric phase and wave-particle duality of the photon. PRA, 111(6), 063709. (www)

  @article{ , abstract = {The concepts of geometric phase and wave-particle duality are interlinked to several fundamental phenomena in quantum physics, but their mutual relationship has remained a largely uncharted topic. Here we address this subject by studying the geometric phase of a photon in double-slit interference. In particular, we discover a general complementarity relation for the photon that connects the geometric phase it exhibits in the observation plane and the which-path information it encases at the two slits. The relation can be seen as quantifying wave-particle duality of the photon via the geometric phase, thus corroborating an important link between two ubiquitous notions in quantum physics.}, archive = {J_PRA}, author = {Elvis Pillinen and Atri Halder and Ari T. Friberg and Tero Setälä and Andreas Norrman}, doi = {10.1103/s3hf-2zyr}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063709}, shortjournal = {Phys. Rev. A}, title = {Geometric phase and wave-particle duality of the photon}, volume = {111}, year = {2025}, }
• (2025). Anomalous dependence of sensitivity on observation time caused by memory retention in a system with broken time-translation symmetry. PRA, 111(6), 063708. (www)

  @article{ , abstract = {In this work, we consider a composite atom-cavity system interacting with a ring resonator. In such a structure, the spontaneous breaking of time-translation symmetry can be observed. We show that a quadratic observation time dependence of the system's sensitivity to perturbations takes place in the broken time-translation symmetry regime and also in the transition area to the normal state. This dependence is due to the system's ability to retain the memory of the initial state of the atom. Outside these areas, the system does not retain the memory of the initial state of the atom, and the sensitivity scales linearly with the observation time. Our results open up a way for the implementation of systems with broken time-translation symmetry in sensing and metrology.}, archive = {J_PRA}, author = {Timofey T. Sergeev and Alexander A. Zyablovsky and Evgeny S. Andrianov}, doi = {10.1103/2pz7-kgxr}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063708}, shortjournal = {Phys. Rev. A}, title = {Anomalous dependence of sensitivity on observation time caused by memory retention in a system with broken time-translation symmetry}, volume = {111}, year = {2025}, }
• (2025). Postselected von neumann measurement with superpositions of orbital angular momentum pointer states. PRA, 111(6), 063707. (www)

  @article{ , abstract = {We investigated an orbital-angular-momentum (OAM) pointer within the framework of von Neumann measurement and discovered its significant impact on optimizing superpositions of Gaussian and Laguerre-Gaussian (LG) states. Calculations of quadrature squeezing, correlation functions, Wigner function, and the signal-to-noise ratio (SNR) support our findings. Specifically, by carefully selecting the anomalous weak value (WV) and the coupling strength between the measured system and the pointer, we demonstrated that the initial Gaussian state transforms into a non-Gaussian state after postselection measurement. We also noticed that in the weak coupling regime it is possible to get perfect quadrature squeezing of our output state with anomalous WVs. This transition highlights the potential of OAM pointer states to enhance the performance of quantum systems by tailoring state properties for specific applications.}, archive = {J_PRA}, author = {Janarbek Yuanbek and Yi-Fang Ren and Yusuf Turek}, doi = {10.1103/tnvf-nrq4}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063707}, shortjournal = {Phys. Rev. A}, title = {Postselected von neumann measurement with superpositions of orbital angular momentum pointer states}, volume = {111}, year = {2025}, }
• (2025). Enhanced sensing by geometric tuning of YIG spheres: Noise reduction, signal amplification, and directional magnetic-field detection. PRA, 111(6), 063706. (www)

  @article{ , abstract = {Noise suppression and directional signal enhancement are essential challenges in detecting weak magnetic fields in cavity electrodynamics systems. Traditional schemes struggle to reduce magnonic probe noise but lack directional sensing capabilities. We exploit an innovative and intrinsic squeezing mechanism by leveraging the geometric configuration of an anisotropic ellipsoidal yttrium iron garnet (YIG) sphere and its interaction with internal demagnetization fields. This mechanism can enhance magnetic field signals and suppress noise in the target direction while suppressing sensitivity in nontarget directions to avoid disturbing the target direction, thus generating a directionally selective sensing scheme realizing high-precision detection in complex environments. In particular, the target-direction sensor performance can be optimized by adjusting the YIG sphere's geometry (e.g., aspect ratio) without complex setups, ensuring high feasibility and scalability. Our approach offers greater flexibility and directionality by tuning the YIG sphere's geometry than existing methods. This innovation provides an alternative approach for weak magnetic field detection in cavity magnonics systems, with potential applications in biomedical imaging, quantum sensing, precision measurement, and environmental monitoring.}, archive = {J_PRA}, author = {Zheng Liu and Ding-hui Xu and Yi-jia Yang and Chang-shui Yu}, doi = {10.1103/mqdg-wvkk}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063706}, shortjournal = {Phys. Rev. A}, title = {Enhanced sensing by geometric tuning of YIG spheres: Noise reduction, signal amplification, and directional magnetic-field detection}, volume = {111}, year = {2025}, }
• (2025). Experimental investigation of the uncertainty relation in pre- and postselected systems. PRA, 111(6), 063705. (www)

  @article{ , abstract = {The uncertainty principle is one of the fundamental principles of quantum mechanics. Exploring such uncertainty relations in pre- and postselected (PPS) systems, where weak measurements on postselected states have been used as a powerful tool for exploring the foundation of quantum mechanics, has so far eluded experimental effort. In this work, we experimentally investigate the Robertson-Heisenberg-type uncertainty relation for two incompatible observables in a PPS system. Through conducting a von Neumann-type measurement, uncertainty relations between two noncommuting Pauli observables are experimentally unveiled. Such uncertainty relations in the PPS system impose limitations on the joint sharp preparation of pre- and postselected states for two incompatible observables. Our experiments would be useful for the development of amplification techniques for precision measurements.}, archive = {J_PRA}, author = {Yue Zhang and Xinyang Che and Yuanbang Wei and Rui Tian and Yi-an Li and Miao Zhang and Shuai Li and Bo Liu}, doi = {10.1103/y287-sf69}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063705}, shortjournal = {Phys. Rev. A}, title = {Experimental investigation of the uncertainty relation in pre- and postselected systems}, volume = {111}, year = {2025}, }
• (2025). Hierarchies of quantum non-gaussian coherences for bosonic systems: A theoretical study. PRA, 111(6), 063704. (www)

  @article{ , abstract = {Quantum coherence in bosonic systems is a fundamental resource for quantum technology applications. In this work, we introduce a framework for analyzing coherence in the Fock-state basis, utilizing context-dependent certification to reveal the quantum non-Gaussian nature of the tested coherence. Rather than relying on global coherence measures, our approach targets specific aspects of coherence, enabling a tailored hierarchical classification. We derive and compare two distinct hierarchies, each representing a different context for coherence in bosonic systems. Motivated by current advancements in optical quantum state engineering, we assess the feasibility and depth of these hierarchies under conditions of loss and thermal noise. The methodology introduced here is versatile and can be extended to multistate and multimode coherences, making it adaptable to a wide range of experimental scenarios and platforms.}, archive = {J_PRA}, author = {Lukáš Lachman and Beate E. Asenbeck and Ambroise Boyer and Priyanka Giri and Alban Urvoy and Julien Laurat and Radim Filip}, doi = {10.1103/t5c6-byhh}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063704}, shortjournal = {Phys. Rev. A}, title = {Hierarchies of quantum non-gaussian coherences for bosonic systems: A theoretical study}, volume = {111}, year = {2025}, }
• (2025). Mechanically induced magnonic frequency combs via the magnetostrictive effect. PRA, 111(6), 063703. (www)

  @article{ , abstract = {Magnonic frequency combs play a significant role in magnonic dynamics and spectroscopy analysis. Here we investigate the generation of magnonic frequency combs in a magnomechanical system in which the magnon mode is driven by a microwave field and the phonon mode is driven by a mechanical field. Using experimentally achievable parameters, we demonstrate that the magnonic frequency combs can be generated even if the amplitude of the microwave driving field is comparatively low, and the bandwidth and sideband plateau of magnonic frequency combs can be extended remarkably with the amplitude of the mechanical driving field increasing. The results show that magnonic frequency combs can be enhanced by the time-varying driving force via the magnetostrictive effect. The proposed method provides a promising route for the generation of low-power and wide-bandwidth magnonic frequency combs. Potential applications range from realizing high-precision microwave frequency metrology to designing new magnonic information processing devices.}, archive = {J_PRA}, author = {Bao Wang and Xiao-Hu Lu and Xiao Jia and Hao Xiong}, doi = {10.1103/PhysRevA.111.063703}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063703}, shortjournal = {Phys. Rev. A}, title = {Mechanically induced magnonic frequency combs via the magnetostrictive effect}, volume = {111}, year = {2025}, }
• (2025). Manipulating spectral transitions and photonic transmission in a non-hermitian optical system through nanoparticle perturbations. PRA, 111(6), 063702. (www)

  @article{ , abstract = {In recent years, extensive research has been dedicated to the study of parity-time ( ) symmetry, which involves the engineered balance of gain and loss in non-Hermitian optics. Complementary to symmetry, the concept of anti- symmetry has emerged as a natural framework for describing the dynamics of open systems with dissipations. In this work, we study spectral transitions and photon transmission in a linear spinning resonator perturbed by nanoparticles. First, we show that by precisely controlling the nanoparticle perturbations, the eigenvalues (or spectra) of a non-Hermitian system satisfying anti- symmetry can transit to that of a quasiclosed Hermitian system. Second, we outline the essential conditions for constructing a quasiclosed system and analyze its dynamic behavior with respect to photon transmission. By adjusting the rotational angular velocity of the spinning resonator and the strength of the nanoparticle perturbations, the quasiclosed system enables a variety of photon distribution behaviors, which may have significant applications in quantum devices. Our findings offer valuable insights for the design of dissipative quantum devices under realistic conditions and for understanding their responses to external perturbations.}, archive = {J_PRA}, author = {Bo-Wang Zhang and Cheng Shang and J. Y. Sun and Zhuo-Cheng Gu and X. X. Yi}, doi = {10.1103/PhysRevA.111.063702}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063702}, shortjournal = {Phys. Rev. A}, title = {Manipulating spectral transitions and photonic transmission in a non-hermitian optical system through nanoparticle perturbations}, volume = {111}, year = {2025}, }
• (2025). Giant emitter magnetometer. PRA, 111(6), 063701. (www)

  @article{ , abstract = {Leveraging the sensitive dependence of a giant atom's relaxation rate on its frequency [A. F. Kockum et al. , Phys. Rev. A 90 , 013837 (2014) ], we propose an effective magnetometer model based on a single giant emitter. In this model, the emitter's frequency is proportional to the applied bias magnetic field. The self-interference effect causes the slope of the decay rate to vary linearly with the number of emitter-waveguide coupling points. The giant emitter magnetometer achieves a sensitivity as high as , demonstrating the significant advantages of the self-interference effect compared to small emitters. We hope our proposal will expand the applications of giant emitters in precision measurement and magnetometry.}, archive = {J_PRA}, author = {Xiaojun Zhang and Xiang Guo and Zhihai Wang}, doi = {10.1103/PhysRevA.111.063701}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063701}, shortjournal = {Phys. Rev. A}, title = {Giant emitter magnetometer}, volume = {111}, year = {2025}, }
• (2025). Loss-free enhancement of photonic spin hall shift by electromagnetically induced transparency. PRA, 111(6), 063523. (www)

  @article{ , abstract = {The photonic spin Hall effect, a result of spin-orbit interaction, has attracted significant interest because of its fundamental importance and potential applications. However, optical losses are ubiquitous, which hampers the enhancement of photonic spin Hall shift (PSHS). In this work, we consider an atomic medium that exhibits both absorption and transparency to investigate and mitigate the effects of loss on PSHS. We demonstrate that laser-induced coherence in an atomic medium, leading to electromagnetically induced transparency (EIT) at resonance, counteracts the detrimental effects of losses on the PSHS. Upon EIT at resonance in a coherent medium enclosed within dielectric slabs, zero reflectivity of the incident polarized state is restored at an incident angle defined by the conventional Brewster's angle to enhance PSHS. Moreover, the tunable refractive index of the atomic medium enables manipulation of PSHS without structural modifications with a tiny loss. Our proposed loss-free approach to PSHS may enable advanced optical sensing and other spin-based applications.}, archive = {J_PRA}, author = {Aizaz Khan and Kezhou Du and Lei Gao and Muzamil Shah and Xinxing Zhou and Dongliang Gao}, doi = {10.1103/1c51-d7sz}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063523}, shortjournal = {Phys. Rev. A}, title = {Loss-free enhancement of photonic spin hall shift by electromagnetically induced transparency}, volume = {111}, year = {2025}, }
• (2025). Predicting microwave resonances in aqueous spheroids with a standing-wave approach. PRA, 111(6), 063522. (www)

  @article{ , abstract = {High-index dielectric materials are promising candidates for photonic technologies that rely on enhanced light-matter interactions. Nanophotonic applications have been hindered by a lack of high-index transparent dielectrics in the visible regime. Despite its low index of refraction at visible wavelengths, water exhibits an index approaching 9 at 2.5 GHz, making it a promising model material for studying morphology-dependent resonances in centimeter-scale objects. Such Mie scattering resonances are well characterized in spheres but are much less understood in spheroids because of the mathematical complexity of multipolar expansions in spheroidal geometries. In this work we combine analytical, numerical, and finite-element methods to study microwave resonances in aqueous spheroids. We obtain three-dimensional standing-wave solutions in aqueous spheroids and show that this conceptually simple description of electromagnetic resonances maps surprisingly well onto the complex resonant landscape of certain spheroidal modes, as elucidated by finite-element simulations. In the process, we identify some size and shape regimes that yield uniquely intense spheroidal resonances.}, archive = {J_PRA}, author = {Yuchen Song and Miao Hu and Aaron D. Slepkov}, doi = {10.1103/ljgk-x9cj}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063522}, shortjournal = {Phys. Rev. A}, title = {Predicting microwave resonances in aqueous spheroids with a standing-wave approach}, volume = {111}, year = {2025}, }
• (2025). Effect of temperature on the dynamic properties of extreme pulses in interband cascade lasers. PRA, 111(6), 063521. (www)

  @article{ , abstract = {This paper investigates the distribution and dynamics of extreme pulses generated by interband cascade lasers at different temperatures, incorporating the effect of ac amplitude. As the temperature increases, both the total number and the percentage of extreme pulses rise and become more regular. The number of generated extreme pulses shows a trend of increase at first and then decrease with the increase of ac amplitude. When the ac amplitude is sufficiently large, the laser is fully modulated and exhibits periodic oscillations. Elevated temperature also alters the locking region, leading to the vanishing of the forbidden band in the extreme pulse distribution. By varying the temperature, the number of extreme pulses changes, and the laser dynamics transition among quasiperiodic, periodic, and chaotic states.}, archive = {J_PRA}, author = {X. Y. Zhu and W. Feng and J. C. Cao and C. Wang}, doi = {10.1103/5zx3-4z1m}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063521}, shortjournal = {Phys. Rev. A}, title = {Effect of temperature on the dynamic properties of extreme pulses in interband cascade lasers}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal open quantum battery network in a photonic waveguide array. PRA, 111(6), 063520. (www)

  @article{ , abstract = {Quantum batteries (QBs) exhibit remarkable charging power and energy potential, suggesting quantum benefits in thermodynamics. However, they face challenges like decoherence, low efficiency, and limited saturation. In this study, we explore the nonreciprocal open quantum batteries network (NOQBN), integrated with photonic waveguide arrays. By leveraging unidirectional waveguide nonreciprocities and reservoir engineering, we achieve targeted energy transfer, where QBs' higher dissipation rates compared to optical charger modes enhance charging energy, but reduce the ergotropy of the NOQBN. Results reveal that collective charging boosts QBs' ergotropy and power output, outperforming isolated QB systems. Moreover, by challenging traditional reciprocal charger-battery paradigms, we successfully adjust environmental dissipation to enhance nonreciprocity, thereby improving energy storage efficiency. Crucially, optimizing the correlation length between QBs within the network further enhances their storage capacity. The NOQBN's nonreciprocal dynamics pioneers a new approach to quantum energy storage, paving the way for applications in driven-dissipative photonic networks and inspiring the development of advanced, integrated nonreciprocal quantum energy devices. This work advances our theoretical understanding of QB networks and provides practical design principles for highly efficient quantum energy devices.}, archive = {J_PRA}, author = {Yaowu Guo and Lianzhen Cao and Jiaqiang Zhao}, doi = {10.1103/fn1b-2m9g}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063520}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal open quantum battery network in a photonic waveguide array}, volume = {111}, year = {2025}, }
• (2025). Enhanced tunable photon-pair generation from a nonlinear metasurface with a guided-mode cavity. PRA, 111(6), 063519. (www)

  @article{ , abstract = {The ability to generate quantum entangled photon pairs through spontaneous parametric down conversion (SPDC) is playing a pivotal role in many applications in quantum technologies, including quantum communications, quantum computation, and quantum imaging. Metasurfaces, two-dimensional arrays of nanostructures with subwavelength thickness, have recently shown extraordinary capability in manipulating classical and quantum states of light and realizing miniaturized SPDC sources. Whereas previous studies have primarily focused on periodic metasurfaces, we uncover the potential of spatially modulated nanopatterns for further SPDC enhancement and state engineering. Specifically, we propose a nonlinear metasurface featuring a lateral guided-mode cavity formed by two distributed Bragg reflectors. With the quasinormal mode theory, we predict an SPDC rate up to 157 Hz/mW, which represents about 30 times rate enhancement when compared to the metasurface without a cavity. Furthermore, the cavity supports a continuous set of high- resonances across a broad bandwidth, allowing the all-optical tuning of the photon-pair emission directions transverse to the cavity by controlling the pump wavelength, which can find applications in quantum imaging.}, archive = {J_PRA}, author = {Tongmiao Fan and Jihua Zhang and Andrey A. Sukhorukov}, doi = {10.1103/p1wr-98wx}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063519}, shortjournal = {Phys. Rev. A}, title = {Enhanced tunable photon-pair generation from a nonlinear metasurface with a guided-mode cavity}, volume = {111}, year = {2025}, }
• (2025). Time-reversal-symmetry bounds on electromagnetic fields. PRA, 111(6), 063518. (www)

  @article{ , abstract = {For linear electromagnetic systems possessing time-reversal symmetry, we present an approach to bound ratios of internal fields excited from different ports, using only the scattering matrix ( matrix), improving upon previous related bounds by Sounas and Alù [D. L. Sounas and A. Alù, Phys. Rev. Lett. 118 , 154302 (2017) ]. By reciprocity, emitted-wave amplitudes from internal dipole sources are bounded in a similar way. When applied to coupled-resonant systems, our method constrains ratios of resonant coupling and decay coefficients. We also obtain a relation for the relative phase of fields excited from the two ports and the ratio of field intensities in a two-port system. In addition, although lossy systems do not have time-reversal symmetry, we can still approximately bound loss-induced nonunitarity of the matrix using only the lossless matrix. We show numerical validations of the near tightness of our bounds in various scattering systems.}, archive = {J_PRA}, author = {Wenchao Ma and Raphaël Pestourie and Steven G. Johnson}, doi = {10.1103/8bcn-796c}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063518}, shortjournal = {Phys. Rev. A}, title = {Time-reversal-symmetry bounds on electromagnetic fields}, volume = {111}, year = {2025}, }
• (2025). X-wave formation in the subnanosecond backward-wave optical parametric oscillator. PRA, 111(6), 063517. (www)

  @article{ , abstract = {Nonlinear -wave formation in the backward wave optical parametric oscillator pumped by subnanosecond laser pulses is studied. The wavelengths of 1064 nm and its second harmonic are used for pumping. (three dimensional space and time) numerical model is implemented to simulate the formation of the generated forward and backward waves. Contrary to the conventional model, the model allows the formation of conical beam structures. The nonlinear -wave propagation in the backward direction with respect to the phase velocity direction is demonstrated in the case of negative -wave velocity.}, archive = {J_PRA}, author = {T. Latvys and J. Banys and V. Jarutis and J. Vengelis and V. Tamulienė}, doi = {10.1103/scvw-1nyf}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063517}, shortjournal = {Phys. Rev. A}, title = {X-wave formation in the subnanosecond backward-wave optical parametric oscillator}, volume = {111}, year = {2025}, }
• (2025). Tunable autofocusing and optical trapping with symmetric butterfly gaussian beams. PRA, 111(6), 063516. (www)

  @article{ , abstract = {We propose an autofocusing beam, named the symmetric butterfly Gaussian beam (SBGB). Its analytical expression in free space is derived, and its transmission characteristics are systematically analyzed. Compared to the symmetric Airy Gaussian beam and symmetric Pearcey Gaussian beam, the SBGB exhibits superior abruptly autofocusing capabilities and enhanced particle trapping abilities. By adjusting the distribution factors, the SBGB can generate a bifocal structure. Interestingly, introducing a second-order chirp factor enables the two focal spots to evolve into orthogonal needlelike structures. The focal size, focal position, and intensity of the SBGB can be flexibly adjusted by tuning the second-order chirp factor. Moreover, we theoretically analyze the trapping properties of the SBGB and explore the trapping force distributions in its focal regions. Experimental results verify that the dual needlelike focal points can stably trap and manipulate multiple silica particles. With outstanding autofocusing performance and unique focal structures, the SBGB holds great potential for applications in optical manipulation, biomedical research, and laser processing.}, archive = {J_PRA}, author = {Yujie Wu and Zijing Zhang and Man Tao and Zhenhang Xu and Chuhong Zhuang and Zihan Liu and Zan Zhang and Weiting Wang and Hongwei Gong and Shigen Ouyang and Dongmei Deng}, doi = {10.1103/tfs1-gy3h}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063516}, shortjournal = {Phys. Rev. A}, title = {Tunable autofocusing and optical trapping with symmetric butterfly gaussian beams}, volume = {111}, year = {2025}, }
• (2025). Spectral reorganization of space-time wave packets in the presence of normal group-velocity dispersion. PRA, 111(6), 063515. (www)

  @article{ , abstract = {Space-time wave packets (STWPs) are pulsed beams that propagate invariantly (without diffraction or dispersion) in linear media. The behavior of STWPs in free space is now well established, and recently their propagation invariance was confirmed in both the normal and anomalous group-velocity dispersion (GVD) regimes. However, rich yet-to-be-observed spectral dynamics have been predicted to occur in the presence of normal GVD, which manifests itself in the reorganization of the spatiotemporal spectrum into distinct structures upon tuning the appropriate optical parameters of the STWP. Indeed, broad varieties of distinct field structures are compatible with propagation invariance in normal GVD, which can be classified in a two-dimensional space parametrized by the group velocity of the STWP and its central axial wave number. Tuning these two parameters gives rise to spatiotemporal spectral reorganization into X-shaped, hyperbolic, parabolic, elliptical, or even spatiotemporally separable spectra. Here, we observe the entire span of spectral reorganization for paraxial STWPs in normally dispersive ZnSe at a wavelength with on-axis pulse widths fs. By tuning the STWP group velocity and central axial wave number while maintaining propagation invariance, we observe transitions in the spatiotemporal spectrum and verify the associated structural changes in the spatiotemporal intensity profile. These results lay the foundations for understanding the potential uses of STWPs in phase-matched nonlinear processes in dispersive media.}, archive = {J_PRA}, author = {Layton A. Hall and Ayman F. Abouraddy}, doi = {10.1103/ymls-2lkq}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063515}, shortjournal = {Phys. Rev. A}, title = {Spectral reorganization of space-time wave packets in the presence of normal group-velocity dispersion}, volume = {111}, year = {2025}, }
• (2025). Efficient chiral mode conversion in topological waveguide arrays by encircling moving exceptional points. PRA, 111(6), 063514. (www)

  @article{ , abstract = {Topological photonic states are important for constructing optical devices immune from structural perturbations, offering a viable solution for robust photonic integrations. Dynamically encircling exceptional points (EPs) of self-intersecting Riemann sheets gives rise to chiral mode transfer, and recently chiral mode converters capable of directionally switching topological photonic states have been constructed in optical waveguide arrays. However, the transmission efficiencies realized in previous studies are inherently low due to path-dependent losses, which hinders their practical application. Here, we proposed to realize efficient chiral topological mode conversion by dynamically encircling the moving EP of the two topological edge modes in lossy waveguide arrays mimicking the non-Hermitian Su-Schrieffer-Heeger lattice via modulation of loss along the propagation direction, which enables reduced average loss in a whole cycle while maintaining the employment of topological properties around an EP. The resultant chiral topological mode converter is highly efficient due to reduced average loss during the passage of EP encirclement, with transfer efficiency as high as in theory with near unity mode purity and considerable transmission in simulation with over of the total output energy taken over by the transferred mode. It is also proven to be robust against mild perturbations of coupling strengths and mode mismatch. The efficient and robust chiral topological mode converter will promote the practical applications of topological photonic states, such as broadband optical switches and optical isolators.}, archive = {J_PRA}, author = {Jia-Ning Zhang and Ming Gao and Jia-bao Yao and Cheng Lv and Pei-geng Zhong and Jie Song and Yong-Yuan Jiang}, doi = {10.1103/kys4-zqnp}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063514}, shortjournal = {Phys. Rev. A}, title = {Efficient chiral mode conversion in topological waveguide arrays by encircling moving exceptional points}, volume = {111}, year = {2025}, }
• (2025). Highly sensitive temperature sensing via quadratic optomechanical coupling. PRA, 111(6), 063513. (www)

  @article{ , abstract = {The effective frequency of a mechanical resonator can be tuned via the spring effect induced by quadratic optomechanical (QOM) coupling, and both spontaneous symmetry breaking and anti-parity-time phase transition were predicted in the QOM systems. Here, we show that the mechanical susceptibility can be enhanced significantly by driving the QOM system with a strong external optical field, and divergence will happen as the driving strength approaches the critical point (CP) for spontaneous symmetry breaking. Based on the CP, we propose a highly sensitive temperature sensor with a mechanical resonator quadratically coupled to an optical mode. We find that the sensitivity of the temperature sensor can be enhanced by several orders of magnitude as the driving strength approaches the CP, and the sensitivity of the temperature sensor remains high in the low-temperature limit. Our work provides an effective way to realize highly sensitive temperature sensing at ultralow temperature in QOM systems.}, archive = {J_PRA}, author = {Yu-Sheng Tang and Xun-Wei Xu and Jie-Qiao Liao and Hui Jing and Le-Man Kuang}, doi = {10.1103/1f8d-44ym}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063513}, shortjournal = {Phys. Rev. A}, title = {Highly sensitive temperature sensing via quadratic optomechanical coupling}, volume = {111}, year = {2025}, }
• (2025). Optical force and torque on a spinning dielectric sphere. PRA, 111(6), 063512. (www)

  @article{ , abstract = {Optical force can enable precise manipulations of small particles for various applications. It is well known that an isotropic lossless dielectric sphere is only subject to forward optical force under the illumination of an electromagnetic plane wave. By using rigorous full-wave simulations, we show that such a sphere can experience a lateral optical force and an optical torque besides the conventional longitudinal force, if it spins with a constant angular velocity. The emergence of the unusual optical force and torque is attributed to the breaking of mirror and cylindrical symmetries by the spinning motion. Using the multipole expansion in source representation, we illustrate how the spinning-induced effective bianisotropy generates the lateral force and torque on the sphere through the interference of electric and magnetic multipoles. We also uncover the effect of Sagnac frequency splitting on the optical force and torque. The results contribute to the understanding of the optical force and torque in moving media and can be applied to realize unconventional optical manipulations of small particles.}, archive = {J_PRA}, author = {Hengzhi Li and Wanyue Xiao and Tong Fu and Zheng Yang and Shubo Wang}, doi = {10.1103/fy5p-sgqg}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063512}, shortjournal = {Phys. Rev. A}, title = {Optical force and torque on a spinning dielectric sphere}, volume = {111}, year = {2025}, }
• (2025). Low-order-mode optical trapping of microspheres in hollow-core photonic crystal fibers. PRA, 111(6), 063511. (www)

  @article{ , abstract = {Hollow-core photonic crystal fibers (HC-PCFs) are a highly appealing tool for the optical trapping of micron-sized dielectric probes. Indeed, controlling the optical modes of HC-PCFs through diffractive spatial light modulators might lead to generate specific and accurate three-dimensional traps. Here, optical traps suitable for controlling dielectric nano- and microspheres using near-infrared wavelengths inside a HC-PCF are analyzed in depth, through a generalized Lorenz-Mie theory approach. The method provides an accurate and enhanced description of versatile trapping configurations, including optical conveyor belts. The applications of these trapping techniques can be various and important, including the development of optical sensors based on the light-matter interaction in the core.}, archive = {J_PRA}, author = {Alessandro Porcelli and Peter Seigo Kincaid and Antonio Alvaro Ranha Neves and Ennio Arimondo and Andrea Camposeo and Dario Pisignano and Donatella Ciampini}, doi = {10.1103/PhysRevA.111.063511}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063511}, shortjournal = {Phys. Rev. A}, title = {Low-order-mode optical trapping of microspheres in hollow-core photonic crystal fibers}, volume = {111}, year = {2025}, }
• (2025). Generalized polarization matrix approach to near-field optical chirality. PRA, 111(6), 063510. (www)

  @article{ , abstract = {For paraxial light beams and electromagnetic fields, the Stokes vector and polarization matrix provide equivalent scalar measures of optical chirality, widely used in linear optics. However, growing interest in nonparaxial fields, with fully three-dimensional polarization components, necessitates an extended framework. Here, we develop a general theory for characterizing optical chirality in arbitrary electromagnetic fields, formulated through extensions of the polarization matrix approach. This framework applies to both near- and far-field optical helicity and chirality. As examples, we demonstrate its relevance to near-zone fields from chiral dipole emission and the focal plane of tightly focused beams.}, archive = {J_PRA}, author = {Kayn A. Forbes and David L. Andrews}, doi = {10.1103/PhysRevA.111.063510}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063510}, shortjournal = {Phys. Rev. A}, title = {Generalized polarization matrix approach to near-field optical chirality}, volume = {111}, year = {2025}, }
• (2025). Dual-resonance metagrating for enhancing or annihilating third-harmonic generation at terahertz frequencies. PRA, 111(6), 063509. (www)

  @article{ , abstract = {Terahertz nonlinear response has considerable potential for applications in fields such as high-speed communication and radar imaging. However, owing to the weakness of its nonlinear effects and the scarcity of high-power sources, its practical applications remain largely constrained. In this work, we present a way to manipulate third-harmonic generation (THG) at terahertz frequencies via the design and study of dual-resonance metagrating with a compound lattice. The compound lattice supports two photonic bands of the magnetic polariton mode and the spoof surface plasmon polariton (SSPP) mode, whose eigenfrequencies satisfy a threefold relationship. Due to the geometric symmetry of the structure, an accidental bound state in the continuum (BIC) emerges at the SSPP band. The combined contribution of the two distinct resonant modes can significantly enhance the THG process at a lower input power. Meanwhile, the quasi-BIC mode operating at the nonlinear frequency has the capacity to confine the generated nonlinear harmonics within the metagrating, thereby suppressing the radiation channel of the third-harmonic light. Specifically, based on the nonlinear efficiency and resonance mechanisms, four different THG regimes are identified, namely, region I (dual-resonance region), region II (annihilation region due to BIC), region III (transition region), and region IV (single-resonance region). Our findings offer an alternative paradigm to control nonlinear processes through metagrating to tailor the light-matter interactions.}, archive = {J_PRA}, author = {Cong Wang and Songsong Li and Yu Chen and Qingjia Zhou and Jie Luo and Shaojun Wang and Lei Gao and Yadong Xu}, doi = {10.1103/PhysRevA.111.063509}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063509}, shortjournal = {Phys. Rev. A}, title = {Dual-resonance metagrating for enhancing or annihilating third-harmonic generation at terahertz frequencies}, volume = {111}, year = {2025}, }
• (2025). Bisingular surface polaritons at the interface of two uniaxial media. PRA, 111(6), 063508. (www)

  @article{ , abstract = {In some anisotropic bulk media (for example, biaxial weakly absorbing crystals) there are special directions along which the plane-wave field distribution has a singular profile of the form . They are also known as Voigt waves. Similar singular profiles also arise in the theory of surface electromagnetic waves in anisotropic media. In this work we consider surface polaritons at the interface of two generally different uniaxial media. The optic axes of both media are parallel to the interface. One of the specific solutions, called bisingular, greatly simplifies the dispersion equation for surface polaritons. In this case the analytical solution in closed form is found, and existence conditions are determined. It is shown that a bisingular surface polariton exists only for certain angles between the optic axes, which are found from two cubic equations. All the parameters of the bisingular surface polariton depend only on permittivities and this angle. If one medium is weakly anisotropic or both media are almost the same, then two angles exist. In the general case of two arbitrary media there can be from two to six such angles.}, archive = {J_PRA}, author = {K. Yu. Golenitskii and N. S. Averkiev}, doi = {10.1103/PhysRevA.111.063508}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063508}, shortjournal = {Phys. Rev. A}, title = {Bisingular surface polaritons at the interface of two uniaxial media}, volume = {111}, year = {2025}, }
• (2025). Self-pulsing laser cavity solitons: Interaction dynamics and transverse carrier diffusion. PRA, 111(6), 063507. (www)

  @article{ , abstract = {Pulsation dynamics of laser cavity solitons is studied numerically in broad-area semiconductor lasers with an intracavity saturable absorber with and without carrier transverse diffusion. We show that the existence range of the self-pulsing laser cavity solitons and their oscillation dynamics are affected by the carrier transverse diffusion such that larger diffusion coefficients lead to self-pulsation dynamics of smaller amplitude and shorter period. Moreover, we studied the interaction of two self-pulsing structures and found regimes of in-phase, antiphase, and partially antisynchronized oscillations depending on the control parameter values and the initial separation distance. The effect of carrier transverse diffusion on the interaction dynamics is also investigated, and it is found that the synchronization time increases with the diffusion coefficient. Synchronization-driven spatial adjustment of self-pulsing laser cavity solitons is also reported, where attractive or repulsive forces are observed to form between the dynamical localized structures.}, archive = {J_PRA}, author = {M. Eslami and A.-R. Samadi and A. Ghaed Amini and R. Golzarian and R. Kheradmand and F. Prati}, doi = {10.1103/PhysRevA.111.063507}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063507}, shortjournal = {Phys. Rev. A}, title = {Self-pulsing laser cavity solitons: Interaction dynamics and transverse carrier diffusion}, volume = {111}, year = {2025}, }
• (2025). Optical pattern formation in self-focusing and self-defocusing diffractively thick media. PRA, 111(6), 063506. (www)

  @article{ , abstract = {Cold atomic clouds constitute highly resonant nonlinear optical media, whose refractive index can easily be tuned via the light frequency. When subjected to a retroreflected laser beam and under appropriate conditions, the cloud undergoes spontaneous symmetry breaking, and spatial patterns develop in the transverse cross section of the beam. We investigate the impact of the sign of the light detuning from the atomic resonance on these patterns, thus directly comparing pattern formation for self-focusing and self-defocusing nonlinearities. Our observations emphasize the need for a “diffractively thick” medium description of the light-cloud interaction in which diffraction and nonlinear propagation inside the sample are taken into account.}, archive = {J_PRA}, author = {G. Labeyrie and I. Kresic and R. Kaiser and T. Ackemann}, doi = {10.1103/PhysRevA.111.063506}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063506}, shortjournal = {Phys. Rev. A}, title = {Optical pattern formation in self-focusing and self-defocusing diffractively thick media}, volume = {111}, year = {2025}, }
• (2025). Bound states and chiral excitation in the effective floquet continuum within tilted waveguide lattices. PRA, 111(6), 063505. (www)

  @article{ , abstract = {We investigate the dynamics of light escaping from a tilted waveguide capable of supporting chiral light excitation into a two-band Su-Schrieffer-Heeger system functioning as a continuum. In a periodic scenario that gives rise to Floquet multibands, our research reveals that the effective bands, exhibiting time-reversal symmetry breaking, host bound states in the continuum (BICs) generated through coupling interference, alongside phenomena reminiscent of spontaneous radiation. Moreover, we analyze the influence of the zero mode on the BICs and the chiral transport of the excited Bloch waves within the tilt-induced Floquet bands. Our results establish a foundational pathway for exploring BICs in systems exhibiting time-reversal symmetry breaking.}, archive = {J_PRA}, author = {Tian-Ze Sheng and Li-Feng Liu and Ying Zhang and Jun Qian and Xiao-Lin Li and Yue-Ping Niu and Shang-Qing Gong}, doi = {10.1103/PhysRevA.111.063505}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063505}, shortjournal = {Phys. Rev. A}, title = {Bound states and chiral excitation in the effective floquet continuum within tilted waveguide lattices}, volume = {111}, year = {2025}, }
• (2025). Reinforcement-learning-assisted nonreciprocal optomechanical gyroscope. PRA, 111(6), 063504. (www)

  @article{ , abstract = {We propose an optomechanical gyroscope architecture based on a spinning cavity optomechanical resonator evanescently coupled to a tapered optical fiber without relying on costly quantum light sources. Our study reveals a striking dependence of the gyroscope's sensitivity on the propagation direction of the driving optical field, manifesting robust quantum nonreciprocal behavior. This nonreciprocity significantly enhances the precision of the angular-velocity estimation, offering a unique advantage over conventional gyroscopic systems. Furthermore, we demonstrate that the operational range of this nonreciprocal gyroscope is fundamentally governed by the frequency of the pumping optical field, enabling localized sensitivity to angular velocity. Leveraging the adaptive capabilities of reinforcement learning (RL), we optimize the gyroscope's sensitivity within a targeted angular-velocity range, achieving unprecedented levels of precision. These results highlight the transformative potential of RL in advancing high-resolution, miniaturized optomechanical gyroscopes, opening new avenues for next-generation inertial sensing technologies.}, archive = {J_PRA}, author = {Qing-Shou Tan and Ya-Feng Jiao and Yunlan Zuo and Lan Xu and Jie-Qiao Liao and Le-Man Kuang}, doi = {10.1103/PhysRevA.111.063504}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063504}, shortjournal = {Phys. Rev. A}, title = {Reinforcement-learning-assisted nonreciprocal optomechanical gyroscope}, volume = {111}, year = {2025}, }
• (2025). Internal dynamics and fission of pure-quartic soliton molecules. PRA, 111(6), 063503. (www)

  @article{ , abstract = {We address the weak interaction of a pair of well-separated pure-quartic solitons (PQSs), which are solutions to a generalized nonlinear Schrödinger equation with the quartic-only dispersion. An asymptotic technique is applied to derive equations for the slow evolution of the temporal separation and phase difference of the PQSs interacting through the overlapping of their exponentially decaying oscillating tails. Based on this approach, various stationary states of bound PQSs (“soliton molecules”) with distinct phase differences are predicted. Their stability is addressed via the numerical calculation of the eigenvalue spectrum of small perturbations, showing instability of the bound states. A systematic numerical analysis demonstrates that the parameter space of the PQS bound states is organized as a self-similar fractal structure, composed of regions populated by robustly oscillating or splitting two-soliton states. The analytical method and results reported here can be extended for bound states of two or several weakly interacting modes in other conservative and dissipative systems.}, archive = {J_PRA}, author = {Zhixiang Deng and Rui Ma and Chunxiang Zhang and Boris Malomed and Dianyuan Fan and Jingsong He and Jun Liu}, doi = {10.1103/PhysRevA.111.063503}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063503}, shortjournal = {Phys. Rev. A}, title = {Internal dynamics and fission of pure-quartic soliton molecules}, volume = {111}, year = {2025}, }
• (2025). High-gain squeezing in lossy resonators: An asymptotic-field approach. PRA, 111(6), 063502. (www)

  @article{ , abstract = {We present a method for describing nonlinear electromagnetic interactions in integrated photonic devices utilizing an asymptotic-in (-out) field formalism. Our method expands upon previous continuous wave asymptotic treatments by describing the evolution nonperturbatively for an arbitrary pulsed input. This is presented in the context of a squeezing interaction within an integrated micro-ring resonator side coupled to an input-output waveguide, but is readily generalizable to other integrated structures, while including a variety of (nonsqueezing) third-order interactions. An example of a single-pump, nondegenerate squeezing interaction is studied, which is shown to match well with standard coupled-mode treatments for high-finesse resonators, as well as previous perturbative treatments dealing with the generation of pairs with low probability.}, archive = {J_PRA}, author = {M. Sloan and A. Viola and M. Liscidini and J. E. Sipe}, doi = {10.1103/PhysRevA.111.063502}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063502}, shortjournal = {Phys. Rev. A}, title = {High-gain squeezing in lossy resonators: An asymptotic-field approach}, volume = {111}, year = {2025}, }
• (2025). Three-photon rabi oscillations in n2+ lasing at 391 nm. PRA, 111(6), 063501. (www)

  @article{ , abstract = {When nitrogen molecules are irradiated by near-infrared lasers around 1000 nm, significant lasing at 391 nm occurs. Here we theoretically investigate the underlying mechanism and identify the formation of population inversion between the and states within the 900- to 1100-nm wavelength range, which is characterized by distinct multipeak structure. Using time-dependent Floquet theory, we demonstrate that the multipeak structure arises from three-photon Rabi oscillations. These oscillations are modulated by nonadiabatic transitions between Floquet states, which ultimately determines the population inversion dynamics. Furthermore, our simulations successfully reproduce the experimentally observed wavelength-dependent lasing signals and reveal that the rarely observed three-photon Rabi oscillations can be reflected in the pulse-duration dependence of the lasing intensity. This work suggests a strategy for controlling lasing through tailored multiphoton interactions, providing valuable insights into the coherent control of molecular dynamics.}, archive = {J_PRA}, author = {Ping Li and Wenli Yang and Xiaofei Li and Shan Xue and Jinbin Li and Hongchuan Du}, doi = {10.1103/PhysRevA.111.063501}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063501}, shortjournal = {Phys. Rev. A}, title = {Three-photon rabi oscillations in n2+ lasing at 391 nm}, volume = {111}, year = {2025}, }
• (2025). Interaction-induced moiré systems in twisted bilayer optical lattices. PRA, 111(6), 063317. (www)

  @article{ , abstract = {Moiré-related physics in twisted bilayer two-dimensional (2D) materials has attracted widespread interest in condensed-matter physics. Simulation of moiré related physics in cold atom platforms is expected to outperform 2D materials thanks to its advantage of higher tunablility. Here, we demonstrate that the cold atom platform enables an alternative mechanism of moiré lattice formation, induced by interlayer interaction with intrinsic “dynamical” character, in contrast with conventional moiré lattice induced by “static” ways such as single-particle interlayer tunneling. Specifically, we consider a twisted bilayer Bose-Hubbard model with vanishing interlayer tunneling, and the bilayer is solely coupled through interlayer interactions that originate from the contact interaction of atoms. We find that this system hosts a plethora of intriguing phases unique to this dynamical lattice, including a variety of Mott insulator (MI) and superfluid (SF) phases either preserving or breaking moiré lattice symmetry, phases with one layer in SF and the other in MI, “interlocked” MI, and self-localized phases at commensurate twist angles, which exhibits the characteristics of Bose glass and quasi-many-body localization in the absence of (quasi)disorder or quasicrystalline lattices. Our prediction can be readily observed in current experimental setups of twisted bilayer optical lattices, opening up alternative avenues for exploring the rich physics of interaction induced moiré systems in cold atoms.}, archive = {J_PRA}, author = {Jian-Hua Zeng and Qizhong Zhu and Liang He}, doi = {10.1103/zpqd-ryjm}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063317}, shortjournal = {Phys. Rev. A}, title = {Interaction-induced moiré systems in twisted bilayer optical lattices}, volume = {111}, year = {2025}, }
• (2025). Solving the SU(N) orbital hatsugai-kohmoto model. PRA, 111(6), 063316. (www)

  @article{ , abstract = {We show that the physics of the ) Hubbard model can be realistically simulated with the recently developed orbital Hatsugai-Kohmoto model. In this approach, the momentum mixing absent from the band Hatsugai-Kohmoto model is included by grouping -Hubbard atoms into a cluster. We take advantage of the rapid convergence of this scheme ( ) and show that for , quantitative agreement with the determinantal quantum Monte Carlo method arises for the double occupancy as well as qualitative agreement for the filling and compressibility across the Mott transition. Additional features of this work are that we can obtain low-temperature physics, which could be qualitatively different from its high-temperature counterpart, and dynamical quantities without resorting to analytical continuation, thereby establishing the orbital Hatsugai-Kohmoto model as a useful alternative perspective for studying strong correlations in ) systems.}, archive = {J_PRA}, author = {Nico A. Hackner and Peizhi Mai and Philip W. Phillips}, doi = {10.1103/1qzc-6c6n}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063316}, shortjournal = {Phys. Rev. A}, title = {Solving the SU(N) orbital hatsugai-kohmoto model}, volume = {111}, year = {2025}, }
• (2025). Nonequilibrium quench dynamics of bose-einstein condensates of microwave-shielded polar molecules. PRA, 111(6), 063315. (www)

  @article{ , abstract = {We theoretically investigate the nonequilibrium dynamics of homogeneous ultracold Bose gases of microwave-shielded polar molecules following a sudden quench of the scattering length at zero temperature. We calculate in particular the quantum depletion, the anomalous density, the condensate fluctuations, and the pair-correlation function using both the time-dependent Bogoliubov approach and the self-consistent time-dependent Hartree-Fock-Bogoliubov approximation. During their time evolution, these quantities exhibit slow or fast oscillations depending on the strength of the shielding interactions. We find that at long timescales the molecular condensate is characterized by nonequilibrium steady-state momentum distribution functions, with depletion, anomalous density, and correlations that deviate from their corresponding equilibrium values. We demonstrate that the pair correlations expand diffusively at short times while they spread ballistically at long times.}, archive = {J_PRA}, author = {Abdelâali Boudjemâa}, doi = {10.1103/6b82-sb2j}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063315}, shortjournal = {Phys. Rev. A}, title = {Nonequilibrium quench dynamics of bose-einstein condensates of microwave-shielded polar molecules}, volume = {111}, year = {2025}, }
• (2025). Three-body physics in the impurity limit of k39 bose-einstein condensates. PRA, 111(6), 063314. (www)

  @article{ , abstract = {Loss spectroscopy is a key tool for investigating systems where important system parameters are linked to intrinsic resonant loss processes. We investigate loss processes of impurity atoms embedded in a medium of a Bose-Einstein condensate close to a Feshbach resonance. In this case, three-body loss processes occur faster than the measurement duration, impeding a direct time-resolved measurement. Here, we discuss how an even faster two-body loss process can be used to probe the system. The time-dependent number of atoms in the medium is reconstructed from such measurements, allowing for the extraction of the three-body loss rate coefficient and its scaling with scattering length. Moreover, the medium atom number is reconstructed from spectroscopic loss measurements. This allows for a comparison of the medium densities based on both the extracted loss rates and the spectroscopically reconstructed atom number. Finally, the number of lost medium atoms per loss event is evaluated and found to exceed 2 at strong interactions, which is attributed to secondary collisions in the medium. These investigations establish the use of a fast loss mechanism as a new tool in the field and provide quantitative measurements of three-body losses at large interaction strengths.}, archive = {J_PRA}, author = {A. M. Morgen and S. S. Balling and M. T. Strøe and T. G. Skov and M. R. Skou and A. G. Volosniev and J. J. Arlt}, doi = {10.1103/54hb-ksqx}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063314}, shortjournal = {Phys. Rev. A}, title = {Three-body physics in the impurity limit of k39 bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Fate of the spatial-temporal order under quantum fluctuation. PRA, 111(6), 063313. (www)

  @article{ , abstract = {Quantum fluctuations are fundamental in many-body physics, often altering the nature of quantum phases beyond mean-field predictions. In this work, we explore their impact on a spatial-temporal ordered phase in a cavity-boson system, a phase previously predicted within the mean-field framework. By incorporating higher-order quantum fluctuations of the cavity field, we derive a set of quantum kinetic equations and numerically analyze the system's dynamics. Our results show that while mean-field spatial-temporal order vanishes over time, oscillatory behavior persists at the level of quantum fluctuations, demonstrating that the phase survives in a modified form. This study underscores the importance of quantum fluctuations in nonequilibrium quantum systems and reveals the limitations of the mean-field approach in predicting the stability of complex quantum phases.}, archive = {J_PRA}, author = {Xiaotian Nie and Wei Zheng}, doi = {10.1103/hlwp-41yr}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063313}, shortjournal = {Phys. Rev. A}, title = {Fate of the spatial-temporal order under quantum fluctuation}, volume = {111}, year = {2025}, }
• (2025). Optimal control in phase space applied to minimal-time transfer of thermal atoms in optical traps. PRA, 111(6), 063312. (www)

  @article{ , abstract = {We present an optimal control procedure for the nonadiabatic transport of ultracold neutral thermal atoms in optical tweezers arranged in a one-dimensional array, with the focus on reaching a minimal transfer time. The particle dynamics is modeled first using a classical approach through the Liouville equation and second through the quantum Wigner equation to include quantum effects. Both methods account for typical experimental noise described as stochastic effects through Fokker-Planck terms. The optimal control process is initialized with a trajectory computed for a single classical particle and determines the phase-space path that minimizes transport time and ensures high transport fidelity to the target trap. This approach provides a fast and efficient method for relocating atoms from an initial configuration to a desired target arrangement, minimizing time and energy costs while ensuring high fidelity. Such an approach may be highly valuable to initialize large atom arrays for quantum simulation or computation experiments.}, archive = {J_PRA}, author = {Omar Morandi and Sara Nicoletti and Vladislav Gavryusev and Leonardo Fallani}, doi = {10.1103/d857-7cwr}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063312}, shortjournal = {Phys. Rev. A}, title = {Optimal control in phase space applied to minimal-time transfer of thermal atoms in optical traps}, volume = {111}, year = {2025}, }
• (2025). Supersolid dipolar phases in planar geometry: Effects of tilted polarization. PRA, 111(6), 063311. (www)

  @article{ , abstract = {The behavior of dipolar Bose-Einstein condensates in planar geometries is investigated, focusing on the effects of the polarization orientation. While perpendicular polarization produces a phase diagram with hexagonal, stripes, and honeycomb phases ending at a single critical point, the presence of an in-plane polarization component transforms the critical point into three critical lines, separating two phases at a time and changing radically the appearance of the phase diagram. All transition lines contain first- and second-order regions, while the phase diagram itself shows a resemblance with those displayed by quasi-one-dimensional dipolar systems. Finally, we investigate the effect of introducing an in-plane polarization on the structural properties of the phases and determine the superfluid fraction. Our results show that this process induces an axial deformation on the hexagonal and honeycomb phases, resulting in an anisotropic behavior in the long-distance properties of the system like superfluidity. We expect that the rich phenomenology observed provides motivation for new experiments and theoretical works.}, archive = {J_PRA}, author = {Daniel Lima and Matheus Grossklags and Vinicius Zampronio and Fabio Cinti and Alejandro Mendoza-Coto}, doi = {10.1103/mlfn-114m}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063311}, shortjournal = {Phys. Rev. A}, title = {Supersolid dipolar phases in planar geometry: Effects of tilted polarization}, volume = {111}, year = {2025}, }
• (2025). Finite-temperature entanglement and coherence in asymmetric bosonic josephson junctions. PRA, 111(6), 063310. (www)

  @article{ , abstract = {We investigate the finite-temperature properties of a bosonic Josephson junction composed of interacting atoms confined by a quasi-one-dimensional asymmetric double-well potential, modeled by the two-site Bose-Hubbard Hamiltonian. We numerically compute the spectral decomposition of the statistical ensemble of states, the thermodynamic and entanglement entropies, the population imbalance, the quantum Fisher information, and the coherence visibility. We analyze their dependence on the system parameters, showing, in particular, how finite temperature and on-site energy asymmetry affect the entanglement and coherence properties of the system. Moreover, starting from a quantum phase model which accurately describes the system over a wide range of interactions, we develop a reliable description of the strong tunneling regime, where thermal averages may be computed analytically using a modified Boltzmann weight involving an effective temperature. We discuss the possibility of applying this effective description to other models in suitable regimes.}, archive = {J_PRA}, author = {Cesare Vianello and Matteo Ferraretto and Luca Salasnich}, doi = {10.1103/v6xk-3xsh}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063310}, shortjournal = {Phys. Rev. A}, title = {Finite-temperature entanglement and coherence in asymmetric bosonic josephson junctions}, volume = {111}, year = {2025}, }
• (2025). Wave-function microscopy: Derivation and anatomy of exact algebraic spinful wave functions and full wigner-molecular spectra of a few highly correlated rapidly rotating ultracold fermionic atoms. PRA, 111(6), 063309. (www)

  @article{ , abstract = {Exploring strongly correlated spinful states of a few fermionic ultracold atoms in a rapidly rotating trap, an example of which was recently realized for two fermionic atoms in an optical tweezer, we derive analytical (algebraic) total-spin-eigenstate wave functions through the development and employment of a theoretical platform that integrates exact numerical diagonalization (full configuration interaction, FCI) with symbolic language processing. For such rapid rotations, where the atoms occupy the lowest Landau level (LLL), the obtained algebraic expressions can address the full LLL spectrum in all its complexity, demonstrating that their spatial, spectral, and spin characteristics manifest formation of collectively rotating and vibrating Wigner molecules. The explicitly exhibited analytic wave functions (for two and three spinful atoms) reproduce precisely the corresponding numerical FCI results and are shown to reach beyond the limited range of applicability of previous Jastrow-type treatments. These results, and their extension to bosonic systems, provide the impetus and analysis tools for future experimental and theoretical simulations of larger mesoscopic systems.}, archive = {J_PRA}, author = {Constantine Yannouleas and Uzi Landman}, doi = {10.1103/6hst-g33w}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063309}, shortjournal = {Phys. Rev. A}, title = {Wave-function microscopy: Derivation and anatomy of exact algebraic spinful wave functions and full wigner-molecular spectra of a few highly correlated rapidly rotating ultracold fermionic atoms}, volume = {111}, year = {2025}, }
• (2025). Two-dimensional bosonic droplets in a harmonic trap. PRA, 111(6), 063308. (www)

  @article{ , abstract = {We investigate a system of bosons in a two-dimensional harmonic trap. In the limit of strong attractive interactions, the bosons make a droplet insensitive to external confinement. For weak interactions, in contrast, the ground state is given by the harmonic trap. In this work, we conduct a variational study of the transition between these two limits. We find that this transition occurs at the critical interaction strength whose value is universal if scaled appropriately with the number of particles. To connect the change in the properties of the system to the classical description of phase transitions, we analyze the static response of the Bose gas related to the isothermal compressibility. Finally, we perform numerically exact calculations for a few particles to demonstrate the effects of finite-range interactions on this transition. We conclude that finite-range effects wash out the point of transition.}, archive = {J_PRA}, author = {Fabian Brauneis and Artem G. Volosniev and Hans-Werner Hammer}, doi = {10.1103/PhysRevA.111.063308}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063308}, shortjournal = {Phys. Rev. A}, title = {Two-dimensional bosonic droplets in a harmonic trap}, volume = {111}, year = {2025}, }
• (2025). Edge-edge correlations without edge states: η-clustering state as the ground state of the extended attractive SU(3) hubbard chain. PRA, 111(6), 063307. (www)

  @article{ , abstract = {We explore the phase diagram of the extended attractive Hubbard chain with two-body hopping and nearest-neighbor attraction at half-filling. In the large on-site attraction limit, we identify three different phases: phase separation (PS); Tomonaga-Luttinger liquid (TLL); and charge density wave (CDW). Our analysis reveals that the -clustering state, a three-component generalization of the -pairing state, becomes the ground state at the boundary between the PS and TLL phases. On an open chain, this state exhibits an edge-edge correlation, which we call boundary off-diagonal long-range order (bODLRO). Using the density matrix renormalization group (DMRG) method, we numerically study the phase diagram of the model with large but finite on-site interactions and find that the numerical results align with those obtained in the strong coupling limit.}, archive = {J_PRA}, author = {Hironobu Yoshida and Niclas Heinsdorf and Hosho Katsura}, doi = {10.1103/PhysRevA.111.063307}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063307}, shortjournal = {Phys. Rev. A}, title = {Edge-edge correlations without edge states: η-clustering state as the ground state of the extended attractive SU(3) hubbard chain}, volume = {111}, year = {2025}, }
• (2025). Topologically nontrivial and trivial flat bands via weak and strong interlayer coupling in twisted bilayer honeycomb optical lattices for ultracold atoms. PRA, 111(6), 063306. (www)

  @article{ , abstract = {In recent years, flat electronic bands in twisted bilayer graphene (TBG) have attracted significant attention due to their intriguing topological properties, extremely slow electron velocities, and enhanced density of states. Extending twisted bilayer systems to new configurations is highly desirable, as it offers promising opportunities to explore flat bands beyond TBG. Here, we study both topological and trivial flat bands in a twisted bilayer honeycomb lattice for ultracold atoms and present the evolution of the flat bands with different interlayer coupling strength (ICS). Our results demonstrate that an isolated topological flat band can emerge at the Dirac-point energy for a specific value of weak ICS, referred to as the “critical coupling.” This occurs over a wide range of twist angles, surpassing the limits of the magic angle in TBG systems. When the ICS is slightly increased beyond the critical coupling value, the topological flat band exhibits degenerate band crossings with both the upper and lower adjacent bands at the high-symmetry point. As the ICS is further increased into the strong coupling regime, trivial flat bands arise around Dirac-point energy. Meanwhile, more trivial flat bands appear, extending from the lowest to higher energy bands, and remain flat as the ICS increases. The topological properties of the flat bands are studied through the winding pattern of the Wilson loop spectrum. Our research provides deeper insights into the formation of flat bands in ultracold atoms with highly controllable twisted bilayer optical lattices, and may contribute to the discovery of new strongly correlated states of matter.}, archive = {J_PRA}, author = {Wenjie Sui and Wei Han and Zheng Vitto Han and Zengming Meng and Jing Zhang}, doi = {10.1103/PhysRevA.111.063306}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063306}, shortjournal = {Phys. Rev. A}, title = {Topologically nontrivial and trivial flat bands via weak and strong interlayer coupling in twisted bilayer honeycomb optical lattices for ultracold atoms}, volume = {111}, year = {2025}, }
• (2025). Band-edge superfluid of bose-einstein condensates in the spin-orbit-coupled zeeman lattice. PRA, 111(6), 063305. (www)

  @article{ , abstract = {Since the first experimental realization of Bose-Einstein condensates in a spin-orbit-coupled Zeeman lattice, a wide range of applications have been found in these systems. Here, we systematically study the ground-state phase diagram of the systems. The spin-orbit-coupled Zeeman lattice generates multiple energy minima in the lowest Bloch band. These minima may locate at Brillouin-zone edges and center, or inside the Brillouin zone. Interacting atoms condensing into these minima constitute ground-state quantum phases. Among these phases, the band-edge condensation states have no analog in either spin-orbit-coupled homogeneous systems or lattice systems without the spin-orbit coupling. They exist in a very broad parameter regime of the spin-orbit-coupled Zeeman lattice system. We address superfluidity of the band-edge states by analyzing their elementary excitations and superfluid fraction.}, archive = {J_PRA}, author = {Huaxin He and Fengtao Pang and Hao Lyu and Yongping Zhang}, doi = {10.1103/PhysRevA.111.063305}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063305}, shortjournal = {Phys. Rev. A}, title = {Band-edge superfluid of bose-einstein condensates in the spin-orbit-coupled zeeman lattice}, volume = {111}, year = {2025}, }
• (2025). Coherent coupling of momentum states: Selectivity and phase control. PRA, 111(6), 063304. (www)

  @article{ , abstract = {We demonstrate the effect of pulse shaping in momentum-selective atomic Bragg diffraction. We compare temporal square pulses, which produce sidelobes in momentum space, with other shapes that can produce more nearly square momentum distributions. We produce pulses that simultaneously address two sets of velocity classes and demonstrate that we can control the differential phase imprinted on them in a way that is insensitive to laser phase fluctuations. Our work marks a significant step forward in testing Bell inequalities using massive particles entangled in momentum.}, archive = {J_PRA}, author = {Charlie Leprince and Victor Gondret and Clothilde Lamirault and Rui Dias and Quentin Marolleau and Denis Boiron and Christoph I. Westbrook}, doi = {10.1103/PhysRevA.111.063304}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063304}, shortjournal = {Phys. Rev. A}, title = {Coherent coupling of momentum states: Selectivity and phase control}, volume = {111}, year = {2025}, }
• (2025). Double unstable avoided crossings and complex-domain-pattern formation in spin-orbit-coupled spin-1 condensates. PRA, 111(6), 063303. (www)

  @article{ , abstract = {We analyze the impact of spin-orbit and Rabi couplings on the dynamical stability of spin-orbit-coupled spin-1 Bose-Einstein condensates for ferromagnetic (FM) and antiferromagnetic (AFM) interactions. Determining the collective excitation spectrum through Bogoliubov–de Gennes theory, we characterize the dynamical stability regime via modulational instability. For AFM interactions, the eigenspectrum reveals the presence of both stable and unstable avoided crossings (UACs), with the first-excited branch undergoing a double unstable avoided crossing. In contrast, with ferromagnetic interactions, only a single UAC, which occurs between the low-lying and first-excited branches, is observed. Furthermore, the eigenvectors demonstrate the transition from densitylike to spinlike behavior, as the collective excitation shows the transition from the stable to the unstable mode for both the FM and AFM interactions. In the multiband instability state, eigenvectors display spin-density mixed mode, while they show spin-flip nature in the avoided crossing regime. Our analysis suggests that spin-orbit coupling enhances the instability gain, while Rabi coupling plays the opposite role. Finally, we corroborate our analytical findings of stable and unstable regimes through numerical simulations of the dynamical evolution of the condensates by introducing the perturbations upon quenching the trap strength. The dynamical phases show the formation of complex domains with AFM interaction, which may be attributed to the double unstable avoided crossings in such a system.}, archive = {J_PRA}, author = {Sanu Kumar Gangwar and Rajamanickam Ravisankar and Henrique Fabrelli and Paulsamy Muruganandam and Pankaj Kumar Mishra}, doi = {10.1103/PhysRevA.111.063303}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063303}, shortjournal = {Phys. Rev. A}, title = {Double unstable avoided crossings and complex-domain-pattern formation in spin-orbit-coupled spin-1 condensates}, volume = {111}, year = {2025}, }
• (2025). Coherent backscattering and coherent forward-scattering effects in variations of the random quantum kicked rotor. PRA, 111(6), 063302. (www)

  @article{ , abstract = {We investigate coherent multiple scattering effects in the random quantum kicked rotor model. By changing the starting time of the Floquet period, two classes of models can be introduced that exhibit similar interference structures. For one of the two classes, these structures appear on top of a nontrivial background, which we describe in detail. Its origin is identified and an approximate analytical formula is proposed. The asymptotic contrast profile, as well as the height of the coherent backscattering and the coherent forward scattering peaks, are also analyzed. Our findings are relevant to provide an interpretation of cold atom experiments aimed at observing such interference effects with matter waves.}, archive = {J_PRA}, author = {Hugo Thomas and Julien Hébraud and Bertrand Georgeot and Gabriel Lemarié and Christian Miniatura and Olivier Giraud}, doi = {10.1103/PhysRevA.111.063302}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063302}, shortjournal = {Phys. Rev. A}, title = {Coherent backscattering and coherent forward-scattering effects in variations of the random quantum kicked rotor}, volume = {111}, year = {2025}, }
• (2025). Topological phases protected by projective space-time inversion symmetry in alkaline-earth-metal-like atoms. PRA, 111(6), 063301. (www)

  @article{ , abstract = {An important aspect in categorizing topological phases is whether the system is spinless or spinful, given that these classes exhibit distinct symmetry algebras, leading to disparate topological classifications. By utilizing the projective presentation strategy, the topological phases of spinless (or spinful) systems can be emulated using spinful (or spinless) systems augmented with gauge fields. In this study, we propose to implement the topological phases safeguarded by the unique projective space-time inversion symmetry inherent to spinful models, using synthetic spinless alkaline-earth-metal-like atoms. Employing the separation of orbital and nuclear-spin degrees of freedom, the model is configured as a rectangular tube penetrated by a uniform magnetic flux through each plaquette, which simulates a spinless ladder endowed with projective space-time inversion symmetry satisfying the algebraic properties of a spinful model. For interacting topological phases with interorbital spin-exchange interactions, which also adhere to space-time inversion symmetry, the four-fold degeneracy of edge modes is split into two pairs of edge modes with two-fold degeneracy. We map the complete phase diagram in the end and discover that these interacting topological phases ultimately evolve into distinct charge-density-wave phases via spontaneous symmetry breaking.}, archive = {J_PRA}, author = {Xiaofan Zhou and Suotang Jia and Jian-Song Pan}, doi = {10.1103/PhysRevA.111.063301}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063301}, shortjournal = {Phys. Rev. A}, title = {Topological phases protected by projective space-time inversion symmetry in alkaline-earth-metal-like atoms}, volume = {111}, year = {2025}, }
• (2025). Background reduction in xe136 double-beta-decay experiments through direct barium-ion detection. PRA, 111(6), 063114. (www)

  @article{ , abstract = {Tagging barium ions in double-beta decay experiments involving atoms offers a promising pathway to achieving an almost background-free environment, which is essential for addressing key unresolved questions in neutrino physics, such as the nature of neutrinos and their mass hierarchy. In this manuscript, I present a detection scheme that relies exclusively on the intrinsic energy levels of the barium ion. This method is based solely on the optical interrogation of its electronic transitions, avoiding the need for additional additives or fluorescent agents in the xenon vessel and thereby simplifying the experimental setup. Throughout the manuscript, I demonstrate the feasibility of this detection concept through numerical simulations under realistic experimental conditions inspired by the Neutrino Experiment with a Xenon TPC experiment. The results show that the fluorescence signature of the barium ion can be reliably detected, indicating that the proposed method is a viable path toward background-free searches for neutrinoless double-beta decay.}, archive = {J_PRA}, author = {A. Peralta Conde}, doi = {10.1103/wd95-mqmd}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063114}, shortjournal = {Phys. Rev. A}, title = {Background reduction in xe136 double-beta-decay experiments through direct barium-ion detection}, volume = {111}, year = {2025}, }
• (2025). Coherent control of ion-photoelectron dynamics through rabi oscillations: An ab initio study. PRA, 111(6), 063113. (www)

  @article{ , abstract = {We present first-principles numerical simulations of photoionization in neon induced by bichromatic extreme ultraviolet pulses with frequencies and , specially chosen to make equal to the energy difference between the and subshells. This allows for the production of photoelectrons from the shell by the pulse and from the shell by the pulse with the same energy. Using the multiconfigurational time-dependent Hartree-Fock method, we explore how Rabi coupling between subshells generates coherence between the corresponding photoelectron wave packets. Our ab initio calculations confirm the analytical results derived from the essential-states approach in Ishikawa et al. , [J. Phys. Chem. A 127 , 10638 (2023) ], validating the theoretical predictions. Although we focus on the Ne and subshells, our approach is applicable to a broad range of systems exhibiting photoionization from multiple subshells. The laser parameters employed in our simulations are available in modern free electron lasers (FELs), and we anticipate that this work could stimulate experimental investigations using FELs to study ion-photoelectron coherence and entanglement.}, archive = {J_PRA}, author = {Bo-Ren Shen and Yi-Jia Mao and Zhao-Han Zhang and Yang Li and Takeshi Sato and Kenichi L. Ishikawa and Feng He}, doi = {10.1103/c338-8n6w}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063113}, shortjournal = {Phys. Rev. A}, title = {Coherent control of ion-photoelectron dynamics through rabi oscillations: An ab initio study}, volume = {111}, year = {2025}, }
• (2025). Signatures of intervalley interferences and valley asymmetries in high-order harmonic generation in pristine graphene. PRA, 111(6), 063112. (www)

  @article{ , abstract = {We theoretically demonstrate the effects of interferences and asymmetries between and valleys for pristine graphene in high-order harmonic generation (HHG) by a single-color laser pulse. It is shown that the allowed orders of the observed overall HHG spectra are attributed to the consequences of quantum interferences between and valleys. The cancellations of forbidden harmonics are caused by the destructive interferences between two different valleys due to the dynamical symmetries of the laser-solid systems. Apparent valley-contrasting and helicity-resolved harmonic signals can be observed for the -order ( ) harmonics when the polarization state of the driving laser field slightly deviates from the ideal circular polarization. The valley discriminations for these emerging -order ( ) harmonics originate from the unequal responses of the HHG from two different valleys within the perturbation regime. In addition, the valley asymmetries of the electronic excitations are also observed by using an elliptically polarized laser pulse. Our work clearly illustrates the essential intervalley interplay in the HHG process for pristine graphene, facilitating the understanding of ultrafast electron dynamics in zero-band-gap materials.}, archive = {J_PRA}, author = {Xi Liu and Dongdong Liu and Yan Sun and Yujie Li and Cui Zhang}, doi = {10.1103/ptlr-mhk3}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063112}, shortjournal = {Phys. Rev. A}, title = {Signatures of intervalley interferences and valley asymmetries in high-order harmonic generation in pristine graphene}, volume = {111}, year = {2025}, }
• (2025). Stimulated x-ray raman scattering for selective preparation of dark states bypassing optical selection rules. PRA, 111(6), 063111. (www)

  @article{ , abstract = {We present an x-ray based stimulated Raman approach to control the preparation of populations and coherent superpositions of (valence) electronic states in generic molecular systems, including optically dark states. Leveraging on the unique properties of core-level excitations as intermediates of the Raman process, we demonstrate that optically forbidden singlet-singlet and singlet-triplet transitions are made accessible. We explore the role of both intrinsic molecular properties (transition dipole moments and involved molecular orbitals) and external field parameters to explain the efficiency and selectivity of the process towards specific classes of electronic states, and to control it towards the amplification of desired populations or superpositions. While the reported mechanism naturally applies to virtually all organic and bio-organic molecules and can straightforwardly be extended to a broader class of molecules, atoms and materials, detailed results for two molecular systems are here reported as a testbed of the proposed approach, for which experimental feasibility is eventually discussed.}, archive = {J_PRA}, author = {Francesco Montorsi and Shaul Mukamel and Filippo Tamassia and Marco Garavelli and Francesco Segatta and Artur Nenov}, doi = {10.1103/2lfz-pqzt}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063111}, shortjournal = {Phys. Rev. A}, title = {Stimulated x-ray raman scattering for selective preparation of dark states bypassing optical selection rules}, volume = {111}, year = {2025}, }
• (2025). Interaction of a poincaré beam with optically polarized atoms in the presence of a constant magnetic field. PRA, 111(6), 063110. (www)

  @article{ , abstract = {Recent studies have highlighted the frequent applications of structured light modes in optically pumped atomic magnetometers. In this work, we theoretically explore how a Poincaré beam probes an optically polarized atomic medium. Specifically, we consider atoms polarized by a plane wave with linear polarization, immersed in a constant external magnetic field. We analyze how the polarization of the pump and probe light fields, along with the external magnetic field, impact the absorption profile. To this end, we employ a density-matrix approach based on the Liouville–von Neumann equation. Our results reveal that the absorption profile exhibits an asymmetric pattern that depends on the magnetic-field strength and the mutual orientation of the pump and probe light propagation directions relative to the quantization axis. For illustration, we assume the incoming radiation drives an electric dipole transition, ( ) ( ), in rubidium atoms subjected to a magnetic field. These findings may aid in designing future experiments on optically pumped atomic magnetometers utilizing structured light modes.}, archive = {J_PRA}, author = {S. Ramakrishna and S. Fritzsche}, doi = {10.1103/5r63-5hl1}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063110}, shortjournal = {Phys. Rev. A}, title = {Interaction of a poincaré beam with optically polarized atoms in the presence of a constant magnetic field}, volume = {111}, year = {2025}, }
• (2025). High-order harmonic generation in the vanadium monoanion and its hexacarbonyl complex. PRA, 111(6), 063109. (www)

  @article{ , abstract = {High harmonic generation (HHG) in the vanadium monoanion ( ) and its hexacarbonyl complex, is investigated using time-dependent density functional theory within the optimized effective potential formalism. By analyzing the field-free electronic structure, field-induced changes in the many-electron potential, and the partitions of the high harmonic spectra, we demonstrate that these anions are valuable for understanding the role of orbital spatial distribution in HHG. Both systems feature degenerate (or near-degenerate) orbitals, with some extending along the field polarization direction. Our analysis reveals that this spatial extensiveness enhances HHG intensity by several orders of magnitude. Additionally, the redistribution of electron density in under intense laser fields generates a negative potential near the nuclei, increasing the apparent ionization potential and significantly extending the high harmonic cutoff.}, archive = {J_PRA}, author = {Xi Chu}, doi = {10.1103/d9jb-9p7r}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063109}, shortjournal = {Phys. Rev. A}, title = {High-order harmonic generation in the vanadium monoanion and its hexacarbonyl complex}, volume = {111}, year = {2025}, }
• (2025). Exactly solvable two-level model with time-dependent coupling, detuning, and loss: Application to strong-field resonance ionization. PRA, 111(6), 063108. (www)

  @article{ , abstract = {We present an exactly solvable two-level model with smoothly varying coupling, detuning, and loss functions. Whenever the common temporal profile of these parameter functions is analytically integrable, the complex population amplitudes are found for all times in simple analytic forms. This makes the model suitable for studying the population and phase dynamics of resonance-enhanced ionization processes. Incorporating two-photon Rabi frequency, dynamical Stark shifts, and one-photon ionization rate into this model, the photon ionization of atomic lithium is studied as a showcase example. Finally, when the intensity profile of the laser pulse has the sine-squared shape, we find the exact analytic expression of the photoelectron spectrum, allowing additional insight into the structure of the Autler-Townes doublet.}, archive = {J_PRA}, author = {Ayoub Ait Elarabi and András Csehi}, doi = {10.1103/ws7n-3z78}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063108}, shortjournal = {Phys. Rev. A}, title = {Exactly solvable two-level model with time-dependent coupling, detuning, and loss: Application to strong-field resonance ionization}, volume = {111}, year = {2025}, }
• (2025). Three-path interferences in the reconstruction of attosecond beatings by interference of two-photon transitions in molecules. PRA, 111(6), 063107. (www)

  @article{ , abstract = {Reconstruction of attosecond beatings by two-photon interferences (RABBIT) has amply been used to retrieve photoionization delays from photoelectron spectra measured in atoms and, more recently, in molecules. For the latter, the molecular orientation and multicenter nature of the potential felt by the escaping electron often makes the extraction of these delays problematic. One of the complications comes from the fact that the energy separation between the states of the resulting molecular cation is of the order of the photon energy of the driving infrared (IR) field, so that, during the ionization process, the IR field may induce resonant transitions between such states. This adds a third ionization path to the standard two-path ionization scheme of RABBIT. Here we present a detailed theoretical study of RABBIT in the acetylene molecule in which we have explicitly evaluated time-resolved photoelectron spectra as those recorded in actual experiments. We do so for both random and well-defined orientations of the molecule, and for photoelectron spectra integrated over and resolved in the photoelectron emission angle. We show that the presence of this additional third path can strongly affect the values and physical meaning of photoionization delays extracted from fits based on the commonly used two-path interference scheme. This is indeed the case for acetylene molecules parallel to the light polarization direction, where the extracted delays strongly depend on the IR frequency, while for molecules perpendicular to the polarization direction the standard two-path RABBIT conditions are fulfilled.}, archive = {J_PRA}, author = {Jorge Delgado and Celso M. González-Collado and Piero Decleva and Alicia Palacios and Fernando Martín}, doi = {10.1103/qzg1-2f7n}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063107}, shortjournal = {Phys. Rev. A}, title = {Three-path interferences in the reconstruction of attosecond beatings by interference of two-photon transitions in molecules}, volume = {111}, year = {2025}, }
• (2025). Noise budget of a trapped on-chip cold-atom rb87 clock. PRA, 111(6), 063106. (www)

  @article{ , abstract = {In this paper, we present a realization of an on chip atomic clock using a cold cloud of atoms. This clock is based on a Ramsey interferometer with a Ramsey time around 600 ms. This is realized with large laboratory temperature drift during the measurement (few degrees per day) and without magnetic-field shielding. We review the experimental implementation of this clock and give a full study of the known noises present in this atomic clock.}, archive = {J_PRA}, author = {M. Dupont-Nivet and B. Wirtschafter and S. Hello and C. I. Westbrook}, doi = {10.1103/PhysRevA.111.063106}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063106}, shortjournal = {Phys. Rev. A}, title = {Noise budget of a trapped on-chip cold-atom rb87 clock}, volume = {111}, year = {2025}, }
• (2025). High-order harmonic generation in a crystal driven by quantum light. PRA, 111(6), 063105. (www)

  @article{ , abstract = {We study intraband high-harmonic generation (HHG) in a crystal driven by quantum light. Previous theoretical studies have developed a framework based on coherent state expansions in terms of distributions to consider nonclassical driving fields for HHG in atoms. Here we adapt this framework to the context of solids and consider an intraband model of ZnO. We investigate the effect of the quantum optical nature of the driving field on the harmonic spectra including the cutoff and the intensity scaling of the harmonics with driving field intensity. Based on analytical calculations in the Floquet limit, we explain why driving with thermal light or bright-squeezed vacuum (BSV) produces a much higher cutoff than when driving with fields described by coherent or Fock states. Further, we derive an expression for the generated time-dependent electric field and its fluctuations and find that it inherits characteristics of the driving field. Finally, we discuss the limitations of an approximative positive representation, which is introduced to be able to reduce the numerical complexity for Fock and BSV driving fields.}, archive = {J_PRA}, author = {Rasmus Vesterager Gothelf and Christian Saugbjerg Lange and Lars Bojer Madsen}, doi = {10.1103/PhysRevA.111.063105}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063105}, shortjournal = {Phys. Rev. A}, title = {High-order harmonic generation in a crystal driven by quantum light}, volume = {111}, year = {2025}, }
• (2025). Quantitative comparison of high-order harmonic yields in ring-shaped organic molecules calculated using time-dependent density-functional theory. PRA, 111(6), 063104. (www)

  @article{ , abstract = {We compare the high-harmonic-generation (HHG) yield driven by a midinfrared laser field in three organic ring-shaped molecules, calculated using time-dependent density-functional theory (TDDFT). We average the yield over the relative orientation of the molecules and the linearly polarized, 1825-nm driving laser pulse to compare to experimental spectra obtained by Alharbi et al. , [ Phys. Rev. A 92 , 041801 (2015) ]. We find that the raw TDDFT-calculated HHG yield in cyclohexane is strongly overestimated compared to those of benzene and cyclohexene, and that this can be attributed to unphysically large contributions from cyclohexane orbitals lying well below the highest-occupied molecular orbital. We demonstrate this by implementing a simple orbital-resolved scaling factor that adjusts the tunneling-ionization contribution to the harmonic yield. The rescaled yields are in much better agreement with experimental results, and in particular, reproduce the correct relative-yield ordering of the three molecules. Our results are encouraging for the use of TDDFT in systematic computations of HHG in large molecules.}, archive = {J_PRA}, author = {Kyle A. Hamer and Stephanie N. Armond and Ravi Bhardwaj and Francois Mauger and Kenneth Lopata and Kenneth J. Schafer and Mette B. Gaarde}, doi = {10.1103/PhysRevA.111.063104}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063104}, shortjournal = {Phys. Rev. A}, title = {Quantitative comparison of high-order harmonic yields in ring-shaped organic molecules calculated using time-dependent density-functional theory}, volume = {111}, year = {2025}, }
• (2025). Terahertz-field-modulated high-order harmonic generation in monolayer MoS2. PRA, 111(6), 063103. (www)

  @article{ , abstract = {The intriguing nonlinear optical response of monolayer transition-metal dichalcogenides offers exciting opportunities for both fundamental research and practical applications. In this work, terahertz-modulated harmonic generation in monolayer molybdenum disulfide is explored through numerical simulations and semiclassical trajectory analysis. We find that the yields of both odd- and even-order harmonics, along with their ratios, can be modulated by the intensity of terahertz pulse. We use the subcycle interference model to elucidate the underlying mechanism of these manipulations. The terahertz pulse alters the trajectory of the electrons excited by the midinfrared pulse, introducing additional dipole phases and enabling the change of the harmonic yields. By varying the delay between the midinfrared and terahertz pulses, the temporal distribution of the terahertz intensity can be reconstructed from the delay-dependent harmonic yields, highlighting the potential for ultrabroadband and ultrasensitive terahertz time-domain spectroscopy.}, archive = {J_PRA}, author = {Xiulan Liu and Jianing Zhang and Yong-Kang Fang and Guanglu Yuan and Zhengliang Li and Liang-You Peng}, doi = {10.1103/PhysRevA.111.063103}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063103}, shortjournal = {Phys. Rev. A}, title = {Terahertz-field-modulated high-order harmonic generation in monolayer MoS2}, volume = {111}, year = {2025}, }
• (2025). Direct observation of two-photon-resonance autler-townes splitting of atomic sodium. PRA, 111(6), 063102. (www)

  @article{ , abstract = {A two-photon resonance in the sodium atom transition is investigated in the strong coupling regime with photoelectron momentum imaging techniques. The kinetic energies of the ionized electron map out the eigenenergies of the dressed states and emerge as the Autler-Townes (AT) splitting, which is proportional to the laser intensity due to the two-photon nature. The partial wave analysis of the angular distribution of the photoelectrons reveals the relative phase shift from dressed states which is related to the attosecond ionization time delays. The phase shift between the two electron wave packets produced from AT splitting are attributed to the combination of the Coulomb phase and the quantum defect phase.}, archive = {J_PRA}, author = {Wankai Li and Yixuan Wang and Xing Li and Tao Yang and Dongdong Zhang and Dajun Ding}, doi = {10.1103/PhysRevA.111.063102}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063102}, shortjournal = {Phys. Rev. A}, title = {Direct observation of two-photon-resonance autler-townes splitting of atomic sodium}, volume = {111}, year = {2025}, }
• (2025). Perturbation-theory approach for predicting vibronic selectivity by entangled-photon-pair absorption. PRA, 111(6), 063101. (www)

  @article{ , abstract = {Using second-order perturbation theory in the light-matter interaction, we derive an analytical approximation for the vibronic populations of a diatomic system excited by ultrabroadband frequency-entangled photons and evaluate the population dynamics for different degrees of entanglement between photon pairs. Our analytical approach makes the same predictions as previously derived via numerical solutions of the complete Schrödinger equation [H. Oka, Phys. Rev. A 97 , 063859 (2018) ], with the added advantage of providing clear physical insights into the vibronic selectivity as a function of the degree of photon correlations while requiring significantly reduced computational effort. Specifically, our analytical expression for the probability of vibronic excitation includes a factor which predicts the enhancement of vibrational selectivity as a function of the degree correlation between the entangled photon pairs, the targeted vibrational energy level, and the vibrational molecular structure encoded in the Franck-Condon factors. Our results illustrate the importance of going beyond the usual approximations in second-order perturbation theory to capture the relevance of the vibrational structure of the molecular system of interest in order to gain a deeper understanding of the possible quantum-enhancement provided by the interaction between quantum light and matter.}, archive = {J_PRA}, author = {C. D. Rodríguez-Camargo and H. Ó. Gestsson and C. Nation and A. R. Jones and A. Olaya-Castro}, doi = {10.1103/PhysRevA.111.063101}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {063101}, shortjournal = {Phys. Rev. A}, title = {Perturbation-theory approach for predicting vibronic selectivity by entangled-photon-pair absorption}, volume = {111}, year = {2025}, }
• (2025). Spin versus position conjugation in quantum simulations with atoms: Application to quantum chemistry. PRA, 111(6), 062823. (www)

  @article{ , abstract = {The permutation symmetry is a fundamental attribute of the collective wave function of indistinguishable particles. It makes a difference for the behavior of collective systems having different quantum statistics but existing in the same environment. Here we show that for some specific quantum conjugation between the spin and spatial degrees of freedom the indistinguishable particles can behave similarly for either quantum statistics. In particular, a mesoscopically scaled collection of atomic qubits, mediated by optical tweezers, can model the behavior of a valent electronic shell compounded with nuclear centers in molecules. This makes possible quantum simulations of mono- and divalent bonds in quantum chemistry by manipulation of up to four bosonic atoms confined with optical microtraps.}, archive = {J_PRA}, author = {N. A. Moroz and K. S. Tikhonov and L. V. Gerasimov and A. D. Manukhova and I. B. Bobrov and S. S. Straupe and D. V. Kupriyanov}, doi = {10.1103/558n-868y}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062823}, shortjournal = {Phys. Rev. A}, title = {Spin versus position conjugation in quantum simulations with atoms: Application to quantum chemistry}, volume = {111}, year = {2025}, }
• (2025). Electric-field-dependent g factors of ThF+. PRA, 111(6), 062822. (www)

  @article{ , abstract = {The factors for , hyperfine levels of the electronic ground state of the cation were calculated as functions of the external electric field. These calculations were performed by diagonalizing the molecular Hamiltonian in the presence of the external electric field. The necessary matrix elements of the Hamiltonian were obtained by combining existing experimental data with ab initio calculations within the relativistic coupled-cluster theory. The calculated -factor difference, for the doublets is in good agreement with the experimental value [K. B. Ng et al. , Phys. Rev. A 105 , 022823 (2022) ]. These calculations were used to analyze systematic effects and to develop methods for their suppression in the experiment aimed at searching for the electron electric dipole moment.}, archive = {J_PRA}, author = {Alexander Petrov and Leonid V. Skripnikov}, doi = {10.1103/85pn-k9mj}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062822}, shortjournal = {Phys. Rev. A}, title = {Electric-field-dependent g factors of ThF+}, volume = {111}, year = {2025}, }
• (2025). Thermal nonequilibrium relaxation of methane-nitrogen system investigated by state-resolved deep-potential-energy molecular dynamics. PRA, 111(6), 062821. (www)

  @article{ , abstract = {Direct molecular simulation and the state-to-state method, as the prevailing theoretical approaches for studying thermally nonequilibrium molecular collisions, strongly rely on available high-precision potential energy surfaces and extensive trajectory calculations, and their application to polyatomic molecular systems remains a challenge. In this paper, the state-resolved deep potential molecular dynamics (SR-DPMD) method is proposed, which performs potential energy surface construction and molecular dynamics simulation based on the deep potential molecular dynamics scheme and then achieves energy state resolution during the simulation through normal mode analysis. Applying this method to the simulation of thermal nonequilibrium dynamics of the methane-nitrogen system and comparing it with the simulation of state-resolved ReaxFF, combining the energy state analysis of five-atom molecules is realized. The results demonstrate that vibration-rotation coupling and vibration-vibration coupling can directly affect the vibrational energy relaxation behavior of molecules. It is evident that the accuracy of the ReaxFF is inadequate to facilitate the energy state resolution of the molecule; however, it is capable of yielding qualitative outcomes concerning the energy relaxation of the molecule during the simulation. Overall, the SR-DPMD method provides a powerful tool for understanding the energy state evolution of polyatomic molecules under nonequilibrium conditions and is expected to provide valuable insights into energy relaxation, chemical reactions, and their coupling processes. The reaction force field is also dedicated to providing new perspectives for the study of thermal nonequilibrium dynamics.}, archive = {J_PRA}, author = {Yongxin Hu and Changmin Guo and Hongwei Song and Jianyi Ma}, doi = {10.1103/2hfd-1zfq}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062821}, shortjournal = {Phys. Rev. A}, title = {Thermal nonequilibrium relaxation of methane-nitrogen system investigated by state-resolved deep-potential-energy molecular dynamics}, volume = {111}, year = {2025}, }
• (2025). Resonant photon scattering in the presence of external fields and its applications for the CERN gamma factory project. PRA, 111(6), 062820. (www)

  @article{ , abstract = {We present a theoretical study of resonant elastic photon scattering by highly charged ions in the presence of external electric and magnetic fields. Special emphasis is placed on head-on collisions of relativistic ion beams and counterpropagating laser photons, as can be observed in ion storage ring experiments. If the collision zone for such a scenario is exposed to a moderate field of a dipole magnet, a fast-moving ion will be subjected to strong electric and magnetic fields in its rest frame due to the Lorentz transformation. To investigate the effect of these fields we performed detailed calculations for the elastic photon scattering by He-like Ca ions moving with the Lorentz factor . Such a scenario is of particular interest for the Gamma Factory project which is supported by the CERN Physics Beyond Colliders framework. Based on the results of our calculations, we argue that even moderate magnetic fields significantly modify the rate of detected photons as well as their emission pattern and polarization. This sensitivity to external fields opens interesting avenues for diverse applications for the Gamma Factory project, such as resonance condition tuning, beam cooling, and polarization control.}, archive = {J_PRA}, author = {Jan Richter and Mieczyslaw Witold Krasny and Jan Gilles and Andrey Surzhykov}, doi = {10.1103/yysz-444v}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062820}, shortjournal = {Phys. Rev. A}, title = {Resonant photon scattering in the presence of external fields and its applications for the CERN gamma factory project}, volume = {111}, year = {2025}, }
• (2025). Blackbody radiation zeeman shift in rydberg atoms. PRA, 111(6), 062819. (www)

  @article{ , abstract = {We consider the Zeeman shift in Rydberg atoms induced by room-temperature blackbody radiation (BBR). BBR shifts to the Rydberg levels are dominated by the familiar BBR Stark shift. However, the BBR Stark shift and the BBR Zeeman shift exhibit different behaviors with respect to the principal quantum number of the Rydberg electron. Namely, the BBR Stark shift asymptotically approaches a constant value given by a universal expression, whereas the BBR Zeeman shift grows steeply with principal quantum number due to the diamagnetic contribution. We show that for transitions between Rydberg states, where only the differential shift between levels is of concern, the BBR Zeeman shift can surpass the BBR Stark shift. We exemplify this in the context of a proposed experiment targeting a precise determination of the Rydberg constant.}, archive = {J_PRA}, author = {K. Beloy and B. D. Hunt and R. C. Brown and T. Bothwell and Y. S. Hassan and J. L. Siegel and T. Grogan and A. D. Ludlow}, doi = {10.1103/m3rh-sdly}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062819}, shortjournal = {Phys. Rev. A}, title = {Blackbody radiation zeeman shift in rydberg atoms}, volume = {111}, year = {2025}, }
• (2025). Progress toward a formulation of density-functional theory for matrix representations. PRA, 111(6), 062818. (www)

  @article{ , abstract = {In quantum chemistry, there is a debate about the existence of density functionals beyond the ground electronic state. Here, we apply the tool kit of density-functional theory (DFT) to analyze the characteristics of the eigenvalues of an arbitrary symmetric matrix. The latter can represent a model Hamiltonian, which is not necessarily obtained from a basis-set representation of the exact physical Hamiltonian. Based on the analogy with an exactly solvable physical model, we introduce a density functional for each eigenvalue of the matrix and show that, similar to an exactly solvable model, only the lowest and highest eigenvalues of an arbitrary symmetric matrix have well-defined single-valued functionals of density with unique convexity or concavity characteristics. All other eigenvalues lack such density functionals, as the respective quantities are multivalued density functions and lack unique convexity or concavity. The problem of the nonexistence of functionals for the excited states can be overcome by forming weighted sums of eigenvalues in analogy with the Gross-Oliveira-Kohn ensemble DFT, which results in well-defined density functionals with admissible characteristics.}, archive = {J_PRA}, author = {Michael Filatov(Gulak and Seung Kyu Min}, doi = {10.1103/85rp-bgtg}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062818}, shortjournal = {Phys. Rev. A}, title = {Progress toward a formulation of density-functional theory for matrix representations}, volume = {111}, year = {2025}, }
• (2025). Ionization and kinetic-energy release in electron-impact dissociation of h3+ and d3+. PRA, 111(6), 062817. (www)

  @article{ , abstract = {Cross sections for electronic excitation and ionization in electron scattering on and have been calculated using the polyatomic molecular convergent close-coupling (MCCC) method adapted to point-group symmetries. Convergence in both the total excitation and ionization cross sections is established within the MCCC framework, yielding agreement with available experiment at all energies above thresholds. Focusing on comparison with available experiment, kinetic-energy release (KER) cross sections for electron-impact dissociation of in several initial vibrational modes have been calculated in a one-dimensional model. Cross sections are presented for dissociative excitation through the , and excited electronic states of and dissociative ionization through the state of . A model for the branching ratios is proposed for the first six excited electronic states and for ionization. Kinetic-energy release cross sections for the production of and are presented. Reasonable agreement with experimental KER cross sections is found at incident energies above 20 eV, while good agreement is found with measured KER cross sections above 40 eV.}, archive = {J_PRA}, author = {Reese K. Horton and Michael V. Pak and Igor Bray and Dmitry V. Fursa}, doi = {10.1103/rmtg-crtm}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062817}, shortjournal = {Phys. Rev. A}, title = {Ionization and kinetic-energy release in electron-impact dissociation of h3+ and d3+}, volume = {111}, year = {2025}, }
• (2025). Prospects for measuring the electron's electric dipole moment with polyatomic molecules in an optical lattice. PRA, 111(6), 062815. (www)

  @article{ , abstract = {We present the conceptual design of an experiment to measure the electron's electric dipole moment (eEDM) using molecules in an optical lattice. The BaOH molecule is laser-coolable and highly sensitive to the eEDM, making it an attractive candidate for such a precision measurement, and capturing it in an optical lattice offers potentially very long coherence times. We study possibilities and limitations of this approach, identify the most crucial limiting factors and ways to overcome them. The proposed apparatus can reach a statistical error of by measuring spin precession on a total number of molecules over a span of 120 days.}, archive = {J_PRA}, author = {Roman Bause and Nithesh Balasubramanian and Ties Fikkers and Eifion H. Prinsen and Kees Steinebach and Arian Jadbabaie and Nicholas R. Hutzler and I. Agustín Aucar and Lukáš F. Pašteka and Anastasia Borschevsky and Steven Hoekstra}, doi = {10.1103/8ltl-7wsb}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062815}, shortjournal = {Phys. Rev. A}, title = {Prospects for measuring the electron's electric dipole moment with polyatomic molecules in an optical lattice}, volume = {111}, year = {2025}, }
• (2025). Ultracold silver-atom collisions and the formation of silver dimers by photo- and magneto-association. PRA, 111(6), 062814. (www)

  @article{ , abstract = {We have performed three theoretical simulations relevant for describing collisions among laser-cooled silver atoms and for the formation of molecules from these colliding atoms. Firstly, we determined the relativistic electronic structure of molecules in ground and low-lying excited states. Secondly, we computed rotational and vibrational levels of the ground and excited electronic states as well as rovibrationally averaged electric transition dipole moments. Using this knowledge, we analyzed a simplified quantum-mechanical model of the one-photon photoassociation process to form electronically excited from microkelvin Ag atoms and make predictions for lineshapes and saturation effects as functions of laser frequency and intensity. Finally and thirdly, we performed coupled-channels calculations, numerical solutions of sets of coupled radial Schrödinger equations of ultracold ground-state Ag collisions in an external magnetic field. These calculations include the effects of two Born-Oppenheimer potentials as well as hyperfine Fermi-contact and Zeeman interactions. We discuss the expected range of -wave scattering lengths as well as strengths and distribution of Fano-Feshbach resonances as a function of the magnetic-field strength for the and isotopes. We highlight the periodicity of the scattering length with small changes in the depths of the Born-Oppenheimer potentials. The Fano-Feshbach resonances can be used to magneto-associate ultracold Ag atoms into weakly bound ground-state dimers.}, archive = {J_PRA}, author = {Eite Tiesinga and Jacek Kłos and Hui Li and Svetlana Kotochigova and David DeMille}, doi = {10.1103/rd26-sgz1}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062814}, shortjournal = {Phys. Rev. A}, title = {Ultracold silver-atom collisions and the formation of silver dimers by photo- and magneto-association}, volume = {111}, year = {2025}, }
• (2025). Ionization cross section of the cu k shell by electron impact from the k threshold to 90 keV, determined on the basis of diagram lines, satellite lines, and the radiative auger effect. PRA, 111(6), 062813. (www)

  @article{ , abstract = {The Cu ionization cross section by electron impact has been measured in the energy range from the -shell threshold to . To this end, a thin Cu film deposited on a thin C backing has been employed. The x rays emitted by the target have been detected by two silicon drift detectors placed at front and back angles with respect to the direction of the incident beam, which allowed us to better assess the peak fit procedure of the multiplet. A careful analysis of the Cu x-ray spectra generated by electron bombardment has been conducted, including not only the diagram lines but also the satellite lines and the counts that come from the radiative Auger effect. This enabled us to obtain the and x-ray production cross sections with relative uncertainties of the order of , and the -shell ionization cross section with a precision around . We show that, in most cases, the ionization cross sections reported according to current practice cannot be compared with the available theoretical calculations because the latter do not account for multiple-ionization effects. Our results agree with the distorted-wave Born approximation only when the x-ray counts from satellite lines, which amount to about of the total, are excluded.}, archive = {J_PRA}, author = {Suelen F. Barros and Kai L. Dardengo and Nora L. Maidana and Alessio Mangiarotti and Vito R. Vanin and José M. Fernández-Varea}, doi = {10.1103/cwp8-7zhm}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062813}, shortjournal = {Phys. Rev. A}, title = {Ionization cross section of the cu k shell by electron impact from the k threshold to 90 keV, determined on the basis of diagram lines, satellite lines, and the radiative auger effect}, volume = {111}, year = {2025}, }
• (2025). Demonstrating correlation trends in the electric dipole polarizabilities of many low-lying states in cs i through first-principles calculations. PRA, 111(6), 062812. (www)

  @article{ , abstract = {Electron correlation and higher-order relativistic effects are probed in the evaluation of scalar and tensor static electric dipole (E1) polarizabilities of several even- and odd-parity states in cesium (Cs) using the Dirac-Hartree-Fock (DHF) method, second-order perturbation theory [MBPT(2)], third-order perturbation theory [MBPT(3)], random phase approximation (RPA), and singles and doubles approximated relativistic coupled-cluster (RCCSD) method. To account for perturbation due to an odd-parity E1 operator on the atomic orbitals, calculations are carried out in the linear response approach. Our final values, with the estimated uncertainties, show reasonably good agreement with the previous calculations and available experimental results. Differences among the DHF, MBPT(2), MBPT(3) and RPA results indicate that pair-correlation (PC) effects play major roles compared to the core-polarization (CP) effects in the determination of values in Cs. From the differences among the MBPT(3) and RCC results, we find correlations among the PC and CP effects and double CP effects together are also significant in these calculations. Contributions from the Breit interactions are found to be quite large in the high-lying states.}, archive = {J_PRA}, author = {A. Chakraborty and B. K. Sahoo}, doi = {10.1103/mjn1-xzcb}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062812}, shortjournal = {Phys. Rev. A}, title = {Demonstrating correlation trends in the electric dipole polarizabilities of many low-lying states in cs i through first-principles calculations}, volume = {111}, year = {2025}, }
• (2025). Projectile excitation to the 2s2p p3 and p1 autoionizing states in swift collisions of he-like carbon and oxygen mixed-state (1s2,1s2sS3,1) ion beams with helium. PRA, 111(6), 062811. (www)

  @article{ , abstract = {The production of the projectile and autoionizing states is investigated in 0.5–1.5 MeV/u collisions of He-like carbon and oxygen mixed-state three-component ion beams with helium targets. The mixed-state beams are produced in the stripping systems of the 5.5-MV Demokritos tandem accelerator. Using high-resolution Auger projectile electron spectroscopy, the normalized Auger electron yields are measured at relative to the beam direction. In addition, a three-electron atomic orbital close-coupling approach, employing full configuration interaction and antisymmetrization of the three-electron, two-center total wave function, is applied to calculate the production cross sections for these states from each of the three initial ion beam components. Thereupon, the theoretical Auger yields are computed and found to be mostly smaller than experiment by factors ranging from near 1 to about 10. Agreement, however, improves when larger fractions, not only based on spin statistics, are projected. Overall, we present a careful and sophisticated analysis with a thorough discussion of these results which show that our current understanding is still incomplete. Nevertheless, our nonperturbative excitation treatment—free from scaling parameters and renormalization—marks a significant advancement in modeling ultrafast multielectron dynamics within open-shell quantum systems.}, archive = {J_PRA}, author = {A. Laoutaris and S. Passalidis and S. Nanos and A. Biniskos and E. P. Benis and A. Dubois and T. J. M. Zouros}, doi = {10.1103/l6x2-cfs9}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062811}, shortjournal = {Phys. Rev. A}, title = {Projectile excitation to the 2s2p p3 and p1 autoionizing states in swift collisions of he-like carbon and oxygen mixed-state (1s2,1s2sS3,1) ion beams with helium}, volume = {111}, year = {2025}, }
• (2025). Measurement of the electric dipole moment of AlCl by stark-level spectroscopy. PRA, 111(6), 062810. (www)

  @article{ , abstract = {We report the measurement of the electric dipole moment of aluminum monochloride (AlCl) using a cryogenic buffer-gas beam source. Using Stark shift spectroscopy, we derive values for the dipole moments in the body-fixed frame of the two lowest vibrational states for the electronic state, D and D, and for the state, D and D. We also show that the ab initio calculations of the dipole moment and energy of AlCl are sensitive to the level of treatment of the spin-orbit orbit coupling. We further lay out the implications of these results for astrophysical models of stellar and planetary evolution that have used a substitute value for the dipole moment of AlCl until now.}, archive = {J_PRA}, author = {Li-Ren Liu and Miguel Aguirre, Jr and Stephen R. Kane and Brian K. Kendrick and Boerge Hemmerling}, doi = {10.1103/hwwm-1mn7}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062810}, shortjournal = {Phys. Rev. A}, title = {Measurement of the electric dipole moment of AlCl by stark-level spectroscopy}, volume = {111}, year = {2025}, }
• (2025). Polarizabilities of low-lying states of silver. PRA, 111(6), 062809. (www)

  @article{ , abstract = {Assembly of ultracold polar molecules containing silver (Ag) from laser-cooled atoms requires knowledge of the dynamic polarizabilities of Ag at convenient laser wavelengths. We present calculations and analysis of the energies and electric-dipole dc and ac polarizabilities of the low-lying states of neutral Ag. Calculations of the properties of the states, where , and , are performed using the linearized coupled cluster single-double method. The properties of the states are obtained within the framework of configuration interaction with 11 and 17 electrons in the valence field. We analyze the different contributions to the polarizabilities and estimate the uncertainties of our predictions.}, archive = {J_PRA}, author = {S. G. Porsev and D. Filin and C. Cheung and M. S. Safronova}, doi = {10.1103/PhysRevA.111.062809}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062809}, shortjournal = {Phys. Rev. A}, title = {Polarizabilities of low-lying states of silver}, volume = {111}, year = {2025}, }
• (2025). Cascading interatomic coulombic electron capture induced by a single incident electron in two- and three-center atomic systems. PRA, 111(6), 062808. (www)

  @article{ , abstract = {In the process of interatomic Coulombic electron capture, an incident free electron is captured at an atomic center and the transition energy is transferred radiationlessly over a rather large distance to a neighboring atom of different species, upon which the latter is ionized. We consider two-step cascade processes where the electron emitted from atom is subsequently captured as well (either at center or yet another atomic center ), leading to the emission of a second electron from one of the centers. We derive formulas for the cross section of this cascading interatomic Coulombic electron capture, which can reach the order of kilobarn for suitable parameters and exhibits a very strong dependence on the interatomic distances. The relevance of this process, which leads to a substantial rearrangement of the electronic configuration, is discussed in various two- and three-center atomic systems.}, archive = {J_PRA}, author = {L. M. Ellerbrock and A. B. Voitkiv and C. Müller}, doi = {10.1103/PhysRevA.111.062808}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062808}, shortjournal = {Phys. Rev. A}, title = {Cascading interatomic coulombic electron capture induced by a single incident electron in two- and three-center atomic systems}, volume = {111}, year = {2025}, }
• (2025). Experimental triple-differential cross sections for electron-impact ionization of 1-methyl-5-nitroimidazole at 97-eV impact energy. PRA, 111(6), 062807. (www)

  @article{ , abstract = {We present the triple-differential cross sections (TDCSs) for electron-impact single ionization of a potential radiosensitizer molecule, 1-methyl,5-nitroimidazole ( ), at an impact energy of 97 eV. The experiment was done using a momentum spectrometer, a so-called reaction microscope, employing the coincidence technique. Modifications of the existing experimental setup to incorporate a vapor target produced from a solid sample are described. Experimental results are compared with the multicenter three-distorted-wave model. The post-collision interaction (PCI) effects are included using the Ward-Macek approximation in the multicenter three-distorted-wave Ward-Macek model. Both experimental and theoretical TDCSs include contributions from the first five valence orbitals which lead to the formation of the parent ion. Qualitative agreement between the theory and the experiment is obtained. The prominent character of the ionized orbitals is evident in both results, along with indications of PCI effects and multiple scattering at the ionic potential, manifested as significant out-of-plane electron emissions.}, archive = {J_PRA}, author = {Deepthy Maria Mootheril and Maomao Gong and Xueguang Ren and Carlos Guerra Castillo and Xiangjun Chen and Gustavo Garcia and Thomas Pfeifer and Alexander Dorn}, doi = {10.1103/PhysRevA.111.062807}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062807}, shortjournal = {Phys. Rev. A}, title = {Experimental triple-differential cross sections for electron-impact ionization of 1-methyl-5-nitroimidazole at 97-eV impact energy}, volume = {111}, year = {2025}, }
• (2025). Benchmarking direct and indirect dipolar spin-exchange interactions between two rydberg atoms. PRA, 111(6), 062806. (www)

  @article{ , abstract = {We report on the experimental characterization of various types of spin-exchange interactions between two individual atoms, where pseudospin degrees of freedom are encoded in different Rydberg states. For the case of the direct dipole-dipole interaction between states of opposite parity, such as between and , we investigate the effects of positional disorder arising from the residual atomic motion on the coherence of spin-exchange oscillations. We then characterize an indirect dipolar spin exchange, i.e., the off-diagonal part of the van der Waals effective Hamiltonian that couples the states and . Finally, we report on the observation of a new type of dipolar coupling, made resonant using addressable light shifts and involving four different Rydberg levels: this exchange process is akin to electrically induced Förster resonance, but featuring local control. It exhibits an angular dependence distinct from the usual form of the resonant dipolar spin-exchange.}, archive = {J_PRA}, author = {Gabriel Emperauger and Mu Qiao and Guillaume Bornet and Cheng Chen and Romain Martin and Yuki Torii Chew and Bastien Gély and Lukas Klein and Daniel Barredo and Antoine Browaeys and Thierry Lahaye}, doi = {10.1103/PhysRevA.111.062806}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062806}, shortjournal = {Phys. Rev. A}, title = {Benchmarking direct and indirect dipolar spin-exchange interactions between two rydberg atoms}, volume = {111}, year = {2025}, }
• (2025). Quantum chemical computations of raman intensities: An ambiguity of the placzek approximation. PRA, 111(6), 062804. (www)

  @article{ , abstract = {Coupled-perturbed (CP) computational methods, in particular those based on the density functional theory (DFT), are indispensable in interpretations of Raman scattering on molecules. The simulations are most often based on the Placzek approximation, ignoring the dependence of energies of the excited electronic states on nuclear coordinates. Thus practical CP DFT computations do not exactly correspond to the more general sum over state (SOS) formalism. We discuss this problem, investigate the SOS convergence, and formulate a distributed origin gauge enabling us to calculate origin-independent Raman optical activity intensities. The variations of the computed spectra caused by the energy gradient terms are investigated with practical examples. The results show that although the contribution of the gradient parts to Raman intensities is rather small in the far from resonance cases, their subtraction may still occasionally improve the simulated spectra. However, the effect is much more important for Raman optical activity and in resonance conditions. The possibility to correct the computed intensities for the gradient contribution thus opens a way for systematic improvements of quantum-mechanical simulations of the spectra.}, archive = {J_PRA}, author = {Jaroslav Šebestík and Petr Bouř}, doi = {10.1103/PhysRevA.111.062804}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062804}, shortjournal = {Phys. Rev. A}, title = {Quantum chemical computations of raman intensities: An ambiguity of the placzek approximation}, volume = {111}, year = {2025}, }
• (2025). Unraveling the structures in the van der waals interactions of alkali-metal rydberg atoms. PRA, 111(6), 062803. (www)

  @article{ , abstract = {Rydberg atoms are used in a wide range of applications due to their peculiar properties like strong dipolar and van der Waals interactions. The choice of Rydberg state has a huge impact on the strength and angular dependence of the interactions, and so a detailed understanding of the underlying processes and resulting properties of the interactions is therefore key to select the most suitable states for experiments. We study the van der Waals interactions in alkali-metal atoms in detail and highlight the structures which allow an understanding and exploitation of the various interaction properties. A particular theme is the identification of Förster resonances with , which offer interaction potentials with a wide range of properties that make them particularly interesting for experimental applications. A second theme is a focus on the underlying structures that shape the angular dependency and sign of the interactions. This understanding — instead of brute-force calculations — allows for a much simpler and more systematic search for suitable pair states. These insights can be used for the selection of tailored interaction potentials subject to experimental constraints and requirements. We use rubidium as an example species in this work and also provide data for cesium and pair states that are coupled via two- or three-photon transitions, i.e. up to states, in the Appendix.}, archive = {J_PRA}, author = {Karen Wadenpfuhl and C. Stuart Adams}, doi = {10.1103/PhysRevA.111.062803}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062803}, shortjournal = {Phys. Rev. A}, title = {Unraveling the structures in the van der waals interactions of alkali-metal rydberg atoms}, volume = {111}, year = {2025}, }
• (2025). Determination of quantum defects and core polarizability of atomic cesium via terahertz and radio-frequency spectroscopy in thermal vapor. PRA, 111(6), 062802. (www)

  @article{ , abstract = {We present new measurements of quantum defects and core polarizabilities in cesium ( ), based on transition frequency measurements between Rydberg states ( ) obtained through THz and radio-frequency spectroscopy in a thermal atomic vapor. We perform a global fitting of our measurements to extract quantum defects of the , and electronic states. Transitions between high angular momentum states ( ) were measured to extract the dipole and quadrupole polarizabilities. We find and respectively. Using these results, and accounting for the covariances between parameters in the global fit, the energies for Rydberg states can be estimated to a precision of a few MHz or less.}, archive = {J_PRA}, author = {Gianluca Allinson and Lucy A. Downes and C. Stuart Adams and Kevin J. Weatherill}, doi = {10.1103/PhysRevA.111.062802}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062802}, shortjournal = {Phys. Rev. A}, title = {Determination of quantum defects and core polarizability of atomic cesium via terahertz and radio-frequency spectroscopy in thermal vapor}, volume = {111}, year = {2025}, }
• (2025). Electronic emission in a single ion-nanoparticle collision. PRA, 111(6), 062801. (www)

  @article{ , abstract = {Electron emission (EE) from insulating polystyrene nanoparticles induced by a single collision with swift ions is investigated. The ions electronic stopping powers explored range from 35 ev/nm to 2.3 kev/nm. A cross-beam experiment is developed to measure charge-state distributions of nanoparticles of 100 nanometer radius. The proportionality between the EE and the stopping power observed when measured using grounded conductive foils is no longer fulfilled. We perform a complementary analysis of nanoparticle charging by using Monte Carlo simulations. We emphasize the role of particle charging by taking into account the effect of the holes on the dynamics of electron emission. The resulting charging effect can be as large as two orders of magnitude for the highest stopping power. This explains rather well the experimentally observed strong sublinearity of electron emission with stopping power. As the nanoparticle size decreases, the simulation suggests that the charging effect diminishes, but remains significant for large stopping power.}, archive = {J_PRA}, author = {Thibault Nguyen Trung and Michel Du Chalard and Marin Chabot and Olivier Sublemontier and Emmanuel Dartois and Thomas Pino and Isabelle Ribaud and Benoit Gervais and Eric Giglio and Jean Duprat and Karine Béroff}, doi = {10.1103/PhysRevA.111.062801}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062801}, shortjournal = {Phys. Rev. A}, title = {Electronic emission in a single ion-nanoparticle collision}, volume = {111}, year = {2025}, }
• (2025). Combining quantum noise reduction resources: A practical approach. PRA, 111(6), 062623. (www)

  @article{ , abstract = {Optomechanical sensors are capable of transducing external perturbations to resolvable optical signals. A particular regime of interest is that of high-bandwidth force detection, where an impulse is delivered to the system over a short period of time. Exceedingly sensitive impulse detection has been proposed to observe very weak signals like those due to long-range interactions with dark matter that require much higher sensitivities than current sensors can provide. Quantum resources to go beyond the traditional standard quantum limit of these sensors include squeezing of the light used to transduce the signal, backaction evasion by measuring the optimal quadrature, and quantum nondemolition (QND) measurements that reduce backaction directly. These methods have been developed in the context of gravitational wave detection for target frequencies in the audio band range. Here, we provide the theoretical limits to quantum noise reduction for higher and broader frequency targets, such as those from dark matter signals, while combining quantum-enhanced readout techniques based on squeezed light and QND measurements with optomechanical sensors. We demonstrate that backaction evasion through QND techniques dramatically reduces the technical challenges presented when using squeezed light for broadband force detection, paving the way for combining multiple quantum noise reduction techniques for enhanced sensitivity in the context of impulse metrology.}, archive = {J_PRA}, author = {Sohitri Ghosh and Matthew A. Feldman and Seongjin Hong and Claire E. Marvinney and Alberto M. Marino and Raphael C. Pooser and Jacob M. Taylor}, doi = {10.1103/PhysRevA.111.062623}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062623}, shortjournal = {Phys. Rev. A}, title = {Combining quantum noise reduction resources: A practical approach}, volume = {111}, year = {2025}, }
• (2025). Resonator-activated entangling gates for spin qubits in quantum dots. PRA, 111(6), 062622. (www)

  @article{ , abstract = {The electron spin in semiconductor quantum dots is a promising candidate for scalable quantum information processing. However, a critical and challenging step is achieving high-fidelity control and entanglement between spatially separated spin qubits. Here we propose a scheme for implementing entangling gates between two long-distance spin qubits based on the resonator-induced phase. Since the scheme only requires microwave control of the resonator, the spin qubits can operate at their sweet spots and exhibit high-frequency flexibility. We investigate the coherent dynamics of the resonator-induced phase gate and demonstrate the potential to achieve a controlled- gate with a high fidelity of 93.5% within a short timescale of tens of nanoseconds under realistic conditions. We also show the robustness of this scheme with respect to perturbations in the control pulse parameters. Furthermore, our scheme can be used to generate nonlocal entangled states and can be easily extended to multiqubit architectures. These results provide strong support for the realization of large-scale quantum computing with spin qubits.}, archive = {J_PRA}, author = {Wan-Qin He and Jin-Rong Liu and Xing-Yu Zhu}, doi = {10.1103/xx7c-36f5}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062622}, shortjournal = {Phys. Rev. A}, title = {Resonator-activated entangling gates for spin qubits in quantum dots}, volume = {111}, year = {2025}, }
• (2025). Parallel teleportation of partially unknown quantum operations with multiple degrees of freedom based on the nitrogen-vacancy-center system. PRA, 111(6), 062621. (www)

  @article{ , abstract = {A scheme is proposed for parallel teleportation of partially unknown quantum operations with multiple degrees of freedom based on a nitrogen-vacancy (NV) center system. An NV center system offers long coherence time and high fidelity for quantum operations. Assisted by the error heralded module and the corresponding circuit, high fidelity parallel teleportation of partially unknown quantum operations can be achieved, with hyperentangled Bell states of polarization and time-bin modes as the quantum channels. In the case of low side leakage and strong coupling, the efficiency and success probability approaching unity can be expectable. The employment of simple module circuits and optical components is beneficial for the implementation of the scheme with currently experimental techniques.}, archive = {J_PRA}, author = {Xiao-Ming Xiu and Zi-Lin Zhao and Zi-Qing Yuan and Si-Ge Chen and Xin-Yi Zhang and Yan-Qiang Ji and Li Dong}, doi = {10.1103/h2ql-8rx3}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062621}, shortjournal = {Phys. Rev. A}, title = {Parallel teleportation of partially unknown quantum operations with multiple degrees of freedom based on the nitrogen-vacancy-center system}, volume = {111}, year = {2025}, }
• (2025). Utilizing evolution time as a resource to enhance quantum sensing by probe qubit dephasing. PRA, 111(6), 062620. (www)

  @article{ , abstract = {We examine a system in which an impurity qubit is immersed in a quasi-two-dimensional dipolar Bose-Einstein condensate whose collective excitations act as a dephasing reservoir for the qubit. The relative dipole-dipole interaction strength is estimated by the probe qubit dephasing. The ultimate precision of this estimation is quantified by the quantum Fisher information (QFI), which can be obtained by means of measuring quantum coherence of the probe qubit. Our findings indicate that, in the interval where roton excitations appear, the QFI oscillates periodically with the evolution time , and the amplitude of these oscillations increases alongside the extension of . Moreover, we analytically determine that the envelope curve formed by the local maximum points satisfies the functional relationship during long-term encoding scenarios, where , and are positive numbers. It is revealed that the highly non-Markovian effects caused by the roton softening of the excitation spectrum allow long evolution time to serve as a resource for enhancing sensing precision. We also study the effects of the reservoir's temperature on the dynamics of the QFI. It is found that lower temperatures have virtually no effect, while higher temperatures can accelerate the growth rate of the QFI with evolution time, reflecting that thermal noise can be used to enhance the quantum advantage in quantum sensing. Our work provides a new pathway for enhancing the sensing precision of dephasing qubits.}, archive = {J_PRA}, author = {Ji-Bing Yuan and Hai-Fei Liu and Ya-Ju Song and Shi-Qing Tang and Xin-Wen Wang and Le-Man Kuang}, doi = {10.1103/74j7-vw6d}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062620}, shortjournal = {Phys. Rev. A}, title = {Utilizing evolution time as a resource to enhance quantum sensing by probe qubit dephasing}, volume = {111}, year = {2025}, }
• (2025). Quantum metrology of a structured reservoir. PRA, 111(6), 062619. (www)

  @article{ , abstract = {Accurately characterizing the properties of structured reservoirs is a key challenge in quantum systems and is of great importance for advances in quantum metrology and sensing. In this work, we employ a two-level system (qubit) as a probe, which is coupled to a structured reservoir consisting of an ancilla qubit and a Markovian environment modeled as a thermal bath. By exploiting non-Markovian dynamics, we systematically investigate the effectiveness of different interaction types between the probe and ancilla for estimating critical parameters, including temperature, ancilla frequency, and system-bath coupling strength. We quantify the precision of parameter estimation using quantum Fisher information (QFI) and analyze the system dynamics in both transient and steady-state regimes. Our findings demonstrate that non-Markovianity substantially enhances parameter estimation in the transient regime, with specific interactions facilitating sustained information backflow and yielding higher QFI values. However, the performance of these interactions is contingent on the parameter under estimation and the operational regime. For instance, certain interactions become prominent in the transient regime but exhibit diminished utility in the steady state, whereas others maintain their effectiveness even at equilibrium. These results stress the importance of judiciously selecting interactions adapted to specific estimation objectives and operational regimes.}, archive = {J_PRA}, author = {Youssef Aiache and Asghar Ullah and Özgür E. Müstecaplıoğlu and Abderrahim El Allati}, doi = {10.1103/ypp6-5bt9}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062619}, shortjournal = {Phys. Rev. A}, title = {Quantum metrology of a structured reservoir}, volume = {111}, year = {2025}, }
• (2025). Fidelity and efficiency analysis for heralded entanglement swapping in lossy channels: Linear and nonlinear optical approaches. PRA, 111(6), 062618. (www)

  @article{ , abstract = {Bell-state measurements (BSMs) of photonic qubits are used for quantum networking protocols to herald the distribution and transfer of quantum information. However, standard BSMs based on linear optics (LO-BSMs) require identical photons and are susceptible to errors from multiphoton emissions, leading to reduced fidelity of protocols, particularly in the absence of postselection. To overcome these challenges, Bell state measurements based on nonlinear optics (NLO-BSMs) have been proposed and implemented, leveraging sum-frequency generation (SFG) to filter out multiphoton emissions and improve the fidelity without postselection. Here, we analyze the fidelity of LO-BSM and NLO-BSM heralded entanglement swapping in lossy channels and compare their performance under realistic conditions. We also explore the impact of state-of-the-art nonlinear photonics platforms on SFG efficiency and highlight how advances in nanophotonics will enable practical, high-fidelity NLO-BSM-based quantum networking applications.}, archive = {J_PRA}, author = {Kejie Fang and Elizabeth A. Goldschmidt}, doi = {10.1103/wz51-smml}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062618}, shortjournal = {Phys. Rev. A}, title = {Fidelity and efficiency analysis for heralded entanglement swapping in lossy channels: Linear and nonlinear optical approaches}, volume = {111}, year = {2025}, }
• (2025). Nearest-neighbor synthesis of controlled-NOT circuits on general quantum architectures. PRA, 111(6), 062617. (www)

  @article{ , abstract = {Noisy intermediate-scale quantum (NISQ) devices have inherent limitations in terms of connectivity and hardware noise. The synthesis of controlled- ( cnot ) circuits considers the physical constraints and transforms quantum algorithms into low-level quantum circuits that can execute on physical chips correctly. In the current trend, quantum chip architectures without Hamiltonian paths are gradually replacing architectures with Hamiltonian paths due to their scalability and low-noise characteristics. To this end, this paper addresses the nearest-neighbor synthesis of cnot circuits in the architectures with and without Hamiltonian paths, aiming to enhance the fidelity of the circuits after execution. First, a key-qubit priority mapping model for general quantum architectures is proposed. Second, the initial mapping is further improved by using tabu search to reduce the number of cnot gates after circuit synthesis and enhance its fidelity. Finally, the noise-aware cnot circuit nearest-neighbor synthesis algorithm for the general architecture is proposed based on the key-qubit priority mapping model. The algorithm is demonstrated on several popular cloud quantum computing platforms and simulators, showing that it effectively optimizes the fidelity of cnot circuits compared with mainstream methods. Moreover, the method can be extended to more general circuits, thereby improving the overall performance of quantum computing on NISQ devices.}, archive = {J_PRA}, author = {Xinyu Chen and Mingqiang Zhu and Xueyun Cheng and Zhijin Guan and Shiguang Feng and Pengcheng Zhu}, doi = {10.1103/13m1-y3br}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062617}, shortjournal = {Phys. Rev. A}, title = {Nearest-neighbor synthesis of controlled-NOT circuits on general quantum architectures}, volume = {111}, year = {2025}, }
• (2025). Reservoir-assisted quantum battery charging at finite temperatures. PRA, 111(6), 062616. (www)

  @article{ , abstract = {Quantum batteries, as highly efficient energy storage devices, have garnered significant research interest. A key challenge in their development is to maximize the extractable energy (ergotropy) when operating within a finite-temperature reservoir. To address this, we apply quantum feedback control to the charger and investigate the effects of fermionic and bosonic thermal reservoirs on the performance of quantum batteries, including stored energy, ergotropy, and charging efficiency, in an open environment. Our findings reveal that, regardless of the type of thermal reservoir, the system exhibits optimal charging parameters. In particular, in a fermionic thermal reservoir, increasing the environmental temperature enhances battery performance, enabling stable and efficient charging. In contrast, within a bosonic thermal reservoir, higher temperatures hinder energy storage and extraction, significantly reducing charging efficiency. Additionally, we explore the impact of battery size and find that, under a fermionic reservoir, increasing the battery size appropriately can further improve performance.}, archive = {J_PRA}, author = {Y. Yao and X. Q. Shao}, doi = {10.1103/vqnk-kzqg}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062616}, shortjournal = {Phys. Rev. A}, title = {Reservoir-assisted quantum battery charging at finite temperatures}, volume = {111}, year = {2025}, }
• (2025). Estimation of imbert-fedorov shifts based on SU(1,1) interferometer breaking through the shot-noise limit. PRA, 111(6), 062615. (www)

  @article{ , abstract = {Imbert-Fedorov (IF) shifts refer to transverse tiny displacements of light beams at the interface of two media. Since the IF shifts are a reflection of the light-matter interaction, they can be applied to sense the properties of the medium or light beam. To evaluate the errors of parameters in various kinds of sensors with high precision, quantum metrology based on the SU(1,1) interferometer is expected to improve the measurement accuracy beyond the shot-noise limit (SNL). We propose a theoretical scheme to investigate the IF shifts and incident angle sensitivity for a Laguerre-Gauss beam by introducing a surface-plasmon-resonance (SPR) sensor into the SU(1,1) interferometer. We derived the sensitivity of the IF shifts and incident angle based on the homodyne detection. Meanwhile, the quantum Cramér-Rao bound and SNL of IF shifts and incident angle are obtained in our scheme. Our results demonstrate that the sensitivity of both IF shifts and incident angle can break through the SNL around the SPR angle by injecting two coherent states with large coherent amplitude. Furthermore, it is possible to get the maximal IF shifts and the optimal IF shifts sensitivity simultaneously on the two sides of the SPR angle. Our scheme provides a method for measuring tiny beam shifts and small angular displacement in SPR sensors. The results can be helpful for the development of quantum metrology based on quantum sensors and a deep understanding of light-matter interactions.}, archive = {J_PRA}, author = {Yuetao Chen and Jing Wang and Qiang Ma and Gaiqing Chen and Mengmeng Luo and Shoukang Chang and Shaoyan Gao}, doi = {10.1103/jb26-qws1}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062615}, shortjournal = {Phys. Rev. A}, title = {Estimation of imbert-fedorov shifts based on SU(1,1) interferometer breaking through the shot-noise limit}, volume = {111}, year = {2025}, }
• (2025). Integrating measurement-device-independent quantum-key-distribution systems into an optical transport network. PRA, 111(6), 062614. (www)

  @article{ , abstract = {Measurement-device-independent (MDI) quantum key distribution (QKD) systems are immune to detector side channel attacks. Integrated into existing fiber optical communication lines by means of a dense wavelength division multiplexing technique, they allow one to build secure telecommunication networks of various typologies. The present work focuses on theoretical research of the noise influence caused by spontaneous Raman scattering, four-wave mixing, and linear channel crosstalk on the performance of MDI QKD systems. We consider symmetric and asymmetric system configurations, as well as possible implementation schemes, for discrete- and continuous-variable versions of the protocol. For all cases, the secure key generation rate is calculated to distinguish the features of MDI QKD system operation and optimal conditions when they are most performative.}, archive = {J_PRA}, author = {Irina Vorontsova and Roman Goncharov and Alexei Santev and Fedor Kiselev and Eduard Samsonov and Vladimir Egorov}, doi = {10.1103/8ml6-p78t}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062614}, shortjournal = {Phys. Rev. A}, title = {Integrating measurement-device-independent quantum-key-distribution systems into an optical transport network}, volume = {111}, year = {2025}, }
• (2025). Mapping of a many-qubit state onto an oscillator using controlled displacements. PRA, 111(6), 062613. (www)

  @article{ , abstract = {We extend the controlled displacement interaction between a qubit and a harmonic oscillator to the multiqubit (qudit) case. We define discrete quadratures of the qudit and show how the qudit state can be displaced in these quadratures controlled by an oscillator quadrature. Using this interaction, a periodic repetition of the state encoded in the qudit, can be deterministically mapped onto the oscillator, which is initialized in a squeezed state. Based on this controlled displacement interaction, we present a full circuit that encodes quantum information in a superposition of qudit quadrature states, and successively prepares the oscillator in the corresponding superposition of approximate Gottesman-Kitaev-Preskill (GKP) states. This preparation scheme is found to be similar to phase estimation, with the addition of a disentanglement gate. Our protocol for GKP state preparation is efficient in the sense, that the set of qubits need only interact with the oscillator through two time-independent interactions, and in the sense that the squeeze factor (in dB) of the produced GKP state grows linearly in the number of qubits used.}, archive = {J_PRA}, author = {Anders J. E. Bjerrum and Ulrik L. Andersen and Peter Rabl}, doi = {10.1103/fdx5-kftm}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062613}, shortjournal = {Phys. Rev. A}, title = {Mapping of a many-qubit state onto an oscillator using controlled displacements}, volume = {111}, year = {2025}, }
• (2025). Four-body coupler for superconducting qubits based on josephson parametric oscillators. PRA, 111(6), 062612. (www)

  @article{ , abstract = {We theoretically propose a circuit of the four-body coupler for superconducting qubits based on Josephson parametric oscillators (JPOs). Our coupler for the four-body interaction has a superconducting loop, similar to a capacitively shunted flux qubit, where an external magnetic flux set to half a flux quantum is threaded. This coupler circuit is a specific setup of the circuit called superconducting nonlinear asymmetric inductive elements (SNAIL) and also is a generalization of the previously proposed one for the four-body interaction of JPOs. We clarify roles of circuit parameters in the four-body interaction and, in particular, show that the four-body coupling constant in our circuit can be significantly increased by tuning capacitance of the coupler or the area ratio of the Josephson junctions of the coupler.}, archive = {J_PRA}, author = {Ryoji Miyazaki and Tsuyoshi Yamamoto}, doi = {10.1103/PhysRevA.111.062612}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062612}, shortjournal = {Phys. Rev. A}, title = {Four-body coupler for superconducting qubits based on josephson parametric oscillators}, volume = {111}, year = {2025}, }
• (2025). Quantum repeaters based on stationary gottesman-kitaev-preskill qubits. PRA, 111(6), 062611. (www)

  @article{ , abstract = {Quantum repeaters that incorporate quantum error correction codes have been shown to be a promising alternative compared with the original quantum repeaters that rely upon probabilistic quantum error detection depending on classical communication over remote repeater stations. A particularly efficient way of encoding qubits into an error correction code is through bosonic codes where even a single oscillator mode serves as a sufficiently large, physical system. Here we consider the bosonic Gottesman-Kitaev-Preskill (GKP) code as a natural choice for a loss-correction-based quantum repeater. However, unlike existing treatments, we focus on the excitation loss that occurs in the local, stationary memory qubits as represented by, for instance, collective atomic spin modes. We analyze and assess the performance of such a GKP-based quantum repeater where, apart from the initial state generations and distributions, all operations can be performed via deterministic linear mode transformations, as opposed to other existing memory-based quantum repeater schemes.}, archive = {J_PRA}, author = {Stefan Häussler and Peter van Loock}, doi = {10.1103/PhysRevA.111.062611}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062611}, shortjournal = {Phys. Rev. A}, title = {Quantum repeaters based on stationary gottesman-kitaev-preskill qubits}, volume = {111}, year = {2025}, }
• (2025). Quantum algorithm for green's-function measurements in the fermi-hubbard model. PRA, 111(6), 062610. (www)

  @article{ , abstract = {In the framework of the hybrid quantum-classical variational cluster approach to strongly correlated electron systems one of the goals of a quantum subroutine is to find single-particle correlation functions of lattice fermions in polynomial time. Previous works suggested to use variants of the Hadamard test for this purpose, which requires an implementation of controlled single-particle fermionic operators. However, for a number of locality-preserving mappings to encode fermions into qubits, a direct construction of such operators is not possible. In this work, we propose a quantum algorithm that uses an analog of the Kubo formula adapted to a quantum circuit simulating the Hubbard model. It allows to access the Green's function of a cluster directly using only bilinears of fermionic operators and circumvents the usage of the Hadamard test. We test our algorithm in practice by using open-access simulators of noisy IBM superconducting chips.}, archive = {J_PRA}, author = {Gino Bishop and Dmitry Bagrets and Frank K. Wilhelm}, doi = {10.1103/PhysRevA.111.062610}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062610}, shortjournal = {Phys. Rev. A}, title = {Quantum algorithm for green's-function measurements in the fermi-hubbard model}, volume = {111}, year = {2025}, }
• (2025). Real-time adaptation of quantum noise channel estimates. PRA, 111(6), 062609. (www)

  @article{ , abstract = {Estimates of noise channels for quantum gates are required for most error-mitigation techniques and are desirable for informing quantum error-correction decoders. These estimates can be obtained by resource-intensive offline characterization techniques, but can become stale due to device drift and fluctuations. We propose a method to address this issue by performing real-time adaptation of noise channel estimates during the execution of a quantum algorithmic circuit using extended flag gadgets, midcircuit measurements, and Bayesian inference. We carry out analytical calculations and numerical simulations employing a Dirichlet prior distribution for the error rates in a Pauli channel to demonstrate and evaluate the technique, which can be seen as a protocol for real-time calibration of high-level gate error information.}, archive = {J_PRA}, author = {Lucas Daguerre and Mohan Sarovar}, doi = {10.1103/PhysRevA.111.062609}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062609}, shortjournal = {Phys. Rev. A}, title = {Real-time adaptation of quantum noise channel estimates}, volume = {111}, year = {2025}, }
• (2025). Mitigation of birefringence in cavity-based quantum networks using frequency-encoded photons. PRA, 111(6), 062608. (www)

  @article{ , abstract = {Atom-cavity systems offer unique advantages for building large-scale distributed quantum computers by providing strong atom-photon coupling while allowing for high-fidelity local operations of atomic qubits. However, in prevalent schemes where the photonic state is encoded in polarization, cavity birefringence introduces an energy splitting of the cavity eigenmodes and alters the polarization states, thus limiting the fidelity of remote entanglement generation. To address this challenge, we propose a scheme that encodes the photonic qubit in the frequency degree of freedom. The scheme relies on resonant coupling of multiple transverse cavity modes to different atomic transitions that are well separated in frequency. We numerically investigate the temporal properties of the photonic wave packet, two-photon interference visibility, and atom-atom entanglement fidelity under various cavity polarization-mode splittings and find that our scheme is less affected by cavity birefringence. Finally, we propose practical implementations in two trapped ion systems, using the fine-structure splitting in the metastable D state of 40 Ca + and the hyperfine splitting in the ground state of 225 Ra + . Our study presents an alternative approach for cavity-based quantum networks that is less sensitive to birefringent effects and is applicable to a variety of atomic and solid-state emitter-cavity interfaces.}, archive = {J_PRA}, author = {Chengxi Zhang and Justin Phillips and Inder Monga and Erhan Saglamyurek and Qiming Wu and Hartmut Haeffner}, doi = {10.1103/PhysRevA.111.062608}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062608}, shortjournal = {Phys. Rev. A}, title = {Mitigation of birefringence in cavity-based quantum networks using frequency-encoded photons}, volume = {111}, year = {2025}, }
• (2025). Experimental secure entanglement-free quantum remote sensing over 50 km of optical fiber. PRA, 111(6), 062607. (www)

  @article{ , abstract = {Secure quantum remote sensing (SQRS) uses quantum states to gather information about distant objects or environments while ensuring secure data transmission against eavesdropping. It has potential applications in various fields, including environmental monitoring, military surveillance, and disaster response, where both data accuracy and transmission security are critical. Recent experiments have demonstrated the feasibility of SQRS using entanglement states. Here, we experimentally demonstrate an SQRS that can estimate a phase without requiring entanglement, offering the practical advantage that single-qubit states are easier to prepare. We successfully estimate the preset phase information at a remote site over a fiber distance of 50 km, which serves as a key step toward long-distance applications.}, archive = {J_PRA}, author = {Wenjie He and Chunfeng Huang and Rui Guan and Ye Chen and Zhenrong Zhang and Kejin Wei}, doi = {10.1103/PhysRevA.111.062607}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062607}, shortjournal = {Phys. Rev. A}, title = {Experimental secure entanglement-free quantum remote sensing over 50 km of optical fiber}, volume = {111}, year = {2025}, }
• (2025). Cost of emulating a small quantum annealing problem in the circuit model. PRA, 111(6), 062606. (www)

  @article{ , abstract = {Demonstrations of quantum advantage for certain sampling problems have generated considerable excitement for quantum computing and have further spurred the development of circuit-model quantum computers, which represent quantum programs as a sequence of quantum gates acting on a finite number of qubits. Amongst this excitement, analog quantum computation has become less prominent, with the expectation that circuit-model quantum computers will eventually be sufficient for emulating analog quantum computation and thus rendering analog quantum computation obsolete. In this work we explore the basic requirements for emulating a specific analog quantum computation in the circuit model: the preparation of a biased superposition of degenerate ground states of an Ising Hamiltonian using an adiabatic evolution. We show that the overhead of emulation is substantial even for this simple problem. This supports using analog quantum computation for solving time-dependent Hamiltonian dynamics in the short term and midterm, assuming analog errors can be made low enough and coherence times long enough to solve problems of practical interest.}, archive = {J_PRA}, author = {Javier Gonzalez-Conde and Zachary Morrell and Marc Vuffray and Tameem Albash and Carleton Coffrin}, doi = {10.1103/PhysRevA.111.062606}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062606}, shortjournal = {Phys. Rev. A}, title = {Cost of emulating a small quantum annealing problem in the circuit model}, volume = {111}, year = {2025}, }
• (2025). Efficient learning and optimizing non-gaussian correlated noise in digitally controlled qubit systems. PRA, 111(6), 062605. (www)

  @article{ , abstract = {Precise qubit control in the presence of spatiotemporally correlated noise is pivotal for transitioning to fault-tolerant quantum computing. Generically, such noise can also have non-Gaussian statistics, which hampers existing non-Markovian noise spectroscopy protocols. By utilizing frame-based characterization and a control-based symmetry analysis, we show how to achieve higher-order spectral estimation for noise-optimized circuit design. Remarkably, we find that the digitally driven qubit dynamics can be solely determined by the complexity of the applied control rather than the nonperturbative nature of the non-Gaussian environment. This enables us to address certain nonperturbative qubit dynamics more simply. We delineate several complexity bounds for learning such high-complexity noise and demonstrate our single- and two-qubit digital characterization and control using a series of numerical simulations. Our results not only provide insights into the exact solvability of (small-size) open quantum dynamics but also highlight a resource-efficient approach for optimal control and possible error-reduction techniques for current qubit devices.}, archive = {J_PRA}, author = {Wenzheng Dong and Yuanlong Wang and Muhammad Qasim Khan}, doi = {10.1103/PhysRevA.111.062605}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062605}, shortjournal = {Phys. Rev. A}, title = {Efficient learning and optimizing non-gaussian correlated noise in digitally controlled qubit systems}, volume = {111}, year = {2025}, }
• (2025). Minimum optical depth multiport interferometers for approximating arbitrary unitary operations and pure states. PRA, 111(6), 062603. (www)

  @article{ , abstract = {Reconfigurable devices which can implement arbitrary unitary operations are crucial for photonic quantum computation, optical neural networks, and boson sampling. Here, we address the problem of, using multiport interferometers, approximating with a given infidelity any pure-state preparation and any unitary operation. By means of numerical calculations, we show that pure states, in any dimension , can be prepared with infidelity with three layers of -dimensional Fourier transforms and three layers of configurable phase shifters. We also present numerical evidence that layers of -dimensional Fourier transforms and layers of configurable phase shifters can produce any unitary operation with infidelity . The conclusions are achieved by numerical simulations in the range from to . These results are interesting in light of the recent availability of multicore fiber-integrated multiport interferometers.}, archive = {J_PRA}, author = {Luciano Pereira and Alejandro Rojas and Gustavo Lima and Aldo Delgado and Gustavo Cañas and Adán Cabello}, doi = {10.1103/PhysRevA.111.062603}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062603}, shortjournal = {Phys. Rev. A}, title = {Minimum optical depth multiport interferometers for approximating arbitrary unitary operations and pure states}, volume = {111}, year = {2025}, }
• (2025). Noisy stark probes as quantum-enhanced sensors. PRA, 111(6), 062602. (www)

  @article{ , abstract = {Wannier-Stark localization has been proven to be a resource for quantum-enhanced sensitivity for precise estimation of a gradient field. An extremely promising feature of such probes is their ability to showcase such enhanced scaling even dynamically with system size, on top of the quadratic scaling in time. In this paper, we address the issue of decoherence that occurs during time evolution and characterize how that affects the sensing performance. We determine the parameter domains in which the enhancement is sustained under dephasing dynamics. In addition, we consider an effective non-Hermitian description of the open quantum system dynamics for describing the effect of decoherence on the sensing performance of the probe. By investigating the static and dynamic properties of the non-Hermitian Hamiltonians, we show that quantum-enhanced sensitivity can indeed be sustained over a certain range of decoherence strength for Wannier-Stark probes. This is demonstrated with two examples of non-Hermitian systems with nonreciprocal couplings.}, archive = {J_PRA}, author = {Saubhik Sarkar and Abolfazl Bayat}, doi = {10.1103/PhysRevA.111.062602}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062602}, shortjournal = {Phys. Rev. A}, title = {Noisy stark probes as quantum-enhanced sensors}, volume = {111}, year = {2025}, }
• (2025). Anomalously slow dynamics of inhomogeneous quantum annealing. PRA, 111(6), 062601. (www)

  @article{ , abstract = {Inhomogeneous quantum annealing (IQA), in which transverse fields are turned off one by one rather than simultaneously, has been proposed as an effective way to avoid the first-order phase transitions that impede conventional quantum annealing (QA). Here we explicitly study the dynamics of IQA, rather than merely the thermodynamics, and find that it is appreciably slower than the phase diagram would suggest. Interestingly, this slowdown manifests both when IQA succeeds in circumventing phase transitions and when it fails. Even in the absence of transitions, such as for the mean-field models that have been analyzed previously, IQA is slower than expected by a factor of the number of spins . More significantly, we show that in non-mean-field models, first-order transitions are likely to be quite common, and the gap at such transitions is not merely exponential in but exactly zero. Thus IQA cannot reach the ground state on any timescale. Both of these results can be understood through the simple observation that a spin's magnetization becomes conserved once its field is turned off during the IQA protocol.}, archive = {J_PRA}, author = {Mohammadhossein Dadgar and Christopher L. Baldwin}, doi = {10.1103/PhysRevA.111.062601}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062601}, shortjournal = {Phys. Rev. A}, title = {Anomalously slow dynamics of inhomogeneous quantum annealing}, volume = {111}, year = {2025}, }
• (2025). State learning from pairs of states. PRA, 111(6), 062428. (www)

  @article{ , abstract = {Suppose you receive a sequence of qubits where each qubit is guaranteed to be in one of two pure states, but you do not know what those states are. Your task is to determine the states. This can be viewed as a kind of quantum state learning, or quantum state estimation. The problem is that, without more information, all that can be determined is the density matrix of the sequence and, in general, density matrices can be decomposed into pure states in many different ways. To solve the problem, additional information, either classical or quantum, is required. We show that if an additional copy of each qubit is supplied (that is, one receives pairs of qubits, both in the same state, rather than single qubits) the task can be accomplished. This is possible because the mixed two-qubit state has a unique decomposition into pure product states. For illustration purposes, we numerically simulate the symmetric, informationally complete measurement of a sequence of qubit pairs and show that the unknown states and their respective probabilities of occurrence can be inferred from the data with high accuracy. Finally, we propose an experiment that employs a product measurement and can be realized with existing technology, and we demonstrate how the data tell us the states and their probabilities. We find that it is enough to detect a few thousand qubit pairs.}, archive = {J_PRA}, author = {Pranjal Agarwal and Nada Ali and Camilla Polvara and Martin-Isbjörn Trappe and Berthold-Georg Englert and Mark Hillery}, doi = {10.1103/tyf3-1zdd}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062428}, shortjournal = {Phys. Rev. A}, title = {State learning from pairs of states}, volume = {111}, year = {2025}, }
• (2025). Efficient implementation of the unitary coupled-cluster ansatz in high-dimensional trapped-ion systems. PRA, 111(6), 062427. (www)

  @article{ , abstract = {The variational quantum eigensolver (VQE) algorithm is particularly well suited for estimating the ground-state energies of molecular systems in the noisy intermediate-scale quantum era. However, the most popular unitary coupled-cluster ansatz requires a large number of qubits and gates that are constrained by short coherence time and hardware noise. In this study, we present schemes for estimating the ground-state energies of the molecules and LiH using the VQE algorithm in a trapped-ion system with a high-dimensional method. It is shown that significantly fewer quantum gates are required to achieve the same result as the qubit-based model. High-dimensional quantum simulation can make more use of quantum resources. Utilizing the recently developed fixed-input-state method, the depth of the circuits can be further reduced. Only one and three single-qubit gates are required for the simulation of the and LiH molecules, respectively. Finally, combined with the zero-noise extrapolation technique to mitigate the effects of noise, the accuracy of the results is significantly improved. These findings indicate that using a fixed input state in high-dimensional quantum simulations can enhance the performance of near-term quantum computing hardware.}, archive = {J_PRA}, author = {Peng Wang and Xueying Yang and Chun-Wang Wu and Chunyan Li and Wei Wu and Ping-Xing Chen}, doi = {10.1103/79nd-mr7f}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062427}, shortjournal = {Phys. Rev. A}, title = {Efficient implementation of the unitary coupled-cluster ansatz in high-dimensional trapped-ion systems}, volume = {111}, year = {2025}, }
• (2025). Super-heisenberg scaling of quantum fisher information using spin-motion states. PRA, 111(6), 062426. (www)

  @article{ , abstract = {We propose a spin-motion state for high-precision quantum metrology with super-Heisenberg scaling of the parameter estimation uncertainty using a trapped ion system. Such a highly entangled state can be created using the Tavis-Cummings Hamiltonian, which describes the interaction between a collective spin system and a single vibrational mode. Our method relies on an adiabatic evolution in which the initial motional squeezing is adiabatically transferred into collective spin squeezing. In the weak squeezing regime, we show that the adiabatic evolution creates a spin-squeezed state, which reduces the quantum projective noise to a sub-shot-noise limit. For strong bosonic squeezing we find that the quantum Fisher information follows a super-Heisenberg scaling law in terms of the number of ions . Furthermore, we discuss the spin-squeezing parameter which quantifies the phase sensitivity enhancement in Ramsey spectroscopic measurements and show that it also exhibits a super-Heisenberg scaling with . Our work enables the development of high-precision quantum metrology based on entangled spin-boson states that lead to faster scaling of the parameter estimation uncertainty with the number of spins.}, archive = {J_PRA}, author = {Venelin P. Pavlov and Peter A. Ivanov}, doi = {10.1103/lznh-gg4j}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062426}, shortjournal = {Phys. Rev. A}, title = {Super-heisenberg scaling of quantum fisher information using spin-motion states}, volume = {111}, year = {2025}, }
• (2025). Quantum observable's reality erasure with spacelike-separated operations. PRA, 111(6), 062425. (www)

  @article{ , abstract = {In 1935, Einstein, Podolsky, and Rosen argued that quantum mechanics is incomplete based on the assumption that local actions cannot influence elements of reality at a distant location (local realism). In this work, using a recently defined quantum reality quantifier, we show that Alice's local quantum operations can be correlated with the erasure of the reality of observables in Bob's causally disconnected laboratory. To this end, we implement a modified optical quantum eraser experiment, ensuring that Alice's and Bob's measurements remain causally disconnected. Using an entangled pair of photons and quantum state tomography, we experimentally verify that, even with the total absence of any form of classical communication, the choice of quantum operation applied by Alice on her photon is correlated with the erasure of a spatial element of reality of Bob's photon. Our results reveal that Bob's photon can entangle two extra noninteracting degrees of freedom, thus confirming that Bob's photon path is not an element of physical reality.}, archive = {J_PRA}, author = {J. S. Araújo and D. S. Starke and A. S. Coelho and J. Maziero and G. H. Aguilar and R. M. Angelo}, doi = {10.1103/jzcw-5krt}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062425}, shortjournal = {Phys. Rev. A}, title = {Quantum observable's reality erasure with spacelike-separated operations}, volume = {111}, year = {2025}, }
• (2025). Wide-band magnetometry based on color centers with transverse zero-field splitting. PRA, 111(6), 062424. (www)

  @article{ , abstract = {Solid-state color centers embedded in diamond, silicon carbide, and other host matrices offer a promising platform for nanoscale quantum sensing. Sometimes a relatively strong transverse zero-field splitting is introduced in a color center due to its local strain and the low symmetry of the host structure. While clock transitions induced by transverse zero-field splitting serve as a method to prolong the coherence time, the Zeeman sublevels of solid-state color centers become insensitive to first-order magnetic-field signals, thereby limiting their utility as magnetometers. In this work, we address this challenge and achieve wide-band ac field detection spanning from hundreds of kilohertz to hundreds of megahertz by utilizing a combination of orthogonal microwaves and phase modulation at different frequencies. Our control method effectively suppresses the system noise and the amplitude fluctuation of the driving field, which extends the coherence time of the quantum system.}, archive = {J_PRA}, author = {Xiayan Ding and Lu Chen and Qiong Chen}, doi = {10.1103/r45s-hskw}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062424}, shortjournal = {Phys. Rev. A}, title = {Wide-band magnetometry based on color centers with transverse zero-field splitting}, volume = {111}, year = {2025}, }
• (2025). No-broadcasting of coherence in terms of wigner-yanase skew information. PRA, 111(6), 062423. (www)

  @article{ , abstract = {No-cloning and no-broadcasting of arbitrary quantum states are intrinsic features differentiating quantum mechanics from the classical realm. Recent studies have explored the broadcasting of quantum features such as asymmetry, magic, and imaginarity within the framework of resource theories. In this work, we study the quantitative aspects of coherence from the perspective of no-broadcasting. Although when the coherence is quantified by a superadditive measure, it can be readily proved that the amount of coherence cannot be broadcast, such an approach becomes invalid for nonsuperadditive measures of coherence. Thus, it is desirable to find methods to study the no-broadcasting of coherence effective for both superadditive and nonsuperadditive coherence measures. By employing a novel characterization of bipartite quantum states with vanishing basis-dependent correlations, we establish a no-broadcasting theorem of coherence in terms of Wigner-Yanase skew information, which is an important version of quantum Fisher information and a nonsuperadditive measure of coherence. The result extends the conventional no-broadcasting from quantum states to information-theoretic contents of quantum states and can be regarded as an instance of no-broadcasting of quantum Fisher information. We also establish no-broadcasting of the relative entropy of coherence, without relying on superadditivity.}, archive = {J_PRA}, author = {Zijian Zhang and Nan Li and Shunlong Luo}, doi = {10.1103/538y-43nf}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062423}, shortjournal = {Phys. Rev. A}, title = {No-broadcasting of coherence in terms of wigner-yanase skew information}, volume = {111}, year = {2025}, }
• (2025). Power-optimized amplitude modulation for robust trapped-ion entangling gates: A study of gate-timing errors. PRA, 111(6), 062422. (www)

  @article{ , abstract = {Trapped-ion systems are a promising route toward the realization of both near-term and universal quantum computers. However, one of the pressing challenges is improving the fidelity of two-qubit entangling gates. These operations are often implemented by addressing individual ions with laser pulses using the Mølmer-Sørensen protocol. Amplitude modulation (AM) is a well-studied extension of this protocol, where the amplitude of the laser pulses is controlled as a function of time. We present an analytical study of AM, using a Fourier series expansion to maintain the generality of the laser amplitude's functional form. We then apply this general AM method to gate-timing errors by imposing conditions on these Fourier coefficients, producing trade-offs between the laser power and fidelity at a fixed gate time. The conditions derived here are linear and can be used, in principle, to achieve arbitrarily high orders of insensitivity to gate-timing errors. Numerical optimization is then employed to identify the minimum-power pulse satisfying these constraints. Our central result is that the leading-order dependence on gate-timing errors is improved from O ( Δ t 2 ) to O ( Δ t 6 ) with the addition of one linear constraint on the Fourier coefficients and to O ( Δ t 10 ) with two linear constraints without a significant increase in the average laser power. The increase approaches zero as more Fourier coefficients are included. In further studies, this protocol can be applied to other error sources and used in conjunction with other error-mitigation techniques to improve two-qubit gates.}, archive = {J_PRA}, author = {Luke Ellert-Beck and Wenchao Ge}, doi = {10.1103/PhysRevA.111.062422}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062422}, shortjournal = {Phys. Rev. A}, title = {Power-optimized amplitude modulation for robust trapped-ion entangling gates: A study of gate-timing errors}, volume = {111}, year = {2025}, }
• (2025). Quantum framework for reinforcement learning: Integrating the markov decision process, quantum arithmetic, and trajectory search. PRA, 111(6), 062421. (www)

  @article{ , abstract = {This paper introduces a quantum framework for addressing reinforcement learning (RL) tasks, grounded in the quantum principles and leveraging a fully quantum model of the classical Markov decision process. By employing quantum concepts and a quantum search algorithm, this work presents the implementation and optimization of the agent-environment interactions entirely within the quantum domain, eliminating reliance on classical computations. Key contributions include the quantum-based state transitions, return calculation, and trajectory search mechanism that utilize quantum principles to demonstrate the realization of RL processes through quantum phenomena. The implementation emphasizes the fundamental role of quantum superposition in enhancing computational efficiency for RL tasks. Results demonstrate the capacity of a quantum model to achieve quantum enhancement in RL, highlighting the potential of fully quantum implementations in decision-making tasks. This work not only underscores the applicability of quantum computing in machine learning but also contributes to the field of quantum reinforcement learning by offering a robust framework for understanding and exploiting quantum computing in RL systems.}, archive = {J_PRA}, author = {Thet Htar Su and Shaswot Shresthamali and Masaaki Kondo}, doi = {10.1103/5lfr-xb8m}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062421}, shortjournal = {Phys. Rev. A}, title = {Quantum framework for reinforcement learning: Integrating the markov decision process, quantum arithmetic, and trajectory search}, volume = {111}, year = {2025}, }
• (2025). Low-depth phase oracle using a parallel piecewise circuit. PRA, 111(6), 062420. (www)

  @article{ , abstract = {We explore the important task of applying a phase exp ( i f ( x ) ) to a computational basis state | x 〉 . The closely related task of rotating a target qubit by an angle depending on f ( x ) is also studied. Such operations are key in many quantum subroutines, and frequently f ( x ) can be well approximated by a piecewise function; examples range from the application of diagonal Hamiltonian terms (such as the Coulomb interaction) in grid-based many-body simulation to derivative pricing algorithms. Here, we exploit a parallelization of the piecewise approach so that all constituent elementary rotations are performed simultaneously, that is, we achieve a total rotation depth of one. Moreover, we explore the use of recursive catalyst “towers” to implement these elementary rotations efficiently. We find that strategies prioritizing execution speed can achieve circuit depth as low as O ( log 2 n + log 2 S ) for a register of n qubits and a piecewise approximation of S sections (presuming prior preparation of enabling resource states), albeit total qubit count then scales with S . In the limit of multiple repetitions of the oracle, we find that catalyst tower approaches have an O ( S n ) T -count.}, archive = {J_PRA}, author = {Zhu Sun and Gregory Boyd and Zhenyu Cai and Hamza Jnane and Bálint Koczor and Richard Meister and Romy Minko and Benjamin Pring and Simon C. Benjamin and Nikitas Stamatopoulos}, doi = {10.1103/m32k-7nq2}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062420}, shortjournal = {Phys. Rev. A}, title = {Low-depth phase oracle using a parallel piecewise circuit}, volume = {111}, year = {2025}, }
• (2025). Monogamy-of-entanglement-inspired protocol for quantifying bipartite entanglement using spin squeezing. PRA, 111(6), 062419. (www)

  @article{ , abstract = {Quantum entanglement is an essential resource for quantum science and technology. However, entanglement detection and quantification, via typical entanglement measures such as linear entanglement entropy or negativity, can be a very challenging task. Here we propose a protocol to detect bipartite entanglement in a system of qubits inspired by the concept of monogamy of entanglement, where, given a total system in a pure state with some bipartite entanglement between two subsystems, subsequent unitary evolution and measurement of one of the subsystems may be used to quantify the entanglement between the two. To address the difficulty of detection, we propose to use spin squeezing to quantify the entanglement within the individual subsystem. Knowing that the relation between spin squeezing and some entanglement measures is not one-to-one, we give some suggestions on how a judicious choice of squeezing Hamiltonian can lead to better results in our protocol. For systems with a small number of qubits, we derive analytical results and show how our protocol can work optimally for Greenberger-Horne-Zeilinger (GHZ) states. For larger systems, we show how the accuracy of the protocol can be improved by a proper choice of the squeezing Hamiltonian. Our protocol presents an alternative for entanglement detection in platforms where state tomography is inaccessible or hard to perform. Additionally, the ideas presented here can be extended beyond spin-only systems to expand their applicability.}, archive = {J_PRA}, author = {Diego Fallas Padilla and Mingjian Zhu and Han Pu}, doi = {10.1103/hvmh-h7h8}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062419}, shortjournal = {Phys. Rev. A}, title = {Monogamy-of-entanglement-inspired protocol for quantifying bipartite entanglement using spin squeezing}, volume = {111}, year = {2025}, }
• (2025). Enhanced hamiltonian learning precision with multistage neural networks. PRA, 111(6), 062418. (www)

  @article{ , abstract = {Learning quantum Hamiltonians with high precision is important for quantum physics and quantum information science. We propose a multistage neural network framework that significantly enhances Hamiltonian learning precision through successive network optimization of residuals. Our approach utilizes time-series data from single-qubit Pauli measurements of random initial states, enabling the estimation of unknown Hamiltonian parameters without prior knowledge of initial states or a specific evolution ansatz. We demonstrate the framework on two-qubit systems, achieving improvement of several orders of magnitude in parameter accuracy, and further extend the method to larger systems by integrating dynamical decoupling techniques. Additionally, the protocol exhibits robustness against experimental noise. This work bridges the gap between scalable Hamiltonian learning and high-precision requirements, offering a practical tool for precise quantum control and metrology.}, archive = {J_PRA}, author = {Zhengjie Kang and Hao Li and Shuo Wang and Jiaojiao Li and Yuanjie Zhang and Zhihuang Luo}, doi = {10.1103/lsvy-g335}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062418}, shortjournal = {Phys. Rev. A}, title = {Enhanced hamiltonian learning precision with multistage neural networks}, volume = {111}, year = {2025}, }
• (2025). Nonstabilizerness of a boundary time crystal. PRA, 111(6), 062417. (www)

  @article{ , abstract = {Boundary time crystals exhibit measurement-induced phase transitions in their steady-state entanglement, with critical behavior that depends on the particular unraveling of the Lindblad dynamics. In this work, we investigate another key measure of quantum complexity—nonstabilizerness (or “magic”)—and show that it follows a markedly different pattern. Importantly, in contrast to entanglement, for large system sizes, nonstabilizerness remains invariant under different unraveling schemes—a property we attribute to the inherent permutational symmetry of the model. Although the steady-state stabilizer entropy does not display a genuine phase transition, it exhibits a singular derivative (a cusp) at the mean-field critical point. Furthermore, we demonstrate that finite-size simulations of the average Lindblad evolution fail to capture the asymptotic behavior of nonstabilizerness in the time-crystal phase, while quantum trajectory unravelings correctly reveal its extensive scaling with system size. These findings offer insights into how different quantum resources manifest in open systems.}, archive = {J_PRA}, author = {Gianluca Passarelli and Angelo Russomanno and Procolo Lucignano}, doi = {10.1103/d7tm-9hkp}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062417}, shortjournal = {Phys. Rev. A}, title = {Nonstabilizerness of a boundary time crystal}, volume = {111}, year = {2025}, }
• (2025). Comparison of encoding schemes for quantum computing of s>1/2 spin chains. PRA, 111(6), 062416. (www)

  @article{ , abstract = {We compare four different encoding schemes for the quantum computing of spin chains with a spin quantum number : a compact mapping, a direct (or one-hot) mapping, a Dicke mapping, and a qudit mapping. The three different qubit encoding schemes are assessed by conducting a Hamiltonian simulation for using a trapped-ion quantum computer. The qudit mapping is tested by running simulations with a simple noise model. The Dicke mapping, in which the spin states are encoded as superpositions of multiqubit states, is found to be the most efficient because of the small number of terms in the qubit Hamiltonian. We also investigate the dependence of the time step length in the Suzuki-Trotter approximation and find that should be inversely proportional to in order to obtain the same accuracy for all .}, archive = {J_PRA}, author = {Erik Lötstedt and Kaoru Yamanouchi}, doi = {10.1103/7mvy-zq7j}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062416}, shortjournal = {Phys. Rev. A}, title = {Comparison of encoding schemes for quantum computing of s>1/2 spin chains}, volume = {111}, year = {2025}, }
• (2025). Temporal correlating power of quantum channels. PRA, 111(6), 062415. (www)

  @article{ , abstract = {Correlations, as intrinsic and intriguing features of quantum systems, have profound implications and applications in quantum information theory. Although substantial progress has been made in understanding and applying spatial correlations (i.e., those across different spatial systems at the same instant of time), temporal correlations (which emerge from the dynamics of a single quantum system across different instants of time) have been relatively less investigated. In this work, we first provide an axiomatic approach to temporal correlations by postulating natural requirements for a reasonable monotone of temporal correlations generated by a quantum channel. Then we study the temporal correlating power of quantum channels in terms of the Jordan product of quantum channels and compare it with the recently introduced notion of state over time. We introduce an information-theoretic monotone of such a power by exploiting the Jordan negativity and reveal its basic properties such as convexity, monotonicity, and unitary invariance. We further illustrate the monotone through several important channels and explicitly evaluate the corresponding temporal correlating power.}, archive = {J_PRA}, author = {Yi Guo and Shunlong Luo}, doi = {10.1103/ms8v-qnj8}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062415}, shortjournal = {Phys. Rev. A}, title = {Temporal correlating power of quantum channels}, volume = {111}, year = {2025}, }
• (2025). Typical behavior of genuine multimode entanglement of pure gaussian states. PRA, 111(6), 062414. (www)

  @article{ , abstract = {Trends of genuine entanglement in Haar uniformly generated multimode pure Gaussian states with fixed average energy per mode are explored. A distance-based metric known as the generalized geometric measure (GGM) is used to quantify genuine entanglement. The GGM of a state is defined as its minimum distance from the set of all nongenuinely entangled states. To begin with, we derive an expression for the Haar-averaged value of any function defined on the set of energy-constrained states. Subsequently, we investigate states with a large number of modes and provide a closed-form expression for the Haar-averaged GGM in terms of the average energy per mode. Furthermore, we demonstrate that typical states closely approximate their Haar-averaged GGM value, with deviation probabilities bounded by an exponentially suppressed limit. We then analyze the GGM content of typical states with a finite number of modes and present the distribution of GGM. Our findings indicate that, as the number of modes increases, the distribution shifts towards higher entanglement values and becomes more concentrated. We quantify these features by computing the Haar-averaged GGM and the standard deviation of the GGM distribution, revealing that the former increases while the latter decreases with the number of modes. Finally, we compare the typical value of the GGM with its maximal value consistent with the imposed energy bound.}, archive = {J_PRA}, author = {Saptarshi Roy}, doi = {10.1103/8bbb-jhzh}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062414}, shortjournal = {Phys. Rev. A}, title = {Typical behavior of genuine multimode entanglement of pure gaussian states}, volume = {111}, year = {2025}, }
• (2025). Clifford circuit initialization for variational quantum algorithms. PRA, 111(6), 062413. (www)

  @article{ , abstract = {We present an initialization method for variational quantum algorithms applicable to intermediate-scale quantum computers. The method explores the efficiently classically simulable Clifford points of a parameterized quantum circuit, using simulated annealing to find a low-energy initial state. We provide numerical evidence of the effectiveness of the technique for different choices of the Hamiltonian structure, number of qubits, and circuit depth. While a number of problems are considered, we note that the method is particularly useful for quantum chemistry problems, for which it is able to capture long-range correlation energy. The presented method could help achieve a quantum advantage in noisy or fault-tolerant intermediate-scale devices by preparing a high-quality initial state.}, archive = {J_PRA}, author = {M. H. Cheng and K. E. Khosla and C. N. Self and M. Lin and B. X. Li and A. C. Medina and M. S. Kim}, doi = {10.1103/PhysRevA.111.062413}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062413}, shortjournal = {Phys. Rev. A}, title = {Clifford circuit initialization for variational quantum algorithms}, volume = {111}, year = {2025}, }
• (2025). Dispersive qubit readout of temperature. PRA, 111(6), 062412. (www)

  @article{ , abstract = {Squeezed light can exponentially increase the signal-to-noise ratio (SNR) of dispersive qubit readout, especially using a combination of injected external squeezing (IES) and intracavity squeezing (ICS). We further investigate whether IES and ICS can also exponentially improve the measurement precision of temperature. In the case of fully thermalized qubits isolated from a thermal bath, the measurement precision of temperature can be improved exponentially when the temperature, the measurement time, or the input photon number approaches 0. In general, thermal fluctuations prevent the action of squeezed light. When multiple qubits maintain interacting with the thermal bath, the Heisenberg scaling can be achieved if the loss rate of the cavity is large and the coupling between the qubit and the optical cavity is weak enough. In the meantime, IES can also further promote the improvement of the measurement precision of the temperature exponentially.}, archive = {J_PRA}, author = {Dong Xie and Chunling Xu}, doi = {10.1103/PhysRevA.111.062412}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062412}, shortjournal = {Phys. Rev. A}, title = {Dispersive qubit readout of temperature}, volume = {111}, year = {2025}, }
• (2025). Lower bounds on the number of rounds of the quantum approximate optimization algorithm required for guaranteed approximation ratios. PRA, 111(6), 062411. (www)

  @article{ , abstract = {The quantum approximate optimization algorithm, also known in its generalization as the quantum alternating operator ansatz, (QAOA) is a heuristic hybrid quantum-classical algorithm for finding high-quality approximate solutions to combinatorial optimization problems, such as maximum satisfiability. While the QAOA is well studied, theoretical results as to its runtime or approximation ratio guarantees are still relatively sparse. We provide some of the first lower bounds for the number of rounds (the dominant component of QAOA runtimes) required for the QAOA. For our main result, we (i) leverage a connection between quantum annealing times and the angles of the QAOA to derive a lower bound on the number of rounds of the QAOA with respect to the guaranteed approximation ratio. We apply and calculate this bound with Grover-style mixing unitaries and (ii) show that this type of QAOA requires at least a polynomial number of rounds to guarantee any constant approximation ratios for most problems. We also (iii) show that the bound depends only on the statistical values of the objective functions and, when the problem can be modeled as a -local Hamiltonian, can be easily estimated from the coefficients of the Hamiltonians. For the conventional transverse-field mixer, (iv) our framework gives a trivial lower bound to all bounded-occurrence local cost problems and for all strictly -local cost Hamiltonians matching known results that constant approximation ratio is obtainable with a constant-round QAOA for a few optimization problems from these classes. Using our proof framework, (v) we recover the Grover lower bound for unstructured search and, with small modification, show that our bound applies to any QAOA-style search protocol that starts in the ground state of the mixing unitaries.}, archive = {J_PRA}, author = {Naphan Benchasattabuse and Andreas Bärtschi and Luis Pedro García-Pintos and John Golden and Nathan Lemons and Stephan Eidenbenz}, doi = {10.1103/PhysRevA.111.062411}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062411}, shortjournal = {Phys. Rev. A}, title = {Lower bounds on the number of rounds of the quantum approximate optimization algorithm required for guaranteed approximation ratios}, volume = {111}, year = {2025}, }
• (2025). Quantum machine learning for multiclass classification beyond kernel methods. PRA, 111(6), 062410. (www)

  @article{ , abstract = {Quantum machine learning is considered one of the current research fields with great potential. In recent years, Havlíček et al. [ Nature (London) 567 , 209 (2019) ] have proposed a quantum machine learning algorithm with quantum-enhanced feature spaces, which effectively addressed a binary classification problem and offered a potential pathway to achieving quantum advantage. However, a straightforward binary classification algorithm falls short in solving multiclass classification problems. In this paper, we propose a quantum algorithm that rigorously demonstrates that quantum kernel methods enhance the efficiency of multiclass classification in real-world applications, providing quantum-enhanced performance. To demonstrate this, we design six distinct quantum kernels within the quantum algorithm to map input data into quantum state spaces and estimate the corresponding quantum kernel matrices. The results from quantum simulations reveal that the quantum algorithm outperforms its classical counterpart in handling six real-world multiclass classification problems. Furthermore, we leverage a variety of performance metrics to comprehensively evaluate the classification and generalization performance of the quantum algorithm. The results demonstrate that the quantum algorithm achieves superior classification and better generalization performance relative to classical counterparts.}, archive = {J_PRA}, author = {Chao Ding and Shi Wang and Yaonan Wang and Weibo Gao}, doi = {10.1103/PhysRevA.111.062410}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062410}, shortjournal = {Phys. Rev. A}, title = {Quantum machine learning for multiclass classification beyond kernel methods}, volume = {111}, year = {2025}, }
• (2025). Optimal estimation of three parallel spins with genuine and restricted collective measurements. PRA, 111(6), 062409. (www)

  @article{ , abstract = {Collective measurements on identical and independent quantum systems can offer advantages in information extraction compared with individual measurements. However, little is known about the distinction between restricted collective measurements and genuine collective measurements in the multipartite setting. In this work we establish a rigorous performance gap based on a simple and old estimation problem, the estimation of a random spin state given three parallel spins. Notably, we derive an analytical formula for the maximum estimation fidelity of biseparable measurements and clarify its fidelity gap from genuine collective measurements. Moreover, we clarify the structure of optimal biseparable measurements. It turns out the maximum estimation fidelity can be achieved by two- and one-copy measurements assisted by one-way communication in one direction, but not the other way. Our work reveals a rich landscape of multipartite nonclassicality in quantum measurements instead of quantum states and is expected to trigger further studies.}, archive = {J_PRA}, author = {Changhao Yi and Kai Zhou and Zhibo Hou and Guo-Yong Xiang and Huangjun Zhu}, doi = {10.1103/PhysRevA.111.062409}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062409}, shortjournal = {Phys. Rev. A}, title = {Optimal estimation of three parallel spins with genuine and restricted collective measurements}, volume = {111}, year = {2025}, }
• (2025). Heisenberg-scaling precision in the estimation of two parameters in a mach-zehnder interferometer. PRA, 111(6), 062408. (www)

  @article{ , abstract = {Achieving the ultimate quantum precision in the estimation of multiple physical parameters simultaneously is a challenge in quantum metrology due to fundamental limitations and experimental challenges in harnessing the necessary quantum resources. We propose an experimentally feasible scheme to reach Heisenberg-scaling precision in the simultaneous estimation of two unknown phase parameters in a Mach-Zehnder interferometer by using squeezed and coherent states of light as input and homodyne detections at the outputs. Our results open a new research paradigm in harnessing the full quantum advantage of multiparameter estimation in distributed quantum sensing and quantum information processing, as enabled by multiphoton quantum interference with scalable experimental resources.}, archive = {J_PRA}, author = {Atmadev Rai and Danilo Triggiani and Paolo Facchi and Vincenzo Tamma}, doi = {10.1103/PhysRevA.111.062408}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062408}, shortjournal = {Phys. Rev. A}, title = {Heisenberg-scaling precision in the estimation of two parameters in a mach-zehnder interferometer}, volume = {111}, year = {2025}, }
• (2025). Choi-defined resource theories. PRA, 111(6), 062407. (www)

  @article{ , abstract = {Many resource theories share an interesting property: An operation is free if and only if its renormalized Choi matrix is a free state. In this article, we refer to resource theories exhibiting this property as Choi-defined resource theories. We demonstrate how and under what conditions one can construct a Choi-defined resource theory, and we prove that when such a construction is possible, the free operations are all and only the completely resource-nongenerating operations. Moreover, we examine resource measures, a complete family of monotones, and conversion distances in such resource theories.}, archive = {J_PRA}, author = {Elia Zanoni and Carlo Maria Scandolo}, doi = {10.1103/PhysRevA.111.062407}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062407}, shortjournal = {Phys. Rev. A}, title = {Choi-defined resource theories}, volume = {111}, year = {2025}, }
• (2025). Feedback-based optimally controlled quantum states. PRA, 111(6), 062406. (www)

  @article{ , abstract = {Quantum optimization, for both classical and quantum functions, is one of the most well-studied applications of quantum computing, but recent trends have relied on hybrid methods that push much of the fine-tuning off onto costly classical algorithms. Feedback-based quantum algorithms, such as FALQON, avoid these fine-tuning problems but at the cost of additional circuit depth and a lack of convergence guarantees. In this work we take the local greedy information collected by Lyapunov feedback control and develop an analytic framework to use it to perturbatively update previous control layers, similar to the global optimal control achievable using Pontryagin optimal control. This perturbative methodology, which we call feedback-based optimally controlled quantum states (FOCQS), can be used to improve the results of feedback-based algorithms, like FALQON, providing better convergence but still no formal guarantees of convergence. Furthermore, this perturbative method can be used to push smooth annealing-like control protocol closer to the control optimum, even providing an iterative approach, albeit with diminishing returns. In numerical testing, we show improvements in convergence and required depth due to these methods over existing quantum feedback control methods.}, archive = {J_PRA}, author = {Lucas T. Brady and Stuart Hadfield}, doi = {10.1103/PhysRevA.111.062406}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062406}, shortjournal = {Phys. Rev. A}, title = {Feedback-based optimally controlled quantum states}, volume = {111}, year = {2025}, }
• (2025). Nonlinear classification capability of quantum neural networks due to emergent quantum metastability. PRA, 111(6), 062405. (www)

  @article{ , abstract = {The power and expressivity of deep classical neural networks can be attributed to nonlinear input-output relations. Such nonlinearities are at the heart of many computational tasks, such as data classification and pattern recognition. Quantum neural networks, on the other hand, are necessarily linear as they process information via unitary operations. Here we show that effective nonlinearities can be implemented in these platforms by exploiting the relationship between information processing and many-body quantum dynamics. The crucial point is that quantum many-body systems can show emergent collective behavior in the vicinity of phase transitions, which leads to an effectively nonlinear dynamics in the thermodynamic limit. In the context of quantum neural networks, which are necessarily finite, this translates into metastability with transient nonergodic behavior. By using a quantum neural network the architecture of which is inspired by dissipative many-body quantum spin models, we show that this mechanism indeed allows one to realize nonlinear data classification, despite the underlying dynamics being local and linear. Our proof-of-principle study may pave the way for the systematic construction of quantum neural networks with emergent nonlinear properties.}, archive = {J_PRA}, author = {Mario Boneberg and Federico Carollo and Igor Lesanovsky}, doi = {10.1103/PhysRevA.111.062405}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062405}, shortjournal = {Phys. Rev. A}, title = {Nonlinear classification capability of quantum neural networks due to emergent quantum metastability}, volume = {111}, year = {2025}, }
• (2025). Variational quantum algorithm based on lagrange polynomial encoding to solve differential equations. PRA, 111(6), 062404. (www)

  @article{ , abstract = {Differential equations (DEs) serve as the cornerstone for a wide range of scientific endeavors, their solutions weaving through the core of diverse fields such as structural engineering, fluid dynamics, and financial modeling. DEs are notoriously hard to solve, due to their intricate nature, and finding solutions to DEs often exceeds the capabilities of traditional computational approaches. Recent advances in quantum computing have triggered a growing interest from researchers for the design of quantum algorithms for solving DEs. In this work, we introduce two different architectures of a novel variational quantum algorithm (VQA) with Lagrange polynomial encoding in combination with derivative quantum circuits using the Hadamard test differentiation to approximate the solution of DEs. To demonstrate the potential of our new VQA, two well-known ordinary differential equations are used: the damped mass-spring system from a given initial condition and the Poisson equation for periodic, Dirichlet, and Neumann boundary conditions. It is shown that the proposed new VQA has a reduced gate complexity compared to previous variational quantum algorithms, for a similar or better quality of the solution.}, archive = {J_PRA}, author = {Josephine Hunout and Sylvain Laizet and Lorenzo Iannucci}, doi = {10.1103/PhysRevA.111.062404}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062404}, shortjournal = {Phys. Rev. A}, title = {Variational quantum algorithm based on lagrange polynomial encoding to solve differential equations}, volume = {111}, year = {2025}, }
• (2025). Operational simultaneous correlations in complementary bases of bipartite states via one-sided semi-device-independent steering. PRA, 111(6), 062403. (www)

  @article{ , abstract = {Recently, a different form of quantum steering, i.e., certification of quantum steering in a one-sided semi-device-independent way, has been formulated [C. Jebarathinam et al. , Phys. Rev. A 108 , 042211 (2023) ]. In this work, we use this phenomenon to provide operational simultaneous correlations in mutually unbiased bases as quantified by the measures in [S. Wu et al ., Sci. Rep. 4 , 4036 (2014) ]. First, we show that for any bipartite state, such measure of simultaneous correlations in two mutually unbiased bases can be operationally identified as exhibiting one-sided semi-device-independent steering in a two-setting scenario. Next, we demonstrate that for two-qubit Bell-diagonal states, quantifying one-sided semi-device-independent steerability provides an operational quantification of information-theoretic quantification of simultaneous correlations in mutually unbiased bases. Then, we provide a different classification of two-qubit separable states with the above-mentioned information-theoretic quantification of simultaneous correlations in mutually unbiased bases and the quantification of one-sided semi-device-independent steerability. Finally, we invoke quantum steering ellipsoid formalism to shed intuitions on the operational characterization of simultaneous correlations in complementary bases of two-qubit states via one-sided semi-device-independent steerability. This provides us with a geometric visualization of the results.}, archive = {J_PRA}, author = {Chellasamy Jebarathinam and Debarshi Das and Huan-Yu Ku and Debasis Sarkar and Hsi-Sheng Goan}, doi = {10.1103/PhysRevA.111.062403}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062403}, shortjournal = {Phys. Rev. A}, title = {Operational simultaneous correlations in complementary bases of bipartite states via one-sided semi-device-independent steering}, volume = {111}, year = {2025}, }
• (2025). Quantum error mitigation for rotation-symmetric bosonic codes with symmetry expansion. PRA, 111(6), 062402. (www)

  @article{ , abstract = {The rotation symmetric bosonic code (RSBC) is a unified framework of practical bosonic codes that have rotation symmetries, such as cat codes and binomial codes. While cat and binomial codes achieve the breakeven point in which the coherence time of the encoded qubits exceeds that of unencoded qubits, the state preparation fidelity needs to be improved for practical quantum computing. Concerning this problem, we investigate the framework of symmetry expansion, a class of quantum error mitigation that virtually projects the state onto the noise-free symmetric subspace by exploiting the system's intrinsic symmetries and postprocessing of measurement outcomes. Although symmetry expansion has been limited to error mitigation of quantum states immediately before measurement, we successfully generalize symmetry expansion for state preparation. Then, we consider two types of stabilization: photon number and phase stabilization. Photon number stabilization can be performed by leveraging the rotation operators. On the other hand, the phase errors can be suppressed via the extension towards phase direction by leveraging the recently proposed projective squeezing method. To implement our method, we use an ancilla qubit and a randomly generated controlled gate between the bosonic code states and the ancilla qubit. Our novel error mitigation method will significantly enhance computation accuracy in the near-term bosonic quantum computing.}, archive = {J_PRA}, author = {Suguru Endo and Yasunari Suzuki and Kento Tsubouchi and Rui Asaoka and Kaoru Yamamoto and Yuichiro Matsuzaki and Yuuki Tokunaga}, doi = {10.1103/PhysRevA.111.062402}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062402}, shortjournal = {Phys. Rev. A}, title = {Quantum error mitigation for rotation-symmetric bosonic codes with symmetry expansion}, volume = {111}, year = {2025}, }
• (2025). Strict advantage of complex quantum theory in a communication task. PRA, 111(6), 062401. (www)

  @article{ , abstract = {Standard formulations of quantum theory are based on complex numbers: Quantum states can be in superpositions, with weights given by complex probability amplitudes. Motivated by quantum theory promising a range of practical advantages over classical for a multitude of tasks, we investigate how the presence of complex amplitudes in quantum theory can yield operational advantages over counterpart real formulations. We identify a straightforward communication task for which complex quantum theory exhibits a provably lower communication cost than not just any classical approach, but also any approach based on real quantum theory. We certify the necessity of complex quantum theory for optimal approaches to the task through geometric properties of quantum state ensembles that witness the presence of basis-independent complexity. This substantiates a strict operational advantage of complex quantum theory. We discuss the relevance of this finding for quantum advantages in stochastic simulation.}, archive = {J_PRA}, author = {Thomas J. Elliott}, doi = {10.1103/PhysRevA.111.062401}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062401}, shortjournal = {Phys. Rev. A}, title = {Strict advantage of complex quantum theory in a communication task}, volume = {111}, year = {2025}, }
• (2025). Identifying quantum resources in convex resource theories with kirkwood-dirac quasiprobabilities. PRA, 111(6), 062217. (www)

  @article{ , abstract = {We show that the Kirkwood-Dirac quasiprobability distributions can detect the presence of quantum resources in all convex resource theories via strictly negative probability outcomes. This negativity serves not only as a hallmark of resourcefulness in such theories, but also quantifies the geometric distance between a resourceful state and its closest free (i.e., nonresourceful) counterpart. Moreover, we demonstrate that these distributions can be rendered informationally complete, providing both a comprehensive description of the quantum state and a direct indicator of the underlying resource. We further discuss the relationship between convex resource theories, between strong anomalous weak values, and negative quasiprobabilities. Finally, by showing that negativity emerges only under measurement incompatibility, our results identify measurement incompatibility as a fundamental mechanism enabling quantum advantage in resourceful states.}, archive = {J_PRA}, author = {Kok Chuan Tan and Souradeep Sasmal}, doi = {10.1103/htcg-9cv2}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062217}, shortjournal = {Phys. Rev. A}, title = {Identifying quantum resources in convex resource theories with kirkwood-dirac quasiprobabilities}, volume = {111}, year = {2025}, }
• (2025). Effective floquet lindblad generators from spectral unwinding. PRA, 111(6), 062216. (www)

  @article{ , abstract = {A mathematical description of the reduced dynamics of an open quantum system can often be given in terms of a completely positive and trace-preserving map, also known as a quantum channel. In a seminal work by Wolf et al. [ Phys. Rev. Lett. 101 , 150402 (2008) ], it was shown that deciding whether a given quantum channel was generated from an underlying effective Markovian dynamics, with time-independent generator of Lindblad form, is generally an NP-hard problem. The difficulty is related to the fact that one has to search through all possible branches of the operator logarithm of the map in order to identify if any of the resulting effective generators is of Lindblad form. In this work we show that in cases where one has access to the full reduced dynamics at all previous times (the dynamical map) one can significantly facilitate the search for an effective generator by making use of Floquet theory. By performing a spectral unwinding such that the effective micromotion is minimized, the effective Floquet generator is often an excellent candidate for an effective generator of Lindblad form. This significantly reduces the complexity of the search for an effective Lindbladian in many (though not all) cases. Our results are relevant for engineering Floquet Lindbladians in complex many-body systems.}, archive = {J_PRA}, author = {Görkem D. Dinc and André Eckardt and Alexander Schnell}, doi = {10.1103/x2qh-12gg}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062216}, shortjournal = {Phys. Rev. A}, title = {Effective floquet lindblad generators from spectral unwinding}, volume = {111}, year = {2025}, }
• (2025). Quantum coherence and distinguishability as complementary resources: A resource-theoretic perspective from wave-particle duality. PRA, 111(6), 062215. (www)

  @article{ , abstract = {Wave-particle duality, a fundamental principle of quantum mechanics, encapsulates the complementary relationship between the wave and particle behaviors of quantum systems. In this paper, we treat quantum coherence and classical distinguishability as complementary resources and uncover a novel duality relation, which is explored through quantum state discrimination under incoherent operations, extending beyond typical interference scenarios. We prove that in an ensemble of mutually orthogonal pure states, the sum of “co-bits,” quantifying the coherence preserved under incoherent free operations, and classical bits, representing the distinguishability extracted via quantum state discrimination, is bounded. This coherence-distinguishability duality relation exposes an inherent tradeoff between the simultaneous preservation of a system's quantum coherence (wavelike property) and the extraction of its classical distinguishability (particlelike property). Our findings provide a fresh perspective on wave-particle duality through quantum resource theories, offering complementary insights into manipulating quantum and classical resources, with implications for quantum foundations and quantum technologies.}, archive = {J_PRA}, author = {Zhiping Liu and Chengkai Zhu and Hua-Lei Yin and Xin Wang}, doi = {10.1103/PhysRevA.111.062215}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062215}, shortjournal = {Phys. Rev. A}, title = {Quantum coherence and distinguishability as complementary resources: A resource-theoretic perspective from wave-particle duality}, volume = {111}, year = {2025}, }
• (2025). Efficient measure of information backflow with a quasistochastic process. PRA, 111(6), 062214. (www)

  @article{ , abstract = {Characterization and quantification of non-Markovian dynamics in open quantum systems are topical issues in the rapidly developing field of quantum computation and quantum communication. A standard approach based on the notion of information backflow detects the flow of information from the environment back to the system. Numerous measures of information backflow have been proposed using different definitions of distinguishability between pairs of quantum states. These measures, however, necessitate optimization over the state space, which can be analytically challenging or numerically demanding. Here we propose an alternative witness and measure of information backflow that is explicitly state independent by utilizing the concept of quasiprobability representation and recent advances in the theory of majorization for quasiprobabilities. We illustrate its use over several paradigmatic examples, demonstrating consistent Markovian conditions with known results and also reported necessary and sufficient conditions for the qutrit system in a random unitary channel. The paper concludes with a discussion of the foundational implications of quantum dynamical evolution.}, archive = {J_PRA}, author = {Kelvin Onggadinata and Teck Seng Koh}, doi = {10.1103/nkcc-43j8}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062214}, shortjournal = {Phys. Rev. A}, title = {Efficient measure of information backflow with a quasistochastic process}, volume = {111}, year = {2025}, }
• (2025). Quantum thermal machine regimes in the transverse-field ising model. PRA, 111(6), 062213. (www)

  @article{ , abstract = {We identify and interpret the possible quantum thermal machine regimes with a transverse-field Ising model as the working substance. In general, understanding the emergence of such regimes in a many-body quantum system is challenging due to the dependence on the many energy levels in the system. By considering infinitesimal work strokes, we can understand the operation from equilibrium properties of the system. We find that infinitesimal work strokes enable both heat engine and accelerator operation, with the output and boundaries of operation described by macroscopic properties of the system, in particular, the net transverse magnetization. At low temperatures, the regimes of operation and performance can be understood from the behavior of low-energy excitations in the system, while at high temperatures an expansion of the free energy in powers of inverse temperature describes the operation. The understanding generalizes to larger work strokes when the temperature difference between the hot and cold reservoirs is large. For hot and cold reservoirs close in temperature, a sufficiently large work stroke can enable refrigerator and heater regimes. Our results and method of analysis will prove useful in understanding the possible regimes of operation of quantum many-body thermal machines more generally.}, archive = {J_PRA}, author = {Vishnu Muraleedharan Sajitha and Bodhaditya Santra and Matthew J. Davis and L. A. Williamson}, doi = {10.1103/jthm-7c2j}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062213}, shortjournal = {Phys. Rev. A}, title = {Quantum thermal machine regimes in the transverse-field ising model}, volume = {111}, year = {2025}, }
• (2025). Lindblad dynamics of open multimode bosonic systems: Algebra of quadratic superoperators, exceptional points, and speed of evolution. PRA, 111(6), 062211. (www)

  @article{ , abstract = {Quantum dynamics of open continuous variable systems is a multifaceted rapidly evolving field of fundamental and technological significance. An important example is a multimode photonic system coupled to a Markovian bath so that temporal evolution of the density matrix is governed by the master equation of the Lindblad form. Theoretical analysis of the Lindblad dynamics complicated by intermode couplings such as dynamical (coherent) and environment-mediated (incoherent) interactions between the modes can be rather involved, even for exactly soluble models. Our algebraic technique uses the Lie algebra of quadratic combinations of left and right superoperators to simplify both quantitative and qualitative analysis of intermode coupling-induced effects in multimode systems by eliminating jump superoperators and reducing the Lindblad equation to the form governed by the effective non-Hermitian Hamiltonian . We show that the spectral properties of the thermal bath Liouvillian are determined by the effective temperature-independent Hamiltonian and employ jump-eliminating transformations for computing its eigenvalues and eigenoperators. It is found that the Liouvillian exceptional points (EPs) are the points in the parameter space where the matrix associated with is nondiagonalizable. For the case of photonic polarization modes modeled as a bimodal bosonic system, we describe the geometry of EPs and apply our method to study how the intermode-couplings-induced effects such as EPs and temperature influence the dynamics of the speed of evolution that governs the quantum speed limit times of polarization qubit states.}, archive = {J_PRA}, author = {Andrei Gaidash and Alexei D. Kiselev and Anton Kozubov and George Miroshnichenko}, doi = {10.1103/2lgr-34qp}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062211}, shortjournal = {Phys. Rev. A}, title = {Lindblad dynamics of open multimode bosonic systems: Algebra of quadratic superoperators, exceptional points, and speed of evolution}, volume = {111}, year = {2025}, }
• (2025). Time-evolving matrix product operator method in a nondiagonal basis set based on the derivative of the path-integral expression. PRA, 111(6), 062210. (www)

  @article{ , abstract = {The time-evolving matrix product operator (TEMPO) method is a powerful tool for simulating open system quantum dynamics. Typically, it is used in problems with diagonal system-bath coupling, where analytical expressions for discretized influence functional are available. In this work, we aim to address issues related to off-diagonal coupling by extending the TEMPO algorithm to accommodate arbitrary basis sets. The proposed approach is based on computing the derivative of the discretized path-integral expression of a generalized influence functional when increasing one time step, which yields an equation of motion valid for a nondiagonal basis set and an arbitrary number of noncommuting baths. The generalized influence functional is then obtained by integrating the resulting differential equation. The applicability of the new method is then tested by simulating one- and two-qubit systems coupled to both - and -type baths.}, archive = {J_PRA}, author = {Shuocang Zhang and Qiang Shi}, doi = {10.1103/2tdf-q8fp}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062210}, shortjournal = {Phys. Rev. A}, title = {Time-evolving matrix product operator method in a nondiagonal basis set based on the derivative of the path-integral expression}, volume = {111}, year = {2025}, }
• (2025). Investigation of the topological quantum phase transition in a superconducting system via quantum walks. PRA, 111(6), 062209. (www)

  @article{ , abstract = {We study topological quantum phase transition in a superconducting system via quantum walks. The physical model is composed of a superconducting ququart (a four-level system) employed as the coin and two resonators exploited to encode the positions of the walker in two distinct directions. The topological properties of the quantum evolutions in one- and two-dimensional quantum walks are characterized by topological invariants, namely, the winding number and the Chern number, respectively. Through theoretical analysis, we derive explicit expressions for the critical points of the coin-flip angles, where the topological invariants jump from zero to nonzero integers, signaling the occurrences of topological quantum phase transitions. We also present approaches to measure these topological invariants. Under available control parameters, numerical simulations demonstrate that the measured topological invariants are in accordance with theoretical predictions and are insensitive to the influence of imperfections including systematic errors and decoherence. Moreover, this proposal is flexible and can be implemented across various physical systems, offering valuable insights into exploring topological quantum phase transitions.}, archive = {J_PRA}, author = {Yi-Hao Kang and Qi-Ping Su and Yu Wang and Lijiong Shen and Chui-Ping Yang}, doi = {10.1103/7dy8-1g4t}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062209}, shortjournal = {Phys. Rev. A}, title = {Investigation of the topological quantum phase transition in a superconducting system via quantum walks}, volume = {111}, year = {2025}, }
• (2025). Effect of self-interaction on feynman's interpretation of the lamb shift. PRA, 111(6), 062208. (www)

  @article{ , abstract = {We derive Bethe's formula for the Lamb shift by extending Feynman's suggestion that the shift could be interpreted as the change, due to the presence of the atom, in electromagnetic field energy. This approach is based on measurable quantities such as a refractive index but has a contribution from virtual photon absorption which is effectively eliminated by a high-energy cutoff in the nonrelativistic theory. We show that this unphysical contribution is canceled when a self-interaction energy is included in Feynman's argument.}, archive = {J_PRA}, author = {Peter W. Milonni and Paul R. Berman and Kanu Sinha}, doi = {10.1103/drlx-hrks}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062208}, shortjournal = {Phys. Rev. A}, title = {Effect of self-interaction on feynman's interpretation of the lamb shift}, volume = {111}, year = {2025}, }
• (2025). Violation of steering inequality for generalized equiangular measurements. PRA, 111(6), 062207. (www)

  @article{ , abstract = {In this article, we study bipartite quantum steering using a general class of measurement operators known as the generalized equiangular measurement. Our approach allows for the construction of steering inequalities that are applicable not only to informationally complete measurements but also to incomplete or lossy scenarios, where the resulting quantum assemblages may be subnormalized. We develop a method to analytically bound the value of steering functionals under local hidden state (LHS) models by employing a generalized inequality for the eigenvalues of positive semidefinite operators, extending classical results such as the Samuelson inequality. This yields universal upper bounds on the LHS value in terms of the parameters defining the frame. Furthermore, we analyze the asymptotic behavior of these bounds in high-dimensional Hilbert spaces and demonstrate the possibility of unbounded quantum violations of steering inequalities. Our formalism encompasses previously known results for mutually unbiased bases and mutually unbiased measurements as special cases, showing that these are particular instances within a unified and more general framework.}, archive = {J_PRA}, author = {Adam Rutkowski and Katarzyna Siudzińska}, doi = {10.1103/PhysRevA.111.062207}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062207}, shortjournal = {Phys. Rev. A}, title = {Violation of steering inequality for generalized equiangular measurements}, volume = {111}, year = {2025}, }
• (2025). Analytical solutions of bilinear bosonic models and exact characterization of non-markovian dynamics. PRA, 111(6), 062206. (www)

  @article{ , abstract = {The precise characterization of dynamics in open quantum systems often presents significant challenges, leading to the introduction of various approximations to simplify a model. One commonly used strategy involves Markovian approximations, assuming a memoryless environment. In this study, such approximations are not used and an analytical dynamical depiction of an open quantum system is provided. The system under consideration is an oscillator that is surrounded by a bath of oscillators. The resulting dynamics are characterized by an integrodifferential equation, which can be solved numerically. Remarkably, an exactly analytical solution exists when its reservoir spectral density is Lorentzian. Furthermore, this analytical solvability remains when rectangular pulse control is applied to the system, though with different parameters due to the pulses. Moreover, distinct dynamical regions emerge, depending on certain parameter values. Notably, the steady-state average excitation number (AEN) of the system shows rapid escalation with increasing non-Markovianity, reflecting the intricacies of real-world dynamics. In cases where there is detuning between the system frequency and the environmental central frequency within a non-Markovian regime, the AEN maintains its initial value for an extended period. Interestingly, the exact analytical solution with pulse control inherently protects the quantum system from decoherence effects without using approximations, while this protection fades as the system approaches the Markovian regime. The pulse control can not only prolong the relaxation time of the oscillator, but can also be used to speed up the relaxation process, depending on the specifications of the pulse.}, archive = {J_PRA}, author = {Zhao-Ming Wang and S. L. Wu and Mark S. Byrd and Lian-Ao Wu}, doi = {10.1103/PhysRevA.111.062206}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062206}, shortjournal = {Phys. Rev. A}, title = {Analytical solutions of bilinear bosonic models and exact characterization of non-markovian dynamics}, volume = {111}, year = {2025}, }
• (2025). Thermodynamics of coherent energy exchanges between lasers and two-level systems. PRA, 111(6), 062205. (www)

  @article{ , abstract = {We study the quantum thermodynamics of a coherent macroscopic electromagnetic field (laser) coupled to a two-level system (qubit) near resonance, from weak- to strong-driving regimes. This combined system is, in turn, weakly coupled to a thermal radiation field and can be described by an autonomous quantum master equation. We show that the laser acts as an autonomous work source and that, in the macroscopic limit, the work produced is independent of the phase of the laser. Using the dressed qubit approach, we show that the variation of energy in the laser is not the work transferred to the dressed qubit, which is instead obtained from the “dressed laser”—a coherent superposition of the laser and the qubit. Using a two-point measurement technique with counting fields, we obtain the full counting statistics for the work of the laser and dressed laser, and show that they satisfy the Crooks fluctuation theorems. We then use these theorems as criteria to investigate the thermodynamic consistency of quantum master equations, first in the autonomous setup for the combined system, then in the nonautonomous setup for the quantum system where the coherent field is eliminated and effectively described by a time-dependent external field. Treating the laser as an external field is known to yield expressions for the work which are in contradiction with quantum thermodynamics predictions in the strong-driving regime. We show that these inconsistencies stem from a confusion between the laser and dressed laser, and show how to correct them. We also derive a generalized Bloch master equation, thermodynamically consistent across all driving regimes, from which the Bloch and Floquet master equations can be obtained using additional approximations (of which we also examine the consistency).}, archive = {J_PRA}, author = {Ariane Soret and Massimiliano Esposito}, doi = {10.1103/PhysRevA.111.062205}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062205}, shortjournal = {Phys. Rev. A}, title = {Thermodynamics of coherent energy exchanges between lasers and two-level systems}, volume = {111}, year = {2025}, }
• (2025). Autonomous coarse-grained cooling of the coldest reservoir not restricted by the second law of thermodynamics. PRA, 111(6), 062204. (www)

  @article{ , abstract = {Nonequilibrium quantum thermodynamics is an intensively developing field with many applications. We study the dynamics of temperatures and chemical potentials of fermionic reservoirs coupled to an open quantum system on a coarse-grained timescale. We show that systematic heat transfer from the cold reservoir to the hot one is allowed in the problem of heat conductance and results in autonomous temporal cooling of the cold reservoir. We show that during the establishment of thermal and chemical equilibrium, nonmonotone evolution of reservoirs' temperatures and chemical potentials is possible, including changes in reservoirs' temperatures and chemical potentials orderliness. Achieved results can be used in the design of quantum thermal machines and nanoelectronic devices.}, archive = {J_PRA}, author = {I. V. Vovchenko and A. A. Zyablovsky and A. A. Pukhov and E. S. Andrianov}, doi = {10.1103/PhysRevA.111.062204}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062204}, shortjournal = {Phys. Rev. A}, title = {Autonomous coarse-grained cooling of the coldest reservoir not restricted by the second law of thermodynamics}, volume = {111}, year = {2025}, }
• (2025). Quantum information with quantumlike bits. PRA, 111(6), 062203. (www)

  @article{ , abstract = {In previous work we proposed a construction of quantum-like bits that could endow a large synchronizing classical system, for example, of oscillators, with quantum-like function that is not compromised by decoherence. In the present paper we investigate further this platform of quantum-like states. First, we discuss a general protocol on how to construct classical synchronizing networks that allow for emergent states. We then study how gates can be implemented on those states. This suggests the possibility of quantum-like information processing on a special class of many-body classical systems. Finally, we show that our approach allows for non-Kolmogorov interference, a feature that separates our model from a classical probabilistic system. This paper aims to explore the mathematical structure of quantum-like resources distilled from classical synchronizing systems and shows how arbitrary gates can be implemented by manipulating many-body correlations.}, archive = {J_PRA}, author = {Graziano Amati and Gregory D. Scholes}, doi = {10.1103/PhysRevA.111.062203}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062203}, shortjournal = {Phys. Rev. A}, title = {Quantum information with quantumlike bits}, volume = {111}, year = {2025}, }
• (2025). Phase diagram of the schwinger model by adiabatic preparation of states on a quantum simulator. PRA, 111(6), 062202. (www)

  @article{ , abstract = {We argue the feasibility of studying the phase structure of a quantum physical system on quantum devices via adiabatic preparation of states. We introduce a method and successfully test it in application to the Schwinger model in the presence of a topological term. We explore the first-order-phase-transition and the no-transition regions of the corresponding phase diagram. The core idea of the method is to separately evolve the ground and the first excited states with a time-dependent Hamiltonian, the time dependence of which interpolates between different values of . Despite our approach being a direct application of the adiabatic theorem, in some cases we are able to demonstrate its advantages in comparison to a different method from the literature that also employs adiabatic state preparation.}, archive = {J_PRA}, author = {Oleg Kaikov and Theo Saporiti and Vasily Sazonov and Mohamed Tamaazousti}, doi = {10.1103/PhysRevA.111.062202}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062202}, shortjournal = {Phys. Rev. A}, title = {Phase diagram of the schwinger model by adiabatic preparation of states on a quantum simulator}, volume = {111}, year = {2025}, }
• (2025). Single-qubit probes for temperature estimation in the presence of collective baths. PRA, 111(6), 062201. (www)

  @article{ , abstract = {We study the performance of single-qubit probes for temperature estimation in the presence of collective baths. We consider a system of two qubits, each locally dissipating into its own bath while being coupled to a common bath. In this setup, we investigate different scenarios for temperature estimation of both the common and local baths. First, we explore how the precision of a single-qubit probe for estimating the common bath temperature can be enhanced by collective effects arising from the shared bath itself, particularly when the second qubit is in resonance with the probe. Interestingly, we find that the presence of local baths on each qubit can either jeopardize or, if these baths are sufficiently cold, enhance this precision. Next, we demonstrate a remote temperature sensing scheme in which one qubit acts as a probe to estimate the temperature of a local bath affecting the other qubit, by leveraging their indirect interaction through the common bath. This approach enables remote temperature sensing without directly coupling the probe to the target qubit or its local environment, thereby minimizing potential disturbances and practical challenges. Notably, we show that the collective Lamb shift, induced by the common bath, plays a crucial role in enabling remote temperature sensing by generating qubit-qubit correlations, even in the case of noninteracting qubits.}, archive = {J_PRA}, author = {Asghar Ullah and Marco Cattaneo and Özgür E. Müstecaplıoğlu}, doi = {10.1103/PhysRevA.111.062201}, journal = {Physical Review a}, month = {6}, number = {6}, pages = {062201}, shortjournal = {Phys. Rev. A}, title = {Single-qubit probes for temperature estimation in the presence of collective baths}, volume = {111}, year = {2025}, }
• (2025). Self-sustained josephson dynamics and self-trapping in supersolids. PRA, 111(5), L051307. (www)

  @article{ , abstract = {We explore the self-sustained Josephson-junction dynamics in dipolar supersolids, predicting the possibility of self-trapping alongside the experimentally observed Josephson oscillations [G. Biagioni et al. , Nature (London) 629 , 773 (2024) ]. Using an asymmetric two-mode (ATM) model to describe a triangular dipolar supersolid, validated through Gross-Pitaevskii simulations, we demonstrate that the system's symmetry enables a consistent two-mode mapping despite the presence of seven droplets. Hence the associated Hamiltonian allows us to straightforwardly determine the self-trapping regime. Additionally, we show that bringing the system into rotation preserves its ability to sustain the Josephson-junction dynamics across its full range and we assess the robustness of the ATM model under these conditions. We further find that the off-axis droplets move in the radial direction during the evolution in accordance with the size of the central droplet. Such movements do not interfere with the model predictions.}, archive = {J_PRA}, author = {Aitor Alaña and Michele Modugno and Pablo Capuzzi and D. M. Jezek}, doi = {10.1103/PhysRevA.111.L051307}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051307}, shortjournal = {Phys. Rev. A}, title = {Self-sustained josephson dynamics and self-trapping in supersolids}, volume = {111}, year = {2025}, }
• (2025). Semisuper efimov effect induced by resonant pair exchange in mixed dimensions. PRA, 111(5), L051306. (www)

  @article{ , abstract = {We introduce a new member to the class of semisuper Efimov effects, where an infinite number of bound states emerge with their binding energies obeying the universal scaling law for sufficiently high excitation . Our system consists of a pair of two-component fermions in three dimensions at infinite scattering length, which furthermore interact with a boson confined in two dimensions so as to form a three-body bound state at zero energy. When another boson is added, the exchange of the resonant pair of fermions between two bosons leads to the semisuper Efimov effect of four such particles with the scaling exponent determined by the mass ratio of bosons to fermions. If bosons exist in three dimensions, an infinite number of bound states do not emerge, but some of them may survive for a large mass ratio, making our findings potentially relevant to two-neutron halo nuclei as well as ultracold atoms.}, archive = {J_PRA}, author = {Yusuke Nishida}, doi = {10.1103/PhysRevA.111.L051306}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051306}, shortjournal = {Phys. Rev. A}, title = {Semisuper efimov effect induced by resonant pair exchange in mixed dimensions}, volume = {111}, year = {2025}, }
• (2025). Shortcut to spin dynamics in quantum mixtures. PRA, 111(5), L051305. (www)

  @article{ , abstract = {The study of the long-time dynamics of quantum systems can be a real challenge, especially in systems such as ultracold gases, where the required timescales may be longer than the lifetime of the system itself. In this Letter, we show that it is possible to access the long-time spin dynamics of a strongly repulsive atomic gas mixture in shorter times. The shortcut-to-dynamics protocol that we propose does not modify the fate of the observables, but effectively jumps ahead in time without changing the system's inherent evolution. Just as the next-chapter button in a movie player that allows to quickly reach the part of the movie one wants to watch, it is a leap into the future.}, archive = {J_PRA}, author = {Pablo Capuzzi and Zehra Akdeniz and Patrizia Vignolo}, doi = {10.1103/PhysRevA.111.L051305}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051305}, shortjournal = {Phys. Rev. A}, title = {Shortcut to spin dynamics in quantum mixtures}, volume = {111}, year = {2025}, }
• (2025). Dimer problem on a spherical surface. PRA, 111(5), L051304. (www)

  @article{ , abstract = {We solve the problem of a dimer moving on a spherical surface and find that its binding energy and wave function are sensitive to the total angular momentum. The dimer gets squeezed in the direction orthogonal to the center-of-mass motion and can qualitatively change its geometry from two dimensional to one dimensional. These results suggest that combining the curved geometry with finite angular momentum may give rise to qualitatively new many-body phenomena in ultracold shell-shaped gases.}, archive = {J_PRA}, author = {A. Tononi and D. S. Petrov and M. Lewenstein}, doi = {10.1103/PhysRevA.111.L051304}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051304}, shortjournal = {Phys. Rev. A}, title = {Dimer problem on a spherical surface}, volume = {111}, year = {2025}, }
• (2025). Interaction shift of the bose-einstein condensation temperature in a dipolar gas. PRA, 111(5), L051303. (www)

  @article{ , abstract = {We report measurements of the Bose-Einstein condensate critical temperature shift due to dipolar interactions, employing samples of ultracold erbium atoms which feature significant (magnetic) dipole-dipole interactions in addition to tunable contact interactions. Using a highly prolate harmonic trapping potential, we observe a clear dependence of the critical temperature on the orientation of the dipoles relative to the trap axis. Our results are in good agreement with mean-field theory for a range of contact interaction strengths. This work creates an opportunity for further investigations into beyond-mean-field effects and the finite-temperature phase diagram in the more strongly dipolar regime where supersolid and droplet states emerge.}, archive = {J_PRA}, author = {Milan Krstajić and Jiří Kučera and Lucas R. Hofer and Gavin Lamb and Péter Juhász and Robert P. Smith}, doi = {10.1103/PhysRevA.111.L051303}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051303}, shortjournal = {Phys. Rev. A}, title = {Interaction shift of the bose-einstein condensation temperature in a dipolar gas}, volume = {111}, year = {2025}, }
• (2025). Unconventional spin hall effect in PT-symmetric spin-orbit-coupled quantum gases. PRA, 111(5), L051301. (www)

  @article{ , abstract = {We theoretically study the intrinsic spin Hall effect in parity-time ( )-symmetric spin-orbit-coupled quantum gases confined in an optical lattice. The interplay of the symmetry and the spin-orbit coupling leads to a doubly degenerate noninteracting band structure in which the spin polarization and the Berry curvature of any Bloch state are opposite to those of its degenerate partner. Using experimentally available systems as examples, we show that such a system with a two-component Fermi gas exhibits an intrinsic spin Hall effect akin to that found in the context of electronic materials. For a two-component Bose gas, however, an unconventional spin Hall effect emerges in which the spin polarization and the currents are coplanar and the spin Hall conductivity displays a characteristic anisotropy. We propose to detect such an unconventional spin Hall effect in harmonically trapped systems using dipole oscillations and perform extensive numerical simulations to validate the proposal. Our work paves the way for quantum simulation of the solid-state intrinsic spin Hall effect and experimental explorations of unconventional spin Hall effects in quantum gases.}, archive = {J_PRA}, author = {Hui Tang and Guan-Hua Huang and Shizhong Zhang and Zhongbo Yan and Zhigang Wu}, doi = {10.1103/PhysRevA.111.L051301}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L051301}, shortjournal = {Phys. Rev. A}, title = {Unconventional spin hall effect in PT-symmetric spin-orbit-coupled quantum gases}, volume = {111}, year = {2025}, }
• (2025). Laser spectroscopy on the hyperfine structure and isotope shift of sympathetically cooled th3+229 ions. PRA, 111(5), L050802. (www)

  @article{ , abstract = {The hyperfine structure of ions in the nuclear ground state is investigated via laser spectroscopy of trapped ions that are sympathetically cooled by laser-cooled ions in a linear Paul trap. The isotope shift to and the hyperfine constants for the magnetic dipole ( ) and electric quadrupole ( ) interactions for the and electronic states of are determined. These measurements provide nuclear moments of with reduced uncertainty and serve as a preparation for improved hyperfine spectroscopy of the 8.4 eV nuclear isomeric state in ions.}, archive = {J_PRA}, author = {G. Zitzer and J. Tiedau and Ch. E. Düllmann and M. V. Okhapkin and E. Peik}, doi = {10.1103/PhysRevA.111.L050802}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050802}, shortjournal = {Phys. Rev. A}, title = {Laser spectroscopy on the hyperfine structure and isotope shift of sympathetically cooled th3+229 ions}, volume = {111}, year = {2025}, }
• (2025). Hyperfine anomaly in mercury and test of the moskowitz-lombardi rule. PRA, 111(5), L050801. (www)

  @article{ , abstract = {We test the Moskowitz-Lombardi rule, originally formulated for mercury, which gives a simple relation between the magnetic moment of an atomic nucleus and the effect of its radial distribution on the hyperfine structure: the magnetic hyperfine anomaly or Bohr-Weisskopf (BW) effect. While the relation for the differential effect between isotopes may be completely determined experimentally, the value for the additive constant that is needed to give the BW effect for a single isotope has remained unverified. In this work, we determine the BW effect in H-like, singly ionized, and neutral mercury isotopes from experimental muonic- data together with differential anomalies and our atomic calculations. We check this result by directly extracting the BW effect from the measured hyperfine constant for using state-of-the-art atomic many-body calculations. From this we deduce an empirical value for the additive constant in the Moskowitz-Lombardi rule, which differs significantly from the values advocated previously. This result allows for increased precision in calculations of the hyperfine structure and improved tests of atomic and nuclear theory.}, archive = {J_PRA}, author = {J. Vandeleur and G. Sanamyan and B. M. Roberts and J. S. M. Ginges}, doi = {10.1103/PhysRevA.111.L050801}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050801}, shortjournal = {Phys. Rev. A}, title = {Hyperfine anomaly in mercury and test of the moskowitz-lombardi rule}, volume = {111}, year = {2025}, }
• (2025). Direct and efficient detection of quantum superposition. PRA, 111(5), L050402. (www)

  @article{ , abstract = {One of the most striking quantum phenomena is superposition, where one particle simultaneously inhabits different states. Most methods to verify coherent superposition are indirect, in that they require the distinct states to be recombined. Here, we adapt an xor game, in which a “test” photon is placed in a superposition of two orthogonal spatial modes, and each mode is sent to separated parties who perform local measurements on their modes without reinterfering the original modes. We show that by using a second identical “measurement” photon the parties are nonetheless able to verify if the test photon was placed in coherent superposition of the two spatial modes. We then turn this game into a resource-efficient verification scheme, obtaining a confidence that the particle is superposed which approaches unity exponentially fast. We demonstrate our scheme using a single photon, obtaining a 99% confidence that the particle is superposed with only 37 copies. Our work shows the utility of xor games to verify quantum resources, allowing us to efficiently detect quantum superposition without reinterfering the superposed modes.}, archive = {J_PRA}, author = {Daniel Kun and Teodor Strömberg and Michele Spagnolo and Borivoje Dakić and Lee A. Rozema and Philip Walther}, doi = {10.1103/PhysRevA.111.L050402}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050402}, shortjournal = {Phys. Rev. A}, title = {Direct and efficient detection of quantum superposition}, volume = {111}, year = {2025}, }
• (2025). Erasing imaginarity: An operational method. PRA, 111(5), L050401. (www)

  @article{ , abstract = {Recently, the resource theory of imaginarity has attracted much attention. As with other resources such as quantum correlations, coherence, and asymmetry, an important task in the resource theory of imaginarity is deimaginarity, which is to transform a state into a free state in the resource theory of imaginarity by the random covariant-free unitary operations. Here, we consider an asymptotic limit of infinitely many copies and vanishingly small error, and analyze the deimaginarity cost. We prove that the deimaginarity cost of a state is equal to its regularized relative entropy of imaginarity, which can be seen as an operational interpretation of the relative entropy of imaginarity.}, archive = {J_PRA}, author = {Xian Shi}, doi = {10.1103/PhysRevA.111.L050401}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050401}, shortjournal = {Phys. Rev. A}, title = {Erasing imaginarity: An operational method}, volume = {111}, year = {2025}, }
• (2025). Generalization of exact operators of the foldy-wouthuysen transformation to arbitrary-spin particles in nonstationary fields. PRA, 111(5), L050203. (www)

  @article{ , abstract = {Time-dependent terms in Hamiltonians and equations of motion are rather important for a quantum-mechanical description of particles with arbitrary spins in nonstationary fields. We use the Foldy-Wouthuysen representation which allows one to obtain the Schrödinger picture of relativistic quantum mechanics. We determine exact nonexponential and exponential operators of the Foldy-Wouthuysen transformation for arbitrary-spin particles in the nonstationary case. Some fundamental properties of these operators and the Foldy-Wouthuysen Hamiltonian are also identified.}, archive = {J_PRA}, author = {Alexander J. Silenko}, doi = {10.1103/PhysRevA.111.L050203}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050203}, shortjournal = {Phys. Rev. A}, title = {Generalization of exact operators of the foldy-wouthuysen transformation to arbitrary-spin particles in nonstationary fields}, volume = {111}, year = {2025}, }
• (2025). Manifolds of exceptional points and effective zeno limit of an open two-qubits system. PRA, 111(5), L050202. (www)

  @article{ , abstract = {We analytically investigate the Liouvillian exceptional point manifolds (LEPMs) of a two-qubits open system, where one qubit is coupled to a dissipative polarization bath. Exploiting a symmetry, we block diagonalize the Liouvillian and show that one symmetry block yields two planar LEPMs while the other one exhibits a more intricate, multisheet topology. The intersection curves of these manifolds provide a phase diagram for effective Zeno transitions at small dissipation. These results are consistent with a perturbative extrapolation from the strong Zeno regime. Interestingly, we find that the fastest relaxation to the nonequilibrium steady state occurs on LEPMs associated with the transition to the effective Zeno regime.}, archive = {J_PRA}, author = {Vladislav Popkov and Carlo Presilla and Mario Salerno}, doi = {10.1103/PhysRevA.111.L050202}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050202}, shortjournal = {Phys. Rev. A}, title = {Manifolds of exceptional points and effective zeno limit of an open two-qubits system}, volume = {111}, year = {2025}, }
• (2025). Optimal control in nearly adiabatic two-level quantum systems via time-dependent resonance. PRA, 111(5), L050201. (www)

  @article{ , abstract = {In this study, we theoretically analyzed a control protocol based on “time-dependent resonance” in nearly adiabatic two-level quantum systems, demonstrating that it exhibits properties equivalent to adiabatic control. This protocol is based on “time-dependent resonance,” where the frequency corresponds to the time-dependent energy gap. Through numerical calculations, we showed that this protocol serves as an optimal control protocol. This approach enables efficient and high-precision transitions to the target state. Our findings provide an alternative perspective on quantum optimal control theory and suggest potential applications in qubit controls and quantum information processing.}, archive = {J_PRA}, author = {Takayuki Suzuki}, doi = {10.1103/PhysRevA.111.L050201}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {L050201}, shortjournal = {Phys. Rev. A}, title = {Optimal control in nearly adiabatic two-level quantum systems via time-dependent resonance}, volume = {111}, year = {2025}, }
• (2025). Erratum: Prospects for the determination of fundamental constants with beyond-state-of-the-art uncertainty using molecular hydrogen ion spectroscopy [Phys. rev. a 109, 042825 (2024)]. PRA, 111(5), 059902. (www)

  @article{ , abstract = {Phys. Rev. A 111, 059902 (2025)}, archive = {J_PRA}, author = {S. Schiller and J.-Ph. Karr}, doi = {10.1103/PhysRevA.111.059902}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {059902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Prospects for the determination of fundamental constants with beyond-state-of-the-art uncertainty using molecular hydrogen ion spectroscopy [Phys. rev. a 109, 042825 (2024)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Precision measurement of the absolute energy of the 2s3s1S0 state in neutral be9 [Phys. rev. a 110, 032818 (2024)]. PRA, 111(5), 059901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 059901 (2025)}, archive = {J_PRA}, author = {K. J. Ahrendsen and T. Karani and W. D. Williams}, doi = {10.1103/PhysRevA.111.059901}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {059901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Precision measurement of the absolute energy of the 2s3s1S0 state in neutral be9 [Phys. rev. a 110, 032818 (2024)]}, volume = {111}, year = {2025}, }
• (2025). Enhanced photonic spin hall effect in atomic-ensemble-based cavity optomechanics. PRA, 111(5), 053719. (www)

  @article{ , abstract = {Cavity optomechanics, which investigates the interaction of electromagnetic fields with mechanical resonators via radiation pressure, offers an intriguing perspective on how quantum mechanical concepts materialize at macroscopic scales. Here, we present a novel approach to investigate the photonic spin Hall effect (SHE) in a multilayered system, by introducing three-level coherent atomic medium inside a mirror and dielectric slab, causing an optomechanical effect on light incidence. Unlike typical photonic SHE systems that rely on fixed material setup, we demonstrate that photon-phonon coupling in an optomechanical cavity permits dynamic manipulation of the spin-orbit interaction of light. We employ the transfer matrix approach for computing the ratio of reflection coefficients for the TM and TE components, illustrating the manipulation of the transverse shift of reflected light from positive to negative near the Brewster angle. Further, we demonstrate that manipulating important variables such as photon-phonon, atom-photon coupling strengths, and atomic Rabi frequency can impact both the magnitude and angular position of the photonic SHE. This optomechanical interaction has significant advantages over conventional approaches because it allows for real-time tuning of the SHE, increasing its potential for applications in optical sensing, spintronic devices, and quantum information processing. Our findings pave the way for further research into dynamically controlled photonic spin-dependent effects, offering a diverse platform to advance light manipulation.}, archive = {J_PRA}, author = {Akhtar Munir and Muzamil Shah and Chunfang Wang}, doi = {10.1103/PhysRevA.111.053719}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053719}, shortjournal = {Phys. Rev. A}, title = {Enhanced photonic spin hall effect in atomic-ensemble-based cavity optomechanics}, volume = {111}, year = {2025}, }
• (2025). Atomic-optical interferometry in fractured loops: A general solution for rydberg radio-frequency receivers. PRA, 111(5), 053718. (www)

  @article{ , abstract = {The development of novel radio-frequency atomic receivers has brought attention to the theoretical description of atom-light interactions in sophisticated multilevel schemes. Of special interest are schemes where several interaction paths interfere with each other, bringing about the phase-sensitive measurement of detected radio fields. In the theoretical modeling of those cases, the common assumptions are often insufficient to determine the boundary detection parameters, such as the receiving bandwidth or saturation point, critical for practical considerations of atomic sensing technology. This evokes the resurfacing of the long-standing problem on how to describe an atom-light interaction in a fractured loop. In such a case, the quantum steady state is not achieved even with constant, continuous interactions. Here we propose a method for modeling such a system, basing our approach on the Fourier expansion of a nonequilibrium steady state. The proposed solution is both numerically effective and able to predict edge cases, such as saturation. Furthermore, as an example, we employ this method to provide a complete description of a Rydberg superheterodyne receiver, obtaining the boundary parameters describing the operation of this atomic detector.}, archive = {J_PRA}, author = {Bartosz Kasza and Sebastian Borówka and Wojciech Wasilewski and Michał Parniak}, doi = {10.1103/PhysRevA.111.053718}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053718}, shortjournal = {Phys. Rev. A}, title = {Atomic-optical interferometry in fractured loops: A general solution for rydberg radio-frequency receivers}, volume = {111}, year = {2025}, }
• (2025). Analytical solution of the open dispersive jaynes-cummings model and perturbative analytical solution of the open quantum rabi model. PRA, 111(5), 053717. (www)

  @article{ , abstract = {The Jaynes-Cummings and quantum Rabi models are fundamental to cavity and circuit quantum electrodynamics, as they describe the simplest form of light-matter interaction, where a single qubit is coupled to a single bosonic mode. A scenario that is commonly encountered in the experimental practice arises when the bosonic mode interacts with an external dissipative thermal bath, making the qubit-boson system open. In this work, we present a new analytical solution of the Lindblad master equations for the open dispersive Jaynes-Cummings model and a perturbative analytical solution of the open quantum Rabi model in the limit of weak qubit-boson coupling , using the holomorphic formalism in Bargmann space. Specifically, we derive the most general solution of the local Lindblad master equation for the open dispersive Jaynes-Cummings model coupled to a thermal bath, with the only assumptions that the initial state of the qubit-boson system is separable. Additionally, we obtain a perturbative analytical solution for the open quantum Rabi model up to second order in . Notably, our findings include a new formula for the qubit's steady state at zeroth order, showing that the stationary populations depend on both qubit and boson frequencies in the quantum Rabi model, but not in the Jaynes-Cummings model, regardless of the value of . Our results are of general interest to the study of open quantum systems in the context of light-matter interaction.}, archive = {J_PRA}, author = {Antti Vaaranta and Marco Cattaneo and Paolo Muratore-Ginanneschi}, doi = {10.1103/PhysRevA.111.053717}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053717}, shortjournal = {Phys. Rev. A}, title = {Analytical solution of the open dispersive jaynes-cummings model and perturbative analytical solution of the open quantum rabi model}, volume = {111}, year = {2025}, }
• (2025). Manipulation of the photonic spin hall effect in a cavity magnomechanical system. PRA, 111(5), 053716. (www)

  @article{ , abstract = {In this paper, we examine the theoretical implications of photonic spin Hall effect (PSHE) amplification in a cavity magnomechanics system. In the framework of the PSHE, we show that spin-orbit interactions cause separation of space across the transverse plane between photons with opposing spins. Our findings reveal that the formation of photonic spin can be tuned across both positive and negative values, depending on the Brewster angle, while varying the magnon-phonon coupling. Notably, we find that in the absence of magnon-phonon coupling, we have magnomechanically induced transparency window at resonance and the PSHE has a higher peak value. Further in the presence of magnon-phonon coupling, the absorption peak occurs at resonance, which leads to a decrease of the PSHE. However, we observe a significant enhancement of the PSHE at two distinct detuning points where light transmission is maximized. Additionally, probe field detuning emerges as a crucial factor in controlling the PSHE. These results suggest that dynamically tuning the coupling between cavity magnons and magnon-phonon modes can greatly enhance the PSHE, presenting new opportunities for advanced nanoscale light manipulation.}, archive = {J_PRA}, author = {Muqaddar Abbas and Ghaisud Din and Hamid R. Hamedi and Pei Zhang}, doi = {10.1103/PhysRevA.111.053716}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053716}, shortjournal = {Phys. Rev. A}, title = {Manipulation of the photonic spin hall effect in a cavity magnomechanical system}, volume = {111}, year = {2025}, }
• (2025). Stochastic collective density-matrix approach for conditional spin squeezing. PRA, 111(5), 053715. (www)

  @article{ , abstract = {In this article, we present a stochastic collective density-matrix approach to numerically study the conditional dynamics of large systems of identical particles in the presence of individual and collective dissipation, as described by stochastic master equations. To illustrate the application potential of the approach, we use it to study the conditional spin squeezing of hundreds of identical atoms in a bad optical cavity subject to homodyne detection. We demonstrate that the conditional spin squeezing can be vividly illustrated by a Gaussian-like distribution on the quantum states of the atomic ensemble, and we examine the influence of various processes, such as the individual atomic dissipation, on this distribution. In the future, the present approach can be used to reveal measurement effects of multiple-level atoms system, to explore generation of exotic nonclassical states, such as cat states, and to gauge approximate approaches, such as the stochastic mean-field approach.}, archive = {J_PRA}, author = {ZhiQing Zhang and Yuan Zhang and HaiZhong Guo and Chongxin Shan and Gang Chen and Klaus Mølmer}, doi = {10.1103/PhysRevA.111.053715}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053715}, shortjournal = {Phys. Rev. A}, title = {Stochastic collective density-matrix approach for conditional spin squeezing}, volume = {111}, year = {2025}, }
• (2025). Quantum theory of the diamond maser: Stimulated and superradiant emission. PRA, 111(5), 053714. (www)

  @article{ , abstract = {We present a quantum theory of diamond masers operating at any temperature using a cavity quantum electrodynamical framework. Special attention is paid to the recently demonstrated room-temperature solid-state masers based on nitrogen-vacancy (NV) defect centers in diamond, but the model can easily be modified for other photoexcited chromophores such as pentacene-doped paraterphenyl, vacancies in silicon-carbide or boron nitride. We show that the eight energy levels involved in the optically pumped NV center polarization process can be mapped to a simple pumped two-level-system. We then derive simple analytical expressions for the optical pump threshold condition for masing as well as the steady-state microwave output power which can be used to design and predict maser performance. Finally, we investigate second-order correlations and find that typical diamond masers operate in an intermediate regime between the good and bad cavity limits where photon emission is driven by both stimulated and superradiant processes.}, archive = {J_PRA}, author = {Christoph W. Zollitsch and Jonathan D. Breeze}, doi = {10.1103/PhysRevA.111.053714}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053714}, shortjournal = {Phys. Rev. A}, title = {Quantum theory of the diamond maser: Stimulated and superradiant emission}, volume = {111}, year = {2025}, }
• (2025). Superradiance-driven optomechanical entanglement. PRA, 111(5), 053713. (www)

  @article{ , abstract = {Entanglement between light and matter has garnered significant interest for wide-ranging applications in quantum technology. However, weak interactions hinder the generation of entanglement. Here, we propose a scheme to achieve bipartite entanglement through superradiant excitation. The optomechanical entanglement exhibits behavior similar to the critical coupling value of superradiant phase transition. We investigate the effects of critical coupling related parameters, such as effective cavity detuning and cavity dissipation, on entanglement. Notably, strong entanglement can be generated even in the unresolved sideband regime. Increasing the number of atoms can reduce the collective coupling strength required to generate entanglement. Additionally, the entanglement is robust against temperature. Our scheme may provide a degree of freedom to manipulate the entanglement driven by superradiance. Our findings may provide a way to enhance the light-matter interaction via atomic assistance, which may be useful for quantum sensing and quantum information.}, archive = {J_PRA}, author = {Kai-Wei Huang and Xin Wang and Yi Ren and Hao Xiong}, doi = {10.1103/PhysRevA.111.053713}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053713}, shortjournal = {Phys. Rev. A}, title = {Superradiance-driven optomechanical entanglement}, volume = {111}, year = {2025}, }
• (2025). Cavity quantum electrodynamics with atom arrays in free space. PRA, 111(5), 053712. (www)

  @article{ , abstract = {Cavity quantum electrodynamics (cavity QED) enables the control of light-matter interactions at the single-photon level, rendering it a key component of many quantum technologies. Its practical realization, however, is complex since it involves placing individual quantum emitters close to mirror surfaces within a high-finesse cavity. In this work, we propose a cavity QED architecture fully based on atoms trapped in free space. In particular, we show that a pair of two-dimensional, ordered arrays of atoms can be described by conventional cavity QED parameters. Such an atom-array cavity exhibits the same cooperativity as a conventional counterpart with matching mirror specifications even though the cavity coupling strength and decay rate are modified by the narrow bandwidth of the atoms. We estimate that an array cavity composed of atoms in an optical lattice can reach a cooperativity of about 10. This value can be increased suppressing atomic motion with larger trap depths and may exceed with an ideal placement of the atoms. To reduce the experimental complexity of our scheme, we propose a spatially dependent ac Stark shift as an alternative to curving the arrays, which may be of independent interest. In addition to presenting a promising platform for cavity QED, our work creates opportunities for exploring novel phenomena based on the intrinsic nonlinearity of atom arrays and the possibility to dynamically control them.}, archive = {J_PRA}, author = {David Castells-Graells and J. Ignacio Cirac and Dominik S. Wild}, doi = {10.1103/PhysRevA.111.053712}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053712}, shortjournal = {Phys. Rev. A}, title = {Cavity quantum electrodynamics with atom arrays in free space}, volume = {111}, year = {2025}, }
• (2025). High-fidelity generation of bell and w states in a giant-atom system via bound states in the continuum. PRA, 111(5), 053711. (www)

  @article{ , abstract = {In this paper, we propose a high-fidelity scheme for generating entangled states in a system of two and three giant atoms coupled to the coupled resonator waveguide. Our approach leverages the bound state in the continuum, which is robust against waveguide disorder. Specifically, we achieve a fidelity exceeding for Bell state generation, overcoming the limitations of conventional decoherence-free interaction mechanisms. This scheme can be readily extended to a three-giant-atom system for generating states. In both the two- and three-atom setups, the maximally entangled states are generated in a short time and remain stable even as time approaches infinity. Our proposal is feasible for implementation on state-of-the-art solid-state quantum platforms and significantly broadens the applications of giant atoms and waveguide QED systems in quantum information processing.}, archive = {J_PRA}, author = {Mingzhu Weng and Hongwei Yu and Zhihai Wang}, doi = {10.1103/PhysRevA.111.053711}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053711}, shortjournal = {Phys. Rev. A}, title = {High-fidelity generation of bell and w states in a giant-atom system via bound states in the continuum}, volume = {111}, year = {2025}, }
• (2025). Rabi oscillation and fractional population via the bound states in the continuum in a giant-atom waveguide QED setup. PRA, 111(5), 053710. (www)

  @article{ , abstract = {We study the dynamics of two giant atoms interacting with a coupled resonator waveguide (CRW) beyond the Markovian approximation. The distinct atomic configurations determine the number of bound states in the continuum (BICs), leading to different dynamical behaviors. Our results show that when the system supports two BICs, Rabi oscillations dominate the dynamics, whereas fractional population dynamics emerge in the presence of a single BIC. The connection between these dynamics and the existence of BICs is further verified by analyzing the photonic distribution in the CRW during time evolution. These findings challenge the conventional notion that the environment always induces dissipation and decoherence. Instead, the bound states in the CRW-emitter coupled system can suppress complete dissipation of the emitters. We also quantitatively illustrate the memory effect of the waveguide, which serves as the environment of the giant-atom feature that can only be captured within our non-Markovian treatment. This work offers an effective approach for controlling dissipative dynamics in open quantum systems.}, archive = {J_PRA}, author = {Hongwei Yu and Xiaojun Zhang and Zhihai Wang and Jin Wang}, doi = {10.1103/PhysRevA.111.053710}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053710}, shortjournal = {Phys. Rev. A}, title = {Rabi oscillation and fractional population via the bound states in the continuum in a giant-atom waveguide QED setup}, volume = {111}, year = {2025}, }
• (2025). Generalized nonlinear interferometer with SU(1,1) echo. PRA, 111(5), 053709. (www)

  @article{ , abstract = {Precision measurements play a pivotal role in testing theoretical models and exploring new physics. Linear Ramsey interferometer is widely employed for measuring physical quantities, enhancing quantum metrology even approaching the Heisenberg limit. However, the linear interferometer is notably susceptible to detection noise, which limits their practical applications. In this paper, we propose an extended SU(1, 1) echo method to realize a generalized nonlinear interferometer, which is resilient to the detection noise. We demonstrate the utility of this approach by applying it to two distinct models: the Lipkin-Meshkov-Glick model and spin-mixing dynamics. Numerical simulations confirm the effectiveness of our proposed method. Additionally, we identify a trade-off in selecting the echoing conditions, which can be utilized to further enhance estimation precision. Our proposal may be easily implemented in many platforms, such as Bose-Einstein condensate, Rydberg atoms, and polar molecules, to enhance the metrology of time and field strength.}, archive = {J_PRA}, author = {Rui Chen and Peng Xu and Shi-Lei Su and Gao-Xiang Li}, doi = {10.1103/PhysRevA.111.053709}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053709}, shortjournal = {Phys. Rev. A}, title = {Generalized nonlinear interferometer with SU(1,1) echo}, volume = {111}, year = {2025}, }
• (2025). Compton scattering mediated by quantum entanglement. PRA, 111(5), 053708. (www)

  @article{ , abstract = {In this paper, the 16 Stokes parameters of a two-photon system are organized into a Stokes matrix. This formalism is then applied to analyze the polarization properties of annihilation photons produced by electron-positron annihilation, with a particular focus on their evolution during Compton scattering interactions. The study demonstrates that when one of the subsystems undergoes Compton scattering, quantum entanglement preserves the polarization symmetry between the scattered and noninteraction photons, while in the absence of entanglement, this symmetry is lost. Moreover, the method simplifies the calculation of the joint differential cross section for multiple scattering scenarios and provides a means to characterize the polarization properties of the individual subsystems. These findings highlight the impact of quantum correlations on scattering behavior, and they offer a framework for further investigation into the polarization dynamics of entangled photon pairs.}, archive = {J_PRA}, author = {Peter Caradonna}, doi = {10.1103/PhysRevA.111.053708}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053708}, shortjournal = {Phys. Rev. A}, title = {Compton scattering mediated by quantum entanglement}, volume = {111}, year = {2025}, }
• (2025). Magnon squeezing induced by virtual photons in a magnon-cavity-qubit system. PRA, 111(5), 053707. (www)

  @article{ , abstract = {The squeezed state of a magnon has garnered widespread attention due to its distinct properties and potential applications. Although preliminary experimental verification has been achieved, numerous technical and theoretical challenges persist. Here, we investigate the nonlinear coupling within the magnon-cavity-qubit system and propose an innovative method for achieving magnon squeezing. By employing virtual photons as a mediator for magnon-qubit interactions and optimizing system parameters, we induce nonlinear coupling. This approach not only enhances the interaction strength between magnons and qubits but also opens up an alternative pathway for achieving magnon squeezing. Our findings significantly enrich the fields of quantum physics and magnetism by providing a method for magnon squeezing, thereby laying a solid foundation for future advancements and applications in quantum technology.}, archive = {J_PRA}, author = {Ai-Bo Xia and Jing Cheng and Ding-Li Tian and Cheng-Jun Han and Y. P. Wang}, doi = {10.1103/PhysRevA.111.053707}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053707}, shortjournal = {Phys. Rev. A}, title = {Magnon squeezing induced by virtual photons in a magnon-cavity-qubit system}, volume = {111}, year = {2025}, }
• (2025). Selective band interaction and long-range hopping in a structured environment with giant atoms. PRA, 111(5), 053706. (www)

  @article{ , abstract = {Giant atoms, which couple to the environment at multiple discrete points, exhibit various nontrivial phenomena in quantum optics due to their nonlocal couplings. In this study, we propose a one-dimensional cross-stitch ladder lattice featuring both a dispersive band and a flat band. By modulating the relative phase between the coupling points, the giant atom selectively interacts with either band. First, we analyze the scenario where the dispersive and flat bands intersect at two points, and the atomic frequency lies within the band. Unlike the small atom, which simultaneously interacts with both bands, a single giant atom with a controllable phase interacts exclusively with the dispersive or flat band. Second, in the band-gap regime, where two atoms interact through bound-state overlaps manifesting as dipole-dipole interactions, we demonstrate that giant atoms enable deterministic long-range hopping and energy exchange with higher fidelity than small atoms. These findings provide promising applications in quantum information processing, offering enhanced controllability and selectivity for quantum systems and devices.}, archive = {J_PRA}, author = {Ying Xia and Jia-Qi Li and Xin Wang}, doi = {10.1103/PhysRevA.111.053706}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053706}, shortjournal = {Phys. Rev. A}, title = {Selective band interaction and long-range hopping in a structured environment with giant atoms}, volume = {111}, year = {2025}, }
• (2025). Correlated photon-pair generation via single-atom cavity-assisted spontaneous four-wave mixing. PRA, 111(5), 053705. (www)

  @article{ , abstract = {We present a detailed study of the generation of photon pairs by spontaneous four-wave mixing in a bicavity system with a single atom inside. Cavity modes lead to larger coupling strength than that of the normally assumed thermal vacuum, and thus higher generation rates are expected. Unlike approaches that have emerged so far, this paper presents an approach based on the solution of the master equation. This method allows us to investigate the photon statistics more strictly, and we show that the choices of pumping detuning and leaking rate of the cavities significantly affect the degree of the autocorrelation, and a higher-purity heralded single photon source is possible. We also derive a concise expression for the output state and the generation rate for the extreme cases where the cavity leaking rate is much smaller or larger than the rate of spontaneous emission.}, archive = {J_PRA}, author = {Yuan Feng (冯媛 and Mao-Hua Wang (王茂桦 and Jin-Hui Wu (吴金辉 and Xiao-Jun Zhang (张晓军}, doi = {10.1103/PhysRevA.111.053705}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053705}, shortjournal = {Phys. Rev. A}, title = {Correlated photon-pair generation via single-atom cavity-assisted spontaneous four-wave mixing}, volume = {111}, year = {2025}, }
• (2025). Light interactions with polar quantum systems. PRA, 111(5), 053704. (www)

  @article{ , abstract = {We investigate the dynamics of polar systems coupled to classical external beams in the ultrastrong coupling regime. The permanent dipole moments (PDMs) sustained by polar systems can couple to the electromagnetic field, giving rise to a variety of processes such as difference frequency and harmonic generation, reflected in the complicated dynamics of the atomic system. Here, we demonstrate that the atomic evolution can be described simply in a dynamic reference frame. We derive a Jaynes-Cummings-like framework with effective parameters describing the frequency shift, coupling strength with the driving field, and a rescaled relaxation rate. The familiar linear scaling of the interaction strength with the field amplitude is replaced with a nonlinear dependence, suggesting potential applications for improving the coherence of quantum system ensembles with permanent dipoles.}, archive = {J_PRA}, author = {Piotr Gładysz and Karolina Słowik}, doi = {10.1103/PhysRevA.111.053704}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053704}, shortjournal = {Phys. Rev. A}, title = {Light interactions with polar quantum systems}, volume = {111}, year = {2025}, }
• (2025). Amplifying hybrid entangled states and superpositions of coherent states. PRA, 111(5), 053703. (www)

  @article{ , abstract = {We compare two amplification schemes, photon addition and then subtraction ( ) and successive photon addition ( ), applied to hybrid entangled states (HESs) and superpositions of coherent states (SCSs). We show that the fidelity and gain of the amplification schemes for HESs are the same as those of coherent states. However, SCSs show quite nontrivial behavior by the amplification schemes, depending on the amplitudes of coherent states, the number of coherent-state components, and the relative phases between the components. This implies that appropriate amplification schemes for SCSs should be chosen depending on the tasks and specific forms of the states. To investigate the quality of amplified states, we calculate the quantum Fisher information, a measure of quantum phase estimation. In terms of the quantum Fisher information, the scheme tends to show better performance for relatively small amplitudes ( ), while the scheme is better in the larger amplitude regime. The performance of the two schemes becomes indistinguishable as the amplitude grows sufficiently large.}, archive = {J_PRA}, author = {InU Jeon and Sungjoo Cho and Hyunseok Jeong}, doi = {10.1103/PhysRevA.111.053703}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053703}, shortjournal = {Phys. Rev. A}, title = {Amplifying hybrid entangled states and superpositions of coherent states}, volume = {111}, year = {2025}, }
• (2025). Beam splitter for dark and bright states of light. PRA, 111(5), 053702. (www)

  @article{ , abstract = {Beam splitters are key elements in optical and photonic systems and are therefore employed in both classical and quantum technologies. Depending on the intended application, these devices can split incident light according to its power, polarization state, or wavelength. In this work, we theoretically present a type of beam splitter capable of separating a light beam into its two-mode bright and dark components. We propose a prototype based on an optical cross-cavity system resonantly coupled to a -type three-level atom. The dark component of the incoming light is transmitted because the antisymmetric collective mode of the cavity setup is decoupled from the atom. Meanwhile, the bright component is reflected due to a quantum interference, which arises from the high cooperativity between the atom and the symmetric collective mode of the cavity setup. Although the device requires only a two-level atom to operate, using a three-level atom allows the device to be turned on or off by controlling the atomic ground states. Our results pave the way for applications of beam splitters that leverage the collective properties of light. Manipulating and exploiting this additional degree of freedom can advance the field of quantum optics and contribute to the development of quantum technologies.}, archive = {J_PRA}, author = {Luiz O. R. Solak and Celso J. Villas-Boas and Daniel Z. Rossatto}, doi = {10.1103/PhysRevA.111.053702}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053702}, shortjournal = {Phys. Rev. A}, title = {Beam splitter for dark and bright states of light}, volume = {111}, year = {2025}, }
• (2025). Latent optical nonclassicality of conditionally prepared states. PRA, 111(5), 053701. (www)

  @article{ , abstract = {The lack of information obtained from informationally incomplete quantum measurements can prevent the detection of quantum resources, such as optical nonclassicality. We develop a technique that overcomes this limitation for single-mode quantum states conditionally prepared through measurements on another mode of a two-mode state. This task is performed by testing steering of latent nonclassicality—a class of correlations beyond quantum entanglement and quantum discord—for which we introduce a rigorous description.}, archive = {J_PRA}, author = {V. S. Kovtoniuk and A. B. Klimov and A. A. Semenov}, doi = {10.1103/PhysRevA.111.053701}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053701}, shortjournal = {Phys. Rev. A}, title = {Latent optical nonclassicality of conditionally prepared states}, volume = {111}, year = {2025}, }
• (2025). Enhanced spatiotemporal optical vortices and vortex chains from hermite-gauss modes with a tilted pulse front. PRA, 111(5), 053523. (www)

  @article{ , abstract = {Hermite-Gaussian (HG) beams are standard modes delivered by continuous or pulsed lasers systems, and pulse-front tilt is one of the most common, detrimental or beneficial, spatiotemporal couplings affecting ultrashort pulses. Combining them, we show that focusing a pulsed HG beam with a tilt generates an elliptical spatiotemporal optical vortex (STOV), or a chain of them. The elliptical STOVs differ from standard STOVs in an additional spatial chirp that is manifested as a wave front temporal rotation, and results in an enhanced transverse orbital angular momentum. The longitudinal field is significantly larger than that of normal STOVs, and may also take the form of an elliptical STOV. Our concept greatly simplifies previous arrangements for the generation of STOVs, whose additional features make them attractive for improving their applications in electron trapping and acceleration, or as driving fields for the generation of higher-order harmonics and other interactions with matter.}, archive = {J_PRA}, author = {Miguel A. Porras and Spencer W. Jolly}, doi = {10.1103/PhysRevA.111.053523}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053523}, shortjournal = {Phys. Rev. A}, title = {Enhanced spatiotemporal optical vortices and vortex chains from hermite-gauss modes with a tilted pulse front}, volume = {111}, year = {2025}, }
• (2025). Exceptional-point-based flat spectrum generation in frequency lattices. PRA, 111(5), 053522. (www)

  @article{ , abstract = {We theoretically investigate the generation of flat-top frequency combs by the exceptional point (EP) in synthetic frequency dimensions. Two coupled ring resonators under amplitude modulation simulate an anti–parity-time symmetric Su-Schrieffer-Heeger frequency lattice. At the phase transition point for the symmetry being completely broken, the bands become real and linearly cross at the EP. We find that when the incident light contains a component along the generalized eigenvector at the EP, a flat spectrum with a uniformly increasing width emerges. Further, we prove that the speed of the spectrum broadening and the spectral amplitude can be controlled flexibly via amplitude modulations. The numerical simulations are performed based on temporal coupled-mode theory. The study exemplifies the novel approach that combines non-Hermiticity and synthetic dimensions to generate flat spectra, which may enable new strategies in spectral shaping and flat-top microcomb design.}, archive = {J_PRA}, author = {Lingzhi Zheng and Linhao Qian and Chao Hong and Wenjing Lv and Shaolin Ke and Zhuoxiong Liu and Shuaifei Ren and Mingfeng Wang and Yiling Song}, doi = {10.1103/PhysRevA.111.053522}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053522}, shortjournal = {Phys. Rev. A}, title = {Exceptional-point-based flat spectrum generation in frequency lattices}, volume = {111}, year = {2025}, }
• (2025). Modeling nonlinear exciton-polariton microcavities using the transfer-matrix method: Spontaneous symmetry breaking and self-focusing. PRA, 111(5), 053521. (www)

  @article{ , abstract = {The transfer-matrix method (TMM) is a widely used technique for modeling linear propagation of electromagnetic waves through stratified layered media. However, since its extension to inhomogeneous and nonlinear systems is not straightforward, much more computationally demanding methods such as finite difference time domain or method of lines are typically used. In this paper, we extend the TMM framework to incorporate the effects of nonlinearity. We consider the case where strong coupling between excitons (electron-hole pairs) and photons leads to the formation of exciton polaritons. This extension is crucial for accurately simulating the behavior of light in polariton microcavities, where nonlinearities arising from exciton-exciton interactions play a key role. We perform efficient simulations of light transmission and reflection in a multidimensional system using the plane-wave basis. Additionally, we compare our extended TMM approach with the state-of-the-art admittance transfer method, and highlight the computational advantage of extended TMM for large-scale systems. The extended TMM not only provides a robust and computationally efficient numerical framework, but also paves the way for the development of future low-power nonlinear optical devices, polariton-based photonic circuits, and quantum photonic technologies.}, archive = {J_PRA}, author = {Karol Sajnok and Michał Matuszewski}, doi = {10.1103/PhysRevA.111.053521}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053521}, shortjournal = {Phys. Rev. A}, title = {Modeling nonlinear exciton-polariton microcavities using the transfer-matrix method: Spontaneous symmetry breaking and self-focusing}, volume = {111}, year = {2025}, }
• (2025). In-phase and out-of-phase period doubling of bound-state solitons in er-doped mode-locked fiber lasers. PRA, 111(5), 053520. (www)

  @article{ , abstract = {We investigate the specific changes of each soliton during the period-doubling of bound solitons in Er-doped mode-locked fiber lasers. Numerical simulations reveal that each soliton in the bound-state soliton can independently undergo period doubling. The different initial states of lasers may lead to in-phase and out-of-phase period doubling of bound-state solitons. These findings are experimentally verified by constructing an Er-doped fiber laser. The real-time spectrum evolution of bound-state solitons was measured using the time-stretched dispersion Fourier transform technique, confirming the existence of in-phase and out-of-phase period-doubling mechanisms in bound-state solitons. This study provides deeper insight into the complex dynamics of solitons in fiber lasers and contributes to the stability analysis of nonlinear systems and the detection of small signals.}, archive = {J_PRA}, author = {Jingxing Li and Baole Lu and Chenyue Lv and Jintao Bai}, doi = {10.1103/PhysRevA.111.053520}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053520}, shortjournal = {Phys. Rev. A}, title = {In-phase and out-of-phase period doubling of bound-state solitons in er-doped mode-locked fiber lasers}, volume = {111}, year = {2025}, }
• (2025). Dynamics of kerr cavity solitons in fiber resonators driven by desynchronized pulses. PRA, 111(5), 053519. (www)

  @article{ , abstract = {The pulsed driving of passive fiber Kerr resonators is an effective approach to generating coherent optical soliton combs with high efficiency. Desynchronization, which is defined as the frequency mismatch between the pumping pulse repetition rate and the cavity round-trip time, is an additional system variable, making the nonlinear system of fiber resonators more complex. Research on the relevant physics of desynchronization is not yet comprehensive. In this article, the complex dynamics of Kerr cavity solitons in a pulsed-pumped normal dispersion fiber Kerr resonator with third-order dispersion (TOD) and desynchronization is studied in simulations. We find that the desynchronization effect plays a critical role in the formation of Kerr cavity solitons. Interestingly, the introduction of desynchronization leads to the formation of breathing Kerr cavity solitons before the onset of stable operation of Kerr cavity solitons. The competition and balance between TOD and desynchronization determine the behavior of Kerr cavity solitons. Without TOD, a strong desynchronization effect results in a breathing state with a sliding shift of pulse peak position. In contrast, a slight desynchronization effect causes the periodic oscillation of pulse peak power without changing the pulse location. The breathing period depends on the absolute value of desynchronization coefficient and the sliding direction is related to the sign of the desynchronization coefficient. Furthermore, a reversible switching between different nonlinear Kerr cavity soliton states is achieved by changing the degree of desynchronization, suggesting that the desynchronization can be used as an additional degree of freedom to control the Kerr cavity soliton dynamics in Kerr resonators. These findings enrich our understanding of Kerr cavity solitons and provide important references for improving the stability of Kerr cavity solitons and the application of efficient resonator frequency combs.}, archive = {J_PRA}, author = {Hongbin Hu and Runhui Zhu and You Yu and Zhiqiang Wang and Zuxing Zhang}, doi = {10.1103/PhysRevA.111.053519}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053519}, shortjournal = {Phys. Rev. A}, title = {Dynamics of kerr cavity solitons in fiber resonators driven by desynchronized pulses}, volume = {111}, year = {2025}, }
• (2025). χ(2)-enabled non-hermitian topological light manipulation. PRA, 111(5), 053518. (www)

  @article{ , abstract = {Topological photonics provides a powerful and robust way to control the flow of light. Recently, the introduction of χ ( 3 ) nonlinearity made it possible to realize non-Hermitian topological photonics. In this work, we propose a χ ( 2 ) -coupled double-chain Su-Schrieffer-Heeger scheme in a periodically poled lithium niobate on insulator (LNOI) waveguide array. By tuning the pump power, one can easily modulate the nonlinear coupling strength, and therefore, manipulate the topological states of signal and idler lights. By designing various configurations based on LNOI waveguide array, we present non-Hermitian phase transition, topological edge state, and photonic zero mode. Our work provides a useful platform to investigate the interaction between χ ( 2 ) nonlinearity, topology, and non-Hermiticity, which have potential applications to manipulate light fields in classical and quantum optics.}, archive = {J_PRA}, author = {Chao Zhou and Xuejing Cui and Qiang Wang and Xiaoyi Xu and PengCheng Chen and Hui Liu and Shining Zhu and Min Xiao and Yong Zhang}, doi = {10.1103/PhysRevA.111.053518}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053518}, shortjournal = {Phys. Rev. A}, title = {χ(2)-enabled non-hermitian topological light manipulation}, volume = {111}, year = {2025}, }
• (2025). Deterministic generation of nonclassical mechanical states in cavity optomechanics via reinforcement learning. PRA, 111(5), 053517. (www)

  @article{ , abstract = {Nonclassical mechanical states, as vital quantum resources for exploring macroscopic quantum behavior, have wide applications in the study of the fundamental quantum mechanics and modern quantum technology. In this work, we propose a scheme for deterministically generating nonclassical mechanical states in cavity optomechanical systems. By working in the eigenrepresentation of the nonlinear optomechanical systems, we identify the carrier-wave resonance conditions and seek optimal driving pulses for state preparations. Concretely, we employ the reinforcement learning method to optimize the pulsed driving fields, effectively suppressing the undesired transitions induced by both the pulsed driving fields and dissipations. This approach enables the high-fidelity preparation of phononic Fock states and superposed Fock states in the single-resonator optomechanical systems, as well as two-mode entangled states in the two-resonator optomechanical systems. The statistical properties of the generated states are also examined. Our results create an opportunity for quantum state engineering in quantum optics and quantum information science via reinforcement learning.}, archive = {J_PRA}, author = {Yu-Hong Liu and Qing-Shou Tan and Le-Man Kuang and Jie-Qiao Liao}, doi = {10.1103/PhysRevA.111.053517}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053517}, shortjournal = {Phys. Rev. A}, title = {Deterministic generation of nonclassical mechanical states in cavity optomechanics via reinforcement learning}, volume = {111}, year = {2025}, }
• (2025). Deterministic generation of single soliton microcombs with enhanced stability using thermal self-starting and simplified temperature control. PRA, 111(5), 053516. (www)

  @article{ , abstract = {Soliton microcombs (SMCs) spontaneously emerge in coherently pumped high-quality (high- ) microcavities and are widely used as on-chip optical frequency combs for precise measurements and spectroscopic applications. In this work, we present a thermal compensation scheme for generating single SMCs. Compared to other methods, the single SMC generated using our approach exhibits remarkable stability, with a lifetime exceeding 24 hours, and can be deterministically generated over a wide temperature range. Utilizing this feature, we successfully achieve thermal self-starting of single SMCs using a simple temperature control process. Over an experiment lasting more than 3 hours (with a cycle time of approximately 200 seconds between soliton generation, decay by design, and restart), the success rate of single SMC generation was 100%.}, archive = {J_PRA}, author = {Kairong Chen and Shaowu Chen and Beichen Yin and Wei Li and Liangsen Feng and Yudong Li and Jiaxu Chen and Tenfei Wu}, doi = {10.1103/PhysRevA.111.053516}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053516}, shortjournal = {Phys. Rev. A}, title = {Deterministic generation of single soliton microcombs with enhanced stability using thermal self-starting and simplified temperature control}, volume = {111}, year = {2025}, }
• (2025). Intensity correlation measurement to simulate two-body bound states in the continuum and probe nonlinear discrete breathers. PRA, 111(5), 053515. (www)

  @article{ , abstract = {We study Hanbury Brown-Twiss spatial intensity correlations in femtosecond laser-fabricated photonic Su-Schrieffer-Heeger lattices using coherent input states with tunable phases. By mapping intensity correlations to the two-body quantum walk, we experimentally simulate edge bound states in the continuum (BICs) of two indistinguishable bosons. These two-body edge BICs show remarkable robustness in the presence of disorder. We then discuss how intensity correlations can capture the dynamics of two identical fermions for which BICs do not exist on the same edge of the lattice. The localization of intensity correlation, observed in the linear regime, persists at weak nonlinearity due to the formation of long-lived edge breathers : spatially localized nonlinear states with oscillating intensity along the propagation distance. For stronger nonlinearities, localized edge states are not formed for a range of phases, destroying the localization of the intensity correlation. Our results highlight the interplay of band structure, initial state, and nonlinearity influencing transport and intensity correlations.}, archive = {J_PRA}, author = {Trideb Shit and Rishav Hui and Marco Di Liberto and Diptiman Sen and Sebabrata Mukherjee}, doi = {10.1103/PhysRevA.111.053515}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053515}, shortjournal = {Phys. Rev. A}, title = {Intensity correlation measurement to simulate two-body bound states in the continuum and probe nonlinear discrete breathers}, volume = {111}, year = {2025}, }
• (2025). Squeezing-induced nonreciprocal transparency and the slow-to-fast-light switch. PRA, 111(5), 053514. (www)

  @article{ , abstract = {We propose a theoretical method to realize nonreciprocal light transmission in an optomechanical device assisted by directional quantum squeezing. Specifically, we consider the device consisting of an optomechanical resonator and a nonlinear optical resonator with directional pumping. We find that optical squeezing occurs along the pump direction when the nonlinear resonator is directionally pumped, enabling nonreciprocal light transmission as well as nonreciprocal group delay (slow light) or advancement (fast light). Furthermore, we find that the efficiency of the second-order sidebands can be enhanced in one direction compared with the opposite direction. Our work provides a promising design for the application of directionally squeezed optomechanical devices in nonreciprocal optical communication and signal processing.}, archive = {J_PRA}, author = {Deng Wang and Bin Yin and Jie Wang and Mei-Yu Peng and HuiZu Lin and Tian-Xiang Lu and Hui Jing}, doi = {10.1103/PhysRevA.111.053514}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053514}, shortjournal = {Phys. Rev. A}, title = {Squeezing-induced nonreciprocal transparency and the slow-to-fast-light switch}, volume = {111}, year = {2025}, }
• (2025). Chaotic self-trapped vortex beams induced by initial spatial chirps in nonlocal nonlinear media. PRA, 111(5), 053513. (www)

  @article{ , abstract = {This paper numerically investigates the breathing behavior and chaotic self-trapped behavior of scalar vortex solitons (SVSs) and vector vortex solitons (VVSs) modulated with initial spatial chirps in thermally nonlocal nonlinear media, such as lead glass. We found that as for the SVS, small spatial chirp induces breathing behavior, while large spatial chirp leads to chaotic self-trapped behavior. This chaotic self-trapped behavior exhibits both chaotic property and trapping property. The transition between these two behaviors can be achieved by varying the magnitude of the spatial chirp. As for the VVS, small spatial chirp induces an asynchronous or synchronous breather-breather pair under short-range interaction. As spatial chirp increases, chaos-chaoticon, entangled and nonentangled chaoticon-chaoticon, and chaoticon-quasisoliton pairs are formed. By adjusting the spatial chirp, we achieve controllable conversion between soliton, breather, chaos, chaoticon, and quasisoliton. The controllable chaotic self-trapped beams and switchable propagation states may provide ideas for chaotic secure communication.}, archive = {J_PRA}, author = {Junjie Li and Huicong Zhang and Zhixuan Wang and Lu Wan}, doi = {10.1103/PhysRevA.111.053513}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053513}, shortjournal = {Phys. Rev. A}, title = {Chaotic self-trapped vortex beams induced by initial spatial chirps in nonlocal nonlinear media}, volume = {111}, year = {2025}, }
• (2025). Strong and noise-tolerant entanglement in dissipative optomechanics. PRA, 111(5), 053512. (www)

  @article{ , abstract = {Macroscopic entanglement, as a critical quantum resource in quantum information science, has been extensively studied in coherent optomechanics over the past decades. However, entanglement in dissipative optomechanics, where the cavity linewidth depends on the position of the mechanical resonator, remains largely unexplored. In this work, we investigate quantum entanglement in a dissipative optomechanical system realized by a Michelson-Sagnac interferometer with a movable membrane. This configuration enables the switching between coherent and dissipative optomechanical couplings at will. With experimentally feasible parameters, we demonstrate that the steady-state mechanical displacement exhibits a nonlinear (linear) dependence on the driving power under coherent (dissipative) coupling. Furthermore, we show that the quantum entanglement generated via dissipative coupling is significantly stronger and more robust to noise than that generated via coherent coupling. When both coherent and dissipative couplings are simultaneously present, the entanglement is weakened due to quantum interference. Our results indicate that dissipative optomechanical coupling can be a promising route for engineering strong and noise-resilient quantum entanglement.}, archive = {J_PRA}, author = {Jiaojiao Chen and Wei Xiong and Dong Wang and Liu Ye}, doi = {10.1103/PhysRevA.111.053512}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053512}, shortjournal = {Phys. Rev. A}, title = {Strong and noise-tolerant entanglement in dissipative optomechanics}, volume = {111}, year = {2025}, }
• (2025). Macroscopic QED and noise currents in time-varying media. PRA, 111(5), 053511. (www)

  @article{ , abstract = {Macroscopic QED (MQED) is the field theory for computing quantum electromagnetic effects in dispersive media. Here, we extend MQED to treat time-varying , dispersive media. For a time-dependent Drude model, we find that the expected replacement within standard MQED does not lead to a permittivity that is similar to that of the classical time-dependent Drude model and can lead to large polarization currents, becoming singular in the limit of a step change in carrier density. We show this unwanted behavior can be removed through instead modifying the reservoir dynamics, quantizing the resulting theory and finding the nonequilibrium, time-varying noise currents, which exhibit extra correlations due to temporal reflections within the material dynamics.}, archive = {J_PRA}, author = {S. A. R. Horsley and R. K. Baker}, doi = {10.1103/PhysRevA.111.053511}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053511}, shortjournal = {Phys. Rev. A}, title = {Macroscopic QED and noise currents in time-varying media}, volume = {111}, year = {2025}, }
• (2025). Theory for measuring topology-based enhanced emission in a double-emitter system including plasmonic antennae. PRA, 111(5), 053510. (www)

  @article{ , abstract = {Hybrid plasmonic-photonic domains showcase remarkable non-Hermitian characteristics, offering unique benefits through their ability to exhibit gain and loss simultaneously. Here, in-depth analysis has been conducted on a multilayered structure that is enhanced by the presence of plasmonic antennae. These antennae are strategically placed to optimize the interaction with light, potentially improving the performance of the structure in various applications. The hybrid waveguide resonance mode, generated by combining the surface-plasmon polariton with waveguide modes and activated by the antenna modes, characterizes the multilayer. The antennae aid in hybridizing waveguide and surface-plasmon modes; in turn, the multilayer structure enhances near-field intensity and allows for tuning far-field responses through multiple resonances. The interaction between antennae is characterized by dark and bright modes, which can create bound states in the continuum because of destructive interference in radiation losses. The nonconservative nature of the open system enables exploration of non-Hermitian properties, complex topology, and exceptional points. Analytical, numerical, and experimental results enable the study of the system's behavior, and display that exceptional points significantly boost emission levels when measurements are taken in their vicinity. In conclusion, systems with hybrid architecture and including plasmonic antennae can provide enhanced sensitivity and demonstrate their potential value across a diverse array of applications. These include advanced sensing technologies and innovative communication systems, where the complete density matrix can be simplified, and non-Hermitian Hamiltonian frames can be utilized to explore entanglement dynamics and analyze systems much larger than feasible.}, archive = {J_PRA}, author = {G. Simone}, doi = {10.1103/PhysRevA.111.053510}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053510}, shortjournal = {Phys. Rev. A}, title = {Theory for measuring topology-based enhanced emission in a double-emitter system including plasmonic antennae}, volume = {111}, year = {2025}, }
• (2025). Symmetry breaking and spatiotemporal pattern formation in photonic time crystals. PRA, 111(5), 053509. (www)

  @article{ , abstract = {In this work, we explore the dynamics of time-varying photonic media with an optical Kerr nonlinearity and an associated phase transition. The interplay between a periodically modulated permittivity and the nonlinearity induces a continuous transition of electromagnetic waves to a state with broken spatial and time translation symmetries. This transition gives rise to a lattice-like wave pattern, in many ways similar to a spatial crystallization in solids. Symmetry breaking triggers the emergence of soft, Goldstone-like modes, which propagate as deformations of the lattice structure, as well as massive Higgs-like modes—spatially uniform oscillations of the field amplitude. We extend the analysis of the nonequilibrium symmetry breaking to -dimensional time-varying media and discuss pattern formation as well as the connection to discrete dissipative time crystals.}, archive = {J_PRA}, author = {Egor I. Kiselev and Yiming Pan}, doi = {10.1103/PhysRevA.111.053509}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053509}, shortjournal = {Phys. Rev. A}, title = {Symmetry breaking and spatiotemporal pattern formation in photonic time crystals}, volume = {111}, year = {2025}, }
• (2025). Enhancing optomechanical force sensing utilizing synthetic magnetism. PRA, 111(5), 053508. (www)

  @article{ , abstract = {In precision force sensing of multimechanical mode optomechanical systems, coherent interference can decouple certain degenerate vibrational modes from the cavity field, leading to incomplete information regarding the measured signal. In this paper, we propose a scheme to enhance and control the detection bandwidth in optomechanical force sensing by exploiting synthetic magnetism achieved through tuning phonon-hopping interactions. By toggling between broken and unbroken dark mode, this approach effectively manages the response bandwidth and exhibits intriguing additional noise characteristics. Specifically, when the dark mode remains unbroken, the thermal noise is robust and reduced to half of that of a standard device. In contrast, when the dark mode is broken, thermal noise increases substantially at mechanical resonance but remains the same as when the dark mode is unbroken at effective detection frequencies. Moreover, our scheme offers the dual benefit of amplifying the mechanical response while suppressing additional noise, with the potential to surpass the standard quantum limit.}, archive = {J_PRA}, author = {Ding-hui Xu and Zheng Liu and Chang-shui Yu}, doi = {10.1103/PhysRevA.111.053508}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053508}, shortjournal = {Phys. Rev. A}, title = {Enhancing optomechanical force sensing utilizing synthetic magnetism}, volume = {111}, year = {2025}, }
• (2025). Mesoscopic theory of wavefront shaping to focus waves deep inside disordered media. PRA, 111(5), 053507. (www)

  @article{ , abstract = {We describe the theory of focusing waves to a predefined focal point deep inside a disordered three-dimensional (3D) opaque medium by the shaping of different field sources outside the medium, also known as wavefront shaping. Our study is motivated by recent experiments where wavefront shaping, mediated by the controlled interference of scattered waves, coexists with a classical diffusion picture where wave interference appears irrelevant. We derive the energy density of the wave field both near the focal point and anywhere else inside the medium, averaged over realizations after optimizing the focus. To this end, we conceive of a point source at the focal point inside that emits waves to an external detector array that—by time reversal—becomes a source array that emits the desired shaped fields like a spatial light modulator. In this picture, the average energy density including the focusing is described by the , and even intensity correlations known from mesoscopic transport theory. We draw the remarkable conclusion that by averaging over optimized wavefronts of the array, associated with different realizations of the disorder, a background energy density is obtained that obeys a diffusion equation in which correlations create an energy source inside. Hence a classical property (diffusion) coexists with interference ( correlations). We derive the peak and background energy density distributions for , and correlations, including for a slab. We find that the relative enhancement of the energy density at the focal point is proportional to the angular opening of the array, which de facto replaces the role of the inverse dimensionless conductance as the universal parameter in the transmission statistics, and it generalizes the number of segments known from experiments. We exploit the concept of a source for “optimized background energy” inside the medium to compare several different energy density profiles proposed in the literature, which are associated with optimized transmission by a slab using wavefront shaping. We explain why the best matching models have the first diffusion mode dominating, as was found in earlier work. Our approach avoids random-matrix theory restricted to waveguide geometries, confirms the role non-Gaussian correlations in the wavefront shaping for focusing deep inside 3D random media, and highlights the notion of an energy source created in this process. Our results are relevant for applications where the internal energy density in opaque media is crucial, varying from white-light illumination, projection optics, semiconductor metrology, (bio)sensing, to photovoltaics.}, archive = {J_PRA}, author = {Bart A. van Tiggelen and Ad Lagendijk and Willem L. Vos}, doi = {10.1103/PhysRevA.111.053507}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053507}, shortjournal = {Phys. Rev. A}, title = {Mesoscopic theory of wavefront shaping to focus waves deep inside disordered media}, volume = {111}, year = {2025}, }
• (2025). Plasmons in metallic nanoclusters exhibit nonharmonic phenomena. PRA, 111(5), 053506. (www)

  @article{ , abstract = {Metallic nanoparticles, frequently applied to improve the efficiency or sensitivity of various antenna-reactor systems, utilize the plasmonic effect due to the unusual ability of plasmons to transmit energy at the nanoscale. The absorption and emission of light by plasmons are especially high in metallic nanoscale clusters with 10 7 − 10 electrons, but not in small clusters with a lower number of electrons. We demonstrate that the exceptional properties of plasmons at the nanoscale are conditioned by a large anharmonicity of plasmon oscillations induced by strong Lorentz friction, which significantly deviates local charge oscillations from the harmonic regime in this scale of metal spatial confinement. Due to this anharmonicity, plasmons can maintain their oscillations despite strong damping associated with efficient energy transfer, even when such large damping would cause a harmonic oscillator to become overdamped and stop. We also identify a sum-rule-type formula for plasmon polaritons in metallic nanochains arising from the anharmonicity of plasmons.}, archive = {J_PRA}, author = {Janusz Edward Jacak and Witold Aleksander Jacak}, doi = {10.1103/PhysRevA.111.053506}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053506}, shortjournal = {Phys. Rev. A}, title = {Plasmons in metallic nanoclusters exhibit nonharmonic phenomena}, volume = {111}, year = {2025}, }
• (2025). Kerr-enhanced optomechanical cooling in the unresolved-sideband regime. PRA, 111(5), 053505. (www)

  @article{ , abstract = {Dynamical backaction cooling has been demonstrated to be a successful method for achieving the motional quantum ground state of a mechanical oscillator in the resolved-sideband regime, where the mechanical frequency is significantly larger than the cavity decay rate. Nevertheless, as mechanical systems increase in size, their frequencies naturally decrease, thus bringing them into the unresolved-sideband regime, where the effectiveness of the sideband cooling approach decreases. Here we demonstrate, however, that this cooling technique in the unresolved-sideband regime can be significantly enhanced by utilizing a nonlinear cavity as shown in the experimental work of Zoepfl et al. [ Phys. Rev. Lett. 130 , 033601 (2023) ]. The above arises due to the increased asymmetry between the cooling and heating processes, thereby improving the cooling efficiency. In addition, we show that injecting a squeezed vacuum into the nonlinear cavity paves the way to ground-state cooling of the mechanical mode. Notably, the required squeezing parameters are far less stringent than in the linear case, simplifying experimental implementation.}, archive = {J_PRA}, author = {N. Diaz-Naufal and L. Deeg and D. Zoepfl and C. M. F. Schneider and M. L. Juan and G. Kirchmair and A. Metelmann}, doi = {10.1103/PhysRevA.111.053505}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053505}, shortjournal = {Phys. Rev. A}, title = {Kerr-enhanced optomechanical cooling in the unresolved-sideband regime}, volume = {111}, year = {2025}, }
• (2025). Quartic soliton solutions of a normal-dispersion-based mode-locked laser. PRA, 111(5), 053503. (www)

  @article{ , abstract = {We studied the characteristics, regions of existence, and stability of different types of solitons for a distributed model of a mode-locked laser whose dispersion is purely quartic and normal. Among the different types of solitons, we identified three main branches that are named according to their different amplitude: low, medium, and high amplitude solitons. It was found that the first solitons are always unstable while the latter two exist and are stable in relatively large regions of the parameter space. Moreover, the stability regions of medium and high amplitude solitons overlap over a certain range of parameters, manifesting effects of bistability. The energy of high amplitude solitons increases quadratically with their width, whereas the energy of medium amplitude solitons may decrease or increase with the width depending on the parameter region. Furthermore, we have investigated the long term evolution of the continuous-wave solutions under modulational instability, showing that medium amplitude solitons can arise in this scenario. Additionally, we assessed the effects of second- and third-order dispersion on medium and high amplitude solitons and found that both remain stable in the presence of these terms.}, archive = {J_PRA}, author = {M. Facão and D. Malheiro and M. I. Carvalho}, doi = {10.1103/PhysRevA.111.053503}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053503}, shortjournal = {Phys. Rev. A}, title = {Quartic soliton solutions of a normal-dispersion-based mode-locked laser}, volume = {111}, year = {2025}, }
• (2025). Optimal conditions for the generation of moderate-order harmonics of a short-wave field by helium atoms. PRA, 111(5), 053502. (www)

  @article{ , abstract = {It is shown that under optimal conditions the generation of the third, fifth, seventh, and ninth harmonics of the short-wave, ultraviolet or vacuum ultraviolet, laser field by helium atoms is mainly due to transitions between bound states, and the maximum energy of the harmonics is achieved under conditions of their resonant multiphoton excitation. In this case, the optima for the generation of the third, fifth, seventh, and ninth harmonics of the field correspond to three-, four-, five-, and six-photon resonances, and the optimal value of the peak field intensity, depending on the harmonic order, varies from to . The total probability of excitation and ionization of an atom at the end of a laser pulse under corresponding conditions exceeds 1/2. With such intensity and not-too-high frequency of the laser field, the Stark effect turns out to be very significant, which allows it to be tuned in resonance with an arbitrary excited state of the atom by changing the intensity of the field without changing its frequency. It is shown that for the laser field parameters maximizing the energy of the harmonic, 3 ≤ ≤ 9, this harmonic dominates in the dipole acceleration spectrum. At the same time, the amplitudes of the remaining harmonics increase as the harmonic order approaches . In particular, under the conditions maximizing the yield of the ninth harmonic, the harmonic amplitudes increase when moving from the third harmonic to the fifth and then to the seventh and ninth harmonics, and the harmonics form an attosecond pulse train. At the same time, under the conditions maximizing the yield of the third harmonic, its amplitude in the dipole acceleration spectrum exceeds not only the amplitudes of the other harmonics, but also the amplitude of the atomic response at the frequency of the driving field.}, archive = {J_PRA}, author = {V. A. Antonov and I. R. Khairulin and M. Yu. Emelin and M. M. Popova and E. V. Gryzlova and M. Yu. Ryabikin}, doi = {10.1103/PhysRevA.111.053502}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053502}, shortjournal = {Phys. Rev. A}, title = {Optimal conditions for the generation of moderate-order harmonics of a short-wave field by helium atoms}, volume = {111}, year = {2025}, }
• (2025). Phase-driven unconventional superradiance phase transition in non-hermitian cascaded quantum rabi cavities. PRA, 111(5), 053501. (www)

  @article{ , abstract = {This study investigates phase-driven symmetry breaking leading to superradiance phase transitions in cascaded non-Hermitian quantum Rabi cavities. Non-Hermiticity is introduced via the phase coupling φ between the atom and the optical field. In the thermodynamic limit of the quantum harmonic oscillator, we analytically derive the superradiance phase boundary, validated by observables. An unconventional quantum phase transition without a Hermitian analog arises when | φ | = π 4 or 3 π 4 , where the phase boundary is uniquely determined by the cavity coupling, at J = 1 2 ( J is the ratio of the cavity coupling strength J to the optical field frequency ω p , and J = J ω p ), independent of the atom-photon coupling strength g . For other φ , the phase boundary relies on both J and g , similar to the scenario observed in Hermitian systems. Furthermore, we identify phase-driven first- and second-order superradiance phase transitions, focusing on the quantum criticality of the second-order transition by determining the critical exponents and the universality class. The feasibility of experimental realization is also discussed, aiming to inspire further studies on non-Hermitian superradiance quantum phase transitions.}, archive = {J_PRA}, author = {Shujie Cheng and Shuai-Peng Wang and G. D. M. Neto and Gao Xianlong}, doi = {10.1103/PhysRevA.111.053501}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053501}, shortjournal = {Phys. Rev. A}, title = {Phase-driven unconventional superradiance phase transition in non-hermitian cascaded quantum rabi cavities}, volume = {111}, year = {2025}, }
• (2025). Vortices in tunable dipolar bose-einstein condensates with attractive interactions. PRA, 111(5), 053320. (www)

  @article{ , abstract = {We investigate the formation of vortices in quasi-two-dimensional dipolar Bose-Einstein condensates (BECs) through the interplay between two-body contact and long-ranged dipole-dipole interactions (DDIs), as both interactions can be tuned from repulsive to attractive. By solving the associated Gross-Pitaevskii equation for a rotating system, our initial approach concentrates on stabilizing a collapsing condensate with attractive -wave two-body interactions by employing sufficiently large repulsive DDIs. Subsequently, the same procedure was applied after reversing the signs of both interactions to evaluate the sensitivity of vortex formation to such an interchange of interactions. As a reference to guide our investigation, valid for generic dipolar atomic species, we have assumed a condensate with the strong dipolar dysprosium isotope, . The correlation of the results with other dipolar BEC systems was exemplified by considering rotating BECs with two other isotopes, namely and . For a purely dipolar condensate (no contact interactions) under fixed rotation, we show how the number of visible vortices increases as the DDI becomes more repulsive, accomplished by tuning the orientation of the dipoles through a characteristic angle parameter.}, archive = {J_PRA}, author = {S. Sabari and R. Sasireka and R. Radha and A. Uthayakumar and Lauro Tomio}, doi = {10.1103/PhysRevA.111.053320}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053320}, shortjournal = {Phys. Rev. A}, title = {Vortices in tunable dipolar bose-einstein condensates with attractive interactions}, volume = {111}, year = {2025}, }
• (2025). Three-body interactions in rabi-coupled bose gases: A perturbative approach. PRA, 111(5), 053319. (www)

  @article{ , abstract = {In ultracold atomic gases, radio-frequency coupling between two spin states can lead to atoms being in a stable coherent superposition of the two states (dressed states). When the two-body interactions (scattering lengths) are different between the two states, it offers the possibility not only to control the interatomic interaction but also to modify the equation of states with emerging three-body terms with different signs and scalings with the parameters. We derive these terms in a unified perturbation framework and show that they correspond to genuine three-body processes found at different orders in perturbation theory. Our work justifies the introduction of contact three-body interactions in dressed-state systems when the spin degree of freedom is integrated out.}, archive = {J_PRA}, author = {S. Tiengo and R. Eid and T. Bourdel}, doi = {10.1103/PhysRevA.111.053319}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053319}, shortjournal = {Phys. Rev. A}, title = {Three-body interactions in rabi-coupled bose gases: A perturbative approach}, volume = {111}, year = {2025}, }
• (2025). Preparation and observation of anomalous counterpropagating edge states in a periodically driven optical raman lattice. PRA, 111(5), 053318. (www)

  @article{ , abstract = {Motivated by the recent observation of real-space edge modes with ultracold atoms [C. Braun et al. , Nat. Phys. 20 , 1306 (2024) ], we investigate the preparation and detection of anomalous counterpropagating edge states, a defining feature of the anomalous Floquet valley-Hall (AFVH) phase, in a two-dimensional periodically driven optical Raman lattice. Modeling the atomic cloud with a Gaussian wave-packet state, we explore, both analytically and numerically, how the population of edge modes depends on the initial-state parameters. In particular, we reveal that, in addition to the internal spin state, the initial momenta parallel and perpendicular to the boundary play essential roles: they independently control the selective population of edge states across distinct momenta and within separate quasienergy gaps. Furthermore, we examine the wave-packet dynamics of counterpropagating edge states and demonstrate that their characteristic motion is robust against long-range disorder. These results establish a theoretical framework for future experimental explorations of the AFVH phase and topological phenomena associated with its unique edge modes.}, archive = {J_PRA}, author = {Hongting Hou and Long Zhang}, doi = {10.1103/PhysRevA.111.053318}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053318}, shortjournal = {Phys. Rev. A}, title = {Preparation and observation of anomalous counterpropagating edge states in a periodically driven optical raman lattice}, volume = {111}, year = {2025}, }
• (2025). Persistent breather and dynamical symmetry in a unitary fermi gas. PRA, 111(5), 053317. (www)

  @article{ , abstract = {SO(2,1) dynamical symmetry makes a remarkable prediction that the breathing oscillation of a scale-invariant quantum gas in an isotropic harmonic trap is isentropic and can persist indefinitely. In two dimensions, this symmetry is broken due to quantum anomaly in the strongly interacting range, and consequently the lifetime of the breathing mode becomes finite. The persistent breather in a strongly interacting system has so far not been realized. Here, we experimentally achieve the long-lived breathing mode in a three-dimensional unitary Fermi gas, which is protected by the SO(2,1) symmetry. The nearly perfect SO(2,1) symmetry is realized by loading the ultracold Fermi gas in an isotropic trap and tuning the interatomic interaction to resonance. The breathing mode oscillates at twice the trapping frequency even for large excitation amplitudes. The ratio of damping rate to oscillation frequency is as small as 0.002, providing an interacting persistent breather. The oscillation frequency and damping rate are nearly constant for different atomic densities and temperatures, demonstrating the robustness of the SO(2,1) symmetry in three dimensions. The factors that lead to the residual damping have also been clarified. This work opens the way to study many-body nonequilibrium dynamics related to the dynamical symmetry.}, archive = {J_PRA}, author = {Dali Sun and Jing Min and Xiangchuan Yan and Lu Wang and Xin Xie and Xizhi Wu and Jeff Maki and Shizhong Zhang and Shi-Guo Peng and Mingsheng Zhan and Kaijun Jiang}, doi = {10.1103/PhysRevA.111.053317}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053317}, shortjournal = {Phys. Rev. A}, title = {Persistent breather and dynamical symmetry in a unitary fermi gas}, volume = {111}, year = {2025}, }
• (2025). Ground state of a mixture of SU(3) fermions and scalar bosons. PRA, 111(5), 053316. (www)

  @article{ , abstract = {We explore a system composed of scalar bosons and fermions in one dimension. Considering only local intra- and interspecies interactions, the system is described by the Bose-Fermi-Hubbard Hamiltonian, which is studied using the density-matrix renormalization-group method. In addition to the common gapless and mixed-Mott-insulator phases, we identify unknown gapped states, in which bosons couple with some or all flavors of fermions. We unveil different flavor-selective states characterized by itinerant fermions that coexist with an insulator state in which the bosons connect with only one- or two-flavor fermions. The states reported here could be implemented in cold-atom experiments.}, archive = {J_PRA}, author = {J. Silva-Valencia and J. J. Mendoza-Arenas}, doi = {10.1103/PhysRevA.111.053316}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053316}, shortjournal = {Phys. Rev. A}, title = {Ground state of a mixture of SU(3) fermions and scalar bosons}, volume = {111}, year = {2025}, }
• (2025). Time-dependent jastrow ansatz: Exact quantum dynamics, shortcuts to adiabaticity, and quantum quenches in strongly correlated many-body systems. PRA, 111(5), 053315. (www)

  @article{ , abstract = {The description of strongly correlated quantum many-body systems far from equilibrium presents a fundamental challenge due to the vast amount of information it requires. We introduce a generalization of the Jastrow ansatz for time-dependent wave functions that offers an efficient and exact description of the time evolution of various strongly correlated systems. Previously known exact solutions are characterized by scale invariance, enforcing self-similar evolution of local correlations, such as the spatial density. However, we demonstrate that a complex-valued time-dependent Jastrow ansatz (TDJA) is not restricted to scale invariance and can describe a broader class of dynamical processes lacking this symmetry. The associated time evolution is equivalent to the implementation of a shortcut to adiabaticity (STA) via counterdiabatic driving along a continuous manifold of quantum states described by a real-valued TDJA, providing a framework for engineering exact STA in strongly correlated many-body quantum systems. We illustrate our findings in systems with inverse-square interactions, such as the Calogero-Sutherland and hyperbolic models, supplemented with pairwise logarithmic interactions, as well as in the long-range Lieb-Liniger model, where bosons experience both contact and Coulomb interactions in one dimension. Our results enable the study of quench dynamics in all these models and serve as a benchmark for numerical and quantum simulations of nonequilibrium strongly correlated systems with continuous variables.}, archive = {J_PRA}, author = {Jing Yang and Adolfo del Campo}, doi = {10.1103/PhysRevA.111.053315}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053315}, shortjournal = {Phys. Rev. A}, title = {Time-dependent jastrow ansatz: Exact quantum dynamics, shortcuts to adiabaticity, and quantum quenches in strongly correlated many-body systems}, volume = {111}, year = {2025}, }
• (2025). Vortices in the many-body excited states of interacting bosons in two dimensions. PRA, 111(5), 053314. (www)

  @article{ , abstract = {Quantum vortices play an important role in the physics of two-dimensional quantum many-body systems, though they usually are understood in the single-particle framework as the mean-field approach. Inspired by the study on the relations between solitons and yrast states, we investigate here the emergence of vortices from the eigenstates of an -body Hamiltonian of interacting particles trapped in a disk. We analyze states that appear by consecutively measuring the positions of particles. These states have densities, phases, and energies closely resembling mean-field vortices. We discuss similarities, but also point out purely many-body features, such as vortex smearing due to the quantum fluctuation of their center. The ab initio analysis of the many-body system, and mean-field approaches are supported by the analysis within the Bogoliubov approach.}, archive = {J_PRA}, author = {Mateusz Ślusarczyk and Krzysztof Pawłowski}, doi = {10.1103/PhysRevA.111.053314}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053314}, shortjournal = {Phys. Rev. A}, title = {Vortices in the many-body excited states of interacting bosons in two dimensions}, volume = {111}, year = {2025}, }
• (2025). Three-body scattering hypervolume of two-component fermions in three dimensions. PRA, 111(5), 053313. (www)

  @article{ , abstract = {We study the zero-energy collision of three fermions, two of which are in the spin-down ( ) state and one of which is in the spin-up ( ) state. Assuming that the two-body and three-body interactions have a finite range, we find a parameter called the three-body scattering hypervolume. We study the three-body wave function asymptotically when three fermions are far apart or one spin- (spin- ) fermion and one pair, formed by the other two fermions, are far apart and derive three asymptotic expansions of the wave function. The three-body scattering hypervolume appears in the coefficients of such expansions at the order of , where is the hyperradius of the triangle formed by the three fermions (we assume that the three fermions have the same mass), and are the sides of the triangle. We compute the -matrix element for three such fermions colliding at low energy in terms of in the absence of two-body interactions. When the interactions are weak, we calculate approximately using the Born expansion. We also analyze the energy shift of three two-component fermions in a large periodic cube due to and generalize this result to the many-fermion system. also determines the three-body recombination rates in two-component Fermi gases, and we calculate the three-body recombination rates in terms of and the density and temperature of the gas.}, archive = {J_PRA}, author = {Jiansen Zhang and Zipeng Wang and Shina Tan}, doi = {10.1103/PhysRevA.111.053313}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053313}, shortjournal = {Phys. Rev. A}, title = {Three-body scattering hypervolume of two-component fermions in three dimensions}, volume = {111}, year = {2025}, }
• (2025). Interaction-induced higher-order topological insulator via floquet engineering. PRA, 111(5), 053312. (www)

  @article{ , abstract = {Higher-order topological insulators have attracted significant interest in both static single-particle and many-body lattice systems. While periodically driven (Floquet) higher-order topological phases have been explored at the single-particle level, the role of interactions in such systems remains less understood. In this paper, we extend previous studies by investigating interaction-induced higher-order topological phases through Floquet engineering. To achieve this, we construct an extended Bose-Hubbard model on a square lattice subjected to periodic driving. We demonstrate the emergence of interaction-induced normal Floquet second-order topological corner states for doublons (i.e., bound boson pairs) from a trivial phase, which exhibit robustness against disorder. Notably, beyond the normal phase, we reveal an interaction-induced anomalous Floquet second-order topological phase, where in-gap corner states of doublons emerge within the gap ( being the driving period). Our model, accessible with state-of-the-art ultracold atom techniques, provides a platform for realizing interaction-driven higher-order topological phases uniquely enabled by periodic driving, with no direct counterparts in static or single-particle systems.}, archive = {J_PRA}, author = {Chun-Ping Su and Zhao-Fan Cai and Tao Liu}, doi = {10.1103/PhysRevA.111.053312}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053312}, shortjournal = {Phys. Rev. A}, title = {Interaction-induced higher-order topological insulator via floquet engineering}, volume = {111}, year = {2025}, }
• (2025). Coexistence of majorana zero modes and the fulde-ferrell-larkin-ovchinnikov state in a dipolar fermionic gas with laser-assisted interwire tunneling. PRA, 111(5), 053311. (www)

  @article{ , abstract = {Spin-orbit coupling (SOC) changes the Fermi surface and creates topological states with non-Abelian Majorana zero modes. However, it also drastically suppresses the Cooper pairing with finite momentum and thus the coexistence of Majorana zero modes and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is still challenging to be observed. In this work we introduce more complex interactions to the platform and investigate the unconventional superfluidity of a dipolar fermionic gas in a biwire configuration with the SOC induced by laser-assisted interwire tunneling. Employing a nonlocal self-consistent Bogoliubov–de Gennes formalism, we reveal a complex phase diagram featuring various topological-superfluid phases. In particular, due to the peculiar competition between the long-range dipolar interaction and the SOC, a phase separation structure emerges, exhibiting a stripe FFLO phase core encompassed by the topological-superfluid states. Moreover, the long-range dipolar interaction induces a remarkable oscillatory structure in the resultant Majorana zero modes at the FFLO phase boundary and enables direct manipulation of these zero modes. Finally, we provide an experimental proposal to realize our system and give the method to detect the novel quantum phase. The discovery of the Majorana zero modes at the interface between the FFLO state and the topological phase, along with their unique properties, deepens our understanding of Majorana fermions and enriches the zoo of Majorana quasiparticles.}, archive = {J_PRA}, author = {Jin-Xin Li and Xing-Dong Zhao and Xue-Jing Feng and Ying-Ying Zhang and Jing-Xue Liu and Lu Qin and Zun-Lue Zhu and Wu-Ming Liu and Liang-Liang Wang}, doi = {10.1103/PhysRevA.111.053311}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053311}, shortjournal = {Phys. Rev. A}, title = {Coexistence of majorana zero modes and the fulde-ferrell-larkin-ovchinnikov state in a dipolar fermionic gas with laser-assisted interwire tunneling}, volume = {111}, year = {2025}, }
• (2025). Many-body interferometry of one-dimensional integrable systems. PRA, 111(5), 053310. (www)

  @article{ , abstract = {We propose using many-body Ramsey interferometry to measure correlation functions of one-dimensional (1D) integrable systems. The 1D transverse-field Ising model, which is conjectured to equilibrate into nonthermal generalized Gibbs ensemble (GGE) steady states, is studied. It is shown that retarded Green's functions, as opposed to ordinary spin-spin correlators considered previously, convincingly distinguish between the GGE and thermal postquench steady states, justifying the assumption of convergence towards the GGE as the system equilibrates. We also propose the experimental protocol for measuring response functions with Ramsey interferometry, which can be used to distinguish between different postquench phases of the model. Our proposal can be realized with current ultracold atom techniques and opens up the possibility to study dynamics in nonthermal ensembles.}, archive = {J_PRA}, author = {Min Liu and Maksims Arzamasovs and Yue Zhang and Rui Tian and Zehou Li and Shuai Li and Bo Liu}, doi = {10.1103/PhysRevA.111.053310}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053310}, shortjournal = {Phys. Rev. A}, title = {Many-body interferometry of one-dimensional integrable systems}, volume = {111}, year = {2025}, }
• (2025). Two-component atomic fermi superfluid with spin-orbital coupling in thin-spherical-shell geometry. PRA, 111(5), 053309. (www)

  @article{ , abstract = {We present a theory of two-component atomic Fermi superfluid with tunable pairing interaction in a thin spherical shell subject to spin-orbit coupling (SOC). By incorporating SOC into the Fermi superfluid in the BCS-Bose Einstein condensation (BEC) crossover, we obtain the energy spectrum and equations of state. While the order parameter and chemical potential are suppressed by SOC on the BCS side, the former remains positive but the latter may be pushed to negative values by SOC. Meanwhile, the compressibility exhibits kinks as the pairing interaction or SOC varies, indicating singular behavior of higher derivatives of the free energy despite the presence of the superfluid order parameter. The minimum of the energy dispersion indicates a decoupling of the energy gap from the order parameter, and the compressibility kinks occur when the energy gap approaches 0. We found the particle-hole mixing in the Fermi superfluid essential for the compressibility kinks since a Fermi gas with the same SOC but no pairing interaction only exhibits complicated dispersions but no singular behavior. Therefore, our results show that a combination of superfluid, SOC, and geometry can lead to interesting phenomena. We also discuss possible experimental realizations and implications.}, archive = {J_PRA}, author = {Yan He and Chih-Chun Chien}, doi = {10.1103/PhysRevA.111.053309}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053309}, shortjournal = {Phys. Rev. A}, title = {Two-component atomic fermi superfluid with spin-orbital coupling in thin-spherical-shell geometry}, volume = {111}, year = {2025}, }
• (2025). Non-hermitian thouless pumping: Interplay between topological charge pumping and directional tunneling. PRA, 111(5), 053308. (www)

  @article{ , abstract = {Motivated by experimental realizations of the lattice models with directional tunneling and the generalized bulk-edge correspondence brought by a similarity transformation, we study the topological charge pumping using the Rice-Mele (RM) model with directional tunneling (also termed as the non-Hermitian RM model). In momentum space, through a similaritylike transformation, we map the non-Hermitian RM model to a Hermitian one. Under the biorthogonal basis, the pumping is dictated by a Chern number of the Hermitian RM model. This can be verified by experiments where both the non-Hermitian RM model and its Hermitian conjugation are realized. Under the right-right vector basis, which is relevant to experiments where only the non-Hermitian one is required, we find that the charge pumping contains a dynamical and a topological part. To reveal the topological contribution, an experimental scheme of canceling the dynamical term is proposed.}, archive = {J_PRA}, author = {Xiaoyi Yang and Chengming Tan and Yangqian Yan and Ren Zhang}, doi = {10.1103/PhysRevA.111.053308}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053308}, shortjournal = {Phys. Rev. A}, title = {Non-hermitian thouless pumping: Interplay between topological charge pumping and directional tunneling}, volume = {111}, year = {2025}, }
• (2025). Transition from spontaneous to explicit symmetry breaking in a finite-sized system: Bosonic bound states of an impurity. PRA, 111(5), 053307. (www)

  @article{ , abstract = {The presence of a single attractive impurity in an ultracold repulsive bosonic system can drive a transition from a homogeneous to a localized state, as we here show for a one-dimensional ring system. In the few-body limit, the localization of the bosons around the impurity, as seen in the pair correlations, is accompanied by low-lying modes that resemble finite-sized precursors of Higgs-Anderson- and Nambu-Goldstone-like modes. Tuning the impurity-boson mass ratio allows for the exploration of the transition from a spontaneous to an explicit breaking of the continuous rotational symmetry of the Hamiltonian. We compare the minimum of the Higgs-Anderson-like mode as a marker of the onset of localization in the few-body limit to mean-field predictions of binding. We find improved agreement between the few-body exact-diagonalization results and mean-field predictions of binding with increasing boson-boson repulsion.}, archive = {J_PRA}, author = {L. Chergui and F. Brauneis and T. Arnone Cardinale and M. Schubert and A. G. Volosniev and S. M. Reimann}, doi = {10.1103/PhysRevA.111.053307}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053307}, shortjournal = {Phys. Rev. A}, title = {Transition from spontaneous to explicit symmetry breaking in a finite-sized system: Bosonic bound states of an impurity}, volume = {111}, year = {2025}, }
• (2025). Timescales and necessary conditions for hydrodynamization in one-dimensional bose gases. PRA, 111(5), 053306. (www)

  @article{ , abstract = {We study the quantum evolution of one-dimensional Bose gases immediately after several variants of high-energy quenches, both theoretically and experimentally. Using the advantages conveyed by the relative simplicity of these nearly integrable many-body systems, we are able to differentiate the behaviors of two distinct but often temporally overlapping processes, hydrodynamization and local prethermalization. We show that the hydrodynamization epoch is itself characterized by two independent timescales, an oscillation period and an observable-dependent damping time. We also show how the existence of a hydrodynamization epoch depends on the exact nature of the high-energy quench. There is a universal character to our findings, which can be applied to the short-time behavior of any interacting many-body quantum system after a sudden high-energy quench. We specifically discuss its potential relevance to heavy-ion collisions.}, archive = {J_PRA}, author = {Yicheng Zhang and Yuan Le and David S. Weiss and Marcos Rigol}, doi = {10.1103/PhysRevA.111.053306}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053306}, shortjournal = {Phys. Rev. A}, title = {Timescales and necessary conditions for hydrodynamization in one-dimensional bose gases}, volume = {111}, year = {2025}, }
• (2025). Supersolid spectroscopy. PRA, 111(5), 053305. (www)

  @article{ , abstract = {We develop a linear-response theory to provide a unified description of two recent spectroscopy protocols for probing one-dimensional supersolid states realized in cold-atom systems. Both protocols involve applying a periodic optical potential to excite the supersolid and determine its excitation frequencies and density response characteristics. This information can be used to estimate the superfluid fraction. We validate our linear-response theory against nonlinear mean-field simulations of the dynamics for ring, box, and harmonically trapped cases. A key focus is the behavior at the band edge—the regime occurring when the optical potential used to excite the system has a wavelength that is twice the value of the supersolid lattice constant. Here symmetry can be used to selectively excite a mode from one of the two low-energy gapless excitation bands. We also consider the application of the spectroscopy protocols to determine the superfluid fraction, showing the relationship to hydrodynamic theory and a Josephson-junction array model. Our analysis and results suggest that the phase protocol we introduce has potential advantages for experimental application over the density protocol.}, archive = {J_PRA}, author = {L. M. Platt and D. Baillie and P. B. Blakie}, doi = {10.1103/PhysRevA.111.053305}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053305}, shortjournal = {Phys. Rev. A}, title = {Supersolid spectroscopy}, volume = {111}, year = {2025}, }
• (2025). Echoes and defects in the calogero model. PRA, 111(5), 053304. (www)

  @article{ , abstract = {In this work, we extend the study of the interplay between scaling symmetries and statistics to one-dimensional fluids by studying the Calogero model in a harmonic trap modulated through time. The latter harbors an interpretation in terms of free particles imbued with exclusion statistics and is an example of a scale invariant fluid in one-dimension displaying dynamical symmetry preserved by harmonic traps. Taking advantage of the dynamical symmetry, two experimentally relevant drive protocols spanning both quasistatic and nonadiabatic regimes are investigated and universal signatures of the interactions and exclusion statistics are uncovered in the ground-state echo amplitude and closely related ground-state fidelity. In particular, under both periodic modulation and slow drive through the gapless point of the trap frequency, enhanced interactions and exclusion are shown to favor the proliferation of defects and to hinder their annihilation, which leads to a universal decrease of ground-state fidelities and echo amplitudes. We also show that increasing exclusion sparks a sharp suppression of the likelihood of intermediate echoes beyond those imposed by the commensurability of a periodic drive and the natural frequency of the trap.}, archive = {J_PRA}, author = {Benjamin Liégeois and Ramasubramanian Chitra and Nicolò Defenu}, doi = {10.1103/PhysRevA.111.053304}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053304}, shortjournal = {Phys. Rev. A}, title = {Echoes and defects in the calogero model}, volume = {111}, year = {2025}, }
• (2025). Vortex phases and domain walls in trapped spinor bose-einstein condensates with inhomogeneous spin-orbital-angular-momentum coupling. PRA, 111(5), 053303. (www)

  @article{ , abstract = {We investigate the ground-state structures and vortex configurations in a two-component Bose-Einstein condensate under the influence of spin-orbital-angular-momentum coupling (SOAMC) with a high spatial inhomogeneity and high characteristic orbital angular momentum. By modulating the coupling strength, we uncover two distinct quantum phases: a stripe phase at low coupling strengths and a new vortex-necklace phase at higher coupling intensities. The latter is characterized by vortices forming a ring-shaped structure that acts as a domain wall, a unique phase boundary between a central stripe phase and an outer single-momentum phase. For a better understanding of this new mixed phase of the system, we develop an analytical model to describe the domain-wall radius as a function of coupling strength, which aligns well with numerical simulations. Our findings contribute to the understanding of SOAMC-driven quantum phase transitions and domain-wall formation, offering new insights into topological phenomena in ultracold atomic systems.}, archive = {J_PRA}, author = {O. O. Prykhodko and L. V. Zadorozhna}, doi = {10.1103/PhysRevA.111.053303}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053303}, shortjournal = {Phys. Rev. A}, title = {Vortex phases and domain walls in trapped spinor bose-einstein condensates with inhomogeneous spin-orbital-angular-momentum coupling}, volume = {111}, year = {2025}, }
• (2025). Vacancy-assisted superfluid drag. PRA, 111(5), 053302. (www)

  @article{ , abstract = {We study superfluid drag in the two-component Bose-Hubbard model with infinitely strong repulsive interactions. In this system, all transport is mediated by the motion of empty sites, or “holes,” and it is hard to move one component without moving the other. We demonstrate, with a combination of analytic and numeric techniques, that the motion of holes leads to strong dissipationless coupling between currents in the two components. This behavior is attributable to polaronic correlations that emerge in the presence of spin currents, which can be observed in experiments. We derive a closed-form expression for the coupling on various lattices in arbitrary spatial dimensions, which we verify through numerical simulations on two-dimensional lattices.}, archive = {J_PRA}, author = {Thomas G. Kiely and Chao Zhang and Erich J. Mueller}, doi = {10.1103/PhysRevA.111.053302}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053302}, shortjournal = {Phys. Rev. A}, title = {Vacancy-assisted superfluid drag}, volume = {111}, year = {2025}, }
• (2025). Evaporative-cooling dynamics and stability of a continuous bose-einstein-condensate source. PRA, 111(5), 053301. (www)

  @article{ , abstract = {We present evaporative cooling simulations based on the direct simulation Monte Carlo method. Our system is a 54-cm-long atom guide with reflective barriers at the beginning and the end. The atom guide is continuously loaded with thermal atoms at the beginning. We show that it is critical to control the gravity component in the guiding direction to sustain a high classical phase-space density at the end of the atom guide. Transient oscillations are observed under certain conditions.}, archive = {J_PRA}, author = {Yun-Jhih Chen and Robert J. Thompson and James M. Kohel}, doi = {10.1103/PhysRevA.111.053301}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053301}, shortjournal = {Phys. Rev. A}, title = {Evaporative-cooling dynamics and stability of a continuous bose-einstein-condensate source}, volume = {111}, year = {2025}, }
• (2025). Schwinger pair production in counterpropagating laser pulses: Identifying volume factors. PRA, 111(5), 053121. (www)

  @article{ , abstract = {We investigate the nonperturbative process of vacuum pair production in a combination of two counterpropagating linearly polarized laser pulses of a finite spatial extent. By means of the locally constant field approximation (LCFA), we calculate the total particle yield for the corresponding four-dimensional setup and compare it with the estimates obtained for simplified low-dimensional scenarios. Within the domain where the LCFA is well justified, we examine a combination of two plane-wave pulses, a standing electromagnetic wave, and a spatially uniform oscillating field and demonstrate that at each of these three levels of approximation, one can accurately predict the actual particle number by multiplying the results by properly chosen volume factors depending on the field parameters. We present closed-form expressions for these factors providing universal prescriptions for evaluating the particle yield. Our final formula connecting the spatially uniform setup with the four-dimensional scenario has a relative uncertainty of the level of . The explicit correspondences deduced in this study not only prove the relevance of the approximate predictions, but also allow one to quickly estimate the number of pairs for various realistic scenarios without performing multidimensional LCFA integrations.}, archive = {J_PRA}, author = {A. G. Tkachev and I. A. Aleksandrov and V. M. Shabaev}, doi = {10.1103/PhysRevA.111.053121}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053121}, shortjournal = {Phys. Rev. A}, title = {Schwinger pair production in counterpropagating laser pulses: Identifying volume factors}, volume = {111}, year = {2025}, }
• (2025). Forces on alkali rydberg atoms due to nonlinearly polarized light. PRA, 111(5), 053120. (www)

  @article{ , abstract = {Trapped Rydberg atoms are highly promising candidates for quantum science experiments. While several approaches have been put forward to exert (trapping) forces on isolated Rydberg atoms, a widely applicable lossless technique is lacking. This paper proposes a robust versatile alternative technique that avoids lifetime compromising losses. Our proposal leverages the vector polarizability, which is induced by nonlinearly polarized light and is shown to be several orders of magnitude larger than the usual scalar and tensor polarizabilities for commonly used alkali Rydberg series such as the , and series with principal quantum number as low as 30. The resulting force can be used to trap isolated Rydberg atoms over long times, which constitutes a key advance that is expected to impact quantum simulation applications, as well as to generate large light–Rydberg-atom hybrid states, which possess nontrivial position-dependent forces.}, archive = {J_PRA}, author = {A. Bhowmik and D. Blume}, doi = {10.1103/PhysRevA.111.053120}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053120}, shortjournal = {Phys. Rev. A}, title = {Forces on alkali rydberg atoms due to nonlinearly polarized light}, volume = {111}, year = {2025}, }
• (2025). High-energy polarized electron beams from the ionization of isolated spin polarized hydrogen atoms. PRA, 111(5), 053119. (www)

  @article{ , abstract = {We propose a laser-based method for the preparation of high-energy polarized electrons, from the ionization of isolated spin polarized hydrogen (SPH) atoms. The SPH atoms are prepared from the photodissociation of hydro-halide molecules, using two consecutive UV pulses of ps duration. By appropriately timing and focusing the pulses, we can spatially separate the highly polarized SPH from other unwanted photoproducts, which then act as the target for the acceleration lasers. We show how elastic collisions define number density and polarization P regimes for the prepolarized targets, and use particle-in-cell simulations to demonstrate the method's feasibility.}, archive = {J_PRA}, author = {Dimitris Sofikitis and Lars Reichwein and Marios G. Stamatakis and Christos Zois and Dimitrios G. Papazoglou and Samuel Cohen and Markus Büscher and Alexander Pukhov and T. Peter Rakitzis}, doi = {10.1103/PhysRevA.111.053119}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053119}, shortjournal = {Phys. Rev. A}, title = {High-energy polarized electron beams from the ionization of isolated spin polarized hydrogen atoms}, volume = {111}, year = {2025}, }
• (2025). Coulomb-related symmetry in laser-induced tunneling ionization of atoms and molecules. PRA, 111(5), 053118. (www)

  @article{ , abstract = {In tunneling ionization of an atom induced by a strong laser field, the system initially located in its ground state will be excited. The time-dependent wave function of the excited system includes bound- and continuum-eigenstate components of the field-free Hamiltonian. Here, we study the relation between the average kinetic energy and potential energy of the bound wave packet composed of coherent superposition of higher bound eigenstates. Our simulations show that around the peak time of the laser field at which the tunneling effect is strong, the bound wave packet still approximately agrees with the virial theorem, which reflects the Coulomb-related spatial symmetry of the system. Our results indicate that during the laser-induced exciting process, the system tends to keep its symmetry before ionization. This observation also holds for small molecules. It gives suggestions on analytically constructing Coulomb-included strong-field models.}, archive = {J_PRA}, author = {Z. Y. Chen and S. Q. Shen and Y. P. Li and Z. Q. Yang and J. Y. Che and Y. J. Chen}, doi = {10.1103/PhysRevA.111.053118}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053118}, shortjournal = {Phys. Rev. A}, title = {Coulomb-related symmetry in laser-induced tunneling ionization of atoms and molecules}, volume = {111}, year = {2025}, }
• (2025). Ionization-coherence-enhanced-vibration photoexcitation in nitrogen ions. PRA, 111(5), 053117. (www)

  @article{ , abstract = {We develop a vibronic coherence model for multiorbital ionization and excitation of nitrogen molecules, based on an up-to-date concept of coherent ionization into excited states [C. H. Yuen and C. D. Lin, Phys. Rev. A 108 , 023123 (2023) ; Phys. Rev. A 109 , 033108 (2024) ]. Compared to other models, where the coherence of excitation dynamics is described with fewer details, our model predicts larger populations at excited states, in particular, at levels corresponding to the transition wavelengths 391 or 428 nm relevant to air lasing in the atmospheric environment. The dependence of population inversion on the pump wavelength is investigated, showing that ionic coherence in ionization injection enhances the vibronic three-photon transition in the postionization process.}, archive = {J_PRA}, author = {Chaohui Zhou and Liang Xu and Jiahao Dong and Shuqiao Li and Yuanqian Yang and Zhengyang Bai and Feng He and Aurélien Houard and André Mysyrowicz and Vladimir T. Tikhonchuk and Yi Liu}, doi = {10.1103/PhysRevA.111.053117}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053117}, shortjournal = {Phys. Rev. A}, title = {Ionization-coherence-enhanced-vibration photoexcitation in nitrogen ions}, volume = {111}, year = {2025}, }
• (2025). Interferometric circular dichroism in photoelectron momentum distributions. PRA, 111(5), 053116. (www)

  @article{ , abstract = {We study polarization effects in photoionization of achiral matter and report on two types of circular dichroism driven by a pair of time-delayed copropagating broadband pulses. Both being of interferometric nature, they manifest in the photoelectron momentum distribution (PMD) and vanish for fully time overlapping pulses having the same carrier-envelope phase. The first type, called atomic interferometric circular dichroism (AICD), is demonstrated in photoionization of the H atom or aligned along the pulse propagation direction . It is shown to be directly visualized through mirroring effects from two key interferograms created in the PMD within two polarization schemes: (i) spiral patterns produced by a pair of counterrotating circularly polarized pulses and (ii) tuning-fork-like patterns driven by linearly and circularly polarized pulses. The second type is dubbed molecular interferometric circular dichroism (MICD) as it occurs in molecular photoionization within the configuration . However, while the MICD occurs in polarization scheme (i), it is shown to interplay with the molecular-symmetry-mixed dichroism [ Phys. Rev. Lett. 123 , 143202 (2019) ] in scheme (ii). Switching the helicities or ordering of the two pulses is shown to be consistent with time-reversal symmetry, except when in scheme (ii). Exhibiting an inversion symmetry, characteristic of unpolarized targets, the manifestation of the AICD and MICD in the PMD can serve as target chirality identification in life and chemical science. Our predictions based on nonstationary quantum-mechanical calculations are within the reach of current attosecond or femtosecond laser technology, making this study timely for experimental verification.}, archive = {J_PRA}, author = {S. McKay and H. B. Ambalampitiya and D. Peng and A. Saenz and J. M. Ngoko Djiokap}, doi = {10.1103/PhysRevA.111.053116}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053116}, shortjournal = {Phys. Rev. A}, title = {Interferometric circular dichroism in photoelectron momentum distributions}, volume = {111}, year = {2025}, }
• (2025). Probing electron correlations in sequential double ionization on the attosecond timescale. PRA, 111(5), 053115. (www)

  @article{ , abstract = {Correlated electron dynamics are pivotal in double ionization (DI) induced by ultrashort laser pulses, yet their direct, time-resolved characterization has remained elusive. Here, we apply the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) technique to directly characterize correlation-driven effects in sequential DI of helium with attosecond resolution. We uncover a previously unobserved scattering phase shift, sensitive to the kinetic energy difference between the two released electrons, corresponding to a time delay of the order of as. Moreover, when the DI pathway proceeds via a doubly excited state, Fano resonances introduce nontrivial phase shifts for both the first electron and its correlated partner. By extracting joint angular distributions at each sideband energy, we provide an intuitive picture to understand these correlation-driven effects. Our findings provide direct, time-resolved insights into electron-electron interactions in DI, demonstrating the power of attosecond chronoscopy in unraveling electron-electron interactions on their natural timescale.}, archive = {J_PRA}, author = {Xu Zhang and Yang Li and Miao Yu and Mingrui He and Wei-Chao Jiang and Yueming Zhou and Peixiang Lu}, doi = {10.1103/PhysRevA.111.053115}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053115}, shortjournal = {Phys. Rev. A}, title = {Probing electron correlations in sequential double ionization on the attosecond timescale}, volume = {111}, year = {2025}, }
• (2025). Phase-space gaussian quantum ensemble for high-order harmonic generation. PRA, 111(5), 053114. (www)

  @article{ , abstract = {We propose a phase-space Gaussian quantum ensemble to depict the high-order harmonic generation process. Our model takes the wave-particle duality and the uncertainty principle into account. It bridges the ab initio calculation with the semiclassical analysis, enabling us to distinguish different channels and reveal the underlying electron dynamics. We investigate the ionization and recombination time of the short, long, and multi-rescattering trajectory harmonics. Our model also provides access to investigate the position-momentum properties. Results demonstrate that the electron has a nonzero initial velocity at the tunnel exit, revealing the nonadiabatic effect. We prove the validity of our analysis by interpreting the observables in the two-color interference experiments. The nonzero transverse harmonic signal for any two-color delay in the orthogonally polarized fields can be explained by the delocalized distribution of the quantum ensemble. Our model can guide the semiclassical analysis and provide a benchmark for high-order harmonic spectroscopy.}, archive = {J_PRA}, author = {Sen Qiao and Liang Li and Hubin Cui and Shiyu Zeng and Shiqi Liang and Pengfei Lan and Peixiang Lu}, doi = {10.1103/PhysRevA.111.053114}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053114}, shortjournal = {Phys. Rev. A}, title = {Phase-space gaussian quantum ensemble for high-order harmonic generation}, volume = {111}, year = {2025}, }
• (2025). Photoionization dynamics in intense few-cycle twisted laser pulses. PRA, 111(5), 053113. (www)

  @article{ , abstract = {Electrons emitted during photoionization provide key insights into light-atom interactions. While conventional laser pulses have been widely studied, the effects of structured light fields, particularly twisted Bessel beams with orbital angular momentum, remain less explored. Previous research has shown that spectral peaks in above-threshold ionization shift with changes in the opening angle and orbital angular momentum of Bessel pulse. However, the precise impact and sensitivity of these parameters on photoelectron momentum distributions (PMD) is still unclear. In this paper, we use the strong-field approximation and saddle-point method to analytically derive the ionization transition amplitude for these pulses. For computational simplicity, we model the atomic target using a hydrogenic orbital wave function, with parameters adapted for krypton to capture the essential ionization dynamics. This allows us to compute the PMD while resolving the effects of both the opening angle and orbital angular momentum.}, archive = {J_PRA}, author = {Danish Furekh Dar and Anne Weber and Shreyas Ramakrishna and Stephan Fritzsche}, doi = {10.1103/PhysRevA.111.053113}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053113}, shortjournal = {Phys. Rev. A}, title = {Photoionization dynamics in intense few-cycle twisted laser pulses}, volume = {111}, year = {2025}, }
• (2025). Orientation-dependent ionization rate of diatomic molecules. PRA, 111(5), 053112. (www)

  @article{ , abstract = {The ionization rate of molecules in strong laser fields depends on the orientation of the ionizing electric field relative to the molecular frame. The orientation dependence of the rate plays an important role in strong-field-based attosecond-scale and imaging methods, motivating us to investigate theoretically whether it can be extracted from the ionization yields or photoelectron momentum distributions obtained by ionization with laser pulses of various polarization forms. As a reference for comparison we use the orientation dependence of the static-field tunneling rate. Numerical solutions of the time-dependent Schrödinger equation for ionization of the ground and first excited states of a model molecule show that linearly or circularly polarized single-color pulses are of limited use for obtaining the orientation-dependent rate accurately. By adding a second harmonic with suitable polarization, i.e., using either linearly polarized two-color fields or counterrotating circularly polarized two-color fields, the agreement of the extracted signal with the exact tunneling rate is substantially improved.}, archive = {J_PRA}, author = {Paul Winter and Manfred Lein}, doi = {10.1103/PhysRevA.111.053112}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053112}, shortjournal = {Phys. Rev. A}, title = {Orientation-dependent ionization rate of diatomic molecules}, volume = {111}, year = {2025}, }
• (2025). Interference structures of an ar atom by orthogonally polarized laser pulses. PRA, 111(5), 053111. (www)

  @article{ , abstract = {Tunneling ionization is one of the basic physical processes in strong-field physics. Photoelectron holographic (PH) interference in tunneling ionization has become one of the research hotspots in strong-field physics. We investigate the interference structure of an Ar atom in orthogonally polarized laser pulses by the quantum-trajectory Monte Carlo (QTMC) model. The results show the “inner spider” holographic interference structure and above-threshold ionization (ATI) ring interference structure in photoelectron momentum distributions (PMDs) of the Ar atom at Δ t = 0 . However, as the time delay increases, the interference structure gradually becomes distorted until it is completely destroyed. We find that the interference structure at the PMDs center can only be identified clearly when the time delay has three or fewer optical periods, which indicates that the stability and observability of the interference structure are closely related to the number of periods of the selected time delay. By tracing the trajectories of ionized electrons, we find that the quadrant of the final position of the ionized electron trajectory is consistent with the quadrant of the PMDs for this time window. Furthermore, we find that the inner spider structure disappears when the Coulomb potential is ignored, which is due to the Coulomb focusing effect by analyzing the emission angle of the ionized electrons.}, archive = {J_PRA}, author = {Ying Guo and Shu-Juan Yan and Cong-Cong Cheng and Xin-Yu Hao and Aihua Liu and Jing Guo}, doi = {10.1103/PhysRevA.111.053111}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053111}, shortjournal = {Phys. Rev. A}, title = {Interference structures of an ar atom by orthogonally polarized laser pulses}, volume = {111}, year = {2025}, }
• (2025). Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field. II. classical considerations. PRA, 111(5), 053110. (www)

  @article{ , abstract = {The saddle-point solutions for strong-laser-field-induced high-order above-threshold ionization, the complete classification of which was recently presented in Phys. Rev. A 111 , 023103 (2025) , are considered classically. In the limit of vanishing ionization potential the system of saddle-point equations simplifies, allowing a semi-analytical treatment. For a monochromatic field, the analytical nonlinear equations obtained this way allow one to determine the maximum (cutoff) photoelectron energies for the backward- and forward-scattering saddle-point solutions for all values of the multi-indices introduced by our classification scheme. These cutoffs are determined for all photoelectron momenta and it is shown how the backward-scattering solutions from one half of the momentum plane are related to the forward-scattering solutions from the other. The case of a bichromatic linearly polarized field is analyzed in detail. The results are rederived with the help of a simple graphical method, which can be used to qualitatively discuss the effect of varying the field parameters.}, archive = {J_PRA}, author = {D. Habibović and W. Becker and D. B. Milošević}, doi = {10.1103/PhysRevA.111.053110}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053110}, shortjournal = {Phys. Rev. A}, title = {Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field. II. classical considerations}, volume = {111}, year = {2025}, }
• (2025). Using the th iii ion for a nuclear clock and searches for new physics. PRA, 111(5), 053109. (www)

  @article{ , abstract = {The nucleus possesses a unique low-frequency transition at 8.4 eV, which is being considered for the development of an extremely accurate nuclear clock. We investigate an electronic bridge process in the Th iii ion, where nuclear excitation is mediated by electronic transitions, and show that selecting appropriate laser frequencies can enhance the nuclear excitation probability by up to times. Electrons also reduce 1.7 times the lifetime of the nuclear excited state. Moreover, the electronic structure of Th iii offers exceptional opportunities for probing new physics. Notably, the ion contains a metastable electronic state coupled to the ground state via a weak transition, which can be utilized for quantum information processing, as well as searches for oscillating dark matter axion and scalar fields, violation of local Lorentz invariance, test of the Einstein equivalence principle, and measurement of the nuclear weak quadrupole moment. Additionally, the electronic states of Th iii present a unique case of level crossing involving the , and single-electron states. This crossing renders high sensitivity of the transition frequencies to potential time variation of the fine-structure constant.}, archive = {J_PRA}, author = {V. A. Dzuba and V. V. Flambaum}, doi = {10.1103/PhysRevA.111.053109}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053109}, shortjournal = {Phys. Rev. A}, title = {Using the th iii ion for a nuclear clock and searches for new physics}, volume = {111}, year = {2025}, }
• (2025). Single and double photoionization of the li-like b2+ ion: Strong ionization-excitation contributions. PRA, 111(5), 053108. (www)

  @article{ , abstract = {Single and double photoionization of the Li-like ion were studied both experimentally and theoretically in the energy range from approximately 250–1200 eV. The cross section for net single ionization in that range is dominated by direct removal of one -shell electron, a process that is described very well by theory. Accordingly, measured yields of photoproducts were normalized to theory to obtain absolute cross sections . Aside from direct single ionization, there are additional contributions to from photoabsorption resonances. The parameters of the Fano profile of the most prominent of these resonances, the triply excited state, were calculated by employing the convergent close coupling (CCC) approach and the theoretical results were experimentally verified. Using the normalization procedure obtained from the investigation of single ionization, also the measured yields of product ions could be put on an absolute cross-section scale. The resulting experimental cross section is in good accord with the CCC calculations revealing unexpectedly strong contributions that arise from ionization with excitation of forming intermediate autoionizing levels, which subsequently decay to by Auger-electron emission. In addition, contributions to from resonant excitation of with could be identified. These triply excited resonances with an empty shell can decay by simultaneous or sequential emission of two electrons and thus contribute to net double photoionization of the parent ion.}, archive = {J_PRA}, author = {A. Müller and P.-M. Hillenbrand and S.-X. Wang and S. Schippers and S. Reinwardt and M. Martins and J. Seltmann and F. Trinter and I. Bray and D. V. Fursa and A. S. Kheifets}, doi = {10.1103/PhysRevA.111.053108}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053108}, shortjournal = {Phys. Rev. A}, title = {Single and double photoionization of the li-like b2+ ion: Strong ionization-excitation contributions}, volume = {111}, year = {2025}, }
• (2025). Relativistic configuration-interaction and coupled-cluster calculations of ir17+ transition energies and properties for optical clock applications. PRA, 111(5), 053107. (www)

  @article{ , abstract = {The transition energies and properties of the ion are calculated using the Kramers-restricted configuration-interaction (KRCI) and Fock-space coupled-cluster (FSCC) methods within the Dirac-Coulomb-Gaunt Hamiltonian framework. These calculations show several forbidden optical transitions between the ground state and the and excited states, underscoring their potential as candidates for optical clock applications. Additionally, key properties of the ground and low-lying excited states are reported, including Landé factors, lifetimes, electric dipole polarizabilities, electric quadrupole moments, hyperfine structure constants, relativistic sensitivities, Lorentz-invariance coefficient tensor, and isotope shifts. The excellent agreement between the results from the KRCI and FSCC methods demonstrates the robustness of the calculations and confirms the reliability of the proposed clock transitions.}, archive = {J_PRA}, author = {H. X. Liu and Y. M. Yu and B. B. Suo and Y. F. Ge and Y. Liu}, doi = {10.1103/PhysRevA.111.053107}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053107}, shortjournal = {Phys. Rev. A}, title = {Relativistic configuration-interaction and coupled-cluster calculations of ir17+ transition energies and properties for optical clock applications}, volume = {111}, year = {2025}, }
• (2025). Four-body coulomb explosion of HCl dimers in strong laser fields. PRA, 111(5), 053106. (www)

  @article{ , abstract = {We performed a four-body coincidence measurement involving , and fragments generated by strong field ionization of the HCl dimer. The energy correlation maps reveal the rapid explosion of two protons and the slow repulsion between two ions during the four-body fragmentation. Moreover, the kinetic energy of the fragments relative to the emission angles provides valuable insights into how the motion of the proton affects the energy distribution between ions. We also performed ab initio calculations to track the real-time movements of the four fragments. The simulations reveal the influence of fast-moving protons on the comparatively slow fragmentation process of ions. This comprehensive approach sheds light on the dynamics and offers valuable insights into the ultrafast fragmentation of molecular clusters.}, archive = {J_PRA}, author = {Xinning Zhao and Xinyu Zhang and Hui Liu and Pan Ma and Xiaokai Li and Chuncheng Wang and Sizuo Luo and Dajun Ding}, doi = {10.1103/PhysRevA.111.053106}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053106}, shortjournal = {Phys. Rev. A}, title = {Four-body coulomb explosion of HCl dimers in strong laser fields}, volume = {111}, year = {2025}, }
• (2025). Application of the uniform approximation to integrals occurring in ionization by a strong elliptically polarized laser field. PRA, 111(5), 053105. (www)

  @article{ , abstract = {Above-threshold detachment of electrons from negative ions by a strong low-frequency elliptically polarized laser field is considered using the strong-field approximation. The detachment probability amplitude is expressed via integral over times of highly oscillatory functions. Particular attention is devoted to application of the asymptotic methods to solve these integrals. For the direct detachment only the integral over the detachment time appears, while for the high-order above-threshold detachment the double integral over the detachment and rescattering times should be solved. Depending on the ellipticity of the laser field, a critical photoelectron energy exists for which the standard saddle-point method fails. The problem can be solved by properly deforming the integration contour in the complex time plane and, for energies higher than this critical energy, taking into account only one of the two saddle-point solutions. However, this procedure still leaves a spike in the photoelectron spectrum near this critical energy. This problem is cured applying the uniform approximation. A formula for the transition amplitude in the uniform approximation is derived, and it is shown how this formula should be modified for the energies higher than the critical one. For high-order above-threshold detachment many more saddle-point solutions contribute. They are classified into pairs. For the saddle-point method each pair produces a spike in the spectrum which spoils the total spectrum. When the contribution of each pair is treated using the uniform approximation with a careful choice of the phase factors after the anti-Stokes transition the agreement with the exact numerical results becomes excellent.}, archive = {J_PRA}, author = {D. B. Milošević}, doi = {10.1103/PhysRevA.111.053105}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053105}, shortjournal = {Phys. Rev. A}, title = {Application of the uniform approximation to integrals occurring in ionization by a strong elliptically polarized laser field}, volume = {111}, year = {2025}, }
• (2025). Fano resonance in the XUV generated by helium with few-cycle intense laser pulses and its classical analogy. PRA, 111(5), 053104. (www)

  @article{ , abstract = {We numerically integrate the Schrödinger equation for a model helium atom irradiated by an intense few-cycle laser pulse and find the emitted XUV spectra. They demonstrate resonant Fano peaks at the frequencies of the transitions from the doubly excited autoionizing states (AISs) to the ground state. Studying XUV intensity and phase, we show that the resonant peak should be described with an essentially complex asymmetry parameter. The Stark shift of the AIS and the decay of the AIS due to photoionization by the laser field result in the asymmetry parameter describing a spiral path in the complex plane when the laser pulse duration increases. This behavior, in particular, corresponds to the decrease of the resonant contribution with the increase of the laser pulse duration, in agreement with published experimental data. Moreover, we find a remarkable similarity of this behavior of the asymmetry parameter in the complex plane to that of the classical double pendulum. We conclude that transient perturbation of the natural frequency and friction in the upper pendulum can be treated as a classical analogy of the transient frequency shift and extra depopulation of the excited state in the quantum system demonstrating the Fano resonance.}, archive = {J_PRA}, author = {S. A. Bondarenko and V. V. Strelkov}, doi = {10.1103/PhysRevA.111.053104}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053104}, shortjournal = {Phys. Rev. A}, title = {Fano resonance in the XUV generated by helium with few-cycle intense laser pulses and its classical analogy}, volume = {111}, year = {2025}, }
• (2025). Pulsed dual-axis alkali-metal–noble-gas comagnetometer. PRA, 111(5), 053103. (www)

  @article{ , abstract = {Alkali-metal–noble-gas comagnetometers are precision probes well suited for tests of fundamental physics and inertial rotation sensing, combining the high sensitivity of the spin-exchange-relaxation-free magnetometers with inherent suppression of magnetic field noise. Past versions of the device utilizing continuous-wave optical pumping are sensitive to rotation and anomalous spin couplings along a single axis perpendicular to the plane spanned by the orthogonal pump and probe laser beams. These devices are susceptible to light shifts in the alkali atoms, and to power and beam pointing fluctuations of both the probe and pump lasers, the latter of which is a dominant source of noise. In this work, we model and implement an approach to alkali-metal–noble-gas comagnetometers using pulsed optical pumping. After each pump laser pulse, an off-resonance probe beam measures the precession of noble-gas-spins-coupled alkali spins via optical rotation in the dark, thus eliminating effects from pump laser light shift and power fluctuations. Performing nonlinear fitting on the sinusoidal transient signal with a proper phase enables independent and simultaneous measurement of signals along two orthogonal axes in the plane perpendicular to the pump beam. Effects from beam pointing fluctuations of the probe beam in the pump-probe plane are fundamentally eliminated, and signal response to pump beam pointing fluctuations is suppressed by compensation from noble-gas nuclear spins.}, archive = {J_PRA}, author = {J. Wang and J. Lee and H. Loughlin and M. Hedges and M. V. Romalis}, doi = {10.1103/PhysRevA.111.053103}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053103}, shortjournal = {Phys. Rev. A}, title = {Pulsed dual-axis alkali-metal–noble-gas comagnetometer}, volume = {111}, year = {2025}, }
• (2025). Probing ultrafast nuclear dynamics in dissociative double ionization of h2 and d2 using a multicycle elliptically polarized femtosecond laser pulse. PRA, 111(5), 053102. (www)

  @article{ , abstract = {Ultrafast nuclear dynamics in laser-induced dissociative double ionization of is challenging to investigate with a multicycle elliptically polarized femtosecond laser pulse due to the difficulty of distinguishing electrons released in neighboring optical cycles. In this study we experimentally reveal these dynamics by employing the same laser technique and overcoming this limitation through comparison with the isotopic counterpart of . By analyzing the internuclear-distance-dependent sum momentum of the ionic fragments, we reconstruct the time-dependent nuclear motions with subcycle temporal resolution. Furthermore, we observe a decrease in the momentum magnitude of the second released electron with increasing internuclear distance, attributed to the combined effects of the instantaneous laser field strength and the Coulomb attraction of the molecular ion at the moment of ionization. Our findings highlight the critical role of isotope effects in elucidating ultrafast nuclear dynamics in laser-induced molecular fragmentation.}, archive = {J_PRA}, author = {Junyang Ma and Shuqi Li and Fan Yang and Yan Yang and Zhenrong Sun}, doi = {10.1103/PhysRevA.111.053102}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053102}, shortjournal = {Phys. Rev. A}, title = {Probing ultrafast nuclear dynamics in dissociative double ionization of h2 and d2 using a multicycle elliptically polarized femtosecond laser pulse}, volume = {111}, year = {2025}, }
• (2025). Frequency shift induced by multielectron polarization in high-order harmonic generation from polar molecules. PRA, 111(5), 053101. (www)

  @article{ , abstract = {Multielectron polarization (MEP) has been identified as an essential factor that must be considered for understanding nonlinear effects resulting from interactions of intense lasers with highly polarizable targets. While recent studies have mostly focused on intensity modulation induced by MEP in high-order harmonic generation (HHG), this work explores a significant MEP effect on another critical HHG feature: harmonic frequency. In particular, we discover MEP-induced frequency shifts up to 0.8 order (1.24 eV) for harmonics in the cutoff region when a polar molecule CO interacts with a few-cycle laser pulse. These frequency shifts are clarified through their relationship with the MEP-induced phase changes of attosecond bursts and then validated numerically by solving the time-dependent Schrödinger equation. Moreover, we also verify them with available experimental data. Furthermore, we demonstrate the universality of these frequency shifts regardless of varying laser parameters. Importantly, we find a close connection between the MEP-induced harmonic frequency shift discovered in this study and MEP-induced intensity modulation of odd-even HHG reported previously. We claim that they are the two manifestations of the MEP effect on HHG, both stemming from the distortion of the phase difference between the two adjacent attosecond bursts. This comprehensive understanding of the MEP effect on HHG from polar molecules is significant for characterizing intrinsic molecular properties and probing molecular dynamics from HHG.}, archive = {J_PRA}, author = {Kim-Ngan H. Nguyen and Doan-An Trieu and Cam-Tu Le and Van-Hoang Le and Ngoc-Loan Phan}, doi = {10.1103/PhysRevA.111.053101}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {053101}, shortjournal = {Phys. Rev. A}, title = {Frequency shift induced by multielectron polarization in high-order harmonic generation from polar molecules}, volume = {111}, year = {2025}, }
• (2025). Dissociative positronium attachment in halogen gases. PRA, 111(5), 052817. (www)

  @article{ , abstract = {We suggest that the observed large annihilation rates of ortho-positronium ( -Ps) in halogen gases are due to the process of dissociative Ps attachment , where stands for a halogen atom. This process is similar to dissociative electron attachment which leads to formation of negative ions. We calculate the cross section and rate of this process for the molecule, for which it is exothermic and therefore can occur at room temperature. We start with the Ps- scattering calculations which take into account electron exchange and correlations within the framework of the free-electron-gas model. The calculations reveal several resonances. Similar to the process of dissociative electron attachment, a resonance contributes to the dissociative Ps attachment at thermal energies. We determine the resonance position and width as functions of the internuclear separation and use them as inputs for the local version of the quasiclassical theory of dissociative attachment. Our calculations yield an anomalously large rate constant for the -Ps annihilation process which is only one order of magnitude lower than those observed for and .}, archive = {J_PRA}, author = {R. S. Wilde and G. F. Gribakin and I. I. Fabrikant}, doi = {10.1103/PhysRevA.111.052817}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052817}, shortjournal = {Phys. Rev. A}, title = {Dissociative positronium attachment in halogen gases}, volume = {111}, year = {2025}, }
• (2025). Testing reachability of the plane-wave impulse approximation in terms of the ratio of spectroscopic factors for (e, 2e) ionization of ne 2s and 2p electrons. PRA, 111(5), 052816. (www)

  @article{ , abstract = {We have tested the reachability of the plane-wave impulse approximation (PWIA) in terms of the ratio of spectroscopic factors for ionization of the Ne and main ionization transitions at large momentum transfer. Experimentally, the ratio was measured, as a function of the ion recoil momentum, in the symmetric noncoplanar geometry and at incident electron energies of , 2.0, 3.0, and 4.0 keV. The accuracy of the PWIA was examined by comparing with a spectroscopic factor ratio predicted by a theoretical electronic structure study as well as those by the distorted-wave Born approximation (DWBA) model and the two Coulomb waves with variable charge (2CWZ) model in which the exchange interaction is not included but the two outgoing electrons are both described by a Coulomb wave with . The DWBA result has been found to be in good agreement with the experiment and the theoretical prediction regarding the spectroscopic factor ratio over the covered range. On the other hand, it has been found that the PWIA and 2CWZ results both reveal almost the same, but an unacceptable, deviation from the theoretical prediction. Furthermore, the deviation has been found to become smaller with the increase in . These observations clearly not only indicate the need of improvement of the PWIA model, but also state that the spectroscopic factor ratio is suited for stringently testing a theoretical scattering model for the reaction at large momentum transfer.}, archive = {J_PRA}, author = {Isao Nakajima and Masakazu Yamazaki and Yuri V. Popov and Salim Houamer and Masahiko Takahashi}, doi = {10.1103/PhysRevA.111.052816}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052816}, shortjournal = {Phys. Rev. A}, title = {Testing reachability of the plane-wave impulse approximation in terms of the ratio of spectroscopic factors for (e, 2e) ionization of ne 2s and 2p electrons}, volume = {111}, year = {2025}, }
• (2025). Electron spin polarization around magnetic nodes under the chirped rotating electric field. PRA, 111(5), 052815. (www)

  @article{ , abstract = {Electron spin polarization in an intense laser field presents a promising avenue for generating highly polarized high-energy electron sources. In this study, we investigate numerically the spin polarization dynamics of an electron in a rotating laser field with a frequency chirp. We consider a standing wave formed by two counterpropagating chirped laser pulses, which have different chirp modes: linear and time-reversed chirp. Our results reveal that the frequency chirp breaks the time symmetry of the field, thereby altering the laser-electron interaction dynamics. Consequently, an electron can gain more net energy from a chirped laser field through optimal phase synchronization between the electron and the laser field. This results in a higher electron quantum parameter and an increased photon emission probability. As a result, the probability of spin flip for an electron during radiation in the magnetic node plane is enhanced, leading to improved electron polarization efficiency. We also find that the polarization degree is highly sensitive to the chirp parameter, and we identify an optimal chirp value that maximizes the polarization degree. By applying this optimal chirp parameter in the time-reversed chirped case, the electron's relative polarization can be enhanced by and reach its maximum value of approximately .}, archive = {J_PRA}, author = {Jinhui Bai and Zhaoyuan Chen and Orkash Amat and Mamat Ali Bake}, doi = {10.1103/PhysRevA.111.052815}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052815}, shortjournal = {Phys. Rev. A}, title = {Electron spin polarization around magnetic nodes under the chirped rotating electric field}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal and nonconservative forces on binary systems of identical atoms. PRA, 111(5), 052814. (www)

  @article{ , abstract = {The dynamical and radiative features of an excited system of two identical atoms are analyzed. The metastability of the system, the directionality of its emission, and its internal forces are studied. Closed-form expressions are derived for the time propagator of the system, for the angular distribution of its spontaneous emission, and for its internal dipole forces, both conservative and nonconservative. The latter reveals the presence of nonreciprocal forces, which leads to a net time-dependent force upon the system. We estimate that, for a free binary system of Li Rydberg atoms, the net internal force may cause a displacement of its center of mass as large as 120 nm over a lifetime.}, archive = {J_PRA}, author = {J. Sánchez-Cánovas and M. Donaire}, doi = {10.1103/PhysRevA.111.052814}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052814}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal and nonconservative forces on binary systems of identical atoms}, volume = {111}, year = {2025}, }
• (2025). Precision study of structural and elastic electron scattering properties of muonic helium systems. PRA, 111(5), 052813. (www)

  @article{ , abstract = {In this study, we investigate the structural properties of the three-body system and the four-body system using explicitly correlated Gaussian basis functions with global vectors. Our results quantitatively demonstrate the pronounced shielding effect of the muon on the nucleus and reveal structural characteristics of and , analogous to those of H and , respectively. Using the confined variational method, we examine -wave electron scattering from at incident energies below 8.7 eV, considering both and symmetries of the two electrons. By fitting near-threshold phase shifts to the modified effective range theory, we determine the scattering lengths to be 5.95 for symmetry and 1.76 for symmetry. Finally, we explore the distortion effects on induced by electron impact.}, archive = {J_PRA}, author = {K. Hu and K.-D. Wang and D.-X. Zhao and M.-S. Wu and J.-Y. Zhang and Z.-C. Yan and K. Varga}, doi = {10.1103/PhysRevA.111.052813}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052813}, shortjournal = {Phys. Rev. A}, title = {Precision study of structural and elastic electron scattering properties of muonic helium systems}, volume = {111}, year = {2025}, }
• (2025). Quasi-sturmian basis set for problems of single ionization of helium by proton impact with rearrangement. PRA, 111(5), 052812. (www)

  @article{ , abstract = {The parabolic convoluted quasi-Sturmian (CQS) approach recently proposed by Zaytsev et al. [ Phys. Rev. A 105 , 062818 (2022) ] to study differential ionization of atomic helium under proton impact is extended to take account of electron capture into the continuum (ECC). In our fully quantum approach, the original four-body proton-helium scattering problem is reduced to finding the continuum state of the Coulomb three-body system ; this is accomplished by representing the required wave function in a basis of CQS functions whose asymptotic behavior corresponds to the ionization dynamics. Contrary to the original CQS approach that uses a basis set suitable for describing the two subsystems and , an appropriate set of Jacobi coordinates allows us to construct CQS functions corresponding to the continuous spectrum of the pair . The extraction of the ionization amplitude from the three-body wave function maintains a closed form character. The extension of the model space by including new basis functions makes it possible to adequately describe the ECC ionization mechanism. Calculations using these CQS functions are presented for 75-keV proton-impact ionization of atomic helium, and for ejected electrons with a velocity far from that of the projectile. Comparison is made with fully differential cross sections (FDCS), measured recently on an absolute scale [Majumdar et al. , Phys. Rev. A 110 , 032814 (2024) ], that show clear signatures of postcollision interactions. The overall agreement between theory and experiment is encouraging. The remaining discrepancies suggest the need to use a combined basis for the correct accounting of the direct ionization channel.}, archive = {J_PRA}, author = {S. A. Zaytsev and D. S. Zaytseva and A. S. Zaytsev and L. U. Ancarani and K. A. Kouzakov and Yu. V. Popov}, doi = {10.1103/PhysRevA.111.052812}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052812}, shortjournal = {Phys. Rev. A}, title = {Quasi-sturmian basis set for problems of single ionization of helium by proton impact with rearrangement}, volume = {111}, year = {2025}, }
• (2025). Anomalies in the rotational spectra of sr86 ultralong-range rydberg molecule dimers. PRA, 111(5), 052811. (www)

  @article{ , abstract = {Anomalies in the rotational structure of dimer ultralong-range Rydberg molecules created in a cold strontium gas by two-photon excitation via the intermediate state are reported. Measurements reveal that the distribution of product rotational states is sensitive to intermediate state detuning. Comparative studies using and , and dimers display no similar behavior, indicating that the observed behavior is peculiar to triplet dimers. While we have no definitive hypothesis as to the physical mechanism responsible for this behavior, possible explanations might involve the very different scattering lengths for and , or the interchange of spin and rotational angular momentum.}, archive = {J_PRA}, author = {C. Wang and Y. Lu and A. Li and S. K. Kanungo and T. C. Killian and F. B. Dunning and S. Yoshida}, doi = {10.1103/PhysRevA.111.052811}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052811}, shortjournal = {Phys. Rev. A}, title = {Anomalies in the rotational spectra of sr86 ultralong-range rydberg molecule dimers}, volume = {111}, year = {2025}, }
• (2025). Influence of the vortex-electron spatial distribution on atomic scattering. PRA, 111(5), 052810. (www)

  @article{ , abstract = {We explore the elastic scattering of nonrelativistic electrons in the form of Bessel-Gaussian (BG), standard Laguerre-Gaussian (sLG), and elegant Laguerre-Gaussian (eLG) packets on atomic targets in the generalized Born approximation. Scattering by hydrogenlike, iron, silver, and golden targets is considered. The incident electron carries a nonzero orbital angular momentum, while sLG and eLG packets have a definite radial quantum number as well. In the scattering of sLG and eLG wave packets by a macroscopic target, sensitivity of the average cross section to the orbital angular momentum is observed, which is absent for BG packets. We discuss the potential experimental realization of vortex-electron wave packets of these three types. The distinguishing features in the scattering results can be employed for imaging purposes and revelation of the packet properties in experiments.}, archive = {J_PRA}, author = {N. Sheremet and A. Chaikovskaia and D. Grosman and D. Karlovets}, doi = {10.1103/PhysRevA.111.052810}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052810}, shortjournal = {Phys. Rev. A}, title = {Influence of the vortex-electron spatial distribution on atomic scattering}, volume = {111}, year = {2025}, }
• (2025). Frequency measurement of the 2 s13–8 d13 two-photon transition in atomic he4. PRA, 111(5), 052809. (www)

  @article{ , abstract = {We present the precise frequency measurement of the two-photon transition in at 544 nm. The 544-nm light is generated by second-harmonic generation with a power-amplified 1088 nm external cavity diode laser (ECDL). To determine the absolute frequency of the transition, the ECDL is stabilized to an optical frequency comb. The absolute frequency of transition is experimentally determined to be 1 101 410 219.422(54) MHz with a fractional uncertainty of . By combining our measured transition frequency with the theoretically calculated ionization energy of the state [Yerokhin et al. , Phys. Rev. A 102 , 012807 (2020) and G. Drake, Springer Handbook of Atomic, Molecular, and Optical Physics (Springer Nature, New York, 2023)] we determine the ionization energy of the state to be 1 152 842 742.652(54) MHz. The Lamb shift is then deduced to be 4057.403(54) MHz according to the theoretical calculation  [Patkóš et al. , Phys. Rev. A 103 , 042809 (2021) ]. We compare our experimental result with previous measurements and find excellent agreement [Dorrer et al. , Phys. Rev. Lett. 78 , 3658 (1997) ; Luo et al. , Phys. Rev. A 94 , 062507 (2016) ; Zheng et al. , Phys. Rev. Lett. 119 , 263002 (2017) ; Zheng et al. , Phys. Rev. A 99 , 032506 (2019) ; Huang et al. , Phys. Rev. A 97 , 032516 (2018) ; Pastor et al. , Phys. Rev. Lett. 92 , 023001 (2004) ; Phys. Rev. Lett. 97 , 139903(E) (2006) ; Rengelink et al. , Nat. Phys. 14 , 1132 (2018) ; Clausen et al. , Phys. Rev. Lett. 127 , 093001 (2021) ; Clausen et al. , Phys. Rev. A 111 , 012817 (2025) ]. A discrepancies of approximately 0.4 MHz remains between the theoretical predictions and the experimental results for the state.}, archive = {J_PRA}, author = {Mu-Hao Wu and Li-Bang Wang}, doi = {10.1103/PhysRevA.111.052809}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052809}, shortjournal = {Phys. Rev. A}, title = {Frequency measurement of the 2 s13–8 d13 two-photon transition in atomic he4}, volume = {111}, year = {2025}, }
• (2025). Collision parameters needed to measure polarization-dependent nonlinear pair creation. PRA, 111(5), 052808. (www)

  @article{ , abstract = {Pair creation by a ray in a high-intensity electromagnetic field (the nonlinear Breit-Wheeler process) is sensitive to the -ray polarization. Here we study the stability required in order to measure this polarization dependence in a head-on collision between a high-power linearly polarized laser and a relativistic electron beam, where the rays produced via nonlinear Compton scattering are highly polarized. We find that the laser strength parameter has to be known to within a few percent and that the alignment of the laser and electron beam cannot fluctuate by more than half the spot size in order to attribute the reduction in positron yield to polarization effects. These collision parameters are difficult to achieve, but may be realized in future precision experiments that focus on beam stability.}, archive = {J_PRA}, author = {Mathias Samuelsson and Thomas G. Blackburn}, doi = {10.1103/PhysRevA.111.052808}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052808}, shortjournal = {Phys. Rev. A}, title = {Collision parameters needed to measure polarization-dependent nonlinear pair creation}, volume = {111}, year = {2025}, }
• (2025). Nonlinear spin dynamics induced by feedback under continuous larmor frequency distributions. PRA, 111(5), 052807. (www)

  @article{ , abstract = {Nonlinear spin dynamics are essential in exploring nonequilibrium quantum phenomena and have broad applications in precision measurement. Among these systems, the combination of a bias magnetic field and feedback mechanisms can induce self-sustained oscillations at the base Larmor frequency due to nonlinearity. These features have driven the development of single-species and multiple-species spin masers. The latter, with multiple discrete Larmor frequencies, provides significant advantages for precision measurement by mitigating uncertainties in precession frequencies due to long-term drifts in experimental conditions. The self-sustained oscillations of single-species and multiple-species spin masers correspond to limit cycles and quasi-periodic orbits of the stable nonlinear dynamics of the systems, respectively; the correspondence is elucidated in a recent study on a related spin system featuring two discrete intrinsic Larmor frequencies under dual bias magnetic fields [T. Wang et al. , Commun. Phys. 8 , 41 (2025) ]. Here, we extend the study to the case where the intrinsic Larmor frequencies of individual spins of the system, given rise to by an inhomogeneous bias magnetic field, form a continuum. We show that generically the stable dynamics of the system includes limit cycles, quasi-periodic orbits, and chaos. We establish the relation between the synchronization frequency of limit cycles and the field inhomogeneity and derive an equation determining the stability of limit cycles. Furthermore, detailed characteristics of different dynamical phases, especially the robustness of limit cycles and quasi-periodic orbits against experimental fluctuations, are discussed. Our findings not only encompass the case of discrete Larmor frequencies, but also provide crucial insights for precision measurement and the exploration of continuous time crystals and quasi-crystals.}, archive = {J_PRA}, author = {Tishuo Wang and Zhihuang Luo and Shizhong Zhang and Zhenhua Yu}, doi = {10.1103/PhysRevA.111.052807}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052807}, shortjournal = {Phys. Rev. A}, title = {Nonlinear spin dynamics induced by feedback under continuous larmor frequency distributions}, volume = {111}, year = {2025}, }
• (2025). Target excitation and ionization in p¯+He(11S,23S) collisions. PRA, 111(5), 052806. (www)

  @article{ , abstract = {Atomic excitation and ionization in antiproton collisions with the helium atom initially in the singlet and triplet states are considered. This is done by employing an implementation of the convergent close-coupling approach to ion-atom collisions using the Coulomb-Sturmian functions. We demonstrate that the unified treatment of excitation and ionization proposed in our previous work [ Phys. Rev. A 110 , 032810 (2024) ] can be applied to targets with more than one electron. This allows us to obtain state-resolved excitation cross sections up to arbitrarily high bound energy levels, including the high-lying Rydberg states, and the singly differential ionization cross section in the entire electron energy range including at and arbitrarily close to the threshold. A comprehensive set of results for the elastic, ionization, and excitation cross sections in both initial configurations of the target is presented. The cross-section data for antiproton collisions with triplet-state helium, previously unavailable, are now determined.}, archive = {J_PRA}, author = {N. W. Antonio and A. S. Kadyrov}, doi = {10.1103/PhysRevA.111.052806}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052806}, shortjournal = {Phys. Rev. A}, title = {Target excitation and ionization in p¯+He(11S,23S) collisions}, volume = {111}, year = {2025}, }
• (2025). Relaxation effects in the photoionization time delay near the 3s cooper minimum of ar. PRA, 111(5), 052805. (www)

  @article{ , abstract = {The discrepancy in the attosecond time delay between theory and experiment near the Cooper minimum (CM) of Ar is addressed. It is found that inclusion of the relaxation effects in the time delay difference between Ar and photoionization near the CM dramatically alters the time delay and brings the theory into substantial agreement with experiment using the relativistic-random-phase approximation with relaxation. The key point is that photoionization is dominated by interchannel coupling in this region and the interchannel coupling matrix elements were found to be considerably altered by the inclusion of relaxation. This implies that relaxation should be important for any atomic or molecular transition that is dominated by interchannel coupling.}, archive = {J_PRA}, author = {A. Ganesan and S. Banerjee and S. Baral and J. Jose and P. C. Deshmukh and S. T. Manson}, doi = {10.1103/PhysRevA.111.052805}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052805}, shortjournal = {Phys. Rev. A}, title = {Relaxation effects in the photoionization time delay near the 3s cooper minimum of ar}, volume = {111}, year = {2025}, }
• (2025). Use of single-body potentials to accurately describe virtual positronium formation in positron collisions. PRA, 111(5), 052804. (www)

  @article{ , abstract = {We present a single-body adiabatic potential to investigate the role of virtual positronium (Ps) formation in positron scattering with atoms at energies below the Ps formation threshold. Our model is applied to positron scattering by hydrogen and noble-gas atoms. The potential is decomposed into two components: the correlation-polarization (CP) potential, derived from perturbation theory for the positron-hydrogen system and generalized for other atoms, and the virtual positronium (VPs) potential. The VPs potential is modeled as a short-ranged attractive term based on the CP component but shifted toward the atom's vicinity, with its strength controlled by a semiempirical parameter fine tuned to match the scattering length to reference values. Our results show that the inclusion of the VPs term is essential for reproducing experimental measurements and results from other theoretical models for both integrated and differential cross sections.}, archive = {J_PRA}, author = {Eliton Popovicz Seidel and Jan Franz and Wagner Tenfen and Felipe Arretche}, doi = {10.1103/PhysRevA.111.052804}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052804}, shortjournal = {Phys. Rev. A}, title = {Use of single-body potentials to accurately describe virtual positronium formation in positron collisions}, volume = {111}, year = {2025}, }
• (2025). Predicting accurate x-ray absorption spectra for interstellar molecules CN+, CN, and CN−: Insights from ab initio simulations. PRA, 111(5), 052803. (www)

  @article{ , abstract = {High-resolution x-ray spectroscopy is an essential tool in high-energy astrophysics, astrochemistry, and x-ray astronomy, enabling detailed studies of celestial objects and their physical and chemical properties. However, comprehensive mapping of high-resolution x-ray spectra for even simple interstellar and circumstellar molecules is still lacking. In this study, we conduct systematic quantum chemical simulations to predict the x-ray-absorption spectra of , CN, and . Our findings provide valuable references for both x-ray astronomy and laboratory studies. We assign the first electronic peak of and CN to transitions, while the peak for corresponds to a transition. We explain that the twofold degeneracy ( and ) of the transitions results in exhibiting a significantly stronger first absorption compared to the other two systems. We further calculate the vibronic fine structures for these transitions using the quantum wave-packet method based on multiconfigurational-level, anharmonic potential-energy curves, revealing distinct energy positions for the 0–0 absorptions at 280.7, 279.6, and 285.8 eV. Each vibronic profile features a prominent 0–0 peak, showing overall similarity but differing intensity ratios of the 0–0 and 0–1 peaks. Notably, introducing a core hole leads to shortened C-N bond lengths and increased vibrational frequencies across all species. These findings enhance our understanding of the electronic structures and x-ray spectra of carbon-nitrogen species, emphasizing the influence of charge state on x-ray absorptions.}, archive = {J_PRA}, author = {Jinyu Li and Sheng-Yu Wang and Lu Zhang and Guoyan Ge and Minrui Wei and Junxiang Zuo and Weijie Hua}, doi = {10.1103/PhysRevA.111.052803}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052803}, shortjournal = {Phys. Rev. A}, title = {Predicting accurate x-ray absorption spectra for interstellar molecules CN+, CN, and CN−: Insights from ab initio simulations}, volume = {111}, year = {2025}, }
• (2025). Mα- and mβ-satellite x-ray emission induced by electron impact on rhenium. PRA, 111(5), 052802. (www)

  @article{ , abstract = {Detailed expressions for satellite intensities have been carefully developed, taking into account Coster-Kronig single and double spectator hole states, and shake-up and shake-off events. The energies corresponding to satellite emissions originating from vacancies can be classified according to their shift from the and parent peaks; for the specific example of rhenium, this approach enabled to analyze the intensity ratio associated with each energy region. These satellite emission energies and intensity ratios are also obtained experimentally for rhenium, after a parameter optimization routine developed previously, applied to a set of x-ray spectra induced by electron irradiation on a solid target, and acquired by means of a wavelength-dispersive spectrometer. These experimental data are compared to those assessed from the analytical expressions derived.}, archive = {J_PRA}, author = {Alejo Carreras and Gustavo Castellano and Jorge Trincavelli and Silvina Segui and María del Rosario Torres Deluigi and Silvina Limandri}, doi = {10.1103/PhysRevA.111.052802}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052802}, shortjournal = {Phys. Rev. A}, title = {Mα- and mβ-satellite x-ray emission induced by electron impact on rhenium}, volume = {111}, year = {2025}, }
• (2025). Z dependence of 4f−5s electric-octupole emission in ag-like ions. PRA, 111(5), 052801. (www)

  @article{ , abstract = {We present spectral measurements performed to identify the highly- forbidden electric-octupole transitions in Ag-like highly charged ions and to study the dependence of their intensities. Theoretical predictions indicate that these transitions can be observed in a narrow range of elements around tungsten , as the strong configuration interaction leads to level crossings and to an increased population of the level. Here we probe the atomic structure and population dynamics in Ag-like ions using extreme-ultraviolet spectral measurements in several elements (Yb, Lu, W, Re, Os, Ir, Au) in the range to 79. The spectra were recorded independently in the compact electron-beam ion trap at the National Institute for Fusion Science and in the electron-beam ion trap at the National Institute of Standards and Technology. The measured wavelengths and the advanced theoretical calculations confirm observations of the transitions in Ag-like ions in the predicted narrow element range.}, archive = {J_PRA}, author = {H. A. Sakaue and E. Takacs and Dipti and D. Kato and N. Nakamura and H. Staiger and J. N. Tan and I. Murakami and H. Ohashi and Yu. Ralchenko}, doi = {10.1103/PhysRevA.111.052801}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052801}, shortjournal = {Phys. Rev. A}, title = {Z dependence of 4f−5s electric-octupole emission in ag-like ions}, volume = {111}, year = {2025}, }
• (2025). Detecting errors in a quantum network with pauli checks. PRA, 111(5), 052629. (www)

  @article{ , abstract = {We apply the quantum error detection scheme Pauli check sandwiching (PCS) to quantum networks by turning it into a distributed multiparty protocol. PCS provides protection on the targeted qubits and generally requires less resource overhead than standard quantum error correction and detection codes. We provide analytical equations for the final fidelity and postselection rate for different PCS checks. We also introduce a recursive version of PCS that generates a family of distance 2 quantum codes that are locally equivalent to Calderbank–Shor–Steane (CSS) codes. Our analytical results are benchmarked against the Bennet-Brassard–Popescu–Schumacher–Smolin–Wooters (BBPSSW) protocol in comparable scenarios. We also perform simulations with noisy gates for entanglement swapping and attain fidelity improvements. Lastly, we discuss various setups and graph state properties of PCS.}, archive = {J_PRA}, author = {Alvin Gonzales and Daniel Dilley and Bikun Li and Liang Jiang and Zain H. Saleem}, doi = {10.1103/PhysRevA.111.052629}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052629}, shortjournal = {Phys. Rev. A}, title = {Detecting errors in a quantum network with pauli checks}, volume = {111}, year = {2025}, }
• (2025). Efficient large-scale quantum optimization via counterdiabatic ansatz. PRA, 111(5), 052628. (www)

  @article{ , abstract = {Quantum approximate optimization algorithm (QAOA) is one of the fundamental variational quantum algorithms, while a version of QAOA that includes counterdiabatic driving, termed digitized counterdiabatic QAOA (DC-QAOA), is generally considered to outperform QAOA for all system sizes when the circuit depth for the two algorithms are held equal. Nevertheless, DC-QAOA introduces more cnot gates per layer, so the overall circuit complexity is a tradeoff between the number of cnot gates per layer and the circuit depth and must be carefully assessed. In this paper, we conduct a comprehensive comparison of DC-QAOA and QAOA on maxcut problem with the total number of cnot gates held equal, and we focus on one implementation of counterdiabatic terms using nested commutators in DC-QAOA, termed as DC-QAOA(NC). We have found that DC-QAOA(NC) reduces the overall circuit complexity as compared to QAOA only for sufficiently large problems, and for maxcut problem the number of qubits must exceed 16 for DC-QAOA(NC) to outperform QAOA. Additionally, we benchmark DC-QAOA(NC) against QAOA on the Sherrington-Kirkpatrick model under realistic noise conditions, finding that DC-QAOA(NC) exhibits significantly improved robustness compared to QAOA, maintaining higher fidelity as the problem size scales. Notably, in a direct comparison between one-layer DC-QAOA(NC) and three-layer QAOA where both use the same number of cnot gates, we identify an exponential performance advantage for DC-QAOA(NC), further signifying its suitability for large-scale quantum optimization tasks. We have further shown that this advantage can be understood from the effective dimensions introduced by the counterdiabatic driving terms. Moreover, based on our finding that the optimal parameters generated by DC-QAOA(NC) strongly concentrate in the parameter space, we have devised an instance-sequential training method for DC-QAOA(NC) circuits, which, compared to traditional methods, offers performance improvement while using even fewer quantum resources. Our findings provide a more comprehensive understanding of the advantages of DC-QAOA circuits and an efficient training method based on their generalizability.}, archive = {J_PRA}, author = {Jie Liu and Xin Wang}, doi = {10.1103/PhysRevA.111.052628}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052628}, shortjournal = {Phys. Rev. A}, title = {Efficient large-scale quantum optimization via counterdiabatic ansatz}, volume = {111}, year = {2025}, }
• (2025). Quantum logic for state preparation, readout, and leakage detection with binary subspace measurements. PRA, 111(5), 052627. (www)

  @article{ , abstract = {We discuss a quantum logic spectroscopy technique that uses the geometric phase gate interaction to implement quantum nondemolition (QND) measurements, distinguishing between two subspaces within a hyperfine manifold of a trapped ion. We then discuss how to use these binary subspace measurements for efficient, high-fidelity state preparation and measurement (SPAM) as well as nondestructive leakage detection. We show how to use (classical) error-correction methods to suppress SPAM error, at least to the extent the binary subspace measurements maintain QND purity. Suppressing SPAM error through redundant operations, rather than precise field engineering, could reduce some of the engineering complexity associated with building larger trapped-ion quantum computers.}, archive = {J_PRA}, author = {R. Tyler Sutherland}, doi = {10.1103/PhysRevA.111.052627}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052627}, shortjournal = {Phys. Rev. A}, title = {Quantum logic for state preparation, readout, and leakage detection with binary subspace measurements}, volume = {111}, year = {2025}, }
• (2025). Fidelity-enhanced variational quantum optimal control. PRA, 111(5), 052625. (www)

  @article{ , abstract = {Creating robust quantum operations is a major challenge in the current noisy intermediate-scale quantum computing era. Recently, the importance of noise-resilient control methods has become more pronounced in the field. Ordinarily, noisy quantum systems are described by the Lindblad equation. However, minimizing noise susceptibility using this equation has proven challenging because of its irreversibility. In this study, we propose a method for creating robust pulses based on the stochastic Schrödinger equation. This equation describes individual noise realizations under any colored noise process, contrary to the Lindblad equation, which describes mean system behavior under white noise. Using stochastic optimal control techniques, our method, fidelity-enhanced variational quantum optimal control, is able to construct higher-fidelity paths than its nonstochastic counterpart. By accounting for both environmental noise sources as well as noise sources inherent to the control system, highly significant increases in fidelity are noted for both single- and multiple-qubit state preparations.}, archive = {J_PRA}, author = {R. J. P. T. de Keijzer and L. Y. Visser and O. Tse and S. J. J. M. F. Kokkelmans}, doi = {10.1103/PhysRevA.111.052625}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052625}, shortjournal = {Phys. Rev. A}, title = {Fidelity-enhanced variational quantum optimal control}, volume = {111}, year = {2025}, }
• (2025). Graph state fission. PRA, 111(5), 052624. (www)

  @article{ , abstract = {Graph states are a fundamental entanglement resource for multipartite quantum applications which are in general challenging to transform efficiently. While fusion operations for merging entangled states are well developed, no direct protocol exists for the reverse process, which we term “fission.” We introduce a simple, yet powerful, protocol that achieves this, allowing a qubit to split while preserving selective connections with minimum entanglement overhead. This tool offers flexible entanglement management with potential applications in secure communication, error correction, and adaptive entanglement distribution.}, archive = {J_PRA}, author = {Jorge Miguel-Ramiro and Wolfgang Dür}, doi = {10.1103/PhysRevA.111.052624}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052624}, shortjournal = {Phys. Rev. A}, title = {Graph state fission}, volume = {111}, year = {2025}, }
• (2025). Low-temperature quantum metrology enhanced by strong coupling. PRA, 111(5), 052623. (www)

  @article{ , abstract = {Equilibrium probes have been widely used in various noisy quantum metrology schemes. However, such an equilibrium-probe-based metrology scenario severely suffers from the low-temperature-error-divergence problem in the weak-coupling regime. To circumvent this limit, we propose a strategy to eliminate the error-divergence problem by utilizing the strong-coupling effects, which can be captured by the reaction-coordinate mapping. The strong couplings induce a noncanonical equilibrium state which greatly enhances the metrology performance. It is found that our metrology precision behaves as a polynomial-type scaling relation, which suggests the reduction of temperature can be used as a resource to improve the metrology performance. Our result is sharply contrary to that of the weak-coupling case, in which the metrology precision exponentially decays as the temperature decreases. Paving a way to realize a high-precision noisy quantum metrology at low temperatures, our result reveals the importance of the non-Markovianity in quantum technologies.}, archive = {J_PRA}, author = {Ze-Zhou Zhang and Hong-Gang Luo and Wei Wu}, doi = {10.1103/PhysRevA.111.052623}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052623}, shortjournal = {Phys. Rev. A}, title = {Low-temperature quantum metrology enhanced by strong coupling}, volume = {111}, year = {2025}, }
• (2025). Continuous dynamical decoupling in non-hermitian two-level systems. PRA, 111(5), 052622. (www)

  @article{ , abstract = {Dynamical decoupling is an effective approach to suppress noise-induced decoherence for the implementation of quantum information processing and quantum technologies. However, current studies of dynamical decoupling mainly focus on Hermitian systems. In this paper, we propose a new approach to implement continuous dynamical decoupling in non-Hermitian two-level systems. For parity-time ( )-symmetric non-Hermitian Hamiltonians, since the dynamics of the system can be transformed into an effective Hermitian case using the vielbein formalism, we theoretically prove and numerically verify that the constructed driving field succeeds in suppressing the noises. We also demonstrate that this method can be extended to systems without symmetries. Our work is beneficial for further studies and applications of dynamic decoupling and non-Hermitian physics in noisy quantum systems.}, archive = {J_PRA}, author = {Yu-bing Yao and Xiang-Fa Zhou and Zheng-Wei Zhou and Xing-Xiang Zhou}, doi = {10.1103/PhysRevA.111.052622}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052622}, shortjournal = {Phys. Rev. A}, title = {Continuous dynamical decoupling in non-hermitian two-level systems}, volume = {111}, year = {2025}, }
• (2025). Uncertain quantum critical metrology: From single- to multiparameter sensing. PRA, 111(5), 052621. (www)

  @article{ , abstract = {Critical quantum metrology relies on the extreme sensitivity of a system's eigenstates near the critical point of a quantum phase transition to Hamiltonian perturbations. This means that these eigenstates are extremely sensitive to all the parameters of the Hamiltonian. In realistic settings, there is always some degree of uncertainty in the control parameters used to tune the system to criticality. These uncertainties, while not the target of estimation, can significantly affect the attainable precision, effectively acting as nuisance parameters in the estimation process. Despite being a practically relevant source of noise, their impact on critical metrology has been largely overlooked. In this work we present a general framework that interpolates between single- and multiparameter estimation settings, enabling a systematic analysis of how such uncertainties influence sensitivity. We apply this framework to the paradigmatic transverse field Ising and Lipkin-Meshkov-Glick models, explicitly demonstrating how uncertainty in control parameters affects the metrological performance of critical sensors. For finite-size systems, we identify a fundamental trade-off between robustness to uncertainty and the ability to retain a quantum advantage at the critical point. Our results contribute to a deeper understanding of the practical limitations of critical quantum metrology and provide a route toward its more resilient implementation.}, archive = {J_PRA}, author = {George Mihailescu and Steve Campbell and Karol Gietka}, doi = {10.1103/PhysRevA.111.052621}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052621}, shortjournal = {Phys. Rev. A}, title = {Uncertain quantum critical metrology: From single- to multiparameter sensing}, volume = {111}, year = {2025}, }
• (2025). Dynamical phonon blockade with a high time resolution in a hybrid system. PRA, 111(5), 052620. (www)

  @article{ , abstract = {We propose a method to realize dynamical phonon blockade in a hybrid spin-mechanical system. Under the weak excitation limit, we demonstrate that by simply controlling the external pump field, antibunching is enhanced in the strong coupling regime and can also be induced in the weak coupling regime. Additionally, we conduct a comprehensive analysis of the proposed scheme and assess the impact of relevant parameters on phonon blockade. Through further optimization of the system using differential evolution algorithms, we achieve a sub-Poissonian phonon source with high purity and strong single-phonon statistics. The results show that the dynamic scheme allows the system to achieve quantum effects at the single-phonon level over a broad parameter range, which improves its robustness. This mechanism also regulates the time interval between consecutive emissions, reducing the requirements for time resolution. Meanwhile, the time window for quantum information is sufficiently broad, providing a practical method for generating single-phonon sources.}, archive = {J_PRA}, author = {Zhuang Geng and Yong-Yuan Jiang and Yan Xia and Jie Song}, doi = {10.1103/PhysRevA.111.052620}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052620}, shortjournal = {Phys. Rev. A}, title = {Dynamical phonon blockade with a high time resolution in a hybrid system}, volume = {111}, year = {2025}, }
• (2025). Simulating the fermi-hubbard model with long-range hopping on a quantum computer. PRA, 111(5), 052619. (www)

  @article{ , abstract = {We investigate the performance and accuracy of digital quantum algorithms for the study of static and dynamic properties of the fermionic Hubbard model at half-filling with next-nearest-neighbor hopping terms. We provide quantum circuits to perform ground and excited state calculations, via the variational quantum eigensolver (VQE) and the quantum equation of motion (qEOM) approach, respectively, as well as product formula decompositions for time evolution. We benchmark our approach on a chain with sites and periodic boundary conditions, computing the charge and spin gaps, the spectral function and spin-spin dynamic correlations. Our results for the ground-state phase diagram are in qualitative agreement with known results in the thermodynamic limit. Finally, we provide concrete scalings for the number of gates needed to implement our protocols on a qubit register with all-to-all connectivities and on a heavy hexagonal coupling map.}, archive = {J_PRA}, author = {Tatiana A. Bespalova and Karlo Delić and Guido Pupillo and Francesco Tacchino and Ivano Tavernelli}, doi = {10.1103/PhysRevA.111.052619}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052619}, shortjournal = {Phys. Rev. A}, title = {Simulating the fermi-hubbard model with long-range hopping on a quantum computer}, volume = {111}, year = {2025}, }
• (2025). Geodesic algorithm for unitary gate design with time-independent hamiltonians. PRA, 111(5), 052618. (www)

  @article{ , abstract = {Larger multiqubit quantum gates allow shallower, more efficient quantum circuits, which could decrease the prohibitive effect of noise on algorithms for noisy intermediate-scale quantum (NISQ) devices and fault-tolerant error correction schemes. Such multiqubit gates can potentially be generated by time-independent Hamiltonians comprising only physical (one- and two-local) interaction terms. Here, we present an algorithm that finds the time-independent Hamiltonian for a target quantum gate on qubits by using the geodesic on the Riemannian manifold of . Differential programming is used to determine how the Hamiltonian should be updated to follow the geodesic to the target unitary as closely as possible. We show that our geodesic algorithm outperforms gradient descent methods for standard multiqubit gates such as Toffoli and Fredkin. The geodesic algorithm is then used to find previously unavailable multiqubit gates implementing high-fidelity parity checks, which could be used in a wide array of quantum codes and increase the clock speed of fault-tolerant quantum computers. The geodesic algorithm is demonstrated on an example relevant to current experimental hardware, illustrating a circuit speed up.}, archive = {J_PRA}, author = {Dylan Lewis and Roeland Wiersema and Juan Carrasquilla and Sougato Bose}, doi = {10.1103/PhysRevA.111.052618}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052618}, shortjournal = {Phys. Rev. A}, title = {Geodesic algorithm for unitary gate design with time-independent hamiltonians}, volume = {111}, year = {2025}, }
• (2025). Improving adiabatic quantum factorization via chopped random-basis optimization. PRA, 111(5), 052617. (www)

  @article{ , abstract = {Integer factorization remains a significant challenge for classical computers and is fundamental to the security of RSA encryption. Adiabatic quantum algorithms present a promising solution, yet their practical implementation is limited by the short coherence times of current noisy intermediate-scale quantum devices and quantum simulators. In this work, we apply the chopped random-basis (CRAB) optimization technique to enhance adiabatic quantum factorization algorithms. We demonstrate the effectiveness of CRAB by applying it to factor the integers ranging from 21 to 2479, achieving significantly improved fidelity of the target state when the evolution time exceeds the quantum speed limit. Notably, this performance improvement shows resilience in the presence of dephasing noise, highlighting CRAB's practical utility in noisy quantum systems. Our findings suggest that CRAB optimization can serve as a powerful tool for advancing adiabatic quantum algorithms, with broader implications for quantum information processing tasks.}, archive = {J_PRA}, author = {Tianlai Yang and Mo Xiong and Ming Xue and Xinwei Li and Jinbin Li}, doi = {10.1103/PhysRevA.111.052617}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052617}, shortjournal = {Phys. Rev. A}, title = {Improving adiabatic quantum factorization via chopped random-basis optimization}, volume = {111}, year = {2025}, }
• (2025). Short two-qubit pulse sequences for exchange-only spin qubits in two-dimensional layouts. PRA, 111(5), 052616. (www)

  @article{ , abstract = {Exchange-only (EO) spin qubits in quantum dots offer an expansive design landscape for engineering scalable device layouts. The study of two-EO-qubit operations, which involve six electrons in six quantum dots, has so far been limited to a small number of possible configurations, and previous works lack analyses of design considerations and implications for quantum error correction. Using a simple and fast optimization method, we generate complete pulse sequences for cx , cz , swap , leakage-controlled cx , and leakage-controlled cz two-qubit gates on 450 unique planar six-dot topologies and analyze differences in sequence length (up to 43% reduction) across topology classes. In addition, we show that relaxing constraints on postoperation spin locations can yield further reductions in sequence length; conversely, constraining these locations in a particular way generates a cxswap operation with minimal additional cost over a standard cx . We integrate this pulse library into the Intel quantum stack and experimentally verify pulse sequences on a Tunnel Falls chip for different operations in a linear-connectivity device to confirm that they work as expected. Finally, we explore architectural implications of these results for quantum error correction. Our work guides hardware and software design choices for future implementations of scalable quantum-dot architectures.}, archive = {J_PRA}, author = {Jason D. Chadwick and Gian Giacomo Guerreschi and Florian Luthi and Mateusz T. Mądzik and Fahd A. Mohiyaddin and Prithviraj Prabhu and Albert T. Schmitz and Andrew Litteken and Shavindra Premaratne and Nathaniel C. Bishop and Anne Y. Matsuura and James S. Clarke}, doi = {10.1103/PhysRevA.111.052616}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052616}, shortjournal = {Phys. Rev. A}, title = {Short two-qubit pulse sequences for exchange-only spin qubits in two-dimensional layouts}, volume = {111}, year = {2025}, }
• (2025). Tensor-decomposition technique for qubit encoding of maximal-fidelity lorentzian orbitals in real-space quantum chemistry. PRA, 111(5), 052615. (www)

  @article{ , abstract = {To simulate the real- and imaginary-time evolution of a many-electron system on a quantum computer based on the first-quantized formalism, we need to encode molecular orbitals (MOs) into qubit states for typical initial-state preparation. We propose an efficient scheme for encoding an MO as a many-qubit state from a Gaussian-type solution that can be obtained from a tractable solver on a classical computer. We employ the discrete Lorentzian functions (LFs) as a fitting basis set, for which we maximize the fidelity to find the optimal Tucker-form state to represent a target MO. For three-dimensional LFs, we provide the explicit circuit construction for the state preparation involving cnot gates. Furthermore, we introduce a tensor decomposition technique to construct a canonical-form state to approximate the Tucker-form state with controllable accuracy. Rank- decomposition reduces the cnot gate count to We demonstrate via numerical simulations that the proposed scheme is a powerful tool for encoding MOs of various quantum chemical systems, paving the way for first-quantized calculations using hundreds or more logical qubits.}, archive = {J_PRA}, author = {Taichi Kosugi and Xinchi Huang and Hirofumi Nishi and Yu-ichiro Matsushita}, doi = {10.1103/PhysRevA.111.052615}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052615}, shortjournal = {Phys. Rev. A}, title = {Tensor-decomposition technique for qubit encoding of maximal-fidelity lorentzian orbitals in real-space quantum chemistry}, volume = {111}, year = {2025}, }
• (2025). Quantum algorithms for inverse participation ratio estimation in multiqubit and multiqudit systems. PRA, 111(5), 052614. (www)

  @article{ , abstract = {Inverse participation ratios (IPRs) and the related participation entropies quantify the spread of a quantum state over a selected basis of the Hilbert space, offering insights into the equilibrium and nonequilibrium properties of the system. In this work, we propose three quantum algorithms to estimate IPRs on multiqubit and multiqudit quantum devices. The first algorithm allows for the estimation of IPRs in the computational basis by single-qubit measurements, while the second one enables measurement of IPR in the eigenbasis of a selected Hamiltonian, without the knowledge about the eigenstates of the system. Next, we provide an algorithm for IPR in the computational basis for a multiqudit system. We discuss resources required by the algorithms and benchmark them by investigating the one-axis twisting protocol, the thermalization in a deformed PXP model, and the ground state of a spin-1 Affleck-Kennedy-Lieb-Tasaki chain in a transverse field.}, archive = {J_PRA}, author = {Yingjian Liu and Piotr Sierant and Paolo Stornati and Maciej Lewenstein and Marcin Płodzień}, doi = {10.1103/PhysRevA.111.052614}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052614}, shortjournal = {Phys. Rev. A}, title = {Quantum algorithms for inverse participation ratio estimation in multiqubit and multiqudit systems}, volume = {111}, year = {2025}, }
• (2025). Superoscillating quantum control induced by sequential selections. PRA, 111(5), 052613. (www)

  @article{ , abstract = {Superoscillation is a counterintuitive phenomenon for its mathematical feature of faster than Fourier, which has allowed novel optical imaging beyond the diffraction limit. In this article we introduce a superoscillating quantum control protocol realized by sequential selections within the framework of weak measurement, which steers the apparatus (target) by repeatedly applying optimal pre- and postselections to the system (controller). Our protocol accelerates the adiabatic transport of trapped ions and the adiabatic quantum search algorithm at a finite energy cost. We demonstrate the accuracy and robustness of the protocol in the presence of decoherence and fluctuating noise and elucidate the trade-off between fidelity and rounds of selections. Our findings open avenues for quantum-state manipulation and wave-packet control using superoscillation across a range of quantum platforms.}, archive = {J_PRA}, author = {Yongcheng Ding and Yiming Pan and Xi Chen}, doi = {10.1103/PhysRevA.111.052613}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052613}, shortjournal = {Phys. Rev. A}, title = {Superoscillating quantum control induced by sequential selections}, volume = {111}, year = {2025}, }
• (2025). Open-quantum-system simulation through exploiting noise on quantum computers. PRA, 111(5), 052612. (www)

  @article{ , abstract = {We present a general framework for simulating open quantum systems by exploiting the device noise. We find that pseudo-identity unitary transformations on system qubits in the presence of noise can generate nontrivial quantum channels driving open-system dynamics. Controlling parameters in these transformations allows us to simulate selective state-to-state transitions as well as the long-lived coherences found in systems such as photosynthetic light-harvesting complexes. These results suggest a general framework in which parameters in pseudo-identity unitary transformations can be chosen to generate arbitrary nonunitary system-bath channels without any additional qubits representing bath dynamics. The demonstrated controllability of the bath through these transformations establishes different possibilities for the efficient simulation of open quantum systems on quantum devices.}, archive = {J_PRA}, author = {Michael Rose and Sabre Kais and David A. Mazziotti}, doi = {10.1103/PhysRevA.111.052612}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052612}, shortjournal = {Phys. Rev. A}, title = {Open-quantum-system simulation through exploiting noise on quantum computers}, volume = {111}, year = {2025}, }
• (2025). Exact space-depth trade-offs in multicontrolled toffoli decomposition. PRA, 111(5), 052611. (www)

  @article{ , abstract = {In this paper we consider the optimized implementation of multicontrolled Toffoli decomposition using the gate set. While there are several recent works in this direction, here we explicitly quantify the trade-off (with concrete formulas) between the Toffoli depth (this means the depth using the classical 2-controlled Toffoli gate) of the -controlled Toffoli decomposition and the number of clean ancilla qubits. Additionally, we achieve a reduced Toffoli (consequently ) depth, which is an extension of the technique introduced by Khattar and Gidney [T. Khattar and C. Gidney, arXiv:2407.17966 ]. In terms of a negative result, we first show that by using such conditionally clean ancilla techniques, the Toffoli depth can never achieve exactly , though it remains of the same order. This highlights the limitation of the techniques exploiting conditionally clean ancillas [J. Nie et al. , arXiv:2402.05053 ; T. Khattar and C. Gidney, arXiv:2407.17966 ]. Then we prove that, in a more general setup, the depth in the decomposition, via Toffoli gates, is lower bounded by , and this bound is achieved following the complete binary tree structure. Since the (2-controlled) Toffoli gate can further be decomposed using gate set, various methodologies are also explored in this regard for trade-off-related implications.}, archive = {J_PRA}, author = {Suman Dutta and Siyi Wang and Anubhab Baksi and Anupam Chattopadhyay and Subhamoy Maitra}, doi = {10.1103/PhysRevA.111.052611}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052611}, shortjournal = {Phys. Rev. A}, title = {Exact space-depth trade-offs in multicontrolled toffoli decomposition}, volume = {111}, year = {2025}, }
• (2025). Multiqubit entanglement generation with squeezed modes. PRA, 111(5), 052610. (www)

  @article{ , abstract = {We present a hybrid continuous variable–discrete variable entanglement generation protocol using linear optics and homodyne measurements, capable of producing multiple high-fidelity Bell pairs per protocol iteration, with an approximate 0.5 success probability. The effectiveness of the protocol is determined by the squeezing strength. To increase the number of Bell pairs, approximately 3 dB of extra squeezing is needed for each additional Bell pair. The protocol also generates single Bell pairs with an approximate 0.75 probability for squeezing strengths , achievable with current technology.}, archive = {J_PRA}, author = {Alexandru Macridin and Andrew Cameron and Cristian Pena and Si Xie and Raju Valivarthi and Panagiotis Spentzouris}, doi = {10.1103/PhysRevA.111.052610}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052610}, shortjournal = {Phys. Rev. A}, title = {Multiqubit entanglement generation with squeezed modes}, volume = {111}, year = {2025}, }
• (2025). Multiuser quantum communication network via time-bin-entanglement-based frequency conversion and bell-state measurement. PRA, 111(5), 052609. (www)

  @article{ , abstract = {Large-scale quantum communication systems often require different channels to be connected to multiple networks via frequency conversion, which requires frequency converters to act as relay points for system connectivity. We propose a quantum network for single-photon frequency conversion based on time-bin entanglement, where legitimate users can realize the spanning of communication bands between users by independently choosing the target conversion frequency mode. The results show that the converter in the network can be used as a bridge to completely connect the two networks by cascading the quadratic nonlinear process. Meanwhile, the converted quantum entangled states are demonstrated in entanglement measurements and can be used for entanglement swapping. This scheme is expected to be widely used in scenarios where different networks share quantum resources, switching communication channels and effectively connecting different multiplexed spectrum. This concept also provides significant applications in large-scale metropolitan area networks.}, archive = {J_PRA}, author = {Zhantong Qi and Yilin Yang and Chennan Wu and Zixuan Liao and Bo Tang and Jiani Lei and Yuanhua Li and Jia Lin and Yuanlin Zheng and Xianfeng Chen}, doi = {10.1103/PhysRevA.111.052609}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052609}, shortjournal = {Phys. Rev. A}, title = {Multiuser quantum communication network via time-bin-entanglement-based frequency conversion and bell-state measurement}, volume = {111}, year = {2025}, }
• (2025). Effects of systematic error on quantum-enhanced atom interferometry. PRA, 111(5), 052608. (www)

  @article{ , abstract = {We develop a framework for describing the effects of systematic state-preparation error in quantum-enhanced atom interferometry on sensing performance. We do this in the context of both spin-squeezed and non-Gaussian states for the two-axis-twisting (TAT), one-axis-twisting (OAT), and twist-and-turn (TNT) state-preparation schemes, and derive general conditions for robustness and susceptibility of quantum states to state-preparation error. In the spin-squeezing regime, we find that OAT is more susceptible to state-preparation error than TAT due to its parameter-dependent phase-space rotation. In the non-Gaussian regime, we find that OAT is robust to state-preparation errors, which can be explained by a small ratio of off-diagonal to diagonal elements in its Fisher-covariance matrix. In contrast, TNT does not exhibit this robustness. We find that the single-parameter unbiased estimators that are habitually used in quantum-enhanced atom interferometry are not always optimal, and that there may be occasions where biased estimators, or two-parameter unbiased estimators, lead to lower net error.}, archive = {J_PRA}, author = {Joshua Goldsmith and Joseph Hope and Simon Haine}, doi = {10.1103/PhysRevA.111.052608}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052608}, shortjournal = {Phys. Rev. A}, title = {Effects of systematic error on quantum-enhanced atom interferometry}, volume = {111}, year = {2025}, }
• (2025). Narrowband and passband composite rotational quantum gates. PRA, 111(5), 052607. (www)

  @article{ , abstract = {High-precision, robust quantum gates are essential components in quantum computation and information processing. In this study, we present an alternative perspective, exploring the potential applicability of quantum gates that exhibit heightened sensitivity to errors. We investigate such sensitive quantum gates, which, beyond their established use in in vivo nuclear magnetic resonance spectroscopy and polarization optics, may offer significant utility in the other areas where selectivity, filtering, sensing, localization, or addressing properties are of interest. Utilizing the composite pulses technique, we derive three fundamental quantum gates with narrowband and passband characteristics—the X ( not ) gate, the hadamard gate, and gates enabling arbitrary rotations. To systematically design these composite pulse sequences, we introduce the SU(2), modified-SU(2), and regularization random search methodologies. These approaches demonstrate superior performance compared to established sequences in the literature, including NB1, SK1, and PB1.}, archive = {J_PRA}, author = {Hayk L. Gevorgyan}, doi = {10.1103/PhysRevA.111.052607}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052607}, shortjournal = {Phys. Rev. A}, title = {Narrowband and passband composite rotational quantum gates}, volume = {111}, year = {2025}, }
• (2025). Accelerating fermionic system simulation on quantum computers. PRA, 111(5), 052606. (www)

  @article{ , abstract = {A potential approach for demonstrating quantum advantage is using quantum computers to simulate fermionic systems. Quantum algorithms for fermionic system simulation usually involve the Hamiltonian evolution and measurements. However, in the second quantization representation, the number of terms in many fermion system Hamiltonians, such as molecular Hamiltonians, is substantial, approximately , where is the number of molecular orbitals. Due to this, the computational resources required for Hamiltonian evolution and expectation value measurements could be excessively large. To address this, we introduce a grouping strategy that partitions these Hamiltonian terms into groups, with the terms in each group mutually commuting. Based on this grouping method, we propose a parallel Hamiltonian evolution scheme that reduces the circuit depth of Hamiltonian evolution by a factor of . Moreover, our grouping measurement strategy reduces the number of measurements needed to , whereas the current best grouping measurement schemes require measurements. Additionally, we find that measuring the expectation value of a group of Hamiltonian terms requires fewer repetitions than measuring a single term individually, thereby reducing the number of quantum circuit executions. Our approach saves a factor of in the overall time for Hamiltonian evolution and measurements, significantly decreasing the time required for quantum computers to simulate fermionic systems.}, archive = {J_PRA}, author = {Qing-Song Li and Jiaxuan Zhang and Huan-Yu Liu and Qingchun Wang and Yu-Chun Wu and Guo-Ping Guo}, doi = {10.1103/PhysRevA.111.052606}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052606}, shortjournal = {Phys. Rev. A}, title = {Accelerating fermionic system simulation on quantum computers}, volume = {111}, year = {2025}, }
• (2025). Principles for optimizing quantum transduction in piezo-optomechanical systems. PRA, 111(5), 052605. (www)

  @article{ , abstract = {Two-way microwave-optical quantum transduction is essential to connecting distant superconducting qubits via optical fiber and to enable quantum networking at a large scale. In Blésin, Tian, Bhave, and Kippenberg's article [ Phys. Rev. A 104 , 052601 (2021) ], they lay out a two-way quantum transducer converting between microwave photons and telecom-band photons by way of an intermediary gigahertz-band phonon mode utilizing piezoelectric and optomechanical interactions respectively (and are the first to work out the quantum piezoelectric coupling). In this work, we examine both the piezoelectric, and optomechanical interactions from first principles, and together with the evanescent coupling between optical modes, discuss what parameters matter most in optimizing this kind of quantum transducer. For its additional utility, we have also compiled a table of relevant properties of optical materials that may be used as elements in transducers.}, archive = {J_PRA}, author = {James Schneeloch and Erin Sheridan and A. Matthew Smith and Christopher C. Tison and Daniel L. Campbell and Matthew D. LaHaye and Michael L. Fanto and Paul M. Alsing}, doi = {10.1103/PhysRevA.111.052605}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052605}, shortjournal = {Phys. Rev. A}, title = {Principles for optimizing quantum transduction in piezo-optomechanical systems}, volume = {111}, year = {2025}, }
• (2025). Generating graph states with a single quantum emitter and the minimum number of fusions. PRA, 111(5), 052604. (www)

  @article{ , abstract = {Graph states are the key resources for measurement- and fusion-based quantum computing with photons, yet their creation is experimentally challenging. We optimize a hybrid graph-state generation scheme using a single quantum emitter and linear optics Bell-state measurements called fusions. We first generate a restricted class of states from a single quantum emitter and then apply fusions to create a target graph state, where we use a dynamic programming approach to find the construction that requires the lowest possible number of fusions. Our analysis yields a lookup table for constructing nonisomorphic graph states with the minimum number of fusions. The lookup table covers all graph states with up to eight qubits and several other ones with up to 14 qubits. We present construction protocols of selected graph states and provide the lookup table. For large graph states that are not in the lookup table, we derive bounds for the required number of fusions using graph-theoretic properties. Finally, we use the lookup table to search for the best graph codes for loss-tolerant encodings, given a fixed number of fusions for their construction.}, archive = {J_PRA}, author = {Matthias C. Löbl and Love A. Pettersson and Andrew Jena and Luca Dellantonio and Stefano Paesani and Anders S. Sørensen}, doi = {10.1103/PhysRevA.111.052604}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052604}, shortjournal = {Phys. Rev. A}, title = {Generating graph states with a single quantum emitter and the minimum number of fusions}, volume = {111}, year = {2025}, }
• (2025). High-rate amplitude-damping shor codes with immunity to collective coherent errors. PRA, 111(5), 052602. (www)

  @article{ , abstract = {We introduce a family of high-rate amplitude-damping (AD) Shor codes, designed to effectively correct AD errors while maintaining immunity to collective coherent (CC) errors. The proposed AD codes can approximately correct up to AD errors, with flexible parameters , and we provide a rigorous proof that these codes satisfy the approximate quantum error-correction conditions. These codes leverage structured stabilizer measurements, enabling efficient detection of AD errors using only local operations and ancillary qubits. We further construct a family of CC-AD Shor codes by concatenating these AD codes with the dual-rail code.}, archive = {J_PRA}, author = {En-Jui Chang and Ching-Yi Lai}, doi = {10.1103/PhysRevA.111.052602}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052602}, shortjournal = {Phys. Rev. A}, title = {High-rate amplitude-damping shor codes with immunity to collective coherent errors}, volume = {111}, year = {2025}, }
• (2025). Deterministic two-photon controlled-Z gate with the two-photon quantum rabi model. PRA, 111(5), 052601. (www)

  @article{ , abstract = {We propose a scheme for realizing a deterministic two-photon controlled- ( cz ) gate based on variants of the two-photon quantum Rabi model, which is feasible within the framework of circuit QED. We begin by utilizing the two-photon interaction to implement the nonlinear sign gate and subsequently we construct the cz gate following the Knill-Laflamme-Milburn scheme [ Nature (London) 409 , 46 (2001) ]. We consider three different regimes: the strong-coupling regime, the perturbative ultrastrong-coupling regime, and the large-detuning regime. Our results indicate that the cz gate operates fast with high fidelity. We also show that the photonic state in the waveguide can be input into the circuit QED system through a variable coupler and released after interaction with almost the same waveform except for a -phase shift. Our scheme offers a suitable approach for achieving fast and deterministic two-photon quantum gates via light-matter interactions.}, archive = {J_PRA}, author = {Jia-Cheng Tang and Jin Zhao and Haitao Yang and Junlong Tian and Pinghua Tang and Shuai-Peng Wang and Lucas Lamata and Jie Peng}, doi = {10.1103/PhysRevA.111.052601}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052601}, shortjournal = {Phys. Rev. A}, title = {Deterministic two-photon controlled-Z gate with the two-photon quantum rabi model}, volume = {111}, year = {2025}, }
• (2025). Exploring the local landscape in the triangle network. PRA, 111(5), 052453. (www)

  @article{ , abstract = {Characterizing the set of distributions that can be realized in the triangle network is a notoriously difficult problem. In this work, we investigate inner approximations of the set of local (classical) distributions of the triangle network. A quantum distribution that appears to be nonlocal is the elegant joint measurement (EJM) [ Entropy 21 , 325 (2019) ], which motivates us to study distributions having the same symmetries as the EJM. We compare analytical and neural-network-based inner approximations and find a remarkable agreement between the two methods. Using neural network tools, we also conjecture network Bell inequalities that give a trade-off between the levels of correlation and symmetry that a local distribution may feature. Our results considerably strengthen the conjecture that the EJM is nonlocal.}, archive = {J_PRA}, author = {Elisa Bäumer and Victor Gitton and Tamás Kriváchy and Nicolas Gisin and Renato Renner}, doi = {10.1103/PhysRevA.111.052453}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052453}, shortjournal = {Phys. Rev. A}, title = {Exploring the local landscape in the triangle network}, volume = {111}, year = {2025}, }
• (2025). Using detector likelihood for benchmarking quantum error correction. PRA, 111(5), 052452. (www)

  @article{ , abstract = {The behavior of real quantum hardware differs strongly from the simple error models typically used when simulating quantum error correction. Error processes are far more complex than simple depolarizing noise applied to single gates, and error rates can vary greatly between different qubits and at different points in the circuit. Nevertheless, it would be useful to distill all this complicated behavior down to a single parameter: an effective error rate for a simple uniform error model. Here we show that this can be done by means of the average detector likelihood, which quantifies the rate at which error detection events occur. We show that this parameter is predictive of the overall code performance for two variants of the surface code: Floquet codes and the 3-CX surface code. This is then used to define an effective error rate at which simulations for a simple uniform noise model result in the same average detector likelihood, as well as a good prediction of the logical error rate.}, archive = {J_PRA}, author = {Ian Hesner and Bence Hetényi and James R. Wootton}, doi = {10.1103/PhysRevA.111.052452}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052452}, shortjournal = {Phys. Rev. A}, title = {Using detector likelihood for benchmarking quantum error correction}, volume = {111}, year = {2025}, }
• (2025). Complementarity relations in multipath interferometers via decomposition of the uncertainty. PRA, 111(5), 052451. (www)

  @article{ , abstract = {In this paper, employing the metric-adjusted skew information, we bring up a family of decompositions of the total uncertainty as quantified by the variance into the quantum uncertainty and classical uncertainty. Based on the decompositions of uncertainty, we further establish a family of complete complementarity relations for predictability, interference, and correlation in multipath interferometers. Explicitly, we show that the predictability can be quantified by the (reverse) total uncertainty, the interference can be quantified by the quantum uncertainty, while the correlation can be quantified by the classical uncertainty. The family of complementarity relations established in this paper generalize previous characterizations of interference in multipath interferometers via the quantum Fisher information [Y. Sun et al. , Phys. Rev. A 108 , 062416 (2023) ]. As an illustration, we calculate the relevant quantities for some extremal quantum states, and also give explicitly the complementarity relations in two-path interferometers, which demonstrate the validity of the quantifiers. We compare our results with two related complementarity relations established recently and highlight the main differences. The results obtained in this work reveal the close connections between uncertainty and complementarity.}, archive = {J_PRA}, author = {Shuangshuang Fu and Xiaohui Li}, doi = {10.1103/PhysRevA.111.052451}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052451}, shortjournal = {Phys. Rev. A}, title = {Complementarity relations in multipath interferometers via decomposition of the uncertainty}, volume = {111}, year = {2025}, }
• (2025). Symmetric quantum joint measurements on multiple qubits. PRA, 111(5), 052450. (www)

  @article{ , abstract = {We investigate the generalization of symmetric quantum joint measurements on multiple qubits. We first describe a method for constructing a symmetric joint measurement basis for three qubits by utilizing single-qubit states corresponding to the four vertices of an isohedral tetrahedron on the Bloch sphere. We then demonstrate the expected tetrahedral symmetry of the current measurement basis and discuss its application in a trilocal star-shaped network. This architecture enables us to generalize the two-qubit symmetric joint measurement to an n -qubit version, preserving the tetrahedral or hexahedral symmetry.}, archive = {J_PRA}, author = {Dong Ding and Ying-Qiu He and Ting Gao and Feng-Li Yan}, doi = {10.1103/PhysRevA.111.052450}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052450}, shortjournal = {Phys. Rev. A}, title = {Symmetric quantum joint measurements on multiple qubits}, volume = {111}, year = {2025}, }
• (2025). Distinguishing graph states by the properties of their marginals. PRA, 111(5), 052449. (www)

  @article{ , abstract = {Graph states are a class of multipartite entangled quantum states that are ubiquitous in quantum information. We study equivalence relations between graph states under local unitaries (LU) to obtain distinguishing methods both in local and in networked settings. Based on the marginal structure of graph states, we introduce a family of easy-to-compute LU invariants. We show that these invariants uniquely identify the entanglement classes of every graph state up to eight qubits and discuss their reliability for larger numbers of qubits. To handle larger graphs, we generalize tools to test for local Clifford (LC) equivalence of graph states that work by condensing large graphs into smaller graphs. In turn, we show that statements on the equivalence of these smaller graphs (which are easier to compute) can be used to infer statements on the equivalence of the original, larger graphs. We analyze LU equivalence in two key settings, with and without allowing for the permutation of qubits. We identify entanglement classes, whose marginal structure does not allow us to distinguish them. As a result, we increase the bound on the number of qubits where the LU-LC conjecture holds from 8 to 10 qubits in the setting where qubit permutations are allowed.}, archive = {J_PRA}, author = {Lina Vandré and Jarn de Jong and Frederik Hahn and Adam Burchardt and Otfried Gühne and Anna Pappa}, doi = {10.1103/PhysRevA.111.052449}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052449}, shortjournal = {Phys. Rev. A}, title = {Distinguishing graph states by the properties of their marginals}, volume = {111}, year = {2025}, }
• (2025). Efficient classical algorithm for simulating boson sampling with heterogeneous partial distinguishability. PRA, 111(5), 052448. (www)

  @article{ , abstract = {Boson sampling is one of the leading protocols for demonstrating a quantum advantage, but the theory of how this protocol responds to noise is still incomplete. We extend the theory of classical simulation of boson sampling with partial distinguishability to the case where the degree of indistinguishability between photon pairs is different between different pairs.}, archive = {J_PRA}, author = {S. N. van den Hoven and E. Kanis and J. J. Renema}, doi = {10.1103/PhysRevA.111.052448}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052448}, shortjournal = {Phys. Rev. A}, title = {Efficient classical algorithm for simulating boson sampling with heterogeneous partial distinguishability}, volume = {111}, year = {2025}, }
• (2025). Quantum trajectory sensing problem and its solution. PRA, 111(5), 052447. (www)

  @article{ , abstract = {The quantum trajectory sensing problem seeks quantum sensor states which enable the trajectories of incident particles to be distinguished using a single measurement. For an -qubit sensor state to unambiguously discriminate a set of trajectories with a single projective measurement, all post-trajectory output states must be mutually orthogonal; therefore, the state coefficients must satisfy a system of constraints which is typically very large. Given that this system is generally challenging to solve directly, we introduce a group-theoretic framework which simplifies the criteria for sensor states and exponentially reduces the number of equations and variables involved when the trajectories obey certain symmetries. These simplified criteria yield general families of trajectory sensor states and provide bounds on the particle-sensor interaction strength required for perfect one-shot trajectory discrimination. Furthermore, we establish a link between trajectory sensing and quantum error correction, recognizing their common motivation to identify perturbations using projective measurements. Our sensor states in fact form quantum codes, and conversely, a number of familiar stabilizer codes (such as toric codes) also provide trajectory sensing capabilities. This connection enables noise-resilient trajectory sensing through the concatenation of sensor states with quantum error-correcting codes.}, archive = {J_PRA}, author = {Zachary E. Chin and Isaac L. Chuang}, doi = {10.1103/PhysRevA.111.052447}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052447}, shortjournal = {Phys. Rev. A}, title = {Quantum trajectory sensing problem and its solution}, volume = {111}, year = {2025}, }
• (2025). Measuring network quantum steerability utilizing artificial neural networks. PRA, 111(5), 052446. (www)

  @article{ , abstract = {Network quantum steering plays a pivotal role in quantum information science, enabling robust certification of quantum correlations in scenarios with asymmetric trust assumptions among network parties. The intricate nature of quantum networks, however, poses significant challenges for the detection and quantification of steering. In this work, we develop a neural network-based method for measuring network quantum steerability, which can be generalized to arbitrary quantum networks and naturally applied to standard steering scenarios. Our method provides an effective framework for steerability analysis, demonstrating remarkable accuracy and efficiency in standard bipartite and multipartite steering scenarios. Numerical simulations involving isotropic states and noisy Greenberger-Horne-Zeilinger states yield results that are consistent with established findings in these respective scenarios. Furthermore, we demonstrate its utility in the bilocal network steering scenario, where an untrusted central party shares two-qubit isotropic states of different visibilities, ν and ω , with trusted end-point parties and performs a single Bell state measurement. Through explicit construction of a network local hidden state model derived from numerical results and incorporation of the entanglement properties of network assemblages, we analytically demonstrate that the network steering thresholds are determined by the curve ν ω = 1 / 3 under the corresponding configuration.}, archive = {J_PRA}, author = {Mengyan Li and Yanning Jia and Fenzhuo Guo and Haifeng Dong and Sujuan Qin and Fei Gao}, doi = {10.1103/PhysRevA.111.052446}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052446}, shortjournal = {Phys. Rev. A}, title = {Measuring network quantum steerability utilizing artificial neural networks}, volume = {111}, year = {2025}, }
• (2025). Exploring the quantum capacity of a gaussian random-displacement channel using gottesman-kitaev-preskill codes and maximum-likelihood decoding. PRA, 111(5), 052445. (www)

  @article{ , abstract = {Determining the quantum capacity of a noisy quantum channel is an important problem in the field of quantum communication theory. In this work, we consider the Gaussian random-displacement channel N σ , a type of bosonic Gaussian channels relevant in various bosonic quantum information processing systems. In particular, we attempt to make progress on the problem of determining the quantum capacity of a Gaussian random-displacement channel by analyzing the error-correction performance of several families of multimode Gottesman-Kitaev-Preskill (GKP) codes. In doing so we analyze the surface-square GKP codes using an efficient and exact maximum-likelihood decoder (MLD) up to a large code distance of d = 39 . We find that the error threshold of the surface-square GKP code is remarkably close to σ = 1 / e ≃ 0.6065 at which the best-known lower bound of the quantum capacity of N σ vanishes. We also analyze the performance of color-hexagonal GKP codes up to a code distance of d = 13 using a tensor-network decoder serving as an approximate MLD. By focusing on multimode GKP codes that encode just one logical qubit over multiple bosonic modes, we show that GKP codes can achieve nonzero quantum state transmission rates for a Gaussian random-displacement channel N σ at larger values of σ than previously demonstrated. Thus, our work reduces the gap between the quantum communication theoretic bounds and the performance of explicit bosonic quantum error-correcting codes in regards to the quantum capacity of a Gaussian random-displacement channel.}, archive = {J_PRA}, author = {Mao Lin and Kyungjoo Noh}, doi = {10.1103/PhysRevA.111.052445}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052445}, shortjournal = {Phys. Rev. A}, title = {Exploring the quantum capacity of a gaussian random-displacement channel using gottesman-kitaev-preskill codes and maximum-likelihood decoding}, volume = {111}, year = {2025}, }
• (2025). Mitigating shot noise in local overlapping quantum tomography with semidefinite programming. PRA, 111(5), 052444. (www)

  @article{ , abstract = {Reduced density matrices (RDMs) are fundamental in quantum information processing, allowing the computation of local observables, such as energy and correlation functions, without the exponential complexity of fully characterizing quantum states. In the context of near-term quantum computing, RDMs provide sufficient information to effectively design variational quantum algorithms. However, their experimental estimation is challenging, as it involves preparing and measuring quantum states in multiple bases, a resource-intensive process susceptible to producing nonphysical RDMs due to shot noise from limited measurements. To address this, we propose a method to mitigate shot noise by reenforcing certain physicality constraints on RDMs. While verifying RDM compatibility with a global state is quantum Merlin-Arthur complete, we relax this condition by enforcing compatibility constraints up to a certain level using a polynomial-size semidefinite program to reconstruct overlapping RDMs from simulated data. Our approach yields, on average, tighter bounds for the same number of measurements compared to tomography without compatibility constraints. We demonstrate the versatility and efficacy of our method by integrating it into an algorithmic cooling procedure to prepare low-energy states of local Hamiltonians. Simulations on frustrated Hamiltonians reveal notable improvements in accuracy and resource efficiency, highlighting the potential of our approach for practical applications in near-term quantum computing.}, archive = {J_PRA}, author = {Zherui Jerry Wang and David Dechant and Yash J. Patel and Jordi Tura}, doi = {10.1103/PhysRevA.111.052444}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052444}, shortjournal = {Phys. Rev. A}, title = {Mitigating shot noise in local overlapping quantum tomography with semidefinite programming}, volume = {111}, year = {2025}, }
• (2025). Quantum nonlocal nonstabilizerness. PRA, 111(5), 052443. (www)

  @article{ , abstract = {Quantum entanglement and quantum nonstabilizerness are fundamental resources that characterize distinct aspects of a quantum state: Entanglement reflects nonlocal correlations, while nonstabilizerness quantifies the deviation from stabilizer states. A quantum state becomes a valuable resource for applications like universal quantum computation only when both quantities are present. Here, we propose that quantum nonlocal nonstabilizerness (NN) serves as an effective measure of this combined resource, incorporating both entanglement and nonstabilizerness. We demonstrate that NN can be precisely computed for two-qubit pure states, establishing a direct relationship with the entanglement spectrum. We then extend the definition of NN to mixed states and explore its presence in many-body quantum systems. We reveal that the two-point NN decays according to a power law in critical states, indicating that it can serve as an effective quantum information probe for phase transitions. Furthermore, we explore measurement-induced NN and uncover an intriguing phenomenon termed “nonstabilizerness swapping,” wherein post-measurement NN decays more slowly than any pre-measurement correlations. The occurrence of this phenomenon provides a sufficient condition for both entanglement swapping and the presence of a nontrivial sign structure. Our results thus represent a pivotal step toward accurately quantifying the “quantumness” of a state and bring insights from multiple perspectives to the property of NN.}, archive = {J_PRA}, author = {Dongheng Qian and Jing Wang}, doi = {10.1103/PhysRevA.111.052443}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052443}, shortjournal = {Phys. Rev. A}, title = {Quantum nonlocal nonstabilizerness}, volume = {111}, year = {2025}, }
• (2025). Bounding large-scale bell inequalities. PRA, 111(5), 052442. (www)

  @article{ , abstract = {Bell inequalities are an important tool for studying nonlocality, however, they quickly become computationally intractable as the system size grows. We consider a method for finding an upper bound for the quantum violation of such inequalities by combining the Navascués-Pironio-Acín (NPA) hierarchy, the method of alternating projections, and a standard memory-efficient optimization algorithm. While our method may not give the tightest upper bound possible, it often does so several orders of magnitude faster than state-of-the-art solvers, with minimal memory usage, thus allowing solutions to problems that would otherwise be intractable. We benchmark using the well-studied inequality as well as a more general large-scale randomized inequality . For randomized inequalities with 130 inputs either side (a first-level moment matrix of size ), our method is faster than both mosek and SCS while giving a bound only above the optimum.}, archive = {J_PRA}, author = {Luke Mortimer}, doi = {10.1103/PhysRevA.111.052442}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052442}, shortjournal = {Phys. Rev. A}, title = {Bounding large-scale bell inequalities}, volume = {111}, year = {2025}, }
• (2025). Stochastic noise can be helpful for variational quantum algorithms. PRA, 111(5), 052441. (www)

  @article{ , abstract = {Saddle points constitute a crucial challenge for first-order gradient descent algorithms. In notions of classical machine learning, they are avoided, for example, by means of stochastic gradient descent methods. In this work, we provide evidence that the saddle-points problem can be naturally avoided in variational quantum algorithms by exploiting the presence of stochasticity. We prove convergence guarantees and present practical examples in numerical simulations and on quantum hardware. We argue that the natural stochasticity of variational algorithms can be beneficial for avoiding strict saddle points, i.e., those saddle points with at least one negative Hessian eigenvalue. This insight that some levels of shot noise could help is expected to add a new perspective to notions of near-term variational quantum algorithms.}, archive = {J_PRA}, author = {Junyu Liu and Frederik Wilde and Antonio Anna Mele and Xin Jin and Liang Jiang and Jens Eisert}, doi = {10.1103/PhysRevA.111.052441}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052441}, shortjournal = {Phys. Rev. A}, title = {Stochastic noise can be helpful for variational quantum algorithms}, volume = {111}, year = {2025}, }
• (2025). Relation between quantum illumination and quantum parameter estimation. PRA, 111(5), 052440. (www)

  @article{ , abstract = {Quantum illumination (QI) leverages entangled lights to detect the presence of low-reflectivity objects within a thermal environment. In a related vein, quantum parameter estimation utilizes nonclassical probes to precisely determine unknown system parameters. Although both fields have been studied extensively, their performances have traditionally been assessed using different figures of merit: signal-to-noise ratio for QI and quantum Fisher information for parameter estimation. In this paper, we reveal the intrinsic connection between these two measures in the context of target detection, thereby providing explicit operational criteria for identifying optimal measurements. We further apply this relationship to various target detection protocols that employ exotic non-Gaussian states derived from coherent states and two-mode squeezed vacuum states.}, archive = {J_PRA}, author = {Wei Zhong and Dong-Qing Wang and Wen-Yi Zhu and Lan Zhou and Ming-Ming Du and Yu-Bo Sheng}, doi = {10.1103/PhysRevA.111.052440}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052440}, shortjournal = {Phys. Rev. A}, title = {Relation between quantum illumination and quantum parameter estimation}, volume = {111}, year = {2025}, }
• (2025). Observation of a full hierarchy of temporal quantum correlations with a superconducting qubit. PRA, 111(5), 052439. (www)

  @article{ , abstract = {Temporal quantum correlations provide an intriguing way of testing quantumness at the macroscopic level, with a logical hierarchy present among the quantum correlations associated with nonmacrorealism, temporal steering, and temporal inseparability. By manipulating the dynamics of a superconducting qubit, we observe the full hierarchy of temporal quantum correlations. Moreover, we show that the rich dynamics of the temporal quantum correlations, such as sudden death or revival of temporal steering, provides a useful and unique measure for benchmarking qubits on a realistic circuit. Our work finds applications in identifying the casual structure in a quantum network, the non-Markovianity of open quantum systems, and the security bounds of quantum key distribution. As an example, we demonstrate the non-Markovianity of a single superconducting qubit on the quantum circuit.}, archive = {J_PRA}, author = {Hao-Cheng Weng and Chen-Yeh Wei and Huan-Yu Ku and Shin-Liang Chen and Yueh-Nan Chen and Chih-Sung Chuu}, doi = {10.1103/PhysRevA.111.052439}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052439}, shortjournal = {Phys. Rev. A}, title = {Observation of a full hierarchy of temporal quantum correlations with a superconducting qubit}, volume = {111}, year = {2025}, }
• (2025). Geometry from quantum temporal correlations. PRA, 111(5), 052438. (www)

  @article{ , abstract = {In this Letter, we show how Euclidean three-space uniquely emerges from the structure of quantum temporal correlations associated with sequential measurements of Pauli observables on a single qubit. Quite remarkably, the quantum temporal correlations which give rise to geometry are independent of the initial state of the qubit, which we show enables an observer to extract geometric data from sequential measurements without the observer having any knowledge of initial conditions. Such results suggest the plausibility that space itself may emerge from quantum temporal correlations, and we formulate a toy model of such a hypothetical phenomenon.}, archive = {J_PRA}, author = {James Fullwood and Vlatko Vedral}, doi = {10.1103/PhysRevA.111.052438}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052438}, shortjournal = {Phys. Rev. A}, title = {Geometry from quantum temporal correlations}, volume = {111}, year = {2025}, }
• (2025). Quantum entanglement and einstein-podolsky-rosen steering in ultrastrongly light-matter-coupled systems. PRA, 111(5), 052437. (www)

  @article{ , abstract = {This work presents a scheme for engineering quantum entanglement and Einstein-Podolsky-Rosen (EPR) steering with Gaussian measurements based on the quantum Hopfield model that incorporates a common thermal reservoir. We begin by examining quantum correlations, specifically quantum entanglement and EPR steering, in the ground state. These quantum correlations primarily stem from squeezing interactions in weak-coupling and normal strong-coupling regimes. As the coupling strength increases, especially upon entering the ultrastrong-coupling regime, the correlations emerge from the combined effect of squeezing and mix-mode interactions. Importantly, this scenario enables the realization of two-way EPR steering. Moreover, lower optical frequencies enhance both quantum entanglement and EPR steering. Further, when considering thermal effects, the ultrastrong-coupling and deep strong-coupling regimes, paired with lower optical frequencies, lead to improved entanglement. The one-way EPR steering for the resonant case can be effectively controlled in the ultrastrong-coupling and deep strong-coupling regimes which originate from the asymmetry of the subsystem and reservoir coupling induced by the diamagnetic term. Additionally, one-way EPR steering can also be produced for the nonresonant case. In this case, the asymmetry of the subsystem and reservoir originates from the combined effect of nonresonant frequencies and the diamagnetic term. Our findings have the potential to inspire further research into quantum information processing that leverages light-matter entanglement and EPR steering.}, archive = {J_PRA}, author = {Yu-qiang Liu and Shan Sun and Yi-jia Yang and Zheng Liu and Xingdong Zhao and Zunlue Zhu and Wuming Liu and Chang-shui Yu}, doi = {10.1103/PhysRevA.111.052437}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052437}, shortjournal = {Phys. Rev. A}, title = {Quantum entanglement and einstein-podolsky-rosen steering in ultrastrongly light-matter-coupled systems}, volume = {111}, year = {2025}, }
• (2025). Supervised binary classification of small-scale digit images and weighted graphs with a trapped-ion quantum processor. PRA, 111(5), 052436. (www)

  @article{ , abstract = {Here we present the results of benchmarking a quantum processor based on trapped ions by performing basic quantum machine learning algorithms. Using a quantum-enhanced support vector machine algorithm with up to five qubits we perform a supervised binary classification on two types of datasets: small binary digit images and weighted graphs with a ring topology. For the first dataset, images are intentionally selected so that they could be classified with 100% accuracy. This allows us to specifically examine different types of quantum encodings of the digit dataset and study the impact of experimental noise. In the second dataset, graphs are divided into two categories based on the spectral structure of their Ising Hamiltonian models, which is related to the NP-hard problem. For this problem we consider an embedding of an exponentially large Hamiltonian spectrum into an entangled state of a linear number of qubits. For both problems, we study various levels of circuit optimization and found that, for all experiments conducted, we achieve classifiers with 100% accuracy on both training and testing datasets. This demonstrates that the quantum processor has the ability to correctly solve the basic classification task under consideration. As we expect, with the increase in the capabilities of quantum processors, they can be utilized for solving machine learning tasks.}, archive = {J_PRA}, author = {Ilia V. Zalivako and Alexander I. Gircha and Evgeniy O. Kiktenko and Anastasiia S. Nikolaeva and Denis A. Drozhzhin and Alexander S. Borisenko and Andrei E. Korolkov and Nikita V. Semenin and Kristina P. Galstyan and Pavel A. Kamenskikh and Vasilii N. Smirnov and Mikhail A. Aksenov and Pavel L. Sidorov and Ksenia Yu. Khabarova and Aleksey K. Fedorov and Nikolay N. Kolachevsky and Ilya A. Semerikov}, doi = {10.1103/PhysRevA.111.052436}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052436}, shortjournal = {Phys. Rev. A}, title = {Supervised binary classification of small-scale digit images and weighted graphs with a trapped-ion quantum processor}, volume = {111}, year = {2025}, }
• (2025). Quantum simulations of macrorealism violation via the quantum nondemolition measurement protocol. PRA, 111(5), 052435. (www)

  @article{ , abstract = {The Leggett-Garg inequalities have been proposed to identify the quantum behavior of a system; specifically, the violation of macrorealism. They are usually implemented by performing two sequential measurements on quantum systems, calculating the correlators of such measurements and then combining them arriving at Leggett-Garg inequalities. However, this approach only provides sufficient conditions for the violation of macrorealism. Recently, an alternative approach was proposed that uses nondemolition measurements and gives both a necessary and sufficient condition for the violation of macrorealism. By storing the information in a quantum detector, it is possible to construct a quasiprobability distribution whose negative regions unequivocally identify the quantum behavior of the system. Here, we perform a detailed comparison between these two approaches. The use of the IBM quantum simulators allows us to evaluate the performance in real-case situations and to include both the statistical and environmental noise. We find that the nondemolition approach is not only able to always identify the quantum features, but it requires fewer resources than the standard Leggett-Garg inequalities. In addition, while the efficiency of the latter is strongly affected by the presence of the noise, the nondemolition approach results incredibly robust and its efficiency remains unchanged by the noise. These results make the nondemolition approach a viable alternative to the Leggett-Garg inequalities to identify the violation of macrorealism.}, archive = {J_PRA}, author = {D. Melegari and M. Cardi and P. Solinas}, doi = {10.1103/PhysRevA.111.052435}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052435}, shortjournal = {Phys. Rev. A}, title = {Quantum simulations of macrorealism violation via the quantum nondemolition measurement protocol}, volume = {111}, year = {2025}, }
• (2025). Locally stable sets without entanglement with minimum cardinality. PRA, 111(5), 052434. (www)

  @article{ , abstract = {Over the past two decades, much progress has been made in the construction of nonlocal sets without entanglement. Recently, Li and Wang [ Quantum 7 , 1101 (2023) ] proposed an open question that an orthogonal product set (OPS) is locally stable with minimum cardinality in , and the numerical lower bound for such a set was given by Wang et al. [ Quantum Inf. Process. 22 , 15 (2023) ], but the existence of the construction remains unresolved. In this work we construct locally stable sets with minimum cardinalities and via 1-orthogonal cyclic product sets in for odd and for even , respectively, thereby partly addressing Li and Wang's open question and confirming the existence of the locally stable OPS with the lower bound. Furthermore, we present a locally stable orthogonal cyclic product set of size in and a locally stable OPS with smaller size in general multipartite systems. Our results show a perfectly cyclic structure of locally stable OPSs and provide new insight into the role of local stability without entanglement in quantum information theory.}, archive = {J_PRA}, author = {Xiao-Fan Zhen and Su-Juan Qin and Zheng-Ping Jin and Hui-Juan Zuo and Fei Gao}, doi = {10.1103/PhysRevA.111.052434}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052434}, shortjournal = {Phys. Rev. A}, title = {Locally stable sets without entanglement with minimum cardinality}, volume = {111}, year = {2025}, }
• (2025). Unification of finite symmetries in the simulation of many-body systems on quantum computers. PRA, 111(5), 052433. (www)

  @article{ , abstract = {Symmetry is fundamental in the description and simulation of quantum systems. Leveraging symmetries in classical simulations of many-body quantum systems can result in significant overhead due to the exponentially growing size of some symmetry groups as the number of particles increases. Quantum computers hold the promise of achieving exponential speedup in simulating quantum many-body systems; however, a general method for utilizing symmetries in quantum simulations has not yet been established. In this work, we present a unified framework for incorporating symmetry group transforms on quantum computers to simulate many-body systems. The core of our approach lies in the development of efficient quantum circuits for symmetry-adapted projection onto irreducible representations of a group or pairs of commuting groups. We provide resource estimations for common groups, including the cyclic and permutation groups. Our algorithms demonstrate the capability to prepare coherent superpositions of symmetry-adapted states and to perform quantum evolution across a wide range of models in condensed-matter physics and ab initio electronic structure in quantum chemistry. Specifically, we execute a symmetry-adapted quantum subroutine for small molecules in first-quantization on noisy hardware and demonstrate the emulation of symmetry-adapted quantum phase estimation for preparing coherent superpositions of quantum states in various irreducible representations of a symmetry group. In addition, we present a discussion of open problems regarding treating symmetries in digital quantum simulations of many-body systems, paving the way for future systematic investigations into leveraging symmetries quantumly for practical quantum advantage. The broad applicability and rigorous resource estimation for symmetry transformations make our framework appealing for achieving provable quantum advantage on fault-tolerant quantum computers, especially for symmetry-related properties.}, archive = {J_PRA}, author = {Victor M. Bastidas and Nathan Fitzpatrick and K. J. Joven and Zane M. Rossi and Shariful Islam and Troy Van Voorhis and Isaac L. Chuang and Yuan Liu}, doi = {10.1103/PhysRevA.111.052433}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052433}, shortjournal = {Phys. Rev. A}, title = {Unification of finite symmetries in the simulation of many-body systems on quantum computers}, volume = {111}, year = {2025}, }
• (2025). Simple hamiltonian dynamics as a powerful resource for image classification. PRA, 111(5), 052432. (www)

  @article{ , abstract = {A quadrillion-dimensional Hilbert space hosted by a quantum processor with over 50 physical qubits has been expected to be powerful enough to perform computational tasks ranging from simulations of many-body physics to complex financial modeling. Despite a few examples and demonstrations, it is still unclear how we can utilize such a large Hilbert space as a computational resource, particularly how a simple and small quantum system could solve nontrivial computational tasks. This paper shows a simple Ising model capable of performing such nontrivial computational tasks in a quantum neural network model. An Ising spin chain as small as ten qubits can solve a practical image classification task with high accuracy. To evaluate the mechanism of its computation, we examine how the symmetries of the Hamiltonian would affect its computational power. We show how the interplay between complexity and symmetries of the quantum system dictates the performance as quantum neural network.}, archive = {J_PRA}, author = {Akitada Sakurai and Aoi Hayashi and W. J. Munro and Kae Nemoto}, doi = {10.1103/PhysRevA.111.052432}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052432}, shortjournal = {Phys. Rev. A}, title = {Simple hamiltonian dynamics as a powerful resource for image classification}, volume = {111}, year = {2025}, }
• (2025). Continuous-variable entanglement with orbital angular momentum multiplexing in coherently prepared media. PRA, 111(5), 052431. (www)

  @article{ , abstract = {Quantum entanglement constitutes a pivotal resource, serving as a fundamental cornerstone within the field of quantum information science. In recent years, the study of vortex light entanglement has garnered widespread attention due to its unique structure and inherent advantages; however, the majority of these investigations are primarily focused on discrete variable systems. In this paper, we present a theoretical framework for generating vortex optical entanglement in coherently prepared media, employing continuous-variable analysis and leveraging Raman scattering as an alternative to the conventional spontaneous parametric down-conversion method. The entanglement arises from the quantum correlation between the two light fields, induced by atomic coherence. Using numerical simulations, we thoroughly explore the impact of various tunable system parameters on the degree of entanglement, ultimately identifying the optimal conditions for maximal entanglement. Our findings offer a reference framework for vortex light entanglement, with potential implications across quantum teleportation, quantum key distribution, quantum computing, high-dimensional quantum information, and other related fields.}, archive = {J_PRA}, author = {Fan Meng and Hao Zhu and Xin-Yao Huang and Guo-Feng Zhang}, doi = {10.1103/PhysRevA.111.052431}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052431}, shortjournal = {Phys. Rev. A}, title = {Continuous-variable entanglement with orbital angular momentum multiplexing in coherently prepared media}, volume = {111}, year = {2025}, }
• (2025). Isoholonomic inequality and tight implementations of holonomic quantum gates. PRA, 111(5), 052430. (www)

  @article{ , abstract = {In holonomic quantum computation, quantum logic gates are realized by cyclic parallel transport of the computational space. The resulting quantum gate corresponds to the holonomy associated with the closed path traced by the computational space. The isoholonomic inequality for gates establishes a fundamental lower bound on the path length of such cyclic transports, which depends only on the spectrum of the holonomy, that is, the eigenvalues of the implemented quantum gate. The isoholonomic inequality also gives rise to an estimate of the minimum time required to execute a holonomic quantum gate, underscoring the central role of the inequality in quantum computation. In this paper, we show that when the codimension of the computational space is sufficiently large, any quantum gate can be implemented using a parallel transporting Hamiltonian in a way that saturates the isoholonomic inequality and the corresponding time estimate. We call such implementations tight. The treatment presented here is constructive and lays the foundation for the development of efficient and optimal implementation strategies in holonomic quantum computation.}, archive = {J_PRA}, author = {Ole Sönnerborn}, doi = {10.1103/PhysRevA.111.052430}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052430}, shortjournal = {Phys. Rev. A}, title = {Isoholonomic inequality and tight implementations of holonomic quantum gates}, volume = {111}, year = {2025}, }
• (2025). Parallel transport in rotating frames and projective holonomic quantum computation. PRA, 111(5), 052429. (www)

  @article{ , abstract = {Nonadiabatic holonomic quantum computation is a promising approach for implementing quantum gates that offers both efficiency and robustness against certain types of errors. A key element of this approach is a geometric constraint known as the parallel transport condition. According to the principle of covariance, this condition must be appropriately modified when changing reference frames. In this paper, we detail how to adjust the parallel transport condition when transitioning from the laboratory frame to a rotating reference frame. Furthermore, building on gauge invariance considerations, we develop a framework for nonadiabatic holonomic quantum computation with projective gates. The parallel transport condition of this framework effectively addresses the problem of global dynamical phases inherent in conventional nonadiabatic holonomic quantum computation. We extend the isoholonomic inequality, which provides a fundamental bound on the efficiency of protocols used to implement holonomic quantum gates, to encompass projective quantum gates. We also determine a minimum execution time for projective holonomic quantum gates and show that this time can be attained when the codimension of the computational space is sufficiently large.}, archive = {J_PRA}, author = {Ole Sönnerborn}, doi = {10.1103/PhysRevA.111.052429}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052429}, shortjournal = {Phys. Rev. A}, title = {Parallel transport in rotating frames and projective holonomic quantum computation}, volume = {111}, year = {2025}, }
• (2025). Measuring entanglement along collective operators. PRA, 111(5), 052428. (www)

  @article{ , abstract = {We introduce a framework for studying multiparty entanglement by analyzing the behavior of collective variables. Throughout the paper, we explore a specific type of multiparty entanglement that can be detected through the fluctuations of a collective observable. We thoroughly analyze its properties and how it can be extended to mixed states while placing it within the context of the existing literature. The novelty of our approach also lies in presenting a graphical point of view. This is done by introducing a spectral space on which the various properties of our entanglement quantifier have a direct pictorial interpretation. Notably, this approach proves particularly effective for assessing entanglement, as we show its ability to extend previously established inequalities. To enhance understanding, we also demonstrate how this framework applies to specific scenarios, encompassing both finite-dimensional cases and infinite-dimensional systems, the latter being exemplified by the time-frequency modal degree of freedom of copropagating single photons.}, archive = {J_PRA}, author = {Éloi Descamps and Arne Keller and Pérola Milman}, doi = {10.1103/PhysRevA.111.052428}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052428}, shortjournal = {Phys. Rev. A}, title = {Measuring entanglement along collective operators}, volume = {111}, year = {2025}, }
• (2025). Sequential information-theoretic protocols in continuous-variable systems. PRA, 111(5), 052427. (www)

  @article{ , abstract = {In order to enable the sequential implementation of quantum information-theoretic protocols in the continuous variable framework, we propose two schemes for resource reusability, resource-splitting protocol and unsharp homodyne measurements . We demonstrate the advantage offered by the first scheme in implementing sequential attempts at continuous-variable teleportation when the protocol fails in the previous round. In the second scheme, unsharp quadrature measurements are employed to implement the detection of entanglement between several pairs of observers. Under specific conditions, our calculations show that it is possible to successfully witness the entanglement of the same two-mode state sequentially by as many as five observers.}, archive = {J_PRA}, author = {Sudipta Das and Ayan Patra and Rivu Gupta and Aditi Sen(De and Himadri Shekhar Dhar}, doi = {10.1103/PhysRevA.111.052427}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052427}, shortjournal = {Phys. Rev. A}, title = {Sequential information-theoretic protocols in continuous-variable systems}, volume = {111}, year = {2025}, }
• (2025). Carving entangled multiparticle states with exponentially improved fidelity. PRA, 111(5), 052426. (www)

  @article{ , abstract = {We propose a method that uses the “no-jump” evolution of a probe to generate entangled multiparticle states of high fidelity. The probe is coupled to a target ensemble of qubits and engineered to exponentially decay at a rate depending on the target collective spin, such that postselecting on observing no probe decay precisely removes select faster-decaying spin components. When a probe and -qubit target interact via a cavity mode of cooperativity , our procedure generates entangled states with infidelities of , an exponential improvement over previous carving schemes. This scheme, which we call “counterfactual” carving, can generate complex entangled states for applications in quantum metrology and quantum computing.}, archive = {J_PRA}, author = {Joshua Ramette and Josiah Sinclair and Zeyang Li and Vladan Vuletić}, doi = {10.1103/PhysRevA.111.052426}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052426}, shortjournal = {Phys. Rev. A}, title = {Carving entangled multiparticle states with exponentially improved fidelity}, volume = {111}, year = {2025}, }
• (2025). Characterizing non-markovian quantum processes by fast bayesian tomography. PRA, 111(5), 052425. (www)

  @article{ , abstract = {To push gate performance to levels beyond the thresholds for quantum error correction, it is important to characterize the error sources occurring on quantum gates. However, the characterization of non-Markovian error poses a challenge to current quantum process tomography techniques. Fast Bayesian tomography (FBT) is a self-consistent tomographic protocol that can be bootstrapped from earlier characterization knowledge and be updated in real time with arbitrary gate sequences. Here we demonstrate how FBT allows for the characterization of key non-Markovian error processes. We introduce two experimental protocols for FBT to diagnose the non-Markovian behavior of two-qubit systems on silicon quantum dots. To increase the efficiency and scalability of the experiment-analysis loop, we develop a web-based FBT software stack. To reduce experiment cost and analysis time, we also introduce a native readout method and warm boot strategy. Our results demonstrate that FBT is a useful tool for probing non-Markovian errors that can be detrimental to the ultimate realization of fault-tolerant operation on quantum computing.}, archive = {J_PRA}, author = {R. Y. Su and J. Y. Huang and N. Dumoulin Stuyck and M. K. Feng and W. Gilbert and T. J. Evans and W. H. Lim and F. E. Hudson and K. W. Chan and W. Huang and Kohei M. Itoh and R. Harper and S. D. Bartlett and C. H. Yang and A. Laucht and A. Saraiva and A. S. Dzurak and T. Tanttu}, doi = {10.1103/PhysRevA.111.052425}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052425}, shortjournal = {Phys. Rev. A}, title = {Characterizing non-markovian quantum processes by fast bayesian tomography}, volume = {111}, year = {2025}, }
• (2025). Inevitable negativity: Additivity commands negative quantum channel entropy. PRA, 111(5), 052424. (www)

  @article{ , abstract = {Quantum channels represent a broad spectrum of operations crucial to quantum information theory, encompassing everything from the transmission of quantum information to the manipulation of various resources. In the domain of states, the concept of majorization serves as a fundamental tool for comparing the uncertainty inherent in both classical and quantum systems. This paper establishes a rigorous framework for assessing the uncertainty in both classical and quantum channels. By employing a specific class of superchannels, we introduce and elucidate three distinct approaches to channel majorization: constructive, axiomatic, and operational. Intriguingly, these methodologies converge to a consistent ordering. This convergence not only provides a robust basis for defining entropy functions for channels but also clarifies the interpretation of entropy in this broader context. Most notably, our findings reveal that any viable entropy function for quantum channels must assume negative values, thereby challenging traditional notions of entropy.}, archive = {J_PRA}, author = {Gilad Gour and Doyeong Kim and Takla Nateeboon and Guy Shemesh and Goni Yoeli}, doi = {10.1103/PhysRevA.111.052424}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052424}, shortjournal = {Phys. Rev. A}, title = {Inevitable negativity: Additivity commands negative quantum channel entropy}, volume = {111}, year = {2025}, }
• (2025). Informational nonequilibrium concentration. PRA, 111(5), 052423. (www)

  @article{ , abstract = {Informational contributions to thermodynamics can be studied in isolation by considering systems with fully degenerate Hamiltonians. In this regime, being in nonequilibrium (termed informational nonequilibrium ) provides thermodynamic resources, such as extractable work, solely from the information content. The usefulness of informational nonequilibrium creates an incentive to obtain more of it, motivating the question of how to concentrate it : can we increase the local informational nonequilibrium of a product state under a global closed system (unitary) evolution? We fully solve this problem analytically, showing that it is impossible for two-qubits, and it is always possible to find states achieving this in higher dimensions. Specifically for two-qutrits, we find that there is a single unitary achieving optimal concentration for every state, for which we uncover a Mpemba-like effect . We further discuss the notion of bound resources in this framework, initial global correlations' ability to activate concentration, and applications to concentrating purity and intrinsic randomness.}, archive = {J_PRA}, author = {Chung-Yun Hsieh and Benjamin Stratton and Hao-Cheng Weng and Valerio Scarani}, doi = {10.1103/PhysRevA.111.052423}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052423}, shortjournal = {Phys. Rev. A}, title = {Informational nonequilibrium concentration}, volume = {111}, year = {2025}, }
• (2025). Quantifying magic resource for quantum channels via channel-state duality. PRA, 111(5), 052420. (www)

  @article{ , abstract = {According to the celebrated Gottesman-Knill theorem, magic resource (nonstabilizerness) is necessary to drive universal quantum computation. Thus characterization and quantification of magic resource for quantum states and quantum channels are significant issues. In this work, we propose a method to construct quantifiers of magic resource for quantum channels from those for quantum states by employing the channel-state duality to convert quantum channels to the corresponding Choi states. We focus on a specific quantifier of magic resource based on characteristic functions (Fourier transforms) of quantum states. This quantifier is well defined for all dimensions and easy to calculate, as opposed to those defined via discrete Wigner functions. It satisfies some desirable properties and provides an upper bound to the mana (a kind of logarithmic negativity of discrete Wigner functions) of quantum channels. Using this quantity, we evaluate the amount of magic resource for some typical quantum channels and compare them with some existing quantifiers of generating-power of magic resource. For the dephasing channels in prime dimensional systems, our quantifier of magic resource essentially characterizes the average generating power of magic resource, while, for general channels, they are quite different and some challenging issues arise.}, archive = {J_PRA}, author = {Xiaohui Li and Shunlong Luo and Zijian Zhang}, doi = {10.1103/PhysRevA.111.052420}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052420}, shortjournal = {Phys. Rev. A}, title = {Quantifying magic resource for quantum channels via channel-state duality}, volume = {111}, year = {2025}, }
• (2025). High-fidelity initialization of a logical qubit with multiple injections. PRA, 111(5), 052419. (www)

  @article{ , abstract = {Quantum error correction represents a significant advancement in large-scale quantum computing. However, achieving fault-tolerant implementations of non-Clifford logical gates with reduced overhead remains a challenge in the popular surface code strategy. Recent advances have underscored the need for a substantial code distance to attain complete fault tolerance. Here, we introduce a continuous fault-tolerant scheme for non-Clifford logical gates via multiple injections. Unlike existing protocols that focus on a single logical chain, our approach utilizes multiple logical chains, each of which can employ the same or different logical rotation angles to initialize a non-Clifford state. Compared to previous efforts, our protocol significantly alleviates the challenges associated with the requirement for a large code distance and reduces the corresponding resource overheads, making it more feasible to be implemented in current midscale chips via the surface code strategy.}, archive = {J_PRA}, author = {Zhi-Cheng He and Zheng-Yuan Xue}, doi = {10.1103/PhysRevA.111.052419}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052419}, shortjournal = {Phys. Rev. A}, title = {High-fidelity initialization of a logical qubit with multiple injections}, volume = {111}, year = {2025}, }
• (2025). Unexpected consequences of postquantum theories in the graph-theoretical approach to correlations. PRA, 111(5), 052418. (www)

  @article{ , abstract = {This work explores the implications of the exclusivity principle (EP) in the context of quantum and postquantum correlations. We first establish a key technical result demonstrating that given the set of correlations for a complementary experiment, the EP restricts the maximum set of correlations for the original experiment to the antiblocking set. Based on it, we can prove our central result: if all quantum behaviors are accessible in Nature, the EP guarantees that no postquantum behaviors can be realized. This can be seen as a generalization of the result of B. Amaral et al. [ Phys. Rev. A 89 , 030101(R) (2014) ], to a wider range of scenarios. It also provides novel insights into the structure of quantum correlations and their limitations.}, archive = {J_PRA}, author = {José Nogueira and Carlos Vieira and Marcelo Terra Cunha}, doi = {10.1103/PhysRevA.111.052418}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052418}, shortjournal = {Phys. Rev. A}, title = {Unexpected consequences of postquantum theories in the graph-theoretical approach to correlations}, volume = {111}, year = {2025}, }
• (2025). Insufficiency of pure-state ensembles in characterizing transformations of entangled states under local operations and classical communication. PRA, 111(5), 052417. (www)

  @article{ , abstract = {The conditions for transforming pure entangled states under local operations and classical communication (LOCC) are well understood. A natural question then arises: Can we determine the transformation conditions for mixed entangled states under LOCC based on the properties of their pure-state ensembles? While much effort has been devoted to this issue, in this paper, we rule out this possibility. Our findings address several open questions, including the following: (i) The conditions for all convex roof entanglement measures are insufficient to guarantee the existence of an LOCC transformation from to , and (ii) the inequalities for all entanglement monotones are not sufficient to ensure the existence of an LOCC transformation from to .}, archive = {J_PRA}, author = {C. L. Liu and Baoqing Sun and D. L. Zhou}, doi = {10.1103/PhysRevA.111.052417}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052417}, shortjournal = {Phys. Rev. A}, title = {Insufficiency of pure-state ensembles in characterizing transformations of entangled states under local operations and classical communication}, volume = {111}, year = {2025}, }
• (2025). Quantum walk on a square lattice with identical particles. PRA, 111(5), 052416. (www)

  @article{ , abstract = {We investigate quantum superposition effects in two-dimensional quantum walks of identical particles with different statistics under particle exchange, starting from various different initial configurations. To characterize interparticle correlation dynamics, we focus on joint properties such as two-particle coincidence probabilities and the spread velocity of the interparticle distance. Regarding spatial modes as an environment for the particles internal degrees of freedom, we study the role played by the particle statistics using standard entanglement witnesses, showing that particles possessing fermionic statistics are more resistant to thermalize with their environment. We analyze the presence of multipartite entanglement in the system's degrees of freedom through the Quantum Fisher Information, revealing that fermionic states generated during the walk are better suited to perform quantum metrology tasks. Finally, we discuss the potential for implementing this model using integrated photonic circuits by exploiting -partite entanglement between individual photons.}, archive = {J_PRA}, author = {Gonzalo Camacho and Jasmin Meinecke and Janik Wolters}, doi = {10.1103/PhysRevA.111.052416}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052416}, shortjournal = {Phys. Rev. A}, title = {Quantum walk on a square lattice with identical particles}, volume = {111}, year = {2025}, }
• (2025). Dynamical multipartite entanglement in a generalized tavis-cummings model with XY spin interaction. PRA, 111(5), 052415. (www)

  @article{ , abstract = {We present the dynamical multipartite entanglement, which is in terms of the quantum Fisher information, of a generalized Tavis-Cummings (TC) model introducing the spin interaction. Since our model cannot be solved exactly, the effective description of the model is theoretically derived and numerically examined. By the Holstein-Primakoff transformation, we show the bridge from the generalized TC model to the central spin model. We also discuss the effect of the temperature, the coupling constant, and the magnetic field on the dynamical multipartite entanglement in the central spin model, where the central spin is initially unentangled. Strong coupling and low temperature are necessary conditions for a genuine multipartite entanglement in the model. The former governs the maximum entanglement, while the latter plays a crucial role in stabilizing the entanglement. The magnetic field modulates the period and amplitude of multipartite entanglement, primarily affecting the stable waveform of it. Our findings allow for a better comprehension of dynamical multipartite entanglement and provide a viable experimental platform for driving advances in quantum metrology and quantum information processing.}, archive = {J_PRA}, author = {Yuguo Su and Zhijie Sun and Yiying Yan and Hengyan Wang and Junyan Luo and Tiantian Ying and Hongbin Liang and Yi-Xiao Huang}, doi = {10.1103/PhysRevA.111.052415}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052415}, shortjournal = {Phys. Rev. A}, title = {Dynamical multipartite entanglement in a generalized tavis-cummings model with XY spin interaction}, volume = {111}, year = {2025}, }
• (2025). Symmetry-protected landau-zener-stückelberg-majorana interference and nonadiabatic topological transport of edge states. PRA, 111(5), 052414. (www)

  @article{ , abstract = {We systematically investigate Landau-Zener-Stückelberg-Majorana (LZSM) interference under chiral-mirror-like symmetry and propose its application to nonadiabatic topological transport of edge states. Protected by this symmetry, complete destructive interference emerges and can be characterized through occupation probability. This symmetry-protected LZSM interference enables state transitions to be achieved within remarkably short timescales. To demonstrate our mechanism, we provide two distinctive two-level systems as examples and survey them in detail. By tuning evolution speed or increasing holding time, the complete destructive interferences are observed. Furthermore, we make use of this mechanism for topological edge states of Su-Schrieffer-Heeger (SSH) chain by taking them as an isolated two-level system. Through carefully designed time sequences, we construct symmetry-protected LZSM interference of topological edge states, enabling nonadiabatic topological transport. Our work unveils an alternative way to study quantum control, quantum state transfer, and quantum communication via nonadiabatic topological transport.}, archive = {J_PRA}, author = {Shi Hu and Shihao Li and Meiqing Hu and Zhoutao Lei}, doi = {10.1103/PhysRevA.111.052414}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052414}, shortjournal = {Phys. Rev. A}, title = {Symmetry-protected landau-zener-stückelberg-majorana interference and nonadiabatic topological transport of edge states}, volume = {111}, year = {2025}, }
• (2025). Noise-adapted quantum error correction for non-markovian noise. PRA, 111(5), 052413. (www)

  @article{ , abstract = {We consider the problem of quantum error correction (QEC) for non-Markovian noise. Using the well-known Petz recovery map, we first show that conditions for approximate QEC can be easily generalized for the case of non-Markovian noise in the strong-coupling regime where the noise map becomes non-completely-positive at intermediate times. While certain approximate QEC schemes are ineffective against quantum non-Markovian noise, in the sense that the fidelity vanishes in finite time, the Petz map adapted to non-Markovian noise uniquely safeguards the code space even at the maximum noise limit. Focusing on the case of non-Markovian amplitude damping noise, we further show that the non-Markovian Petz map also outperforms the standard, stabilizer-based QEC code. Since implementing such a non-Markovian map poses practical challenges, we also construct a Markovian Petz map that achieves a similar performance, with only a slight compromise on the fidelity. Finally, we also study an example of non-Markovian Pauli noise, namely the non-Markovian dephasing channel. In this case, we show that the non-Markovian Petz recovery preserves the code space even at the high-noise limit for certain noise-adapted codes, whereas the Markovian Petz and stabilizer recoveries are ineffective.}, archive = {J_PRA}, author = {Debjyoti Biswas and Shrikant Utagi and Prabha Mandayam}, doi = {10.1103/PhysRevA.111.052413}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052413}, shortjournal = {Phys. Rev. A}, title = {Noise-adapted quantum error correction for non-markovian noise}, volume = {111}, year = {2025}, }
• (2025). Generating entanglement of two acoustic modes by driving the qubit in a circuit quantum acoustodynamics system. PRA, 111(5), 052412. (www)

  @article{ , abstract = {We propose how to generate the entanglement of two long-lived phonon modes in a circuit quantum acoustodynamics system, which consists of a multimode high-frequency bulk acoustic wave resonator and a transmon-type superconducting qubit. Two acoustic modes couple to the qubit through piezoelectric interaction, and the qubit is driven by a microwave field. Under the condition of far detuning between the qubit and acoustic modes, the qubit can be eliminated adiabatically, thus establishing the indirect interaction between the two acoustic modes. We demonstrate that such an indirect interaction can be a parametric-amplification-type interaction by appropriately choosing the drive frequency and strength, so the entanglement between acoustic modes can be created by the direct unitary evolution. We numerically analyze the parameter conditions for generating the entanglement in detail and evaluate the influence of system dissipations and noise. The results show that the scheme can be realized using currently available parameters and has strong robustness against the dissipations and the environmental temperature. This work may provide an efficient resource for the quantum information processing based on the phononic systems.}, archive = {J_PRA}, author = {Mei-Rong Wei and Qi Guo and Gang Li and Tiancai Zhang}, doi = {10.1103/PhysRevA.111.052412}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052412}, shortjournal = {Phys. Rev. A}, title = {Generating entanglement of two acoustic modes by driving the qubit in a circuit quantum acoustodynamics system}, volume = {111}, year = {2025}, }
• (2025). Dynamics of correlations and entanglement generation in electron-molecule inelastic scattering. PRA, 111(5), 052411. (www)

  @article{ , abstract = {The dynamics and processes involved in particle-molecule scattering, including nuclear dynamics, are described and analyzed using various quantum information quantities throughout the different stages of the scattering. The main process studied and characterized with the information quantities is the interatomic Coulombic electronic capture, an inelastic process that can lead to dissociation of the target molecule. The analysis focuses on a one-dimensional transversely confined NeHe molecule model used to simulate the scattering between an electron and a ion (molecule). The time-independent Schrödinger equation is solved using the finite element method with a self-developed Julia package FEMTISE to compute potential energy curves and the parameters of the interactions between particles. The time-dependent Schrödinger equation is solved using the multiconfiguration time-dependent Hartree algorithm. The time-dependent electronic and nuclear probability densities are calculated for different electron incoming energies, evidencing elastic and inelastic processes that can be correlated to changes in von Neumann entropy, von Neumann mutual information, and Shannon mutual information. The expectation value of the position of the particles, as well as their standard deviations, are analyzed along the whole dynamics and related to the entanglement during the collision and after the process is over, thus highlighting the dynamics of entanglement generation. It is shown that the correlations generated in the collision are partially retained only when the inelastic process is active.}, archive = {J_PRA}, author = {Martin Mendez and Federico M. Pont}, doi = {10.1103/PhysRevA.111.052411}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052411}, shortjournal = {Phys. Rev. A}, title = {Dynamics of correlations and entanglement generation in electron-molecule inelastic scattering}, volume = {111}, year = {2025}, }
• (2025). Extremal maximal entanglement. PRA, 111(5), 052410. (www)

  @article{ , abstract = {A pure multipartite quantum state is called absolutely maximally entangled if all reductions of no more than half of the parties are maximally mixed. However, an -qubit absolutely maximally entangled state exists only when equals 2, 3, 5, and 6. A natural question arises when it does not exist: Which -qubit pure state has the largest number of maximally mixed -party reductions? We denote this number by . It was shown that by Higuchi and Sudbery [ Phys. Lett. A 273 , 213 (2000) ] and by Huber et al. [ Phys. Rev. Lett. 118 , 200502 (2017) ]. In this paper, we give a general upper bound of by linking the well-known Turán problem in graph theory and provide lower bounds using constructive and probabilistic methods. In particular, we show that , which is the third known value for this problem.}, archive = {J_PRA}, author = {Wanchen Zhang and Yu Ning and Fei Shi and Xiande Zhang}, doi = {10.1103/PhysRevA.111.052410}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052410}, shortjournal = {Phys. Rev. A}, title = {Extremal maximal entanglement}, volume = {111}, year = {2025}, }
• (2025). Characterization of randomness in quantum circuits of continuous gate sets. PRA, 111(5), 052409. (www)

  @article{ , abstract = {In the accompanying paper [Y. Mitsuhashi, et al. , Phys. Rev. Lett. 134 , 180404 (2025) ], we established the method of characterizing the maximal order of asymptotic unitary designs generated by symmetric local random circuits, and explicitly specified the order in the cases of , and symmetries. Here, we provide full details on the derivation of the main theorems for general symmetry and for concrete symmetries. Furthermore, we consider a general framework where we have access to a finite set of connected compact unitary subgroups, which includes symmetric local unitary gate sets.}, archive = {J_PRA}, author = {Yosuke Mitsuhashi and Ryotaro Suzuki and Tomohiro Soejima and Nobuyuki Yoshioka}, doi = {10.1103/PhysRevA.111.052409}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052409}, shortjournal = {Phys. Rev. A}, title = {Characterization of randomness in quantum circuits of continuous gate sets}, volume = {111}, year = {2025}, }
• (2025). Port-based telecloning of an unknown quantum state. PRA, 111(5), 052408. (www)

  @article{ , abstract = {Telecloning is a protocol introduced by Murao et al. [ Phys. Rev. A 59 , 156 (1999) ] to distribute copies of an unknown quantum state to many receivers in a way that beats the trivial “clone-and-teleport” protocol. In the last decade, a new type of teleportation called port-based teleportation , in which the receiver can recover the state simply by looking at the correct port without having to actively perform correction operations, has been widely studied. In this paper, we consider the analog of telecloning, in which conventional teleportation is replaced by the port-based variant. To achieve this, we generalize the optimal measurement used in port-based teleportation and develop a new one that achieves port-based telecloning. Numerical results show that, in certain cases, the proposed protocol is strictly better than the trivial clone-and-teleport approach.}, archive = {J_PRA}, author = {Reiji Okada and Kohtaro Kato and Francesco Buscemi}, doi = {10.1103/PhysRevA.111.052408}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052408}, shortjournal = {Phys. Rev. A}, title = {Port-based telecloning of an unknown quantum state}, volume = {111}, year = {2025}, }
• (2025). Broadband spectroscopy of quantum noise. PRA, 111(5), 052407. (www)

  @article{ , abstract = {Characterizing noise is key to the optimal control of the quantum system it affects. Using a single-qubit probe and appropriate sequences of and non- pulses, we show how one can characterize the noise a quantum bath generates across a wide range of frequencies—including frequencies below the limit set by the probe's time. To do so we leverage an exact expression for the dynamics of the probe in the presence of non- pulses and a general inequality between the symmetric (classical) and antisymmetric (quantum) components of the noise spectrum generated by a Gaussian bath. We analyze the robustness of our method on state-preparation and measurement errors and pulse imperfection. Simulation demonstrates the effectiveness of our method.}, archive = {J_PRA}, author = {Yuanlong Wang and Gerardo A. Paz-Silva}, doi = {10.1103/PhysRevA.111.052407}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052407}, shortjournal = {Phys. Rev. A}, title = {Broadband spectroscopy of quantum noise}, volume = {111}, year = {2025}, }
• (2025). Hypothesis testing of symmetry in quantum dynamics. PRA, 111(5), 052406. (www)

  @article{ , abstract = {Symmetry plays a crucial role in quantum physics, dictating the behavior and dynamics of physical systems. In this paper, we develop a hypothesis-testing framework for quantum dynamics symmetry using a limited number of queries to the unknown unitary operation and establish the quantum max-relative entropy lower bound for the type-II error. We construct optimal ancilla-free protocols that achieve optimal type-II error probability for testing time-reversal symmetry ( symmetry) and diagonal symmetry ( symmetry) with limited queries. Contrasting with the advantages of indefinite causal-order strategies in various quantum information processing tasks, we show that parallel, adaptive, and indefinite causal-order strategies have equal power for our tasks. We establish optimal protocols for symmetry testing and symmetry testing for six and five queries, respectively, from which we infer that the type-II error exhibits a decay rate of with respect to the number of queries . This represents a significant improvement over the basic repetition protocols without using global entanglement, where the error decays at a slower rate of .}, archive = {J_PRA}, author = {Yu-Ao Chen and Chenghong Zhu and Keming He and Yingjian Liu and Xin Wang}, doi = {10.1103/PhysRevA.111.052406}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052406}, shortjournal = {Phys. Rev. A}, title = {Hypothesis testing of symmetry in quantum dynamics}, volume = {111}, year = {2025}, }
• (2025). Quantum data-hiding scheme using orthogonal separable states. PRA, 111(5), 052405. (www)

  @article{ , abstract = {We consider bipartite quantum state discrimination and present a quantum data-hiding scheme utilizing an orthogonal separable state ensemble. Using a bound on local minimum-error discrimination, we provide a sufficient condition for the separable state ensemble to be used in constructing a quantum data-hiding scheme. Our results are illustrated with various examples in bipartite quantum systems. As our scheme employs separable states of low-dimensional quantum systems, it becomes more feasible for practical implementation.}, archive = {J_PRA}, author = {Donghoon Ha and Jeong San Kim}, doi = {10.1103/PhysRevA.111.052405}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052405}, shortjournal = {Phys. Rev. A}, title = {Quantum data-hiding scheme using orthogonal separable states}, volume = {111}, year = {2025}, }
• (2025). Improving parameter estimation in gaussian channels using quantum coherence. PRA, 111(5), 052404. (www)

  @article{ , abstract = {Gaussian quantum channels are relevant operations in continuous variable systems. In general, given an arbitrary state, the action on it is well known, provided that the quantum channels are completely characterized. In this work, we have studied the role played by quantum coherence in the estimation of Gaussian channel parameters. For this purpose, we start by considering an initial single-mode vacuum state where coherence is generated through displaced or/and squeezing operations. Then, we consider a probe state with two resources, the average thermal number and the quantum coherence. The results are computed using the quantum Fisher information (QFI) as well as some gain functions defined in the work. We applied the estimation protocol for two paradigmatic bosonic Gaussian channels: the thermal attenuator and the thermal amplifier. Our results show that for the vacuum initial state, coherence can be exploited to obtain a high QFI. Moreover, we can state two important facts: the first being that for a small parameter region of a channel, the QFI depends on the mechanism used to generate the coherence, while the second is that the QFI depends not only on the amount of coherence but also on how it changes as a function of the parameter to be estimated. For the probe state, including also an average thermal number, the two examples show that thermal resources are not always beneficial to the QFI and that this depends on the channel structure. For the attenuator channel, the optimal probe state is only limited by the ability to implement an average thermal number and generate an amount of coherence, while for the amplifier channel, the vacuum probe state with coherence is the optimal state. Finally, we obtain a direct relation between the quantum Fisher information and the relative entropy of coherence, allowing, in principle, an experimental verification based on the measurement of the covariance matrix of the probe system.}, archive = {J_PRA}, author = {Jonas F. G. Santos and Carlos H. S. Vieira and Wilder R. Cardoso}, doi = {10.1103/PhysRevA.111.052404}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052404}, shortjournal = {Phys. Rev. A}, title = {Improving parameter estimation in gaussian channels using quantum coherence}, volume = {111}, year = {2025}, }
• (2025). Machine-learning insights into the entanglement-trainability correlation of parametrized quantum circuits. PRA, 111(5), 052403. (www)

  @article{ , abstract = {Variational quantum algorithms (VQAs) have emerged as the leading strategy to obtain quantum advantages on the current noisy intermediate-scale devices. However, their entanglement-trainability correlation indicates that deep circuits are generally untrainable due to the barren plateau phenomenon, which challenges their applications. In this work, we suggest a gate-to-tensor encoding method for parametrized quantum circuits (PQCs), with which two long short-term memory networks are trained to predict both entangling capability and trainability. We call these LG networks. The remarkable capabilities of LG networks afford a statistical way to investigate the entanglement-trainability correlation of PQCs within a data set encompassing millions of generated circuits. This machine-learning-driven method first confirms the negative correlation between entanglement and trainability. Then, we observe that circuits with any values of entangling capability and trainability exist. These circuits with high entanglement and high trainability possess an appropriate high portion of nearest-neighbor nonlocal gates. Furthermore, the trained LG networks can be employed to construct PQCs with specific entanglement and trainability, demonstrating their practical applications in VQAs.}, archive = {J_PRA}, author = {Shikun Zhang and Yang Zhou and Zheng Qin and Rui Li and Chunxiao Du and Zhisong Xiao and Yongyou Zhang}, doi = {10.1103/PhysRevA.111.052403}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052403}, shortjournal = {Phys. Rev. A}, title = {Machine-learning insights into the entanglement-trainability correlation of parametrized quantum circuits}, volume = {111}, year = {2025}, }
• (2025). Slow decay rate of correlations induced by long-range extended dzyaloshinskii-moriya interactions. PRA, 111(5), 052402. (www)

  @article{ , abstract = {We examine the impact of long-range Dzyaloshinskii-Moriya (DM) interaction in the extended model on the phase diagram as well as the static and dynamical properties of quantum and classical correlation functions. It is known that in the nearest-neighbor model with DM interaction, the transition from the gapless chiral phase to a gapped one occurs when the strengths of the DM interaction and anisotropy coincide. We exhibit that the critical line gets modified with the range of interactions which decay according to power law. Specifically, instead of being gapless in the presence of a strong DM interaction, a gapped region emerges which grows with the increase of the moderate fall-off rate (quasi-long-range regime) in the presence of a transverse magnetic field. The gapless chiral phase can also be separated from a gapped one by the decay patterns of quantum mutual information and classical correlation with distant sites of the ground state which are independent of the fall-off rate in the gapless zone. We observe that the corresponding critical lines that depend on the fall-off rate can also be determined from the effective central charge involved in the scaling of entanglement entropy. We illustrate that in a nonequilibrium setting, the relaxation dynamics of classical correlation, the decay rate of total correlation, and the growth rate of entanglement entropy can be employed to uncover whether the evolving Hamiltonian and the Hamiltonian corresponding to the initial state are gapped or gapless.}, archive = {J_PRA}, author = {Tanoy Kanti Konar and Leela Ganesh Chandra Lakkaraju and Aditi Sen(De}, doi = {10.1103/PhysRevA.111.052402}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052402}, shortjournal = {Phys. Rev. A}, title = {Slow decay rate of correlations induced by long-range extended dzyaloshinskii-moriya interactions}, volume = {111}, year = {2025}, }
• (2025). Clifford-dressed variational principles for precise loschmidt echoes. PRA, 111(5), 052401. (www)

  @article{ , abstract = {We extend the recently introduced Clifford-dressed time-dependent variational principle (TDVP) to efficiently compute many-body wave-function amplitudes in the computational basis. This advancement enhances the study of Loschmidt echoes, which generally require accurate calculations of the overlap between the evolved state and the initial wave function. By incorporating Clifford-disentangling gates during TDVP evolution, our method effectively controls entanglement growth while keeping the computation of these amplitudes accessible. Specifically, it reduces the problem to evaluating the overlap between a matrix product state (MPS) and a stabilizer state, a task that remains computationally feasible within the proposed framework. To demonstrate the effectiveness of this approach, we first benchmark it on the one-dimensional transverse-field Ising model. We then apply it to more challenging scenarios, including a nonintegrable next-to-nearest-neighbor Ising chain and a two-dimensional Ising model. Our results highlight the versatility and efficiency of the Clifford-augmented MPS, showcasing its capability to go beyond the evaluation of simple expectation values. This makes it a powerful tool for exploring various aspects of many-body quantum dynamics.}, archive = {J_PRA}, author = {Antonio Francesco Mello and Alessandro Santini and Mario Collura}, doi = {10.1103/PhysRevA.111.052401}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052401}, shortjournal = {Phys. Rev. A}, title = {Clifford-dressed variational principles for precise loschmidt echoes}, volume = {111}, year = {2025}, }
• (2025). Spatial offset of excited states in non-hermitian lattices. PRA, 111(5), 052218. (www)

  @article{ , abstract = {We investigate the behavior of light-wave packets injected into non-Hermitian microcavity lattices under highly dissipative conditions. While all eigenstates of the lattice exhibit exponential decay, a specifically excited state maintains coherent propagation. In a one-dimensional lattice, this state undergoes a spatial displacement shift away from the injection position, which is a fundamental property of non-Hermitian systems with a point gap when the spectrum encircles a finite region in the complex plane. Extending such a shift to two-dimensional lattices reveals a geometrically anomalous -shaped wave-packet formation with orientation-tunable arms. Notably, this geometric control mechanism enables all-optical steering of non-Hermitian photonic states without requiring structural modifications.}, archive = {J_PRA}, author = {Xiaohan Jiang and Yuanyuan Pan and Yang Zhang and Ye Xiong}, doi = {10.1103/PhysRevA.111.052218}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052218}, shortjournal = {Phys. Rev. A}, title = {Spatial offset of excited states in non-hermitian lattices}, volume = {111}, year = {2025}, }
• (2025). Negativity of nondemolition quasiprobability distribution as a necessary and sufficient condition for macrorealism violation. PRA, 111(5), 052217. (www)

  @article{ , abstract = {Quantum nondemolition measurements define a noninvasive protocol to extract information from a monitored quantum system. This protocol exploits an additional quantum system that is sequentially coupled to the system and eventually measured to reconstruct temporal correlations developed by the system. In reference to a given measurement observable, the protocol's outcomes are well described by a quasiprobability distribution, which can be negative. In this paper, we prove that the presence of negative regions in this distribution defined at three times is a necessary and sufficient condition for the violation of macrorealism. This approach falls within the category of sequential noninvasive measurability and automatically satisfies all no-signaling-in-time conditions at multiple times by design. We show that reconstructing the negativity is a much stronger condition than the violation of the Leggett-Garg inequalities, commonly used for the same task, as they may be satisfied even if the macrorealism is violated. Quantum nondemolition measurements provide a clear and operational tool to identify violations of macrorealism directly. Thus, our result could also be applied to the study of the quantum-to-classical transition and in all those fields where quantumness certification is desirable.}, archive = {J_PRA}, author = {Paolo Solinas and Stefano Gherardini}, doi = {10.1103/PhysRevA.111.052217}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052217}, shortjournal = {Phys. Rev. A}, title = {Negativity of nondemolition quasiprobability distribution as a necessary and sufficient condition for macrorealism violation}, volume = {111}, year = {2025}, }
• (2025). Topological quantum thermometry. PRA, 111(5), 052216. (www)

  @article{ , abstract = {An optimal local quantum thermometer is a quantum many-body system that saturates the fundamental lower bound for the thermal state temperature estimation accuracy [L. Correa et al. , Phys. Rev. Lett. 114 , 220405 (2015) ]. Such a thermometer has a particular energy-level structure with a single ground state and highly degenerated excited-state manifold, with an energy gap proportional to the estimated temperature. In this paper, we show that the optimal local quantum thermometer can be realized in an experimentally feasible system of spinless fermions confined in a one-dimensional optical lattice described by the Rice-Mele model. We characterize the system's sensitivity to temperature changes in terms of quantum Fisher information and the classical Fisher information obtained from experimentally available site occupation measurements.}, archive = {J_PRA}, author = {Anubhav Kumar Srivastava and Utso Bhattacharya and Maciej Lewenstein and Marcin Płodzień}, doi = {10.1103/PhysRevA.111.052216}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052216}, shortjournal = {Phys. Rev. A}, title = {Topological quantum thermometry}, volume = {111}, year = {2025}, }
• (2025). Parametric hypersensitivity and transport in the steady-state open-system holstein model. PRA, 111(5), 052215. (www)

  @article{ , abstract = {We demonstrate that the nonequilibrium steady state (NESS) of an open-system Holstein model with linear bias displays extreme sensitivity to the closed-system parameters. This sensitivity is shown to correspond to avoided crossings in the closed-system spectrum, as previously demonstrated in the Rabi model. We then develop a kinetic model to analyze the effects of environmental parameters on NESS hypersensitivity. This reveals that hypersensitivity only exists in intermediate environmental parameter regimes, a prediction that is verified numerically. The inherent spatial character of the Holstein model offers a natural connection to transport, revealing that transport properties in the steady-state regime can be optimized by simultaneously coordinating the closed- and open-system parameters.}, archive = {J_PRA}, author = {Nishaant Jacobus and Paul Brumer and Chern Chuang}, doi = {10.1103/PhysRevA.111.052215}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052215}, shortjournal = {Phys. Rev. A}, title = {Parametric hypersensitivity and transport in the steady-state open-system holstein model}, volume = {111}, year = {2025}, }
• (2025). Subskin modes in a nonlinear non-hermitian system. PRA, 111(5), 052214. (www)

  @article{ , abstract = {Subskin modes are distinct from conventional skin modes because they localize not at the system's edge but rather below the edge. Unlike skin modes, where a substantial number of them can accumulate at the boundaries of a system due to the non-Hermitian skin effect, subskin modes are typically limited in number to one or a few, and emerge only when the size of the system and the couplings are related in a very specific way. Nonlinear interactions can lift the restrictions on the couplings for the formation of these modes. The findings reveal the potential of subskin modes for practical applications and new research in non-Hermitian systems.}, archive = {J_PRA}, author = {C. Yuce}, doi = {10.1103/PhysRevA.111.052214}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052214}, shortjournal = {Phys. Rev. A}, title = {Subskin modes in a nonlinear non-hermitian system}, volume = {111}, year = {2025}, }
• (2025). Heisenberg and heisenberg-like representations via hilbert-space-bundle geometry in the non-hermitian regime. PRA, 111(5), 052213. (www)

  @article{ , abstract = {The equivalence between the Schrödinger and Heisenberg representations is a cornerstone of quantum mechanics. However, this relationship remains unclear in the non-Hermitian regime, particularly when the Hamiltonian is time dependent. In this paper, we address this gap by establishing the connection between the two representations, incorporating the metric of the Hilbert space bundle. We not only demonstrate the consistency between the Schrödinger and Heisenberg representations but also present a Heisenberg-like representation grounded in the generalized vielbein formalism, which provides a clear and intuitive geometric interpretation. Unlike the standard Heisenberg representation, where the metric of the Hilbert space is encoded solely in the dual states, the Heisenberg-like representation distributes the metric information between both the states and the dual states. Despite this distinction, it retains the same Heisenberg equation of motion for operators. Within this formalism, the Hamiltonian is replaced by a Hermitian counterpart, while the “non-Hermiticity” is transferred to the operators. Moreover, this approach extends to regimes with a dynamical metric (beyond the pseudo-Hermitian framework) and to systems governed by time-dependent Hamiltonians.}, archive = {J_PRA}, author = {Chia-Yi Ju and Adam Miranowicz and Jacob Barnett and Guang-Yin Chen and Franco Nori}, doi = {10.1103/PhysRevA.111.052213}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052213}, shortjournal = {Phys. Rev. A}, title = {Heisenberg and heisenberg-like representations via hilbert-space-bundle geometry in the non-hermitian regime}, volume = {111}, year = {2025}, }
• (2025). Effect of atom-oscillator interaction on the aging transition in coupled oscillators. PRA, 111(5), 052212. (www)

  @article{ , abstract = {Oscillators are often employed as a model of radiation fields, which may couple to an atom and play an important role for creating and manipulating nonclassical states in quantum metrology, quantum simulation, and quantum information. Aging transitions in coupled oscillators have been studied extensively in both the classical and quantum contexts. It is well known that the onset of aging transitions can be modulated by the dissipative coupling between oscillators. In this study, we propose an alternative way to modulate the aging transition through coherent couplings between a two-level atom and the oscillators. Our findings reveal that, compared to atom-free systems in both classical and quantum regimes, the atom-oscillator coherent interaction reduces the inactive-to-total oscillator ratio required for aging transitions. Analytical results of the transition for both the classical oscillators and quantum oscillators suggest that the decay rate of the atom and the atom-oscillator coupling strength jointly change the aging transition point. The physics behind the observation is also elucidated in this article. Our research introduces a readily implementable strategy for manipulating aging transitions in more intricate systems, thereby advancing the control and understanding of these critical transitions in quantum technologies.}, archive = {J_PRA}, author = {Huining Zhang and X. Z. Hao and X. X. Yi}, doi = {10.1103/PhysRevA.111.052212}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052212}, shortjournal = {Phys. Rev. A}, title = {Effect of atom-oscillator interaction on the aging transition in coupled oscillators}, volume = {111}, year = {2025}, }
• (2025). Möbius games and other bell tests for relativity. PRA, 111(5), 052211. (www)

  @article{ , abstract = {We derive multiparty games that, if the winning chance exceeds a certain limit, prove the incompatibility of the parties' causal relations with any partial order. This, in turn, means that the parties exert a backaction on the causal relations; the causal relations are dynamical. The games turn out to be representable by directed graphs, for instance by an orientation of the Möbius ladder. We discuss these games as device-independent tests of space-time's dynamical nature in general relativity. To do so, we design relativistic settings where, in the Minkowski space-time, the winning chance is bound to the limits. In contrast, we find otherwise tame processes with classical control of causal order that win the games deterministically. These suggest a violation of the bounds in gravitational implementations. We obtain these games by uncovering a “pairwise central symmetry” of the correlations in question. This symmetry allows us to recycle the facets of the acyclic subgraph polytope studied by Grötschel, Jünger, and Reinelt in the mid-80s for combinatorial optimization. In addition, we derive multiparty games in a scenario where the polytope dimension grows only linearly in the number of parties. Here, exceeding the limits not only proves the dynamical nature of the causal relations, but also that the correlations are incompatible with any global causal order.}, archive = {J_PRA}, author = {Eleftherios-Ermis Tselentis and Ämin Baumeler}, doi = {10.1103/PhysRevA.111.052211}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052211}, shortjournal = {Phys. Rev. A}, title = {Möbius games and other bell tests for relativity}, volume = {111}, year = {2025}, }
• (2025). Entropy flow in a parametric amplifier. PRA, 111(5), 052210. (www)

  @article{ , abstract = {Computations of entropy in thermodynamics rely on discreteness of the spectra of the subsystems. We argue that, for cases with continuous spectra (typically, radiation), there is a useful definition of entropy flow based on discretizing the signal into Gabor's “atoms,” say, by means of a windowed Fourier transform. In particular, applying this method to a degenerate parametric amplifier (paramp) driven by a classical pump and coupled to a zero-temperature Markovian bath, we find that the output entropy flux vanishes at large times, even though the energy and photon number fluxes remain nonzero. This is consistent with the manner in which the paramp is expected to release information about its initial state. We relate the quenching of the entropy flow to development of the off-diagonal coherences in the output and discuss possible relevance of this mechanism to the black-hole information problem. We also propose to use measurements of the off-diagonal coherences as a means of extracting the rates at which high-entropy subsystems release information to linear environments.}, archive = {J_PRA}, author = {Sergei Khlebnikov}, doi = {10.1103/PhysRevA.111.052210}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052210}, shortjournal = {Phys. Rev. A}, title = {Entropy flow in a parametric amplifier}, volume = {111}, year = {2025}, }
• (2025). Quantum thermodynamics as a gauge theory. PRA, 111(5), 052209. (www)

  @article{ , abstract = {Thermodynamics is based on a coarse-grained approach, from which its fundamental variables emerge, effectively erasing the complicated details of the microscopic dynamics within a macroscopic system. The strength of thermodynamics lies in the universality provided by this paradigm. In contrast, quantum mechanics focuses on describing the dynamics of microscopic systems, aiming to make predictions about experiments we perform, a goal shared by all fundamental physical theories, which are often framed as gauge theories in modern physics. Recently, a gauge theory for quantum thermodynamics was introduced, defining gauge-invariant work and heat, and exploring their connections to quantum phenomena. In this work, we extend that theory in two significant ways. First, we incorporate energy spectrum degeneracies, which were previously overlooked. Additionally, we define gauge-invariant entropy, exploring its properties and connections to other physical and informational quantities. This results in a complete framework for quantum thermodynamics grounded in the principle of gauge invariance. To demonstrate some implications of this theory, we apply it to well-known critical systems.}, archive = {J_PRA}, author = {Gabriel Fernandez Ferrari and Łukasz Rudnicki and Lucas C. Céleri}, doi = {10.1103/PhysRevA.111.052209}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052209}, shortjournal = {Phys. Rev. A}, title = {Quantum thermodynamics as a gauge theory}, volume = {111}, year = {2025}, }
• (2025). Measurement incompatibility at both parties unrelated to bell nonlocality in a two-input and two-output setting. PRA, 111(5), 052208. (www)

  @article{ , abstract = {Two important ingredients necessary for obtaining Bell nonlocal correlations between two spatially separated parties are an entangled state shared between them and an incompatible set of measurements employed by each of them. However, not all entangled states can give rise to Bell nonlocality. Here, we are interested in a complementary question, regarding the role of the sets of incompatible measurements in enabling Bell nonlocality, for arbitrary entangled states. It is known that for some sets of more than two jointly incompatible measurements performed by one of the parties, there does not exist an entangled state and another set of incompatible measurements for the other party, which will result in Bell nonlocality. However, in the two-input and two-output setting per party, measurement incompatibility at a single party will always guarantee Bell nonlocality. Thus, it is interesting to ask whether all sets of incompatible measurements at both parties, in the two-input and two-output setting per party, will result in Bell nonlocality for some shared state. We first observe that Bell nonlocality can always be established when both parties employ any set of incompatible projective measurements. On the other hand, going beyond projective measurements, we present a class of incompatible positive operator-valued measures, employed by both observers, which can never activate Bell nonlocality. Furthermore, we find a sufficient criterion for achieving Bell nonlocal correlations given a fixed amount of pure two-qubit entanglement and a fixed amount of incompatibility of projective measurements applied by either both parties or a single party.}, archive = {J_PRA}, author = {Priya Ghosh and Chirag Srivastava and Swati Choudhary and Ujjwal Sen}, doi = {10.1103/PhysRevA.111.052208}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052208}, shortjournal = {Phys. Rev. A}, title = {Measurement incompatibility at both parties unrelated to bell nonlocality in a two-input and two-output setting}, volume = {111}, year = {2025}, }
• (2025). Spin-dependent force and inverted harmonic potential for rapid creation of macroscopic quantum superpositions. PRA, 111(5), 052207. (www)

  @article{ , abstract = {Creating macroscopic spatial superposition states is crucial for investigating matter-wave interferometry and advancing quantum sensor technology. Currently, two potential methods exist to achieve this objective. The first involves using inverted harmonic potential (IHP) to spatially delocalize quantum states through coherent inflation [ New J. Phys. 19 , 123029 (2017) ]. The second method employs a spin-dependent force to separate two massive wave packets spatially [ Phys. Rev. Lett. 111 , 180403 (2013) ]. The disadvantage of the former method is the slow initial coherent inflation, while the latter is hindered by the diamagnetism of spin-embedded nanocrystals, which suppresses spatial separation. In this study, we integrate two methods: first, we use the spin-dependent force to generate initial spatial separation, and second, we use IHP to achieve coherent inflating trajectories of the wave packets. This approach enables the attainment of massive large spatial superposition in minimal time. For instance, a spatial superposition with a mass of and a size of around is realized in 0.1 s. We also calculate the evolution of wave packets in both harmonic potential (HP) and IHP using the path integral approach.}, archive = {J_PRA}, author = {Run Zhou and Qian Xiang and Anupam Mazumdar}, doi = {10.1103/PhysRevA.111.052207}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052207}, shortjournal = {Phys. Rev. A}, title = {Spin-dependent force and inverted harmonic potential for rapid creation of macroscopic quantum superpositions}, volume = {111}, year = {2025}, }
• (2025). Time-convolutionless master equation applied to adiabatic elimination. PRA, 111(5), 052206. (www)

  @article{ , abstract = {In open quantum systems theory, reduced models are invaluable for conceptual understanding and computational efficiency. Adiabatic elimination is a useful model reduction method for systems with separated timescales, where a reduced model is derived by discarding rapidly decaying degrees of freedom. So far, adiabatic elimination has been formulated using a geometric approach, which provides a versatile and general framework. This article introduces a reformulation of adiabatic elimination through the framework of the time-convolutionless (TCL) master equation, a widely recognized tool for computing projected time evolution in open quantum systems. We show that the TCL master equation formulation yields results equivalent to those obtained from the geometric formulation. By applying the TCL master equation formulation to typical examples, we demonstrate a practical methodology for performing adiabatic elimination calculation. This study not only bridges two previously independent approaches, thereby making the adiabatic elimination method accessible to a broader audience, but also enables the analysis of complex cases that are challenging within the geometric formulation. Additionally, it reveals a geometric interpretation of the TCL master equation formalism.}, archive = {J_PRA}, author = {Masaaki Tokieda and Angela Riva}, doi = {10.1103/PhysRevA.111.052206}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052206}, shortjournal = {Phys. Rev. A}, title = {Time-convolutionless master equation applied to adiabatic elimination}, volume = {111}, year = {2025}, }
• (2025). Characterizing quantum state-space with a single quantum measurement. PRA, 111(5), 052205. (www)

  @article{ , abstract = {Can the state-space of -dimensional quantum theory be derived from studying the behavior of a single “reference” measuring device? The answer is yes, if the measuring device corresponds to a complex-projective 3-design. In this privileged case, not only does each quantum state correspond to a probability distribution over the outcomes of a single measurement, but also the probability distributions which correspond to quantum states can be elegantly characterized as those which respect a generalized uncertainty principle. The latter takes the form of a lower-bound on the variance of a natural class of observables as measured by the reference. We give simple equations which pure-state probability distributions must satisfy, and contextualize these results by showing how 3-designs allow the structure-coefficients of the Jordan algebra of observables to be extracted from the probabilities which characterize the reference measurement itself. This lends credence to the view that quantum theory ought to be primarily understood as a set of normative constraints on probability assignments which reflect nature's lack of hidden variables and further cements the significance of 3-designs in quantum information science.}, archive = {J_PRA}, author = {Matthew B. Weiss}, doi = {10.1103/PhysRevA.111.052205}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052205}, shortjournal = {Phys. Rev. A}, title = {Characterizing quantum state-space with a single quantum measurement}, volume = {111}, year = {2025}, }
• (2025). Two fundamental solutions to the rigid kochen-specker set problem and the solution to the minimal kochen-specker set problem under one assumption. PRA, 111(5), 052204. (www)

  @article{ , abstract = {Recent results show that Kochen-Specker (KS) sets of observables are fundamental to quantum information, computation, and foundations beyond previous expectations. Among KS sets, those that are unique up to unitary transformations (i.e., “rigid”) are especially important. The problem is that we do not know any rigid KS set in , the smallest quantum system that allows for KS sets. Moreover, none of the existing methods for constructing KS sets leads to rigid KS sets in . Here, we show that two fundamental structures of quantum theory define two rigid KS sets. One of these structures is the supersymmetric informationally complete positive-operator-valued measure. The other is the minimal state-independent contextuality set. The second construction provides a clue to solve the minimal KS problem, the most important open problem in this field. We prove that there is no KS set of 30 elements that can be obtained from the minimal state-independent contextuality set by completing bases and adding elements that are orthogonal to two previous elements. We conjecture that 31 is the solution to the minimal KS set problem.}, archive = {J_PRA}, author = {Stefan Trandafir and Adán Cabello}, doi = {10.1103/PhysRevA.111.052204}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052204}, shortjournal = {Phys. Rev. A}, title = {Two fundamental solutions to the rigid kochen-specker set problem and the solution to the minimal kochen-specker set problem under one assumption}, volume = {111}, year = {2025}, }
• (2025). Parametric approximation as an open-quantum-system problem. PRA, 111(5), 052203. (www)

  @article{ , abstract = {In this work we develop an open quantum system view of the parametric approximation, which allows us to obtain systematic perturbative corrections to it. We consider the Jaynes-Cummings model with dissipation, assuming that the field is in the regime close to the parametric approximation with depletion. We obtain non-unitary corrections to the parametric approximation and additional dynamical Lamb-shift contributions to it. For high detuning, these nonunitary corrections appear to be non-Markovian before depletion. We also show that even after depletion, initial non-Markovian behavior contributes to the dynamics via laser-induced polishing of the density matrix.}, archive = {J_PRA}, author = {Artem Karasev and Alexander Teretenkov}, doi = {10.1103/PhysRevA.111.052203}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052203}, shortjournal = {Phys. Rev. A}, title = {Parametric approximation as an open-quantum-system problem}, volume = {111}, year = {2025}, }
• (2025). Superclassical non-markovian open quantum dynamics. PRA, 111(5), 052202. (www)

  @article{ , abstract = {We characterize a class of superclassical non-Markovian open quantum system dynamics that are defined by their lack of measurement invasiveness when the corresponding observable commutates with the premeasurement state. This diagonal noninvasiveness guarantees that joint probabilities for measurement outcomes fulfill classical Kolmogorov consistency conditions. These features are fulfilled regardless of the previous (measurement) system history and are valid at arbitrary later times after an arbitrary system initialization. It is shown that a subclass of depolarizing dynamics, which are based on a (time-irreversible) nonunitary system-environment coupling, satisfy the required properties. The relationship with other operational [S. Milz et al. , Phys. Rev. X 10 , 041049 (2020) ] and nonoperational [M. Banacki et al. , Phys. Rev. A 107 , 032202 (2023) ] notions of classicality in non-Markovian open quantum systems is studied in detail and exemplified through different examples.}, archive = {J_PRA}, author = {Adrián A. Budini}, doi = {10.1103/PhysRevA.111.052202}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052202}, shortjournal = {Phys. Rev. A}, title = {Superclassical non-markovian open quantum dynamics}, volume = {111}, year = {2025}, }
• (2025). General-relativistic particle trajectories via quantum mechanical weak values and the schwarzschild-alcubierre spacetime. PRA, 111(5), 052201. (www)

  @article{ , abstract = {We show that the average trajectories of relativistic quantum particles in Schwarzschild spacetime, obtained via quantum mechanical weak measurements of momentum and energy, are equivalent to the predicted flow lines of probability current in curved spacetime quantum theory. We subsequently demonstrate that these trajectories correspond exactly to classical null geodesics in a hybrid Schwarzschild-Alcubierre spacetime. This threefold equivalence demonstrates how quantum theory in curved spacetime can be formulated via operationally defined measurements, and that such a theory may be interpreted deterministically, in the spirit of hidden-variable models such as Bohmian mechanics, through the novel connection to an underlying “guiding metric.”}, archive = {J_PRA}, author = {Joshua Foo and Cameron Bellamy and Timothy C. Ralph}, doi = {10.1103/PhysRevA.111.052201}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {052201}, shortjournal = {Phys. Rev. A}, title = {General-relativistic particle trajectories via quantum mechanical weak values and the schwarzschild-alcubierre spacetime}, volume = {111}, year = {2025}, }
• (2025). Antihydrogen chemistry. PRA, 111(5), 050101. (www)

  @article{ , abstract = {A survey of antimatter reactions is presented, including the formation of the antihydrogen atom and anionic, cationic, and molecular species by collisional and radiative processes. Our approach is rooted in the detailed knowledge available for many matter counterpart (hydrogenic) reactions, due to their importance in controlling early Universe chemistry. We point out that the availability of trapped antihydrogen at densities similar to those pertaining to the epoch of hydrogen chemistry will soon be available. In addition, using modern atomic physics techniques, it should be feasible to control antimatter in the laboratory to facilitate antihydrogen chemistry. Our purpose is to summarize what is known from hydrogen chemistry that is of relevance for antimatter and to indicate, based on possible reaction rates, which processes may be fruitful to pursue to create new antimatter entities as probes of fundamental symmetries. We include antihydrogen, positrons, and antiprotons in our discussion and additionally the electron due to its propensity to form positronium and perhaps to participate in certain reactions. We attempt to indicate whether further theoretical/computational work is necessary to add to the assessment of reaction rates, and we discount processes where the projected rates are too low to be of interest, given foreseeable experimental capabilities.}, archive = {J_PRA}, author = {Mark C. Zammit and Christopher J. Baker and Svante Jonsell and Stefan Eriksson and Michael Charlton}, doi = {10.1103/PhysRevA.111.050101}, journal = {Physical Review a}, month = {5}, number = {5}, pages = {050101}, shortjournal = {Phys. Rev. A}, title = {Antihydrogen chemistry}, volume = {111}, year = {2025}, }
• (2025). Probing non-gaussian correlations through entanglement generation in a many-body quantum system. PRA, 111(4), L041302. (www)

  @article{ , abstract = {In understanding strongly correlated quantum systems, quantifying the non-Gaussian nature of interparticle correlations is invaluable. We show that, for a uniform quantum gas, there exists a natural connection between non-Gaussian correlations and the generation of momentum-space entanglement. Furthermore, this entanglement can be directly measured in an experiment using time-of-flight techniques. To create a prototype of our method, we numerically study entanglement generation in a degenerate Bose gas following a quench to the unitary regime, where Gaussian and non-Gaussian correlations are generated sequentially in time.}, archive = {J_PRA}, author = {J. van de Kraats and D. J. M. Ahmed-Braun and V. E. Colussi and S. J. J. M. F. Kokkelmans}, doi = {10.1103/PhysRevA.111.L041302}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041302}, shortjournal = {Phys. Rev. A}, title = {Probing non-gaussian correlations through entanglement generation in a many-body quantum system}, volume = {111}, year = {2025}, }
• (2025). Scaling laws governing the collapse of a bose-einstein condensate. PRA, 111(4), L041301. (www)

  @article{ , abstract = {We study the collapse of an attractive Bose-Einstein condensate, where an unstable system evolves towards a singularity, by numerically solving the underlying cubic-quintic nonlinear Schrödinger equation. We find good agreement between our simulations and the atom-loss measurements with a K 39 condensate. Our simulations reveal an interplay of weak collapse and the propensity of the system to form a hotspot and we uncover scaling laws that govern this behavior. We also identify promising signatures of the theoretically predicted, but so far experimentally elusive, elastic three-body interactions.}, archive = {J_PRA}, author = {Sebastian J. Morris and Christopher J. Ho and Simon M. Fischer and Jiří Etrych and Gevorg Martirosyan and Zoran Hadzibabic and Christoph Eigen}, doi = {10.1103/PhysRevA.111.L041301}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041301}, shortjournal = {Phys. Rev. A}, title = {Scaling laws governing the collapse of a bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Resonant stroboscopic rydberg dressing: Electron-motion coupling and multibody interactions. PRA, 111(4), L041104. (www)

  @article{ , abstract = {Rydberg dressing traditionally refers to a technique where interactions between cold atoms are imprinted through the far off-resonant continuous-wave excitation of high-lying Rydberg states. Dipolar interactions between these electronic states are then translated into effective interactions among ground-state atoms. Motivated by recent experiments, we investigate two dressing protocols, in which Rydberg atoms are resonantly excited in a stroboscopic fashion. The first one is nonadiabatic, meaning Rydberg states are excited by short pulses. In this case, mechanical forces among Rydberg atoms result in electron-motion coupling, which generates effective multibody interactions. In the second, adiabatic protocol, Rydberg states are excited by smoothly varying laser pulses. We show that also, in this protocol, substantial multibody interactions emerge.}, archive = {J_PRA}, author = {Chris Nill and Sylvain de Léséleuc and Christian Groß and Igor Lesanovsky}, doi = {10.1103/PhysRevA.111.L041104}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041104}, shortjournal = {Phys. Rev. A}, title = {Resonant stroboscopic rydberg dressing: Electron-motion coupling and multibody interactions}, volume = {111}, year = {2025}, }
• (2025). Resonance nuclear excitation of the th229 nucleus via electronic bridge process in th ii. PRA, 111(4), L041103. (www)

  @article{ , abstract = {The 8.4-eV transition in the nucleus is the basis for a high-precision nuclear clock with exceptional sensitivity to new physics effects. We have identified several cases in the ion where electronic excitations closely resonate with the nuclear excitation, with the smallest energy difference being . We investigate the electronic bridge process, in which nuclear excitation is induced via electronic transitions, and demonstrate that a proper selection of laser frequencies can lead to a dramatic enhancement of this effect. Additionally, we show that the interaction with electrons significantly shortens the lifetime of the nuclear excited state.}, archive = {J_PRA}, author = {V. A. Dzuba and V. V. Flambaum}, doi = {10.1103/PhysRevA.111.L041103}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041103}, shortjournal = {Phys. Rev. A}, title = {Resonance nuclear excitation of the th229 nucleus via electronic bridge process in th ii}, volume = {111}, year = {2025}, }
• (2025). Space-dependent photoelectron dynamics driven by intense vector vortex beams. PRA, 111(4), L041102. (www)

  @article{ , abstract = {Vortex beams are exotic states of classical light fields that contain orbital angular momentum (OAM) due to their space-dependent phases. While the experimental realization of intense low-frequency optical vortices has led to the discovery and application of OAM conservation in high-harmonic generation, there is not a comparable signature of light's OAM on photoelectrons. Here we propose using a linear combination of vortex modes, referred to as a vector vortex beam, for strong-field ionization of atoms. We then demonstrate that the input vortex beam's position-dependent phase can be obtained from the resulting electron momentum distribution following strong-field ionization. We validate this method by performing classical trajectory Monte Carlo simulations and comparing momentum distributions corresponding to different ionization locations within the beam profile, demonstrating that one can unambiguously determine the ionizing radiation's OAM index. These results are suitable for the added control offered by vortex light compared to Gaussian or plane-wave radiation in intense light-matter interactions.}, archive = {J_PRA}, author = {Alex Schimmoller and Spencer Walker and Harrison Pasquinilli and Alexandra S. Landsman}, doi = {10.1103/PhysRevA.111.L041102}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041102}, shortjournal = {Phys. Rev. A}, title = {Space-dependent photoelectron dynamics driven by intense vector vortex beams}, volume = {111}, year = {2025}, }
• (2025). Complete retrieval of attosecond photoelectron dynamics from partially coherent states in entangled photoemission. PRA, 111(4), L041101. (www)

  @article{ , abstract = {We show that the complete photoemission dynamics in situations of electron-ion entanglement can be retrieved from photoelectron spectral measurements without information on the ion. To this end, we develop an energy-time analysis of the photoelectron's reduced density matrix based on first principles. We test and assess our approach with numerical simulations on a low-dimensional model molecule in interaction with broadband composite pulses concealing the vibrational resolution. Our method is directly applicable to recent experimental schemes measuring the photoelectron reduced density matrices in atomic and molecular photoemission. Therefore, it opens a new window on the dynamics of decoherence and entanglement at the attosecond timescale.}, archive = {J_PRA}, author = {Morgan Berkane and Richard Taïeb and Gabriel Granveau and Pascal Salières and Charles Bourassin-Bouchet and Camille Lévêque and Jérémie Caillat}, doi = {10.1103/PhysRevA.111.L041101}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L041101}, shortjournal = {Phys. Rev. A}, title = {Complete retrieval of attosecond photoelectron dynamics from partially coherent states in entangled photoemission}, volume = {111}, year = {2025}, }
• (2025). Gaussian-basis-set approach to one-loop self-energy. PRA, 111(4), L040802. (www)

  @article{ , abstract = {We report a method for the evaluation of the one-loop self-energy, to all orders in the external binding field, using a Gaussian-basis-set expansion. This choice of basis is motivated by its widespread use in molecular calculations. For a one-electron atom, our results show excellent agreement with those obtained using the exact Dirac-Coulomb wave functions. The developed method can be of interest for high-precision studies of heavy few-electron molecular systems, where the rigorous computation of QED corrections is currently a formidable task.}, archive = {J_PRA}, author = {Dávid Ferenc and Maen Salman and Trond Saue}, doi = {10.1103/PhysRevA.111.L040802}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040802}, shortjournal = {Phys. Rev. A}, title = {Gaussian-basis-set approach to one-loop self-energy}, volume = {111}, year = {2025}, }
• (2025). Penning-trap mass measurement of he3. PRA, 111(4), L040801. (www)

  @article{ , abstract = {We have determined the atomic mass of He 3 to 12 parts per trillion relative precision from a measurement of the cyclotron frequency ratio of He + 3 and C 4 + 12 in a Penning trap. From the obtained mass of the He + 3 ion, the mass of the neutral atom can be calculated without loss of precision: m ( He 3 ) = 3.016 029 322 011 ( 35 ) u. This result provides independent, high-precision data for the last missing link between the masses in the regime of light ions, thereby resolving discrepancies in the reported masses of light atomic nuclei from various experiments.}, archive = {J_PRA}, author = {O. Bezrodnova and S. Sasidharan and W. Quint and S. Sturm and K. Blaum}, doi = {10.1103/PhysRevA.111.L040801}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040801}, shortjournal = {Phys. Rev. A}, title = {Penning-trap mass measurement of he3}, volume = {111}, year = {2025}, }
• (2025). Optimal sensing of photon addition and subtraction on nonclassical light. PRA, 111(4), L040601. (www)

  @article{ , abstract = {We demonstrate that the Wasserstein distance W 1 corresponding to optical tomograms of nonclassical states faithfully captures changes that arise due to photon addition to or subtraction from these states. W 1 is a true measure of distance in the quantum state space and is sensitive to the underlying interference structures that arise in the tomogram after changes in the photon number. Our procedure is universally applicable to the cat and squeezed states, the former displaying the characteristic negativity in its Wigner function, while the latter does not do so. We explicate this in the case of the squeezed vacuum and even coherent states and show that photon addition (or subtraction) is mirrored in the shift in the intensity of specific regions in the tomogram. Further, we examine the dependence of W 1 on the squeezing parameter and its sensitivity to different quadratures.}, archive = {J_PRA}, author = {Soumyabrata Paul and Arman and S. Lakshmibala and Prasanta K. Panigrahi and S. Ramanan and V. Balakrishnan}, doi = {10.1103/PhysRevA.111.L040601}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040601}, shortjournal = {Phys. Rev. A}, title = {Optimal sensing of photon addition and subtraction on nonclassical light}, volume = {111}, year = {2025}, }
• (2025). Detecting quantum resources in a semi-device-independent framework. PRA, 111(4), L040402. (www)

  @article{ , abstract = {We investigate whether one can detect the presence of a quantum resource in some operational task or equivalently whether every quantum resource provides an advantage over its free counterpart in some black box scenarios where one does not have much information about the devices. For any dimension d , we find that for any resource theory with less than d 2 number of linearly independent free states or free operations, there exist correlations that can detect the presence of a quantum resource. For this purpose, we introduce the framework for detecting quantum resources semidevice independently by considering the prepare-and-measure scenario with the restriction on the dimension of the quantum channel connecting the preparation box with the measurement box. We then explicitly construct witnesses to observe the presence of various quantum resources. We expect these results will open avenues for detecting and finding uses of quantum resources in general operational tasks.}, archive = {J_PRA}, author = {Shubhayan Sarkar and Chandan Datta}, doi = {10.1103/PhysRevA.111.L040402}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040402}, shortjournal = {Phys. Rev. A}, title = {Detecting quantum resources in a semi-device-independent framework}, volume = {111}, year = {2025}, }
• (2025). Protecting quantum information via many-body dynamical localization. PRA, 111(4), L040401. (www)

  @article{ , abstract = {Dynamically localized states in quantum many-body systems are fundamentally important in understanding quantum thermalization and have applications in quantum information processing. Here we explore many-body dynamical localization (MBDL) without disorders in a nonintegrable quantum XY spin chain under periodical and quadratic kicks. We obtain the localization phase regimes with the MBDL and delocalized states and show dynamical observables to extract the phase regipmes. For proper kick strengths in the MBDL phase, we reveal a local dynamical decoupling effect for persistent Rabi oscillation of certain spins. Furthermore, we propose the MBDL-protected quantum information at high temperatures and present an analysis of the dynamical decoupling to obtain the required system parameters for quantum storage. Compared to other nonthermalized states, the disorder-free MBDL states require much fewer repetitions and resources, providing a promising way to protect and store quantum information robust against thermal noises.}, archive = {J_PRA}, author = {Ling-Zhi Tang and Dan-Wei Zhang and Hai-Feng Yu and Z. D. Wang}, doi = {10.1103/PhysRevA.111.L040401}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040401}, shortjournal = {Phys. Rev. A}, title = {Protecting quantum information via many-body dynamical localization}, volume = {111}, year = {2025}, }
• (2025). Thermodynamic phases in first detected return times of quantum many-body systems. PRA, 111(4), L040202. (www)

  @article{ , abstract = {We study the probability distribution of the first return time to the initial state of a quantum many-body system subject to global projective measurements at stroboscopic times. We show that this distribution can be mapped to a continuation of the canonical partition function of a classical spin chain with noninteracting domains at equilibrium, which is entirely characterized by the Loschmidt amplitude of the quantum many-body system. This allows us to conclude that this probability may decay either algebraically or exponentially at long times, depending on whether the spin chain displays a ferromagnetic or a paramagnetic phase. We illustrate this idea on the example of the return time of N adjacent fermions in a tight-binding model, revealing a rich phase behavior, which can be tuned by scaling the probing time as a function of N . The analysis presented here provides an overarching understanding of many-body quantum first detection problems in terms of equilibrium thermodynamic phases. Our theoretical predictions are in excellent agreement with exact numerical computations.}, archive = {J_PRA}, author = {Benjamin Walter and Gabriele Perfetto and Andrea Gambassi}, doi = {10.1103/PhysRevA.111.L040202}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040202}, shortjournal = {Phys. Rev. A}, title = {Thermodynamic phases in first detected return times of quantum many-body systems}, volume = {111}, year = {2025}, }
• (2025). Universal criticality of nonequilibrium quantum phase transition in a driven-dissipative kerr cavity. PRA, 111(4), L040201. (www)

  @article{ , abstract = {The driven-dissipative nonlinear photon systems provide a promising platform to model the nonequilibrium quantum phase transitions. However, the critical property of such a phase transition has remained elusive. With the scaling theory, we accurately measure the critical point and critical exponents of the second-order quantum phase transition in a bosonic mode with a Kerr nonlinearity. The results show that the dissipative phase transition exhibits a weak universality class, in which the universality classes of the close and open quantum Rabi models in the previous studies are both included. Further, one may understand the spatial dimension d = 1 and the correlation length from the photon occupation probability distribution. When coupled to a quantum-dot electronic circuit, such quantum criticality can be detected by a simple transport signature. As an application, the photocurrent in an unbiased quantum dot system can be significantly enhanced near the phase transition.}, archive = {J_PRA}, author = {Jun-Yi Liu and Lei-Lei Nian and Nengji Zhou and Long Xiong and Jing-Tao Lü and Bo Zheng}, doi = {10.1103/PhysRevA.111.L040201}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {L040201}, shortjournal = {Phys. Rev. A}, title = {Universal criticality of nonequilibrium quantum phase transition in a driven-dissipative kerr cavity}, volume = {111}, year = {2025}, }
• (2025). Erratum: Long-distance distribution of qubit-qubit entanglement using gaussian-correlated photonic beams [Phys. rev. a 105, 062454 (2022)]. PRA, 111(4), 049903. (www)

  @article{ , abstract = {Phys. Rev. A 111, 049903 (2025)}, archive = {J_PRA}, author = {J. Agustí and Y. Minoguchi and J. M. Fink and P. Rabl}, doi = {10.1103/PhysRevA.111.049903}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {049903}, shortjournal = {Phys. Rev. A}, title = {Erratum: Long-distance distribution of qubit-qubit entanglement using gaussian-correlated photonic beams [Phys. rev. a 105, 062454 (2022)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Robustness of optimal probabilistic storage and retrieval of unitary channels to noise [Phys. rev. a 106, 052416 (2022)]. PRA, 111(4), 049902. (www)

  @article{ , abstract = {Phys. Rev. A 111, 049902 (2025)}, archive = {J_PRA}, author = {Jaroslav Pavličko and Mário Ziman}, doi = {10.1103/PhysRevA.111.049902}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {049902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Robustness of optimal probabilistic storage and retrieval of unitary channels to noise [Phys. rev. a 106, 052416 (2022)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Quantum state exclusion through offset measurement [Phys. rev. a 110, 042211 (2024)]. PRA, 111(4), 049901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 049901 (2025)}, archive = {J_PRA}, author = {Caleb McIrvin and Ankith Mohan and Jamie Sikora}, doi = {10.1103/PhysRevA.111.049901}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {049901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Quantum state exclusion through offset measurement [Phys. rev. a 110, 042211 (2024)]}, volume = {111}, year = {2025}, }
• (2025). Purification of gaussian states by photon subtraction or addition. PRA, 111(4), 043719. (www)

  @article{ , abstract = {Photon subtraction (PS) can enhance entanglement, which, for pure states, induces a decrease in the purity of reduced states. In contrast, by analyzing the purities of Gaussian states before and after subtracting or adding a single photon, we prove that the purity of a Gaussian state can be increased by less than 20%. On the one hand, it reveals that PS and photon addition (PA) can reduce entanglement, and on the other hand, it shows that PS or PA can achieve a limited amount of Gaussian state purification. Through the analysis of several examples, we demonstrate the inherent mechanism and applicable scope of photon-subtraction-based purification. We further compare the performance between PS and PA for purifying single-mode Gaussian states, and analyze their capabilities in generating Wigner negativity within purification regimes. In a multimode system, we find that PS can simultaneously increase entanglement and purify some of the reduced states. These findings demonstrate the new application potential of PS and PA, specifically their capability to directly suppress Gaussian noise.}, archive = {J_PRA}, author = {Kun Zhang and Huijun Li and Jietai Jing and Nicolas Treps and Mattia Walschaers}, doi = {10.1103/PhysRevA.111.043719}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043719}, shortjournal = {Phys. Rev. A}, title = {Purification of gaussian states by photon subtraction or addition}, volume = {111}, year = {2025}, }
• (2025). Quantum squeezed-reservoir engineering in laguerre-gaussian cavity optomechanics. PRA, 111(4), 043718. (www)

  @article{ , abstract = {Entanglement and squeezing are two useful resources in quantum technologies. Recent studies have increasingly focused on generating these nonclassical features in macroscopic objects. However, establishing entanglement and squeezing in the degrees of freedom of mechanical motion of macroscopic objects is generally hindered by thermal fluctuations of their environments. Here, we propose a scheme to generate steady-state squeezing and entanglement between two rotating mirrors of a Laguerre-Gaussian cavity by quantum squeezed-reservoir engineering. It is revealed that, by injecting a broadband squeezed light into the cavity, stable squeezing in the relative momentum and entanglement between the two rotating mirrors are created. Compared to the previous work where only the entanglement between the two rotating mirrors appears under the condition of different angular frequencies, our result highlights the stable entanglement of the two mirrors with identical frequency and the simultaneous presence of the entanglement and squeezing of the two mirrors. Our finding deepens our understanding of macroscopic quantum phenomena of Laguerre-Gaussian cavity optomechanical system.}, archive = {J_PRA}, author = {Rongfang Liu and Jun-Hong An}, doi = {10.1103/PhysRevA.111.043718}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043718}, shortjournal = {Phys. Rev. A}, title = {Quantum squeezed-reservoir engineering in laguerre-gaussian cavity optomechanics}, volume = {111}, year = {2025}, }
• (2025). Single-photon isolation and nonreciprocal frequency conversion in atom-waveguide systems. PRA, 111(4), 043717. (www)

  @article{ , abstract = {In this work, we utilize a two-level atom and a Λ -type atom to link two identical waveguides, subsequently extending the model to a giant-atom configuration. Our analytical solutions and numerical simulations demonstrate that this setup can achieve single-photon isolation and nonreciprocal frequency conversion by tuning the atom-waveguide coupling strengths g i , respectively. We also examine single-photon scattering in the giant-atom model within both the Markovian and non-Markovian regimes. The results reveal that ultranarrow scattering windows are induced by the phases ϕ 1 and ϕ 2 under specific conditions, making them well suited for precise frequency conversion and sensing. Additionally, in the non-Markovian regime, the spectra exhibit irregular polygonal shapes, offering enhanced opportunities for exploring nonreciprocal frequency conversion in the off-resonant regime. Our work provides an alternative perspective on achieving optical nonreciprocity at the single-photon level in atom-waveguide systems.}, archive = {J_PRA}, author = {Jun-Cong Zheng and Xiao-Wei Zheng and Xin-Lei Hei and Yi-Fan Qiao and Xiao-Yu Yao and Xue-Feng Pan and Yu-Meng Ren and Xiao-Wen Huo and Peng-Bo Li}, doi = {10.1103/PhysRevA.111.043717}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043717}, shortjournal = {Phys. Rev. A}, title = {Single-photon isolation and nonreciprocal frequency conversion in atom-waveguide systems}, volume = {111}, year = {2025}, }
• (2025). Superradiant phase transitions in the quantum rabi model: Overcoming the no-go theorem through anisotropy. PRA, 111(4), 043716. (www)

  @article{ , abstract = {Although the superradiant phase transition (SRPT) is prohibited in the paradigmatic quantum Rabi model due to the no-go theorem caused by the A 2 term, we demonstrate two distinct types of SRPTs emerging from the normal phase in the anisotropic quantum Rabi model. A discontinuous phase transition between the two types of superradiant phases also emerges in the presence of a strong A 2 term. Additionally, a rich phase diagram featuring a triple point, which connects first- and second-order phase transitions, is derived analytically and confirmed through numerical diagonalization at large effective system sizes. Finally, distinct critical behavior at the triple point is revealed and contrasted with that of a single continuous SRPT. This work may open a new avenue for observing SRPTs in their intrinsic form without altering the A 2 term, while also offering a practical platform for exploring rich quantum phenomena.}, archive = {J_PRA}, author = {Tian Ye and Yan-Zhi Wang and Xiang-You Chen and Qing-Hu Chen and Hai-Qing Lin}, doi = {10.1103/PhysRevA.111.043716}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043716}, shortjournal = {Phys. Rev. A}, title = {Superradiant phase transitions in the quantum rabi model: Overcoming the no-go theorem through anisotropy}, volume = {111}, year = {2025}, }
• (2025). Direct experimental observation of sub-poissonian photon statistics by means of multiphoton scattering on a two-level system. PRA, 111(4), 043715. (www)

  @article{ , abstract = {A cascade of two-level superconducting artificial atoms—a source and a probe—strongly coupled to a semi-infinite waveguide is a promising tool for observing nontrivial phenomena in quantum nonlinear optics. The probe atom can scatter an antibunched radiation emitted from the source, thereby generating a field with specific properties. We experimentally demonstrate wave mixing between nonclassical light from the coherently cw-pumped source and another coherent wave acting on the probe. We observe unique features in the wave mixing stationary spectrum which differs from the mixing spectrum of two classical waves on the probe. These features are well described by adapting the theory of Gardiner et al. [ Phys. Rev. A 50 , 1792 (1994) ] for a strongly coupled cascaded system of two atoms. We further analyze the theory to predict nonclassical mixing spectra for various ratios of atoms' radiative constants. Both experimental and numerical results confirm the domination of the multiphoton scattering process with only a single photon from the source. We evaluate entanglement of atoms in the quasistationary state and illustrate the connection between the expected second-order correlation function of the source field and wave mixing side peaks corresponding to a certain number of scattered photons.}, archive = {J_PRA}, author = {A. Yu. Dmitriev and A. V. Vasenin and S. A. Gunin and S. V. Remizov and A. A. Elistratov and W. V. Pogosov and O. V. Astafiev}, doi = {10.1103/PhysRevA.111.043715}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043715}, shortjournal = {Phys. Rev. A}, title = {Direct experimental observation of sub-poissonian photon statistics by means of multiphoton scattering on a two-level system}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal photon blockade induced by parametric amplification in an asymmetrical cavity. PRA, 111(4), 043714. (www)

  @article{ , abstract = {We propose a scheme to generate and manipulate nonreciprocal photon blockade effect in an asymmetrical Fabry-Pérot cavity, which consists of a single two-level atom and a second-order nonlinear medium. By utilizing the intrinsic spatial asymmetry of cavity and applying a parametric amplification pumping laser to the nonlinear medium, we can realize direction-dependent single-photon and two-photon blockade effects. For nonreciprocal single-photon blockade, our proposal is robust across a wide range of parameters, such as the cavity or atomic detuning, coupling strength, and atomic decay. Within similar parameter ranges, nonreciprocal two-photon blockade can be achieved and modulated by finely adjusting the parametric amplification pumping. Our project offers a feasible access to generating high-quality and tunable nonreciprocal single- or two-photon sources and paves a new avenue for investigating the nonreciprocity of photon quantum statistical properties.}, archive = {J_PRA}, author = {Shao-Xiong Wu and Xue-Chen Gao and Huan-Huan Cheng and Cheng-Hua Bai}, doi = {10.1103/PhysRevA.111.043714}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043714}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal photon blockade induced by parametric amplification in an asymmetrical cavity}, volume = {111}, year = {2025}, }
• (2025). Targeted quantum routing of single photons in a giant-atom waveguide-QED system. PRA, 111(4), 043713. (www)

  @article{ , abstract = {In this paper, we propose a single-photon routing scheme using a hybrid system, where a two-level giant atom is coupled to a pair of one-dimensional coupled-resonator waveguides. Using the discrete-coordinate scattering approach, exact expressions of the four scattering coefficients are obtained, and the single-photon routing properties are studied. We find that the single-photon routing properties are closely related to the size of the giant atom, the coupling strength between the giant atom and waveguides, and the phase difference between two coupled channels of the atom-upper (lower) waveguide. Without considering the effect of phases of the atom-waveguide coupling coefficients, the probability for a single-photon routing from one waveguide to the other does not exceed 50 % . However, by properly selecting coupling points between the giant atom and two waveguides, and the phase difference between two atom-upper (lower) waveguide coupling coefficients, a single photon can be transferred from the input port to an arbitrarily selected output port deterministically, i.e., with 100 % probability. It is also found that chiral and nonreciprocal single-photon scattering can be realized in our model by properly adjusting the phase difference between two atom-upper (lower) waveguide coupled channels. Our paper offers a promising route towards achieving tunable single-photon routing and constructing optical scalable quantum networks.}, archive = {J_PRA}, author = {Yong Wang and Wen-An Li and Yuan Chen}, doi = {10.1103/PhysRevA.111.043713}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043713}, shortjournal = {Phys. Rev. A}, title = {Targeted quantum routing of single photons in a giant-atom waveguide-QED system}, volume = {111}, year = {2025}, }
• (2025). Quantum hyperspins: Highly nonclassical collective behavior in quantum-optical parametric oscillators. PRA, 111(4), 043712. (www)

  @article{ , abstract = {We report on the emergence of a highly nonclassical collective behavior in quantum parametric oscillators, which we name quantum hyperspin, induced by a tailored nonlinear interaction. This is the second quantized version of classical multidimensional spherical spins, as X Y spins in two dimensions, and Heisenberg spins in three dimensions. In the phase space, the quantum hyperspins are represented as spherical shells whose radius scales with the number of particles in a way such that it cannot be factorized even in the limit of large particle number. We show that the nonlinearly coupled quantum oscillators form a high-dimensional entangled state that is surprisingly robust with respect to the coupling with the environment. Such a behavior results from a properly engineered reservoir. Networks of entangled quantum hyperspins are a new approach to quantum simulations for applications in computing, Ising machines, and high-energy physics models. We analyze from first principles through ab initio numerical simulations the properties of quantum hyperspins, including the interplay of entanglement and coupling frustration.}, archive = {J_PRA}, author = {Marcello Calvanese Strinati and Claudio Conti}, doi = {10.1103/PhysRevA.111.043712}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043712}, shortjournal = {Phys. Rev. A}, title = {Quantum hyperspins: Highly nonclassical collective behavior in quantum-optical parametric oscillators}, volume = {111}, year = {2025}, }
• (2025). Programmable integrated source of polarization and frequency-bin hyperentangled photon pairs. PRA, 111(4), 043711. (www)

  @article{ , abstract = {We present a system capable of generating programmable polarization and frequency-bin hyperentangled photon pairs in an integrated photonic device. The structure is composed of ring resonators, each generating photon pairs with the same polarization in two pairs of frequency bins via spontaneous four-wave mixing. By combining several rings and controlling the amplitude and phase of the pump field, one can construct several hyperentangled states in a piece-by-piece fashion. For example, we consider a system composed of four rings and show that the density operator of the generated state describes a polarization and frequency-bin hyperentangled state. Finally, we calculate the expected generation rate and discuss the device efficiency.}, archive = {J_PRA}, author = {Colin Vendromin and J. E. Sipe and Marco Liscidini}, doi = {10.1103/PhysRevA.111.043711}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043711}, shortjournal = {Phys. Rev. A}, title = {Programmable integrated source of polarization and frequency-bin hyperentangled photon pairs}, volume = {111}, year = {2025}, }
• (2025). Exotic behavior of parity in the superradiant phase of the quantum rabi model. PRA, 111(4), 043710. (www)

  @article{ , abstract = {Parity describing the symmetry of quantum-mechanical wave functions under space inversion transformation not only plays an essential role in solving quantum systems but also can be used to manipulate and measure the motional quantum states of hybrid quantum systems such as the quantum Rabi model (QRM) and/or its variants through parity measurements. Here we address an exotic parity behavior of the QRM in its superradiant phase by numerical exact diagonalization, namely, the parities of eigenstates of the QRM behave irregularly in the strong-coupling regime but the sum of parities for each pair of neighboring eigenstates beginning from the ground state remains vanishing. It is found that this exotic behavior originates from the comparability of the photon distribution in the odd and even components of Fock basis when the eigenenergies of each pair of neighboring eigenstates approach close enough to each other, and physically this is due to the emergent double-well potential induced by the strong coupling between the single-mode photon field and the two-level atom. The result not only uncovers the physics not known previously in the QRM but also makes an intrinsic limitation on the measurement precision of motional quantum states through parity measurements in modern quantum science and technology.}, archive = {J_PRA}, author = {Yun-Tong Yang and Junpeng Liu and Hong-Gang Luo}, doi = {10.1103/PhysRevA.111.043710}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043710}, shortjournal = {Phys. Rev. A}, title = {Exotic behavior of parity in the superradiant phase of the quantum rabi model}, volume = {111}, year = {2025}, }
• (2025). Stability of macroscopic spin ensembles against inhomogeneous dephasing. PRA, 111(4), 043709. (www)

  @article{ , abstract = {Spin ensembles play a pivotal role in various quantum applications such as metrology and simulations of many-body physics. Recent research has proposed utilizing spin cat states to encode logical quantum information, with logical lifetimes potentially on the order of seconds, achieved via enhanced collective interactions that scale with system size. We investigate the dynamics of spin cat states under inhomogeneous broadening, revealing a phenomenon termed “parity-sensitive inhomogeneous dephasing”: For small amplitudes, odd cat states are significantly more susceptible to inhomogeneous dephasing than even cat states due to the difference in parity symmetry. This discrepancy between even and odd cat states vanishes at large amplitudes and behaves similarly to a spin coherent state with the same amplitude. To analyze the stability of the spin coherent state, we perform a mean-field analysis of the driven-dissipative dynamics, from which we identify a synchronization phase transition wherein the ensemble becomes completely dephased beyond a critical inhomogeneous linewidth. The mean-field analysis suggests that the dissipative stabilization can suppress the decoherence effects from inhomogeneous broadening. We argue that the stability of the mean-field model provides a reasonable estimate for that of spin cat states with a large amplitude in the full quantum model. Our findings shed light on the stability of collective spin states, which is important for advancing quantum technologies.}, archive = {J_PRA}, author = {Wai-Keong Mok and Leong-Chuan Kwek and Steven Touzard}, doi = {10.1103/PhysRevA.111.043709}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043709}, shortjournal = {Phys. Rev. A}, title = {Stability of macroscopic spin ensembles against inhomogeneous dephasing}, volume = {111}, year = {2025}, }
• (2025). Tunable photonic spin hall effect in a tripod atom-light configuration. PRA, 111(4), 043708. (www)

  @article{ , abstract = {We propose a four-level tripod atom-light coupling scheme to manipulate the photonic spin Hall effect (PSHE) in the reflected probe light. Our study demonstrates that the tripod configuration enables enhanced PSHE near the Brewster angle upon reflection for the probe field, with significantly stronger transverse shifts at resonance compared to off-resonance conditions. The PSHE shift is maximized when all fields are resonant, aligning with the transparency point of the system, and is notably weaker under off-resonant conditions, where gain effects dominate. Additionally, the tripod scheme enables an enhanced transverse shift for the signal field at resonance, resulting in dual-field PSHE enhancement. This combined enhancement of transverse shift for both probe and signal fields underscores the superiority of the tripod configuration in achieving maximized PSHE shifts, surpassing prior schemes and opening new possibilities for advanced applications in spin-photonic devices.}, archive = {J_PRA}, author = {Muqaddar Abbas and Pei Zhang and Hamid R. Hamedi}, doi = {10.1103/PhysRevA.111.043708}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043708}, shortjournal = {Phys. Rev. A}, title = {Tunable photonic spin hall effect in a tripod atom-light configuration}, volume = {111}, year = {2025}, }
• (2025). Designing a compact cavity-enhanced source of entangled photons. PRA, 111(4), 043707. (www)

  @article{ , abstract = {Entanglement will be the key resource of future large-scale quantum networks, enabling quantum communication and advanced quantum applications like distributed quantum sensing and distributed quantum computing. To this end, entanglement will have to be distributed over large distances and efficiently coupled to quantum devices at the network nodes. This requires the entangled photons to have wavelengths and bandwidths compatible with the quantum memories in quantum repeater nodes or quantum devices at client nodes. Here, we present a cavity-enhanced source design using two nonlinear crystals inside a single cavity. We provide detailed considerations balancing the complexity of the cavity design with the photon bandwidth and the entanglement quality.}, archive = {J_PRA}, author = {Žiga Pušavec and Lara Ulčakar and Rainer Kaltenbaek}, doi = {10.1103/PhysRevA.111.043707}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043707}, shortjournal = {Phys. Rev. A}, title = {Designing a compact cavity-enhanced source of entangled photons}, volume = {111}, year = {2025}, }
• (2025). Critical spectrum of the anisotropic two-photon quantum rabi model. PRA, 111(4), 043706. (www)

  @article{ , abstract = {The anisotropic two-photon quantum Rabi model is studied using the Bogoliubov operator approach. Doubly degenerate exceptional states are identified using analytical methods. By adjusting the position of the last exceptional point belonging to two adjacent energy levels, we derive a condition for the absence of the discrete spectrum at the critical coupling where “spectral collapse” occurs. In this special case, the spectrum becomes fully continuous above a threshold energy, with no bound states existing, whereas the ground state remains gapped in the general case. More interestingly, we rigorously find that a finite number of bound states exist between two anisotropy-dependent critical atomic frequencies, with infinitely many bound states beyond this frequency regime. In this manner, all issues in the two-photon quantum Rabi model are resolved.}, archive = {J_PRA}, author = {Jiong Li and Daniel Braak and Qing-Hu Chen}, doi = {10.1103/PhysRevA.111.043706}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043706}, shortjournal = {Phys. Rev. A}, title = {Critical spectrum of the anisotropic two-photon quantum rabi model}, volume = {111}, year = {2025}, }
• (2025). Correlating two qubits via a common cavity. PRA, 111(4), 043705. (www)

  @article{ , abstract = {Generation of quantum entanglement between a pair of qubits is studied in a cavity-QED platform. The qubit pair is placed inside a common cavity environment. We show that the relative strength of qubit-photon couplings is crucial for establishing interqubit entanglement. Resonance as well as off resonance between the qubits and photon are considered. For the off-resonant case we detect a threshold value of the coupling ratio, beyond which the maximally entangled state is always available. The resonant case displays interesting nonmonotonic behavior, where the maximum entanglement peaks at an intermediate coupling ratio. The driven-dissipative dynamics of our model exhibits nontrivial dependence of steady-state entanglement on the drive strength.}, archive = {J_PRA}, author = {Amit Dey}, doi = {10.1103/PhysRevA.111.043705}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043705}, shortjournal = {Phys. Rev. A}, title = {Correlating two qubits via a common cavity}, volume = {111}, year = {2025}, }
• (2025). Extended analysis of distillation and purification of squeezed states of light. PRA, 111(4), 043704. (www)

  @article{ , abstract = {Squeezed states of light are one of the most important fundamental resources for quantum optics, optical quantum information processing, and quantum sensing. Recently, it has been experimentally demonstrated that the squeezing of single-mode squeezed vacuum states can be enhanced by probabilistic two-photon subtraction. A further enhancement of the squeezing is subsequently possible by heralded Gaussification, which distills a Gaussian state from the de-Gaussified two-photon subtracted state. Here we provide an extended theoretical analysis of squeezing distillation and purification. We consider a more general scheme in which photon subtraction is combined with a weak coherent displacement. This more flexible scheme allows us to enhance squeezing for an arbitrary input squeezing value. Moreover, if the modified two-photon subtraction operation is properly chosen, then arbitrary strong squeezing can be distilled by subsequent Gaussification. We go beyond pure states and show that the combination of photon subtraction and heralded Gaussification cannot suppress losses that have affected the input state. To overcome this limitation, we propose an alternative de-Gaussifying operation based on a Fock-state filter that removes the single-photon state. With this de-Gaussifying operation and subsequent re-Gaussification, pure single-mode squeezed states can be distilled from a large class of mixed input states. Interestingly, we have found that squeezing distillation by two-photon subtraction is closely related to certain methods for generating Gottesman-Kitaev-Preskill states, which are crucial for optical quantum computing.}, archive = {J_PRA}, author = {Jaromír Fiurášek and Stephan Grebien and Roman Schnabel}, doi = {10.1103/PhysRevA.111.043704}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043704}, shortjournal = {Phys. Rev. A}, title = {Extended analysis of distillation and purification of squeezed states of light}, volume = {111}, year = {2025}, }
• (2025). Strongly quadrature-squeezed light from a single multilevel atom. PRA, 111(4), 043703. (www)

  @article{ , abstract = {We propose schemes for steady-state emission of quadrature-squeezed light from a single-atom cavity quantum electrodynamics system. Two effective atom-cavity interaction models are suggested, motivated by correlated photon-pair emissions and multiphoton coherences that manifest themselves as squeezing of light emitted from the cavity. We consider idealized models to examine the mechanisms and optimal regimes for generating squeezed light. We also demonstrate realizations of these models based on both single 8 7 R b and 1 3 3 C s atoms, using combinations of laser- and laser-plus-cavity-driven Raman transitions between magnetic sublevels in a single ground hyperfine state. We show that these systems can in principle produce a much stronger level of squeezing than has previously been possible from a single-atom source.}, archive = {J_PRA}, author = {Alex Elliott and Scott Parkins}, doi = {10.1103/PhysRevA.111.043703}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043703}, shortjournal = {Phys. Rev. A}, title = {Strongly quadrature-squeezed light from a single multilevel atom}, volume = {111}, year = {2025}, }
• (2025). Correlated relaxation and emerging entanglement in arrays of Λ-type atoms. PRA, 111(4), 043702. (www)

  @article{ , abstract = {We present a theoretical framework for investigating the nonclassical collective relaxation in arrays of -type three-level atoms, where the two optical transitions are coupled to a pair of orthogonal chiral or achiral waveguide modes. We demonstrate that the atomic entanglement emerges in the course of relaxation and persists in the final steady state of the system. We also reveal the entanglement among the emitted photons as well as between the atoms and the photons. The presence and the degree of the entanglement depend crucially on the interatomic distance and the chirality of the waveguide. Our findings open a new way to engineer dissipation-induced entanglement.}, archive = {J_PRA}, author = {Denis Ilin and Alexander V. Poshakinskiy and Alexander S. Solntsev}, doi = {10.1103/PhysRevA.111.043702}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043702}, shortjournal = {Phys. Rev. A}, title = {Correlated relaxation and emerging entanglement in arrays of Λ-type atoms}, volume = {111}, year = {2025}, }
• (2025). Large-baseline quantum telescopes assisted by partially distinguishable photons. PRA, 111(4), 043701. (www)

  @article{ , abstract = {Quantum entanglement can be used to extend the baseline of telescope arrays in order to increase the spatial resolution. In one proposal by Marchese and Kok [ Phys. Rev. Lett. 130 , 160801 (2023) ], identical single photons are shared between receivers and interfere with a star photon. In this paper we consider two outstanding questions: (i) what is the precise effect of the low photon occupancy of the mode associated with the starlight? and (ii) what is the effect on the achievable resolution of imperfect indistinguishability (or partial distinguishability) between the ground and star photons? We find that the effect of distinguishability is relatively mild, but low photon occupancy of the optical mode of the starlight quickly deteriorates the sensitivity of the telescope for higher auxiliary photon numbers.}, archive = {J_PRA}, author = {Subhrajit Modak and Pieter Kok}, doi = {10.1103/PhysRevA.111.043701}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043701}, shortjournal = {Phys. Rev. A}, title = {Large-baseline quantum telescopes assisted by partially distinguishable photons}, volume = {111}, year = {2025}, }
• (2025). Formulation of threshold excitation intensity for light amplification in organic whispering-gallery-mode resonators. PRA, 111(4), 043530. (www)

  @article{ , abstract = {We have formulated a threshold intensity for the light excitation required to amplify the photoluminescent (PL) intensity confined in organic whispering-gallery-mode (WGM) resonators. The parameters included in the formula comprise the propagation loss, the resonator thickness, the energy of the light, the light confinement factor, the stimulated emission cross section, the PL quantum yield, and the fraction of the exciton energy that can be afforded to generate the stimulated emission for each PL peak. To compare the theoretical with the experimental , we fabricated 300-nm-thick disk-shaped WGM resonators from the highly efficient blue laser molecule 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorene (terfluorene) on 1-µm-high glass microdisks with diameters ranging from 3 to 10 µm. The theoretical replicated the experimentally obtained values, thus demonstrating the validity of the proposed formula. The value in the WGM resonators was three orders of magnitude higher than the corresponding value reported for a simple slab-type waveguide that was fabricated from terfluorene. We assessed the mechanism that causes the high using the proposed formula and found that the high value mainly originated from attenuation of the confined PL emission that occurred during orbiting within the WGM resonators. This result suggests that the formula will be beneficial in clarifying the dominant factor that governs .}, archive = {J_PRA}, author = {Kazuki Imada and Seina Miyamoto and Takeshi Komino and Tokuji Yokomatsu and Kazusuke Maenaka}, doi = {10.1103/PhysRevA.111.043530}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043530}, shortjournal = {Phys. Rev. A}, title = {Formulation of threshold excitation intensity for light amplification in organic whispering-gallery-mode resonators}, volume = {111}, year = {2025}, }
• (2025). Energy scalability limits of dissipative solitons. PRA, 111(4), 043529. (www)

  @article{ , abstract = {In this study, we apply a thermodynamical approach to elucidate the primary constraints on the energy scaling of dissipative solitons (DS). We rely on the adiabatic theory of strongly chirped DS and define the DS energy scaling in terms of dissipative soliton resonance (DSR). Three main experimentally verifiable signatures identify a transition to DSR: (i) growth of a Lorentzian spike at the centrum of the DS spectrum, which resembles a spectral condensation in Bose-Einstein condensate, (ii) saturation of the spectrum broadening, and (iii) asymptotic DS stretching. We connect the DSR breakup with three critical factors: (i) decoupling of two correlation scales inherent in strongly chirped DS, (ii) resulting rise of the DS entropy with energy, which provokes its disintegration, and (iii) transition to a nonequilibrium phase, which is characterized by negative temperature. The breakup results in multiple stable DS generation. Theoretical results are in good qualitative agreement with the experimental data from a Kerr-lens mode-locked Cr 2 + :ZnS chirped-pulse oscillator (CPO) that paves the way for optimizing high-energy femtosecond pulse generation in solid-state CPO and all-normal-dispersion fiber lasers.}, archive = {J_PRA}, author = {Vladimir L. Kalashnikov and Alexander Rudenkov and Evgeni Sorokin and Irina T. Sorokina}, doi = {10.1103/PhysRevA.111.043529}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043529}, shortjournal = {Phys. Rev. A}, title = {Energy scalability limits of dissipative solitons}, volume = {111}, year = {2025}, }
• (2025). Collective explosive dynamics of soliton rains in a figure-8 tm-doped fiber laser. PRA, 111(4), 043528. (www)

  @article{ , abstract = {We report the explosive events of unidirectional and bidirectional soliton rains (SRs) in a Tm-doped fiber laser mode locked by the nonlinear amplifying loop mirror technology. It is observed that the explosive evolution undergoes a disintegrating process from a multi-SR state to a normal SR, and to a soliton group followed by annihilation, and eventually to the explosion. Continuous observations reveal that each explosion exhibits a decay, a sudden drop, and an eruption of energy, thereby manifesting a quasiperiodic characteristic. A numerical experiment has effectively simulated the explosive processes and confirmed the Q -switching effect inside the collective soliton explosions. An analysis of the orbit diagrams derived from nonlinear mapping solidly substantiates the origin of the SR explosions: a gain-modulated mode-locking mechanism. These findings unveil an extreme collective soliton behavior in dissipative systems.}, archive = {J_PRA}, author = {Bo Yang Su and Jin Jer Huang and Ze Xin Du and Xin Lu Zhang}, doi = {10.1103/PhysRevA.111.043528}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043528}, shortjournal = {Phys. Rev. A}, title = {Collective explosive dynamics of soliton rains in a figure-8 tm-doped fiber laser}, volume = {111}, year = {2025}, }
• (2025). Topological π/2 modes in photonic waveguide arrays. PRA, 111(4), 043527. (www)

  @article{ , abstract = {Periodic driving is a powerful tool to generate exotic topological phases without static counterparts, such as the anomalous chiral edge modes from bulk bands with zero Chern number and topological modes exhibiting period-doubled dynamics. Recently, a new class of Floquet topological mode, namely, the mode, which carries four-period periodicity and has potential applications in quantum computing, was proposed based on a square-root method and realized in an acoustic system. Here we propose a laser-written waveguide array lattice to realize topological modes in photonics. Our photonic model simulates a square-root periodically driven Su-Schrieffer-Heeger model and has a rich phase diagram allowing for the coexistence of conventional zero, modes, and the new modes. Through numerical simulations of the wave equation, we uncover the unique four-period evolution feature of the modes. Our model, which only contains four waveguides per unit cell and two driving steps, is easy to implement with current fabrication techniques and may find applications in quantum optics.}, archive = {J_PRA}, author = {Gang Jiang and Siyuan Zhang and Weiwei Zhu and Y. X. Zhao and Haoran Xue}, doi = {10.1103/PhysRevA.111.043527}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043527}, shortjournal = {Phys. Rev. A}, title = {Topological π/2 modes in photonic waveguide arrays}, volume = {111}, year = {2025}, }
• (2025). Modulating a photonic graphene lattice by the lorentz-like transformation. PRA, 111(4), 043526. (www)

  @article{ , abstract = {Photonic lattice modulations, such as lattice distortions achieved by stress-strain engineering, have been crucial for the development of various fields of photonics, in particular, topological photonics. Here we modulate the Hermitian and non-Hermitian photonic graphene lattices by utilizing a Lorentz-like transformation applied to the lattice sites. The modulated lattice may fall into two categories, according to the symmetry axis of the lattice. If the axis is aligned in the diagonal direction through the unit cells, the lattice belongs to case II; otherwise, it belongs to case I. For the case-I transformed lattice, the Dirac cones always disappear from the band structure, whereas for the case-II transformed lattice, the Dirac cones only disappear if the transformation angle θ is larger than that of the regular lattice, θ = π / 2 . The Lorentz-like transformation always helps to restore the parity-time ( PT ) symmetry in the non-Hermitian case-I photonic graphene lattices. In the case II of transformed non-Hermitian lattices, the PT symmetry can be restored as well, but only for θ > π / 2 . When θ < π / 2 , one obtains exceptional lines in the band structure of the lattice. These results demonstrate that the Lorentz-like transformation can serve as an effective tool to modulate photonic lattices and thus may inspire novel ideas in the manipulation of photonic topological insulators.}, archive = {J_PRA}, author = {Zhuo Zhang (张卓 and Milivoj R. Belić and Yongdong Li (李永东 and Tao Wang (王涛 and Yiqi Zhang (张贻齐}, doi = {10.1103/PhysRevA.111.043526}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043526}, shortjournal = {Phys. Rev. A}, title = {Modulating a photonic graphene lattice by the lorentz-like transformation}, volume = {111}, year = {2025}, }
• (2025). Measurement of the inner horizon in the analog of rotating bañado-teitelboim-zanelli black holes by an improved photon fluid. PRA, 111(4), 043525. (www)

  @article{ , abstract = {We study how to include the inner horizon in the analog of rotating black holes using photon fluids. We find that a vortex beam carrying an improved phase can simulate the rotating Bañado-Teitelboim-Zanelli (BTZ) black holes experimentally. In the experiment, we develop a new photon fluid model in a graphene-methanol thermal optical solution, and measure the variation of photon fluid velocity with the radial position using a Fourier plane light-spot localization method, while also determining the variation of phonon velocity with the same radial position from the optical vortex intensity distribution. The result provides an extension for the application of optical vortex and a potential possibility for the future experimental exploration about the properties of BTZ black holes and even the anti–de Sitter space.}, archive = {J_PRA}, author = {Siyao Wu and Ling Chen and Bolong Yi and Lei Li and Baocheng Zhang}, doi = {10.1103/PhysRevA.111.043525}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043525}, shortjournal = {Phys. Rev. A}, title = {Measurement of the inner horizon in the analog of rotating bañado-teitelboim-zanelli black holes by an improved photon fluid}, volume = {111}, year = {2025}, }
• (2025). Corrections to the optomechanical hamiltonian from quadratic fluctuations of a moving mirror. PRA, 111(4), 043524. (www)

  @article{ , abstract = {We extend the theory of the radiation pressure to include quadratic fluctuations in the position of a moving mirror. This enables the introduction of a generalized radiation pressure operator that captures higher-order effects in the mirror-field coupling. For mechanical resonators with frequencies comparable to the fundamental cavity frequency, the resulting corrections to the optomechanical Hamiltonian are quadratic in the standard radiation pressure coupling. These corrections are expected to play a significant role in the strong-coupling regime of optomechanics, electromechanics, and superconducting circuit analogs.}, archive = {J_PRA}, author = {Salvatore Butera}, doi = {10.1103/PhysRevA.111.043524}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043524}, shortjournal = {Phys. Rev. A}, title = {Corrections to the optomechanical hamiltonian from quadratic fluctuations of a moving mirror}, volume = {111}, year = {2025}, }
• (2025). Solving the inverse problem for the design of omnidirectional lenses with an ultimately high numerical aperture. PRA, 111(4), 043523. (www)

  @article{ , abstract = {We introduce a type of lens that focuses a plane wave into a spherical one, where light comes from all directions. Our method also suggests the design of ideal optical tweezers or, in the reverse direction, photodetection of nearly all of the light emitted from an omnidirectional source. Our design trades off simple isotropic nonmagnetic materials for requiring a high refractive index. Despite many challenges, we believe that our proposed lens can evolve, with optimization and some help from conventional lenses, to fabricable lenses that will help in boosting collection efficiency of photons in ion-photon quantum experiments.}, archive = {J_PRA}, author = {Shay Rabani and Kirill Shvalb and Boris Malomed and Tal Carmon}, doi = {10.1103/PhysRevA.111.043523}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043523}, shortjournal = {Phys. Rev. A}, title = {Solving the inverse problem for the design of omnidirectional lenses with an ultimately high numerical aperture}, volume = {111}, year = {2025}, }
• (2025). Shaping terahertz harmonic frequency combs with frequency-dependent external reflectors. PRA, 111(4), 043522. (www)

  @article{ , abstract = {We present a method for engineering harmonic frequency combs (HFCs) in the terahertz spectral region. This approach involves interfacing a quantum cascade laser (QCL) with an external reflector featuring frequency-dependent reflectivity. A notable advantage of this method over existing ones is its dual functionality in shaping HFCs, allowing for control over both the frequency offset and comb spacing based on the external reflectivity profile. Moreover, the resulting HFCs manifest as sequences of short pulses in the time domain. Consequently, our method enables the generation of ultrashort picosecond pulses passively, providing a distinct alternative to conventional pulse generation systems reliant on active bias current modulation, which struggle with modulation frequencies significantly higher than the first beat note. This offers intriguing prospects for utilizing HFCs in pump and probe spectroscopy, a field already recognized in the literature as one of the most compelling applications of these states. Furthermore, we demonstrate that these HFCs can be triggered from an initial condition of free-running unlocked dynamics, eliminating the need for assuming free-running comb emission. Thus, the utilization of an external, frequency-dependent reflector is capable of enhancing the coherence of the QCL emission.}, archive = {J_PRA}, author = {Carlo Silvestri and Xiaoqiong Qi and Thomas Taimre and Aleksandar D. Rakić}, doi = {10.1103/PhysRevA.111.043522}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043522}, shortjournal = {Phys. Rev. A}, title = {Shaping terahertz harmonic frequency combs with frequency-dependent external reflectors}, volume = {111}, year = {2025}, }
• (2025). Optomechanically induced transparency on exceptional surfaces. PRA, 111(4), 043521. (www)

  @article{ , abstract = {Exceptional points (EPs) are singularities in non-Hermitian systems where the transmission spectrum exhibits significant variation at the phase transition point. Here, we propose a practical method for investigating the optomechanically induced transparency spectrum in a non-Hermitian cavity optomechanical system. By exploiting two kinds of exceptional surfaces (ESs) derived from the design of the waveguide structure, we study the transmission spectra and fast-slow light phenomena at various EPs on these ESs, and we identify ES-protected transmission spectra that are robust to parameter fluctuations. Consequently, the system exhibits a complete reversal of both transmission and fast-slow light behavior at EPs compared with those at non-EPs when the phase transition occurs. Unlike previous studies that focus solely on an isolated EP, our approach enables the exploration of system characteristics with different EPs, providing greater flexibility for experimental design.}, archive = {J_PRA}, author = {Yang Pan and H.-L. Zhang and Y.-F. Jiao and Y. Wang and D.-Y. Wang and S.-L. Su and Hui Jing}, doi = {10.1103/PhysRevA.111.043521}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043521}, shortjournal = {Phys. Rev. A}, title = {Optomechanically induced transparency on exceptional surfaces}, volume = {111}, year = {2025}, }
• (2025). Neutron beam shaping by ghost projection. PRA, 111(4), 043520. (www)

  @article{ , abstract = {We present a method to shape a neutron beam and project any specified target image using a single universal patterned mask that is transversely displaced. The method relies on “ghost projection,” which is a reversed form of classical ghost imaging. A set of submask regions that combine to construct the required beam shape is computed; illumination of each region with the determined exposure time projects the shaped beam. We demonstrate this method experimentally, using the Dingo neutron imaging beamline at the OPAL nuclear research reactor (Australia). The ability to shape a neutron beam “on demand” allows selective dose delivery away from sensitive areas of samples, such as in cultural heritage artifacts. It also benefits irradiation techniques, e.g., in testing the resilience of electronic components for space and defense technologies or neutron therapies.}, archive = {J_PRA}, author = {Andrew M. Kingston and Alaleh Aminzadeh and Lindon Roberts and Jeremy M. C. Brown and Filomena Salvemini and Joseph J. Bevitt and Ulf Garbe and David M. Paganin}, doi = {10.1103/PhysRevA.111.043520}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043520}, shortjournal = {Phys. Rev. A}, title = {Neutron beam shaping by ghost projection}, volume = {111}, year = {2025}, }
• (2025). Helicity-selected near-circularly polarized attosecond pulses generated from mixed he-ne gases. PRA, 111(4), 043519. (www)

  @article{ , abstract = {We present and theoretically demonstrate a method for generating helicity-selected near-circularly polarized attosecond pulses in mixed He-Ne gases using bichromatic counter-rotating circularly polarized (BCCP) fields. High-order harmonics driven by BCCP fields exhibit circular polarization for individual orders in the frequency domain, but adjacent orders have opposite helicities. By utilizing the He-Ne mixture, we select only one helical component of the harmonics, resulting in the generation of highly elliptically polarized attosecond pulses in the time domain. Our analyses based on the quantum-orbit theory and the strong-field approximation further clarify that the polarization of attosecond pulses is governed by the interference mechanism of high-order harmonics emitted by He and Ne. This combination of BCCP fields and an atomic mixture which requires no alignment in experiments significantly simplifies the generation of elliptically polarized harmonics dominated by one helical component, thereby paving the way for an efficient and robust method to generate bright attosecond pulses with large ellipticity.}, archive = {J_PRA}, author = {Chunyang Zhai and Xiaosong Zhu and Yingbin Li and Qingbin Tang and Benhai Yu and Pengfei Lan and Peixiang Lu}, doi = {10.1103/PhysRevA.111.043519}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043519}, shortjournal = {Phys. Rev. A}, title = {Helicity-selected near-circularly polarized attosecond pulses generated from mixed he-ne gases}, volume = {111}, year = {2025}, }
• (2025). Intensity correlations in transmission and four-wave-mixing signals intermediated by hot rubidium atoms. PRA, 111(4), 043518. (www)

  @article{ , abstract = {We investigate the influence of the distribution of atom velocities in a hot rubidium sample on the correlation between field-intensity fluctuations of two independently generated four-wave mixing signals and between the transmission signals. The nonlinear process is driven by a single continuous-wave (cw) laser in a pure two-level system due to the forward geometry with circular and parallel polarization of the input fields. The intensity cross correlations of the four-wave mixing signals and the transmission signals present an oscillatory behavior with a clear dependence on the power of the incident fields, which indicates a connection with Rabi oscillations. A two-level theoretical model using stochastic differential equations to account for the mechanism of conversion of phase noise into amplitude noise shows good agreement with our experimental results. Moreover, we show how the response of the system is affected by the different atomic velocity groups.}, archive = {J_PRA}, author = {A. A. C. de Almeida and A. S. Alvarez and N. R. de Melo and M. R. L. da Motta and M. P. M. de Souza and S. S. Vianna}, doi = {10.1103/PhysRevA.111.043518}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043518}, shortjournal = {Phys. Rev. A}, title = {Intensity correlations in transmission and four-wave-mixing signals intermediated by hot rubidium atoms}, volume = {111}, year = {2025}, }
• (2025). Generation of an ultrashort soliton train by pumping two identical time-delayed pulses in a third-order nonlinear composite medium. PRA, 111(4), 043517. (www)

  @article{ , abstract = {We report the generation of an ultrashort soliton train by pumping two identical time-delayed femtosecond pulses in a third-order nonlinear composite medium with normal dispersion. The entire composite medium is composed of two segments, the first segment with self-focusing nonlinearity and the second segment with self-defocusing nonlinearity. In the self-focusing segment, a temporal pulse sequence is generated via the formation of a dark soliton train due to the nonlinearity acting on the modulation. In the self-defocusing segment, these temporal pulses can be effectively compressed into the controlled and isolated ultrashort solitons via the temporal compression method, as long as the time delay between double pulses and the ratio of the self-focusing segment are suitably set. Interestingly, when the ratio of the self-focusing segment is relatively small, a giant soliton can be produced by the combined effect of temporal compression and soliton collision, which exhibits an extremely high intensity and a significant redshift but does not need to follow the L -shaped intensity probability distribution.}, archive = {J_PRA}, author = {Saili Zhao and Tongxing Sun and Shuo Liu and Ruijun Guo and Yong Zeng}, doi = {10.1103/PhysRevA.111.043517}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043517}, shortjournal = {Phys. Rev. A}, title = {Generation of an ultrashort soliton train by pumping two identical time-delayed pulses in a third-order nonlinear composite medium}, volume = {111}, year = {2025}, }
• (2025). Polarization and amplitude tuning of terahertz radiation from laser-induced air filaments. PRA, 111(4), 043516. (www)

  @article{ , abstract = {Terahertz radiation with tunable polarization and amplitude can facilitate applications in many fields such as biological diagnosis and terahertz imaging. Using the photocurrent model and far-field coherent superposition method, we show that two-color laser-induced air filaments can generate terahertz radiation with independent control on both its polarization and amplitude when a circularly polarized fundamental wave and an elliptically polarized second harmonic are adopted. The polarization of the terahertz radiation, including polarization angle and polarization ellipticity, can be controlled independently by tuning the initial relative phase between two-color components and the filament length, respectively. Meanwhile, by increasing the polarization ellipticity of the second harmonic from − 1 (with polarization opposite to the fundamental wave) to 1, the amplitude of the terahertz radiation can be tuned continuously from 0 to its maximum with its polarization fixed at a desirable state. Our studies provide an all-optical method for the manipulation of multiple parameters of terahertz radiation, which is useful for terahertz science.}, archive = {J_PRA}, author = {Hanzhi Zhang and Linzheng Wang and Yanping Chen and Zhelin Zhang and Zhengming Sheng}, doi = {10.1103/PhysRevA.111.043516}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043516}, shortjournal = {Phys. Rev. A}, title = {Polarization and amplitude tuning of terahertz radiation from laser-induced air filaments}, volume = {111}, year = {2025}, }
• (2025). Generation of non-gaussian states in a cyclic four-wave-mixing system with photon-number projections. PRA, 111(4), 043515. (www)

  @article{ , abstract = {Continuous-variable entanglement, especially in the non-Gaussian states exhibiting Wigner negativity, is essential for realizing quantum advantages in quantum information processing tasks. Here, we propose a method to efficiently generate multimode non-Gaussian entangled states using a single Rb vapor cell integrated with a cyclic optical system. By employing multiple pump light pulses and recycling the output signal light as a seed light, our system is equivalent to implementing the multiple cascaded four-wave mixing processes while maintaining resource efficiency. Through the analysis of the properties of multipartite steering and entanglement in the cyclic system, we find a hierarchical Gaussian steering structure, which enables the photon number projection on superior signal mode to prepare a multimode entangled non-Gaussian state in the idler modes. Conversely, the projection on each subordinate idler mode can induce more negativity in the signal mode. More importantly, our approach significantly improves the success probability of photon number projections, thereby augmenting the yield of non-Gaussian states and enhancing their potential for delivering robust quantum advantages.}, archive = {J_PRA}, author = {Boxuan Jing and Feng-Xiao Sun and Yu Xiang and Qiongyi He}, doi = {10.1103/PhysRevA.111.043515}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043515}, shortjournal = {Phys. Rev. A}, title = {Generation of non-gaussian states in a cyclic four-wave-mixing system with photon-number projections}, volume = {111}, year = {2025}, }
• (2025). Pancharatnam-berry phase and angular momentum of self-evolving vector bessel beams. PRA, 111(4), 043514. (www)

  @article{ , abstract = {Self-evolving vector Bessel beams exhibit a spatially varying polarization profile that gradually evolves as the beam field propagates. Such beams can also carry both spin and orbital angular momentum. We show that in our recently introduced metasurface platform it is possible to gain control over the entire range of possible values for both types of angular momentum by tuning the incident field polarization. We also propose a geometric phase related to the polarization changes due to the propagation of the output field. We find a hitherto unrecognized conservation of the sum of the normalized geometric phase and orbital and spin angular momentum for all incident polarization states.}, archive = {J_PRA}, author = {Jiaqi Yang and Tommi K. Hakala and Ari T. Friberg}, doi = {10.1103/PhysRevA.111.043514}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043514}, shortjournal = {Phys. Rev. A}, title = {Pancharatnam-berry phase and angular momentum of self-evolving vector bessel beams}, volume = {111}, year = {2025}, }
• (2025). Observation of the talbot effect from a surface-acoustic-wave dynamic grating. PRA, 111(4), 043513. (www)

  @article{ , abstract = {We demonstrate the dynamical Talbot effect caused by optical diffraction from standing surface acoustic waves (SAWs). The Talbot effect is a wave interference phenomenon in the Fresnel regime, and we observe it with a fiber-based scanning optical interferometer on a SAW Fabry-Perot cavity. By studying the interferometric signal at 1 GHz, next to the usual phase term we discover the existence of an amplitude-modulated term which vanishes at periodic positions when we displace the acoustic device relative to the beam focus. With this, we reveal the optical Talbot effect where, despite the curved wavefronts of the optical field, the conventional Talbot length appears. Finally, we propose to use the amplitude modulation as a different way of imaging surface acoustic waves.}, archive = {J_PRA}, author = {M. Fisicaro and Y. C. Doedes and T. A. Steenbergen and M. P. van Exter and W. Löffler}, doi = {10.1103/PhysRevA.111.043513}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043513}, shortjournal = {Phys. Rev. A}, title = {Observation of the talbot effect from a surface-acoustic-wave dynamic grating}, volume = {111}, year = {2025}, }
• (2025). Exploring non-euclidean photonics: Pseudosphere microlaser. PRA, 111(4), 043512. (www)

  @article{ , abstract = {Classical and wave properties of microlasers with the shape of a truncated pseudosphere are investigated through experiments and numerical simulations. These pseudosphere microlasers are surface-like organic microlasers with constant negative curvature, which were fabricated with high optical quality by direct laser writing. It is shown that they behave, in many ways, similar to two-dimensional flat disks, regardless of their different Gaussian curvature. We derive the monodromy matrices for geodesics on the pseudosphere and demonstrate that the periodic geodesics are marginally stable. Actually, due to the rotational symmetry, the pseudosphere is an integrable system with marginally stable dynamics.}, archive = {J_PRA}, author = {H. Girin and S. Bittner and X. Checoury and D. Decanini and B. Dietz and A. Grigis and C. Lafargue and J. Zyss and C. Xu (徐晨妮 and P. Sebbah and M. Lebental}, doi = {10.1103/PhysRevA.111.043512}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043512}, shortjournal = {Phys. Rev. A}, title = {Exploring non-euclidean photonics: Pseudosphere microlaser}, volume = {111}, year = {2025}, }
• (2025). Adaptive distributed-feedback semiconductor laser. PRA, 111(4), 043511. (www)

  @article{ , abstract = {To solve the difficulty in wavelength adaptability of external-cavity semiconductor lasers, external-cavity distributed feedback has been proven to be an effective method to achieve adaptive narrow-linewidth semiconductor lasers. For the structural design and precise manufacturing of adaptive semiconductor lasers, the principle of laser linewidth compression based on distributed feedback needs to be explored. In this article, we propose a theoretical model for analyzing the operational mechanism of the adaptive distributed-feedback semiconductor laser. Theoretical and experimental results show that achieving adaptive linewidth compression requires tens of or more feedback points. On the basis of sufficient feedback points, increasing the feedback length and ratio can achieve an ultranarrow laser linewidth and high side-mode suppression ratio. This work provides a model analysis tool for exploring the ideal configuration of adaptive narrow-linewidth semiconductor lasers, which paves the way for the design and manufacturing of high-performance semiconductor lasers.}, archive = {J_PRA}, author = {Chaoze Zhang and Tianyu Guan and Ligang Huang and Yujia Li and Laiyang Dang and Yuqin Mao and Lei Gao and Leilei Shi and Guolu Yin and Chaoyang Gong and Tao Zhu}, doi = {10.1103/PhysRevA.111.043511}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043511}, shortjournal = {Phys. Rev. A}, title = {Adaptive distributed-feedback semiconductor laser}, volume = {111}, year = {2025}, }
• (2025). Nonsymmetric evanescent coupling in photonics. PRA, 111(4), 043510. (www)

  @article{ , abstract = {Asymmetrical interactions are ubiquitous in nature, and in physics their study becomes fundamental. Despite the prevalence of evanescent coupling in physics, little attention has been paid to wave function profiles, with symmetrical reciprocal interactions often assumed for practical reasons. This work challenges that assumption by analytically demonstrating the origin of nonsymmetrical coupling in a photonic platform, focusing on the behavior of evanescent tails from adjacent waveguides. We experimentally validate an asymmetrical dynamics by studying detuned photonic directional couplers, fabricated via femtosecond laser writing, and corroborate our findings through continuous numerical simulations.}, archive = {J_PRA}, author = {Rodrigo A. Vicencio and Diego Román-Cortés and Martín Rubio-Saldías and Paloma Vildoso and Luis E. F. Foa Torres}, doi = {10.1103/PhysRevA.111.043510}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043510}, shortjournal = {Phys. Rev. A}, title = {Nonsymmetric evanescent coupling in photonics}, volume = {111}, year = {2025}, }
• (2025). Spectral enrichment of optical microresonator combs by means of a frequency-shifting loop. PRA, 111(4), 043509. (www)

  @article{ , abstract = {A fairly large number of optical frequency comb (OFC) generation methods have been proposed and practically implemented to date. All of them have their own advantages and disadvantages. For example, the application of bulk whispering gallery modes or on-chip optical ring microresonators allows one to obtain soliton Kerr combs in the spectral band achieving tens of nm and containing hundreds of lines. However, the spectral spacing between these lines will be determined by the dimensions of the microresonator and, as a rule, ranges from tens to hundreds of GHz. On the other hand, the application of frequency-shifting loop (FSL) systems with an acousto-optic (AO) device as the frequency shifter allows one to obtain OFCs with a frequency spacing of tens of MHz, but the spectral band of the AO FSL OFCs containing several thousand lines will hardly exceed 0.5 nm. In this paper, we propose a method to expand the AO FSL OFCs' spectral band applying multifrequency optical seeding. As a source of such seeding we propose to use lines of a soliton comb spectrum generated with an optical microresonator. This approach can also be considered as a method for enriching the optical spectrum of the microresonator OFC by adding spectral components generated in AO FSLs with a frequency spacing that is a multiple of the seeding soliton microcomb lines' frequency spacing. The paper presents the results of an experiment that confirms the possibility of implementation of such a concept.}, archive = {J_PRA}, author = {Sergey N. Mantsevich and Ekaterina I. Kostyleva and Andrei N. Danilin and Darja A. Brukvina and Kirill N. Min'kov and Nikita Yu. Dmitriev}, doi = {10.1103/PhysRevA.111.043509}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043509}, shortjournal = {Phys. Rev. A}, title = {Spectral enrichment of optical microresonator combs by means of a frequency-shifting loop}, volume = {111}, year = {2025}, }
• (2025). Application of madelung hydrodynamics to plasmonics and nonlinear optics in two-dimensional materials. PRA, 111(4), 043508. (www)

  @article{ , abstract = {This paper explores the application of Madelung hydrodynamic models to study two-dimensional electron gases, with a focus on nonlocal plasmonics and nonlinear optics. We begin by reviewing the derivation of the Madelung equations. Using the Madelung equations in conjunction with Poisson's equation, we calculate the spectrum of magnetoplasmons and the magneto-optical conductivity in the electrostatic regime, incorporating nonlocal corrections due to the Fermi pressure. In the absence of a magnetic field, we analyze nonlinear and nonlocal second-harmonic generation, demonstrating how plasmon excitation enhances this process. We further discuss the emergence of self-modulation phenomena driven by nonlinearity, leading to the renormalization of the plasmon dispersion. Notably, we show that nonlinearity amplifies nonlocal effects and, leveraging the hydrodynamic formalism, derive a simple analytic expression for the renormalized spectra.}, archive = {J_PRA}, author = {Simão S. Cardoso and A. J. Chaves and N. Asger Mortensen and N. M. R. Peres}, doi = {10.1103/PhysRevA.111.043508}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043508}, shortjournal = {Phys. Rev. A}, title = {Application of madelung hydrodynamics to plasmonics and nonlinear optics in two-dimensional materials}, volume = {111}, year = {2025}, }
• (2025). Molecular optomechanically induced transparency. PRA, 111(4), 043507. (www)

  @article{ , abstract = {Molecular cavity optomechanics (COM), characterized by remarkably efficient optomechanical coupling enabled by a highly localized light field and ultrasmall effective mode volume, holds significant promise for advancing applications in quantum science and technology. Here, we study optomechanically induced transparency and the associated group delay in a hybrid molecular COM system. We find that even with an extremely low optical quality factor an obvious transparency window can appear, which is otherwise unattainable in a conventional COM system. Furthermore, by varying the ports of the probe light, the optomechanically induced transparency or absorption can be achieved, along with corresponding slowing or advancing of optical signals. These results indicate that our scheme provides an alternative method for adjusting the storage and retrieval of optical signals in such a molecular COM device.}, archive = {J_PRA}, author = {Bin Yin and Jie Wang and Mei-Yu Peng and Qian Zhang and Deng Wang and Tian-Xiang Lu and Ke Wei and Hui Jing}, doi = {10.1103/PhysRevA.111.043507}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043507}, shortjournal = {Phys. Rev. A}, title = {Molecular optomechanically induced transparency}, volume = {111}, year = {2025}, }
• (2025). Pulse compression by photoexcitation-induced dynamics of bragg mirrors. PRA, 111(4), 043506. (www)

  @article{ , abstract = {We propose dynamical Bragg mirrors as a means to compress intense short optical pulses. We show that strong-field photoexcitation of carriers changes the refractive index of the layers and leads to motion of the resonance-defined boundary of the Bragg mirror. In a reflection geometry, this counterpropagating motion leads to significant compression of the incident pulse. We utilize a finite-difference time-domain numerical model to predict up to a six-fold pulse compression in the few-femtosecond regime. Modification of the refractive index and properties of the compressed pulse as a function of the incident pulse parameters are investigated.}, archive = {J_PRA}, author = {Z. Ruziev and K. Yabana and A. Husakou}, doi = {10.1103/PhysRevA.111.043506}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043506}, shortjournal = {Phys. Rev. A}, title = {Pulse compression by photoexcitation-induced dynamics of bragg mirrors}, volume = {111}, year = {2025}, }
• (2025). Unusual response of the chemical contribution to the plasmonic excited near field in enhanced raman spectra of molecules on metal substrates. PRA, 111(4), 043505. (www)

  @article{ , abstract = {Surface-enhanced vibrational spectroscopy is a powerful tool widely used in scientific research and industry for label-free and sensitive identification of molecular species. Two main enhancement mechanisms, namely, electromagnetic enhancement and chemical enhancement, have been accepted to be collectively responsible for striking modifications in the enhanced spectra of molecules absorbed on metal plasmonic substrates. However, the two effects and their respective contribution in various metal- or dielectric-molecule systems remain imperfectly understood. Here we exemplify a hybrid molecule-metal system and decouple the two contributions to surface-enhanced Raman-scattering (SERS) intensity. Our findings demonstrate the nanoscale near-field enhancement can be estimated with only the measured far-field SERS intensity. Notably, the chemical effect on the SERS signal exhibits an essentially different response against the enhanced near field between molecular vibrational lines. Hence, this work may be helpful in better understanding the origin of the anomalously changed Raman patterns when adsorbates upon metal surfaces, but also offers heuristic insights into the underlying interactions between various enhancement effects in surface-enhanced vibrational spectroscopy.}, archive = {J_PRA}, author = {Yixin Dai and Ling Yue and Wenxue Li and Lin Pang}, doi = {10.1103/PhysRevA.111.043505}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043505}, shortjournal = {Phys. Rev. A}, title = {Unusual response of the chemical contribution to the plasmonic excited near field in enhanced raman spectra of molecules on metal substrates}, volume = {111}, year = {2025}, }
• (2025). Enhancement of high-order harmonic generation based on landau damping in laser interactions with plasma. PRA, 111(4), 043504. (www)

  @article{ , abstract = {High-order harmonic generation (HHG) plays a key role in producing coherent extreme ultraviolet (EUV) and x-ray radiation, which is crucial for applications in attosecond science and high-energy density physics. The intensity and order of high-order harmonics are crucial for advancing their applications. In this paper, a scheme is proposed to generate harmonics by the relativistic oscillating mirror (ROM) based on the energy exchange between electron and excited plasma wave by Landau damping, which employs dual laser pulses to sequentially excite the plasma surface electron oscillation to enhance the intensity and order of harmonics. Through theory and numerical analysis, we discover that our scheme significantly enhances the intensity of higher-order harmonics by an order of magnitude compared to typical harmonic generation methods of the same energy, and observe the higher-order harmonics. Furthermore, we investigate the essential factors affecting energy exchange in Landau damping and find that there exists an optimal pulse interval and energy ratio to maximize the energy exchange. The scheme based on Landau damping for generating high-order harmonics offers an alternative perspective for advancing HHG research and applications.}, archive = {J_PRA}, author = {Li Xiong and Xin Chen and Pengfan Chen and Anrong Fan and Xiaobao Mao and Yuhao Feng and Yangfan He and Xiaofei Lan}, doi = {10.1103/PhysRevA.111.043504}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043504}, shortjournal = {Phys. Rev. A}, title = {Enhancement of high-order harmonic generation based on landau damping in laser interactions with plasma}, volume = {111}, year = {2025}, }
• (2025). Coherent optical imaging of moving objects hidden in a heavily scattering random medium. PRA, 111(4), 043503. (www)

  @article{ , abstract = {Experimental results are presented that provide insight into the physics of statistical imaging in heavily scattering random media based on measured speckle correlations as a function of the change in position of a moving object. In this way, definitive interpretation of a rather complex and earlier theory is achieved, making this work an experimental complement to that theory paper [ Phys. Rev. A 101 , 063827 (2020) ]. Motion could be natural, where the set of positions is estimated or separately obtained, or directed, where a mechanical stage can be used to adjust the object's position. In the experiment, a coherent laser illuminates two scattering diffusers, while an object is translated between them in the resulting speckled field and images are collected in a transmission configuration. Results are shown for various objects of differing size and geometry, allowing the theory to be validated and interpreted with new understanding. This work demonstrates imaging opportunities, and applications include material characterization, environmental imaging and sensing, and deep-tissue in vivo imaging.}, archive = {J_PRA}, author = {Ryan L. Hastings and David W. Alexander and Kevin J. Webb}, doi = {10.1103/PhysRevA.111.043503}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043503}, shortjournal = {Phys. Rev. A}, title = {Coherent optical imaging of moving objects hidden in a heavily scattering random medium}, volume = {111}, year = {2025}, }
• (2025). Precision gyroscope from the helicity of light. PRA, 111(4), 043502. (www)

  @article{ , abstract = {We describe a gyroscope that measures rotation based on the effects of the rotation on the polarization of light. Rotation induces a differential phase shift in the propagation of left- and right-circularly polarized light and this phase shift can be measured in suitably designed interferometric setups. The signal in this setup is independent of the frequency of light, unlike various sources of noise such as vibrations, which cause phase shifts that depend on the frequency. Such vibrations are the practical limit on the sensitivity of conventional Sagnac-style optical interferometers that are typically used as gyroscopes. In the proposed setup, one can potentially mitigate this source of noise by simultaneously using two (or more) sources of light that have different frequencies. The signal in this setup scales with the total storage time of the light. Due to its frequency independence, it is thus most optimal to measure the signal using superconducting radio-frequency systems where the high finesse of the available cavities enables considerably longer storage times than is possible in an optical setup.}, archive = {J_PRA}, author = {Michael A. Fedderke and Roni Harnik and David E. Kaplan and Sam Posen and Surjeet Rajendran and Francesco Serra and Vyacheslav P. Yakovlev}, doi = {10.1103/PhysRevA.111.043502}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043502}, shortjournal = {Phys. Rev. A}, title = {Precision gyroscope from the helicity of light}, volume = {111}, year = {2025}, }
• (2025). Interferometric mass photometry at the quantum limit of sensitivity. PRA, 111(4), 043501. (www)

  @article{ , abstract = {We present an innovative optical imaging system for measuring parameters of a small particle such as a macromolecule or nanoparticle at the quantum limit of sensitivity. In comparison to the conventional confocal interferometric scattering (iSCAT) approach, our setup adds a second arm to form a Michelson interferometer that allows us to tune a relative phase. We evaluate the quantum Cramér-Rao bound (QCRB) for different quantum states, including single-mode coherent states, multifrequency coherent states, and phase-averaged coherent states. Our results show that the proposed setup can achieve the QCRB of sensitivity and outperform iSCAT for all considered quantum states for the mass and phase estimation of a particle.}, archive = {J_PRA}, author = {Fabian Müller and Emre Köse and Alfred J. Meixner and Erik Schäffer and Daniel Braun}, doi = {10.1103/PhysRevA.111.043501}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043501}, shortjournal = {Phys. Rev. A}, title = {Interferometric mass photometry at the quantum limit of sensitivity}, volume = {111}, year = {2025}, }
• (2025). Three-component bose-einstein condensates and wetting without walls. PRA, 111(4), 043320. (www)

  @article{ , abstract = {In previous work within Gross-Pitaevskii (GP) theory for ultracold gases, wetting phase transitions were predicted for a phase-segregated two-component Bose-Einstein condensate (BEC) adsorbed at an optical wall. The wetting phase diagram was found to depend on intrinsic atomic parameters, being the masses and the scattering lengths, and on the extrinsic wall boundary condition. Here we study wetting transitions in GP theory without an optical wall in a setting with three phase-segregated BEC components instead of two. The boundary condition is removed by replacing the wall with the third component and treating the three phases on an equal footing. This leads to an unequivocal wetting phase diagram that depends only on intrinsic atomic parameters. It features first-order and critical wetting transitions, and prewetting phenomena. The phase boundaries are computed by numerical solution of the GP equations. In addition, useful analytic results are obtained by extending the established double-parabola approximation to three components.}, archive = {J_PRA}, author = {Joseph O. Indekeu and Nguyen Van Thu and Jonas Berx}, doi = {10.1103/PhysRevA.111.043320}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043320}, shortjournal = {Phys. Rev. A}, title = {Three-component bose-einstein condensates and wetting without walls}, volume = {111}, year = {2025}, }
• (2025). Quantum network tomography of small rydberg arrays by machine learning. PRA, 111(4), 043319. (www)

  @article{ , abstract = {Configurable arrays of optically trapped Rydberg atoms are a versatile platform for quantum computation and quantum simulation, also allowing controllable decoherence. We demonstrate theoretically that they also enable proof-of-principle demonstrations for a technique to build models for open quantum dynamics using machine learning with artificial neural networks, recently proposed by Mukherjee et al. [ Quantum Sci. Technol. 10 , 02LT01 (2025) ]. Using the outcome of quantum transport through a network of sites that correspond to excited Rydberg atoms, the multistage neural-network algorithm successfully identifies the number of atoms (or nodes in the network) and, subsequently, their location. It further extracts an effective interaction Hamiltonian and decoherence operators induced by the environment. To probe the Rydberg array, one initiates dynamics repeatedly from the same initial state and then measures the transport probability to an output atom. Large datasets are generated by varying the position of the latter. Measurements are required in only one single basis, making the approach complementary to, e.g., quantum process tomography. Due to steeply increasing requirements for training data size, the present implementation appears best suited for networks of just a few sites. The cold-atom platform discussed in this article can be used to explore the performance of the proposed protocol when training the neural network with simulation data but then applying it to construct models based on experimental data.}, archive = {J_PRA}, author = {K. Mukherjee and J. Schachenmayer and S. Whitlock and S. Wüster}, doi = {10.1103/PhysRevA.111.043319}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043319}, shortjournal = {Phys. Rev. A}, title = {Quantum network tomography of small rydberg arrays by machine learning}, volume = {111}, year = {2025}, }
• (2025). Maxon and roton solitons in a rydberg-dressed bose-einstein condensate. PRA, 111(4), 043318. (www)

  @article{ , abstract = {We present a scheme to generate maxon and roton solitons via the maxon and roton excitations of a Rydberg-dressed Bose-Einstein condensate (BEC). We show that the strong, long-range Rydberg-Rydberg interaction between Rydberg atoms can drastically alter the linear excitation spectrum of the quasiparticles (phonons) on the homogeneous background of the BEC, which displays obvious maxon-roton character and can be tuned actively by adjusting the strength of the Rydberg-Rydberg interaction and Rydberg blockade radius. We also show that the system supports both bright maxon and dark roton solitons if the center wave numbers of excited wave packets are chosen respectively to be those of the maxon and roton. Moreover, we corroborate that both the maxon and roton solitons are dynamical stable during the evolution if system parameters are kept in the domain where the homogeneous background of the BEC is modulationally stable. The results reported are beneficial not only for understanding the physical property of Rydberg-dressed BECs, but also for creating and actively manipulating new types of nonlinear matter-wave excitations in cold atomic gases.}, archive = {J_PRA}, author = {Yuxi Chen and Chao Hang and Guoxiang Huang}, doi = {10.1103/PhysRevA.111.043318}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043318}, shortjournal = {Phys. Rev. A}, title = {Maxon and roton solitons in a rydberg-dressed bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Attractive and repulsive angulons in superfluid environments. PRA, 111(4), 043317. (www)

  @article{ , abstract = {We investigate the in- and out-of-equilibrium phenomena of a rotational impurity—specifically, a linear molecule—coupled to a nonconventional environment, a helium nanodroplet. By employing a Lee-Low-Pines-like transformation combined with a multireference configuration approach, we self-consistently account for the molecule's backaction on the superfluid bath and accurately capture the complex entanglement between the molecule's rotational degrees of freedom and the bath excitations. Our findings reveal that in the ground state, the impurity induces a density defect in the superfluid bath, giving rise to two novel types of excited states: (a) attractive angulon states, analogous to bound states in photonic crystals and Yu-Shiba-Rusinov bound states in superconductors, localized within the density defect region, and (b) long-lived repulsive angulon states in dilute environments. Rotational spectroscopy demonstrates a crossover from repulsive to attractive angulon states as the bath density increases. This work paves the way for exploring novel nonequilibrium phenomena of quantum impurities in interacting environments.}, archive = {J_PRA}, author = {Wei Zhang and Zhongda Zeng and Tao Shi}, doi = {10.1103/PhysRevA.111.043317}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043317}, shortjournal = {Phys. Rev. A}, title = {Attractive and repulsive angulons in superfluid environments}, volume = {111}, year = {2025}, }
• (2025). Tunable pairing with local spin-dependent rydberg molecule potentials in an atomic fermi superfluid. PRA, 111(4), 043316. (www)

  @article{ , abstract = {We explore the energy spectrum and eigenstates of two-component atomic Fermi superfluids with tunable pairing interactions in the presence of spin-dependent ultralong-range Rydberg molecule (ULRM) potentials, within the Bogoliubov–de Gennes formalism. The attractive ULRM potentials lead to local-density accumulation, while their difference results in a local polarization potential and induces the in-gap Yu-Shiba-Rusinov (YSR) states whose energies lie below the bulk energy gap. A transition from equal population to population imbalance occurs as the pairing strength falls below a critical value, accompanied by the emergence of local Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)–like states characterized by out-of-phase wave functions and lower energies compared to the YSR states. The negative contribution emanating from the FFLO-like states also causes a sign change in the gap function within the ULRM potentials. Depending on the Rydberg excitation, the transition towards population imbalance can be on either the BCS or the Bose-Einstein condensation side of the Fermi superfluid. Additionally, spin-polarized bound states arise along with oscillatory “clumpy states” to compensate for the local-density difference. We discuss possible experimental realizations of the composite Rydberg-atom–Fermi-superfluid system.}, archive = {J_PRA}, author = {Chih-Chun Chien and Seth T. Rittenhouse and S. I. Mistakidis and H. R. Sadeghpour}, doi = {10.1103/PhysRevA.111.043316}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043316}, shortjournal = {Phys. Rev. A}, title = {Tunable pairing with local spin-dependent rydberg molecule potentials in an atomic fermi superfluid}, volume = {111}, year = {2025}, }
• (2025). Tunable intrinsic anomalous hall effect in a shaken square optical lattice. PRA, 111(4), 043315. (www)

  @article{ , abstract = {We investigate the intrinsic anomalous linear and nonlinear Hall effect in a square optical lattice under the shaking. We find that the on-resonant shaking can induce a valley independent term which leads to the valley Hall effect. While the off-resonant shaking induces a valley-dependent term and the system shows an anomalous Hall effect. Furthermore, the nonlinear valley Hall effect also appears in this system, and the nonlinear valley Hall conductivities can be controlled by varying the shaking frequency and amplitude. These results will be useful for controlling the valley degree of freedom with ultracold atoms in an optical lattice.}, archive = {J_PRA}, author = {G.-B. Zhu and H.-M. Yang and Q. Sun and W.-M. Liu and A.-C. Ji}, doi = {10.1103/PhysRevA.111.043315}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043315}, shortjournal = {Phys. Rev. A}, title = {Tunable intrinsic anomalous hall effect in a shaken square optical lattice}, volume = {111}, year = {2025}, }
• (2025). Critical velocity for wake vortex generation behind a plate in a superflow. PRA, 111(4), 043314. (www)

  @article{ , abstract = {We study theoretically the critical velocity U c for quantum vortex generation by a thin plate-shaped obstacle moving through a uniform two-dimensional Bose-Einstein condensate. Our results based on the Gross-Pitaevskii theory reveal that the critical velocity monotonically decreases with increasing the plate size L . In the limit of large L , the critical velocity is asymptotic to L − 1 / 2 predicted by the potential flow theory for an incompressible ideal fluid with a phenomenological length correction. As L decreases, however, the incompressible analysis breaks down quantitatively. By performing a perturbative analysis to incorporate compressibility into the potential flow theory, we successfully reproduced the numerical results analytically over a wide parameter range.}, archive = {J_PRA}, author = {Haruya Kokubo and Hiromitsu Takeuchi and Kenichi Kasamatsu}, doi = {10.1103/PhysRevA.111.043314}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043314}, shortjournal = {Phys. Rev. A}, title = {Critical velocity for wake vortex generation behind a plate in a superflow}, volume = {111}, year = {2025}, }
• (2025). Machine learning out-of-equilibrium correlations in the bose-hubbard model. PRA, 111(4), 043313. (www)

  @article{ , abstract = {Calculating the out-of-equilibrium dynamics of many-body quantum systems theoretically is a challenging problem. Essentially exact results can be obtained for the out-of-equilibrium correlations in the Bose-Hubbard model in one dimension, but higher dimensions require approximate methods. One such method is the two-particle irreducible strong coupling (2PISC) approach [M. R. C. Fitzpatrick and M. P. Kennett, Nucl. Phys. B 930 , 1 (2018) ]. Calculations of the single-particle correlations using this method yield values of the velocity for correlation spreading that match well with exact methods in one dimension and experiments in one and two dimensions. However, the 2PISC method is less accurate for determining the amplitude of correlations, especially in the regime where interactions are not very strong. Viewing the calculation of the single-particle correlations as an image correction problem, we train a neural network (NN) to take input from the 2PISC approach to reproduce the output of exact diagonalization calculations. We show that the predictions of the NN improve on 2PISC results for parameters outside the training region. Our approach is not specific to the Bose-Hubbard model and may find application to the out-of-equilibrium dynamics of other quantum many-body systems.}, archive = {J_PRA}, author = {Ali Mokhtari-Jazi and Malcolm P. Kennett}, doi = {10.1103/PhysRevA.111.043313}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043313}, shortjournal = {Phys. Rev. A}, title = {Machine learning out-of-equilibrium correlations in the bose-hubbard model}, volume = {111}, year = {2025}, }
• (2025). Inelastic quantum boltzmann equation of single-component fermi gases. PRA, 111(4), 043312. (www)

  @article{ , abstract = {This work is a companion paper to X.-Y. Gao et al. , Phys. Rev. Lett. 134 , 153402 (2025) , where we discuss the nonequilibrium two-body loss dynamics of a single-component ultracold Fermi gas and its possible thermalization. This paper provides detailed information on the derivation and analysis of the inelastic quantum Boltzmann equation (IQBE) used to describe the system. We demonstrate that the Mellin transform is a powerful tool for solving and approximating the IQBE for free-space systems. In this case, the particle-number dynamics are beyond the description of the widely used phenomenological two-body equation. For harmonically trapped systems, we propose a fast-flowing approximation to simplify the numerical evaluation of the IQBE. We verify the approximation in an analogous quasi-one-dimensional system and apply it to three-dimensional calculations, obtaining satisfactory agreement with recent experimental results. Furthermore, we compare the nonequilibrium results with those obtained using a thermal ansatz in both situations, providing a systematic understanding of the antievaporation phenomena observed in such systems.}, archive = {J_PRA}, author = {Xin-Yuan Gao and Yangqian Yan}, doi = {10.1103/PhysRevA.111.043312}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043312}, shortjournal = {Phys. Rev. A}, title = {Inelastic quantum boltzmann equation of single-component fermi gases}, volume = {111}, year = {2025}, }
• (2025). Probing p-wave effects in spin-density separation of bose mixtures with the dynamic structure factor. PRA, 111(4), 043311. (www)

  @article{ , abstract = {Quantum mixtures of Bose gases with tunable s - and p -wave interactions offer a versatile platform to explore strongly correlated phases and exotic phenomena. While repulsive interactions often drive phase separation, the interplay of p -wave interactions with spin-density decoupling remains underexplored. In this work we employ the path-integral field theory to investigate the role of p -wave interactions in three-dimensional two-component Bose gas. We derive the Lee-Huang-Yang corrections to the ground-state energy and quantum depletion, revealing how p -wave interactions modify equations of state of the model system. Furthermore, we demonstrate that p -wave interactions predominantly renormalize the spin-sector effective mass in the language of decoupling the density and spin-density degrees of freedom. This effect manifests in the dynamic structure factor, computed via hydrodynamic theory, where Bragg spectroscopy can detect a tunable splitting between spin and density modes. Our results bridge theoretical predictions with experimental observables, offering insights into anisotropic interaction effects in quantum gases and their implications for probing emergent phases.}, archive = {J_PRA}, author = {Xiaoran Ye and Zhaoxin Liang}, doi = {10.1103/PhysRevA.111.043311}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043311}, shortjournal = {Phys. Rev. A}, title = {Probing p-wave effects in spin-density separation of bose mixtures with the dynamic structure factor}, volume = {111}, year = {2025}, }
• (2025). Obstructed superfluid in the attractive qi-wu-zhang-hubbard model. PRA, 111(4), 043310. (www)

  @article{ , abstract = {Motivated by the recent realization of the Qi-Wu-Zhang (QWZ) model for the minimal spin-orbit-coupled quantum anomalous Hall phase in ultracold fermions, we introduce the on-site attractive interaction and map out the topological phase diagram for the Qi-Wu-Zhang-Hubbard (QWZH) model at the mean-field level. We show that, in addition to the conventional chiral topological superfluids (TSs) with nonzero Chern number, there is also an obstructed superfluid (OSF) with zero Chern number in the extended region of phase space. This phase is characterized by gapless edge states completely detaching from the bulk energy bands and two Z 2 numbers. We find the gapless edge states in OSF are protected by particle-hole symmetry and robust for the disorder. The appearance of OSF demonstrates that it is not sufficient to label TSs in the two-dimensional D class only by Chern numbers. These different topological phases in the attractive QWZH model can be detected experimentally by spin-resolved time-of-flight imaging. We also plot the phase diagram of the attractive QWZH model with one-dimensional spin-orbit coupling and find a series of TSs with gapless Dirac points. Considering the successful realization of the QWZ model and the tremendous progress in manipulating cold atom systems, our work provides a possible route to realize OSF in cold fermionic systems in the future.}, archive = {J_PRA}, author = {Beibing Huang and Chaofei Liu and Ning Xu}, doi = {10.1103/PhysRevA.111.043310}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043310}, shortjournal = {Phys. Rev. A}, title = {Obstructed superfluid in the attractive qi-wu-zhang-hubbard model}, volume = {111}, year = {2025}, }
• (2025). Acoustic black holes, white holes, and wormholes in bose-einstein condensates in two dimensions. PRA, 111(4), 043309. (www)

  @article{ , abstract = {In a previous article, we studied stationary solutions to the dynamics of a Bose-Einstein condensate corresponding to acoustic (or Unruh) black or white holes, namely, configurations where the flow becomes supersonic, creating a horizon for phonons. In this paper, we consider again the Gross-Pitaevskii equation, but looking for stationary numerical solutions in the case where the couplings are position dependent in a prescribed manner. Initially, we consider a two-dimensional quantum gas in a funnel-like spatial metric. We then reinterpret this solution as a solution in a flat metric but with spatially dependent coupling and external potential. In these solutions, the local speed of sound and the magnitude of flow velocity cross, indicating the existence of a supersonic region and therefore of sonic analogs of black and white holes and wormholes. We discuss the numerical techniques used. We also study phase (and density) fluctuations in these solutions and derive approximate acoustic metric tensors. For certain external potentials, we find uniform-density acoustic-black-hole configurations and obtain their Hawking temperature.}, archive = {J_PRA}, author = {Sachin Vaidya and Martin Kruczenski}, doi = {10.1103/PhysRevA.111.043309}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043309}, shortjournal = {Phys. Rev. A}, title = {Acoustic black holes, white holes, and wormholes in bose-einstein condensates in two dimensions}, volume = {111}, year = {2025}, }
• (2025). Acceleration-driven dynamics of josephson vortices in coplanar superfluid rings. PRA, 111(4), 043308. (www)

  @article{ , abstract = {Precise control of topologically protected excitations, such as quantum vortices in atomtronic circuits, opens new possibilities for future quantum technologies. We theoretically investigate the dynamics of Josephson vortices (rotational fluxons) induced by coupled persistent currents in a system of coplanar double-ring atomic Bose-Einstein condensates. We study the Josephson effect in an atomic Josephson junction formed by coaxial ring-shaped condensates. Tunneling superflows, initiated by an imbalance in atomic populations between the rings, are significantly influenced by the persistent currents in the inner and outer rings. This results in pronounced Josephson oscillations in the population imbalance for both corotating and nonrotating states. If a linear acceleration is applied to the system, our analysis reveals peculiar azimuthal tunneling patterns and dynamics of Josephson vortices which leads to nonzero net tunneling current and shows sensitivity to the acceleration magnitude. When multiple Josephson vortices are present, asymmetric vortex displacements that correlate with both the magnitude and direction of acceleration can be measured, offering the potential for quantum sensing applications.}, archive = {J_PRA}, author = {Yurii Borysenko and Nataliia Bazhan and Olena Prykhodko and Dominik Pfeiffer and Ludwig Lind and Gerhard Birkl and Alexander Yakimenko}, doi = {10.1103/PhysRevA.111.043308}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043308}, shortjournal = {Phys. Rev. A}, title = {Acceleration-driven dynamics of josephson vortices in coplanar superfluid rings}, volume = {111}, year = {2025}, }
• (2025). Assessing small accelerations using a bosonic josephson junction. PRA, 111(4), 043307. (www)

  @article{ , abstract = {Bosonic Josephson junctions provide a versatile platform for exploring quantum tunneling and coherence phenomena in ultracold atomic systems. While extensive research has examined the Josephson-junction dynamics in various double-well configurations, most studies have been limited to inertial reference frames. In the present work we pose the question how placing a Josephson junction in a noninertial reference frame would impact the quantum tunneling. Our findings demonstrate that accelerating a Josephson junction alters the tunneling dynamics. Conversely, tunneling behavior can be used to assess the acceleration of the system. By analyzing the changes in physical properties, we can assess the acceleration of the double well. We begin with the most simple noninertial frame: moving with constant acceleration. The tunneling time decreases exponentially as acceleration increases, making it effective for measuring larger accelerations. However, for smaller accelerations, accurate assessment requires accounting for many-body depletion, which decreases linearly as acceleration rises. Next we explore a more complex scenario where the acceleration is time dependent. In this case, the acceleration is mapped onto the tunneling time period and depletion, which again serve as predictors of acceleration. We also explore how the tunneling time and condensate depletion are affected by changes in the interparticle interaction. We go further by conducting a detailed analysis of the change in tunneling dynamics when the system deviates from constant or zero acceleration. The quantitative analysis shows that the depletion changes exponentially near constant acceleration, while around zero acceleration, the change follows a polynomial pattern. A comprehensive analysis of the effects of damped motion on the condensate depletion is performed as well. All in all, we quantify how the tunneling process and the mean-field and many-body properties evolve in a noninertial system of increasing complexity.}, archive = {J_PRA}, author = {Rhombik Roy and Ofir E. Alon}, doi = {10.1103/PhysRevA.111.043307}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043307}, shortjournal = {Phys. Rev. A}, title = {Assessing small accelerations using a bosonic josephson junction}, volume = {111}, year = {2025}, }
• (2025). Induced interactions and bipolarons in spin-orbit-coupled bose-einstein condensates. PRA, 111(4), 043306. (www)

  @article{ , abstract = {Impurities immersed in a Bose-Einstein condensate (BEC) can interact indirectly through the exchange of Bogoliubov excitations. These impurities, which form dressed quasiparticles known as Bose polarons due to their interaction with the BEC, can pair up to form a bound state called a bipolaron, via an induced interaction. Previous studies on induced interactions have focused primarily on cases with an isotropic excitation spectrum. In this work, we investigate the properties of induced interactions and bipolarons mediated by anisotropic Bogoliubov excitations using field theory. Taking a BEC with spin-orbit coupling as an example, we show that the induced interaction becomes anisotropic. Notably, a double-minima feature appears in the induced interaction in momentum space due to the exchange of roton excitations. Additionally, we calculate the binding energy and wave functions of these bipolarons induced by anisotropic interactions. Unlike previously studied bipolarons formed through the exchange of isotropic phonon excitations, we identify an alternative type of bipolaron whose wave functions feature a double-peak structure under strong impurity-boson interactions. Our work extends the theory of induced interactions from isotropic to anisotropic systems, and it reveals the novel features in both the induced interactions and bipolarons arising from BEC with an unconventional excitation spectrum.}, archive = {J_PRA}, author = {Zhe Yang and Shanshan Ding and Qizhong Zhu}, doi = {10.1103/PhysRevA.111.043306}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043306}, shortjournal = {Phys. Rev. A}, title = {Induced interactions and bipolarons in spin-orbit-coupled bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Effective tight-binding models in optical moiré potentials. PRA, 111(4), 043305. (www)

  @article{ , abstract = {A twist between two periodic systems offers the possibility to drastically control quantum transport properties. At discrete sets of commensurate twisting angles, a moiré periodic pattern is formed, and the low-energy single-particle spectrum forms distinct bands and gaps. Here, we consider twisted systems at a commensurate angle made of two continuous-space periodic potentials. We devise a general approach, based on a hierarchy of energy scales, to derive effective tight-binding models that capture the energy spectrum, focusing on the case of square lattices. Localized states in the moiré unit cell are coupled by strong intracell and weak intercell tunnelings, generating a series of energy bands and subbands that correspond to distinct, periodic lattices. For sufficiently deep potentials, we find excellent agreement between the spectrum of the continuous-space system and the tight-binding approximation thus constructed. Our approach allows for the interpretation of moiré band structures and the extraction of parameters for the effective tight-binding models. Applications to the physics of many-body systems and extensions to other twisted models are also discussed.}, archive = {J_PRA}, author = {Dean Johnstone and Shanya Mishra and Zhaoxuan Zhu and Laurent Sanchez-Palencia}, doi = {10.1103/PhysRevA.111.043305}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043305}, shortjournal = {Phys. Rev. A}, title = {Effective tight-binding models in optical moiré potentials}, volume = {111}, year = {2025}, }
• (2025). Quenching from superfluid to free bosons in two dimensions: Entanglement, symmetries, and the quantum mpemba effect. PRA, 111(4), 043304. (www)

  @article{ , abstract = {We study the nonequilibrium dynamics of bosons in a two-dimensional optical lattice after a sudden quench from the superfluid phase to the free-boson regime. The initial superfluid state is described approximately using both the Bogoliubov theory and the Gaussian variational principle. The subsequent time evolution remains Gaussian, and we compare the results from each approximation of the initial state by examining different aspects of the dynamics. First, we analyze the entanglement entropy and observe that, in both cases, it increases linearly with time before reaching a saturation point. This behavior is attributed to the propagation of entangled pairs of quantum depletions in the superfluid state. Next, we explore the fate of particle-number symmetry, which is spontaneously broken in the superfluid phase. To do so, we use the entanglement asymmetry, a recently introduced observable that enables us to track symmetry breaking within a subsystem. We observe that its evolution varies qualitatively depending on the theory used to describe the initial state. However, in both cases, the symmetry remains broken and is never restored in the stationary state. Finally, we assess the time it takes to reach the stationary state by evaluating the quantum fidelity between the stationary reduced density matrix and the time-evolved one. Interestingly, within the Gaussian variational principle, we find that an initial state further from the stationary state can relax more quickly than one closer to it, indicating the presence of the recently discovered quantum Mpemba effect. We derive the microscopic conditions necessary for this effect to occur and demonstrate that these conditions are never met in the Bogoliubov theory.}, archive = {J_PRA}, author = {Shion Yamashika and Pasquale Calabrese and Filiberto Ares}, doi = {10.1103/PhysRevA.111.043304}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043304}, shortjournal = {Phys. Rev. A}, title = {Quenching from superfluid to free bosons in two dimensions: Entanglement, symmetries, and the quantum mpemba effect}, volume = {111}, year = {2025}, }
• (2025). Scattering halos in strongly interacting feshbach molecular bose-einstein condensates. PRA, 111(4), 043303. (www)

  @article{ , abstract = {We investigate the scattering halos resulting from collisions between discrete momentum components in the time-of-flight expansion of interaction-tunable Li 2 6 molecular Bose-Einstein condensates. A key highlight of this study is the observation of the influence of interactions on the collisional scattering process. We measure the production of scattering halos at different interaction levels by varying the number of particles and the scattering length, and quantitatively assess the applicability of perturbation theory. To delve into a general theory of scattering halos, we introduce a scattering factor and obtain a universal relation between it and the halo ratio. Furthermore, we simulate the formation of scattering halos under nonperturbative conditions and discuss the contribution of in-trap dynamics to the scattering halos through a return pulse experiment. This study enhances our understanding of the physical mechanisms underlying scattering processes in many-body systems and provides new perspectives for further theoretical research.}, archive = {J_PRA}, author = {Yuying Chen and Zhengxi Zhang and Chi-Kin Lai and Yun Liang and Hongmian Shui and Haixiang Fu and Fansu Wei and Xiaoji Zhou}, doi = {10.1103/PhysRevA.111.043303}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043303}, shortjournal = {Phys. Rev. A}, title = {Scattering halos in strongly interacting feshbach molecular bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Stationary states of a trapped SU(3) spin-orbit-coupled bose gas with soft-core interaction. PRA, 111(4), 043302. (www)

  @article{ , abstract = {We consider a SU(3) spin-orbit-coupled Bose gas with nonlocal soft-core interactions confined in a harmonic trapping potential. The presence of SU(3) spin-orbit coupling induces three minima of the single-particle spectrum. In the absence of spin-exchange interaction, our results show that regardless of the sign of the soft-core interaction, the ground state occupies one single minimum in the momentum space and corresponds to a threefold-degenerate magnetized phase. For the ferromagnetic condensate, the ground state shows an amplitude-modulated plane-wave state, where its modulated amplitude and frequency are related to the strength of the soft-core interaction and SU(3) spin-orbit coupling, respectively. In particular, due to the subtle balance of the soft-core interaction and SU(3) spin-orbit coupling, a stable higher-order spin vortex lattice can be formed in the lattice phase of an antiferromagnetic condensate, where the density distributions of each component and the total system show spatial configurations with threefold and sixfold symmetries, respectively. We also give an experimental protocol to observe such states within current experimental capacity.}, archive = {J_PRA}, author = {Jia Liu and Jing Feng and Si-Lin Chen and Lin Wen and Wei Han and Xiao-Fei Zhang and Xue-Ying Yang}, doi = {10.1103/PhysRevA.111.043302}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043302}, shortjournal = {Phys. Rev. A}, title = {Stationary states of a trapped SU(3) spin-orbit-coupled bose gas with soft-core interaction}, volume = {111}, year = {2025}, }
• (2025). Stabilization of bose-bose mixtures on a spherical surface induced by the lee-huang-yang correction. PRA, 111(4), 043301. (www)

  @article{ , abstract = {Motivated by recent experimental advances in bubble traps which confine atoms on a thin shell, we investigate the stabilization of droplet states of a Bose-Bose mixture on a spherical surface due to quantum fluctuations. We analytically calculate the energy of a weakly interacting Bose-Bose mixture on a spherical surface with attractive interspecies and repulsive intraspecies interactions using the Bogoliubov approximation. Our findings show that the energy per particle has a minimum at a finite density in the presence of the Lee-Huang-Yang (LHY) term, which indicates the presence of liquidlike droplet state stabilized by quantum fluctuations. We also numerically solve the extended Gross-Pitaevskii equation, incorporating both bubble traps and an additional repulsive LHY correction derived from the Bogoliubov spectrum of a three-dimensional homogeneous mixture. Our calculations show that, due to the size limitations of the sphere, droplet states can only exist within specific parameter ranges. We also verify the transition between droplet states and uniform condensates in spherical confinement potentials, as well as the coexistence of the two. Our results pave the way for future exploration of quantum droplets in curved geometries with nontrivial real-space topologies.}, archive = {J_PRA}, author = {Wen-Hao Li and Ming Gong and Zheng-Wei Zhou and Xiang-Fa Zhou}, doi = {10.1103/PhysRevA.111.043301}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043301}, shortjournal = {Phys. Rev. A}, title = {Stabilization of bose-bose mixtures on a spherical surface induced by the lee-huang-yang correction}, volume = {111}, year = {2025}, }
• (2025). Dissociative frustrated triple ionization of ArKr dimers induced by a linearly polarized two-color femtosecond laser field. PRA, 111(4), 043114. (www)

  @article{ , abstract = {We experimentally investigate the dissociative frustrated triple ionization of ArKr dimers induced by a relative phase-controlled linearly polarized two-color femtosecond laser field. In this process, one of the three ionized electrons is recaptured by the triply ionized ArKr, leading to fragmentation via two distinct Rydberg channels: ( A ⁢ r + * , K ⁢ r + ) and ( A ⁢ r + , K ⁢ r + * ). Coincidence measurements are performed for the resulting fragments. By examining the sum momentum of the two fragments along the symmetry axis of the spectrometer in relation to their total kinetic energy release, we establish a method for selectively identifying events corresponding to each Rydberg channel from the raw data. Furthermore, we demonstrate that the emission directions of the Rydberg fragments in the ( A ⁢ r + * , K ⁢ r + ) and ( A ⁢ r + , K ⁢ r + * ) channels can be manipulated by adjusting the relative phase of the two-color laser fields. Notably, these two channels exhibit distinct behaviors in the relative phase-dependent asymmetry as a function of the kinetic energy release of the fragments. Based on the observed asymmetry patterns and the enhanced ionization mechanism, we elucidate the pathways leading to the formation of the ( A ⁢ r + * , K ⁢ r + ) and ( A ⁢ r + , K ⁢ r + * ). Our findings provide an experimental approach and deeper insight into molecular dissociative frustrated ionization in femtosecond laser fields.}, archive = {J_PRA}, author = {Junyang Ma and Shuqi Li and Yan Yang and Zhenrong Sun}, doi = {10.1103/PhysRevA.111.043114}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043114}, shortjournal = {Phys. Rev. A}, title = {Dissociative frustrated triple ionization of ArKr dimers induced by a linearly polarized two-color femtosecond laser field}, volume = {111}, year = {2025}, }
• (2025). Theoretical study of spin polarization in multiphoton ionization of the HI molecule. PRA, 111(4), 043113. (www)

  @article{ , abstract = {Spin polarization in the multiphoton ionization of the HI molecule with intense 395 nm, circularly polarized laser pulses is investigated theoretically. To this end, we numerically solve the time-dependent Schrödinger equation in the basis of spherical spinors employing the time-dependent single-center method. We investigate the influence of the ionizing-pulse parameters, such as peak intensity, time envelope, and duration, as well as molecular orientation in space on the computed spin polarization of photoelectrons emitted by the multiphoton ionization of HOMO, HOMO-1, and HOMO-2 states of the molecule.}, archive = {J_PRA}, author = {Anton N. Artemyev and Eric Kutscher and Boris M. Lagutin and Philipp V. Demekhin}, doi = {10.1103/PhysRevA.111.043113}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043113}, shortjournal = {Phys. Rev. A}, title = {Theoretical study of spin polarization in multiphoton ionization of the HI molecule}, volume = {111}, year = {2025}, }
• (2025). Radiative cooling of the deprotonated cyan fluorescent protein chromophore anion. PRA, 111(4), 043112. (www)

  @article{ , abstract = {An electrospray ion source has been coupled to a cryogenic electrostatic ion-beam storage ring to enable experimental studies of the fundamental properties of biomolecular ions and their reactions in the gas phase on longer timescales than with previous instruments. Using this equipment, we have measured the vibrational radiative cooling rate of the deprotonated anion of the chromophore of the cyan fluorescent protein, a color-shifted mutant of the iconic green fluorescent protein. Time-resolved dissociation rates of collisionally activated ions are first measured to benchmark a model of the dissociation rate coefficient. Storage time-dependent laser-induced dissociation rates are then measured to probe the evolution of the internal energy distribution of the stored ion ensemble. We find that significant heating of the electrosprayed ions occurs upon their extraction from the ion source, and that the radiative cooling rate is consistent with the prediction of a simple harmonic cascade model of vibrational relaxation.}, archive = {J_PRA}, author = {James Flotte de Pouzols and Arun Subramani and Eleanor K. Ashworth and James N. Bull and Henrik Cederquist and Jordan Dezalay and Nanna Holmgaard List and Paul Martini and José E. Navarro Navarrete and Henning T. Schmidt and Henning Zettergren and Boxing Zhu and Mark H. Stockett}, doi = {10.1103/PhysRevA.111.043112}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043112}, shortjournal = {Phys. Rev. A}, title = {Radiative cooling of the deprotonated cyan fluorescent protein chromophore anion}, volume = {111}, year = {2025}, }
• (2025). High-order harmonic generation in quantum light by a generalized von neumann lattice method. PRA, 111(4), 043111. (www)

  @article{ , abstract = {Studies of high harmonic generation (HHG) have entered a new stage by using the quantum light instead of the classical field. Recent theoretical progress has demonstrated promising features, such as the significantly higher maximum harmonic photon energy in a squeezed or thermal light field, which is not observed under classical field conditions with the same number of fundamental mode photons. However, there are many approximations in the theoretical treatments. More accurate methods are required to check the appealing results. By employing the generalized von Neumann lattice basis, here we develop a general and precise method to describe the HHG process, taking into account the coherent superposition of the diagonal part components and the nondiagonal part components from the overlap of the coherent states. It can be extended to calculate the multimode quantum light, such as two-mode squeezed vacuum. Our study provides a powerful tool for investigating the full properties of quantum light in HHG.}, archive = {J_PRA}, author = {Yi-Ben Wang and Xue-Bin Bian}, doi = {10.1103/PhysRevA.111.043111}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043111}, shortjournal = {Phys. Rev. A}, title = {High-order harmonic generation in quantum light by a generalized von neumann lattice method}, volume = {111}, year = {2025}, }
• (2025). Time- and energy-domain interference in the dynamically dressed rabi-cycling atom. PRA, 111(4), 043110. (www)

  @article{ , abstract = {We investigate the multipeak structure observed in resonant two-photon ionization of hydrogen, where Rabi oscillations occur. Our results show that the weak peaks appear both between and outside the Autler-Townes (AT) doublets for a rectangular pulse, in contrast to the sin-squared pulse case, where the peaks only appear between the AT doublets. Utilizing a three-level model, we demonstrate that the multipeak structure for the rectangular pulse is attributed to single-slit diffraction in the time domain, rather than to dynamic interference as in the sin-squared pulse. Furthermore, we show that the photoelectron yield of these peaks oscillates with laser intensity for both pulse shapes, with the yields from resonant and nonresonant paths oscillating in opposite directions. This oscillatory behavior is attributed to interference between split energy levels in the energy domain. Our work completes the understanding of the multipeak structure in Rabi oscillations for different laser pulse shapes and provides a way to manipulate the yield of these peaks through laser intensity.}, archive = {J_PRA}, author = {Yutong Deng and Xu Zhang and Yueming Zhou and Peixiang Lu}, doi = {10.1103/PhysRevA.111.043110}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043110}, shortjournal = {Phys. Rev. A}, title = {Time- and energy-domain interference in the dynamically dressed rabi-cycling atom}, volume = {111}, year = {2025}, }
• (2025). Electromagnetically-induced-transparency cooling with a tripod structure in a hyperfine trapped ion with mixed-species crystals. PRA, 111(4), 043109. (www)

  @article{ , abstract = {Cooling of atomic motion is a crucial tool for many branches of atomic physics, ranging from fundamental physics explorations to quantum information and sensing. For trapped ions, electromagnetically-induced-transparency (EIT) cooling has received attention for the relative speed, low laser power requirements, and broad cooling bandwidth of the technique. However, in applications where the ion used for cooling has hyperfine structure to enable long coherence times, it is difficult to find a closed three-level system in which to perform standard EIT cooling. Here, we demonstrate successful EIT cooling on Mg + 25 by the addition of an extra laser frequency; this method can be applied to any ion with nonzero nuclear spin. Furthermore, we simultaneously EIT cool all axial modes in mixed-species crystals Be + 9 − Mg + 25 and Be + 9 − Mg + 25 − Be + 9 through the Mg + 25 ion. This demonstrates the viability of EIT cooling in architectures where the laser-cooled species can host high-fidelity hyperfine qubits.}, archive = {J_PRA}, author = {Jenny J. Wu and Pan-Yu Hou and Stephen D. Erickson and Adam D. Brandt and Yong Wan and Giorgio Zarantonello and Daniel C. Cole and Andrew C. Wilson and Daniel H. Slichter and Dietrich Leibfried}, doi = {10.1103/PhysRevA.111.043109}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043109}, shortjournal = {Phys. Rev. A}, title = {Electromagnetically-induced-transparency cooling with a tripod structure in a hyperfine trapped ion with mixed-species crystals}, volume = {111}, year = {2025}, }
• (2025). Statistical theory of cumulant mapping in an imperfect apparatus. PRA, 111(4), 043108. (www)

  @article{ , abstract = {Cumulant mapping has recently been suggested [Frasinski, Phys. Chem. Chem. Phys. 24 , 20776 (2022) ] as an efficient approach to observing multiparticle fragmentation pathways while bypassing the restrictions of the usual coincidence-measurement approach. We present a formal analysis of the cumulant-mapping technique in the presence of moderate external noise, which induces spurious correlations between the fragments. Suppression of a false-cumulant signal may impose severe restrictions on the stability of the experimental setup and/or the permissible average event rate, which increase with cumulant order. We demonstrate that cumulant mapping in an imperfect apparatus remains competitive for dominant processes and for pathways with a background-free marker fragment. We further show that the false-cumulant contributions increase faster than linearly with the average event rate, providing a simple test for the experimental data analysis.}, archive = {J_PRA}, author = {S. Patchkovskii and J. Mikosch}, doi = {10.1103/PhysRevA.111.043108}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043108}, shortjournal = {Phys. Rev. A}, title = {Statistical theory of cumulant mapping in an imperfect apparatus}, volume = {111}, year = {2025}, }
• (2025). Dalgarno-lewis equation and its application to ultrafast two-photon processes: Short- and long-range terms for intermediate states. PRA, 111(4), 043107. (www)

  @article{ , abstract = {One long-term goal of attophysics is to deepen our knowledge on the ultrafast dynamics of quantum systems with the prospect of stirring electrons in their natural time and space scales. Two-photon processes are the lowest-order methods able to provide such information. Despite the long history backing two-photon studies and the success of many different exact and approximate methods, there are still some details to be unraveled. We use the Dalgarno-Lewis method to obtain both numerically exact results and accurate analytic expressions for short- and long-range contributions to the wave packets condensing information from the initial state and its coupling with the infinitely many virtual intermediate states in these two-photon processes. We identify some specific conditions under which short- and long-range terms adding up into the intermediate state induce radial matrix elements to hold competing coherent contributions for both single- and two-color cases. In the first case, interference structures marking a regime change may appear. On the second, short-range contributions may mask the compliance with propensity rules.}, archive = {J_PRA}, author = {D. I. R. Boll and A. Palacios and O. A. Fojón}, doi = {10.1103/PhysRevA.111.043107}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043107}, shortjournal = {Phys. Rev. A}, title = {Dalgarno-lewis equation and its application to ultrafast two-photon processes: Short- and long-range terms for intermediate states}, volume = {111}, year = {2025}, }
• (2025). Impact of micromotion and field-axis misalignment on the excitation of rydberg states of ions in a paul trap. PRA, 111(4), 043106. (www)

  @article{ , abstract = {Trapped ions are among the most advanced platforms for quantum simulation and computation. Their capabilities can be further augmented by making use of electronically highly excited Rydberg states, which enable the realization of long-range electric dipolar interactions. Most experimental and theoretical studies so far have focused on the excitation of ionic Rydberg states in linear Paul traps, which generate confinement by a combination of static and oscillating electric fields. These two fields need to be carefully aligned to minimize so-called micromotion, caused by the time-dependent electric field. The purpose of this work is to systematically understand the qualitative impact of micromotion on the Rydberg excitation spectrum, when the symmetry axes of the two electric fields do not coincide. Considering this scenario not only is important in the case of possible field misalignment but becomes inevitable for Rydberg excitations in two- and three-dimensional ion crystals, we develop a minimal model describing a single trapped Rydberg ion, which we solve numerically via Floquet theory and analytically using a perturbative approach. We calculate the excitation spectra and analyze in which parameter regimes addressable and energetically isolated Rydberg lines persist, which are important requirements for conducting coherent manipulations.}, archive = {J_PRA}, author = {Wilson S. Martins and Joseph W. P. Wilkinson and Markus Hennrich and Igor Lesanovsky}, doi = {10.1103/PhysRevA.111.043106}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043106}, shortjournal = {Phys. Rev. A}, title = {Impact of micromotion and field-axis misalignment on the excitation of rydberg states of ions in a paul trap}, volume = {111}, year = {2025}, }
• (2025). Coherent superposition mediating energy flow between fundamental and third-harmonic modes. PRA, 111(4), 043105. (www)

  @article{ , abstract = {We predict a coherent superposition mediating a significant periodic energy flow between the fundamental and third-harmonic modes. It is found for the linearly polarized electromagnetic field, where a lower bound S state | g 〉 is coupled to an upper bound S state | b 〉 , where the energy difference between these states is about two photons and the coupling occurs due to the above threshold ionization from these states together. Exceptional point on complex quasienergy surfaces of the dressed resonances | g 〉 and | b 〉 indicates coherent superposition that manifests itself dynamically as the Rabi cycle. The cycle is irreversible, being gradually quenched by the above threshold ionization while emitting strong third-harmonic and fundamental pulses. We provide a numerical evidence confirming the existence of such a process in the helium atom.}, archive = {J_PRA}, author = {Petra Ruth Kaprálová-Žďánská}, doi = {10.1103/PhysRevA.111.043105}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043105}, shortjournal = {Phys. Rev. A}, title = {Coherent superposition mediating energy flow between fundamental and third-harmonic modes}, volume = {111}, year = {2025}, }
• (2025). Resolving distinct ionization channels via interferometric phase analysis of partial waves. PRA, 111(4), 043104. (www)

  @article{ , abstract = {We extend the interferometric method to multiphoton ionization, aiming to disentangle different ionization channels simultaneously for resonance-enhanced multiphoton ionization by numerically solving the time-dependent Schrödinger equation. The approach is based on the interference of the bichromatic ionization using an ω − 4 ω pulse pair. By tuning the relative phase of the two-color laser pulse, we can extract the partial-wave complex amplitudes from the photoelectron angular distributions. Our analysis shows that controlling the fundamental frequency of the bichromatic pulses enables us to resolve resonant and nonresonant channels simultaneously. Taking the hydrogen atom as the prototype, at the resonant frequency, while the g partial wave is resonance-free, the quantum phases of the s and d partial waves and the corresponding Wigner time delays are significantly influenced by the intermediate resonance. Given that the above pulses are now accessible through high-harmonic sources or free-electron lasers, such investigations could disentangle the ionization channels of more complex targets.}, archive = {J_PRA}, author = {Tao Chen and Yi-Jia Mao and Yang Li and Feng He}, doi = {10.1103/PhysRevA.111.043104}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043104}, shortjournal = {Phys. Rev. A}, title = {Resolving distinct ionization channels via interferometric phase analysis of partial waves}, volume = {111}, year = {2025}, }
• (2025). Quantum tunneling without a barrier. PRA, 111(4), 043103. (www)

  @article{ , abstract = {Tunneling is an iconic concept that captures the peculiarity of quantum dynamics but, despite its ubiquity, questions remain. We focus on strong-field tunneling, which is vital to all attosecond science. We find an unexpected optical tunneling event that happens when the instantaneous electric field vanishes and there is no barrier. This event arises from a color switchover in a strongly polychromatic field. The tunneling without a barrier reveals the disconnect between the standard intuition built on the picture of a quasistatic barrier and the nonadiabatic nature of the process.}, archive = {J_PRA}, author = {Anne Weber and Margarita Khokhlova and Emilio Pisanty}, doi = {10.1103/PhysRevA.111.043103}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043103}, shortjournal = {Phys. Rev. A}, title = {Quantum tunneling without a barrier}, volume = {111}, year = {2025}, }
• (2025). Quantum beating and cyclic structures in the phase-space dynamics of the kramers-henneberger atom. PRA, 111(4), 043102. (www)

  @article{ , abstract = {We investigate the phase-space dynamics of the Kramers-Henneberger (KH) atom solving the time-dependent Schrödinger equation for reduced-dimensionality models and using Wigner quasiprobability distributions. We find that, for the time-averaged KH potential, coherent superpositions of eigenstates perform a cyclic motion confined in momentum space, whose frequency is proportional to the energy difference between the two KH eigenstates. This cyclic motion is also present if the full time-dependent dynamics are taken into consideration. However, there are time delays regarding the time-averaged potential, and some tail-shaped spilling of the quasiprobability flow towards higher momentum regions. These tails are signatures of ionization, indicating that, for the potential studied in this work, a small momentum spread is associated with stabilization. A comparison of the quasiprobability flow with classical phase-space constraints shows that, for the KH atom, the momentum must be bounded from above. This is a major difference from a molecule, for which the quasiprobability flow is confined in position space for small internuclear separation. Furthermore, we assess the stability of different propagation strategies and find that the most stable scenario for the full dynamics is obtained if the system is initially prepared in the KH ground state.}, archive = {J_PRA}, author = {A. Tasnim Aynul and L. Cruz Rodriguez and C. Figueira de Morisson Faria}, doi = {10.1103/PhysRevA.111.043102}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043102}, shortjournal = {Phys. Rev. A}, title = {Quantum beating and cyclic structures in the phase-space dynamics of the kramers-henneberger atom}, volume = {111}, year = {2025}, }
• (2025). Two-photon cooling of calcium atoms. PRA, 111(4), 043101. (www)

  @article{ , abstract = {We demonstrate cooling of calcium atoms using a two-photon transition from the 1 S 0 ground state to the upper 4 s 5 s 1 S 0 state via the 1 P 1 intermediate state. We achieve temperatures as low as 260 µ K in a magnetooptical trap (MOT), well below the Doppler limit ( T D = 0.8 m K ) of the 1 P 1 state. We characterize the temperature, lifetime, and confinement of the MOT over a range of experimental parameters, observing no reduction in lifetime due to coupling to the higher state. We perform theoretical simulations of the cooling scheme and observe good agreement with the experimental results. The two-photon cooling scheme presented in this work provides an alternative to the standard Doppler cooling applied to alkaline-earth atoms, based on a sequence of two magnetooptical traps. The advantages of our scheme are the possibility of varying the effective linewidth of the 1 P 1 state, a higher transfer efficiency (close to 100 % ), and a more straightforward experimental implementation.}, archive = {J_PRA}, author = {Wojciech Adamczyk and Silvan Koch and Claudia Politi and Henry Fernandes Passagem and Christoph Fischer and Pavel Filippov and Florence Berterottière and Daniel Kienzler and Jonathan Home}, doi = {10.1103/PhysRevA.111.043101}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {043101}, shortjournal = {Phys. Rev. A}, title = {Two-photon cooling of calcium atoms}, volume = {111}, year = {2025}, }
• (2025). Exploring the enhancement of radiative recombination through field-induced recombination. PRA, 111(4), 042828. (www)

  @article{ , abstract = {The enhancement of electron-ion radiative-recombination rates at low energies remains an open issue, particularly following the proposal of field-induced recombination (FIR) as a potential mechanism and the corresponding calculations by Hörndl et al. [ Phys. Rev. A 74 , 052712 (2006) ]. We present a refined model for FIR and radiative stabilization, incorporating a two-step cascade process. Our simulations determine the bound-state distribution , revealing a turning point at low principal quantum numbers that underscores the limitations of previous extrapolations. Furthermore, we show that in regions with high and low , exceeds the statistical approximation, due to the influence of a magnetic field. With an expanded sample size of at least trajectories, our model accurately estimates recombination rates for bare ions, including , and , achieving excellent agreement with experimental data.}, archive = {J_PRA}, author = {K. Q. Shi and Z. K. Huang and H. B. Wang and X. B. Zhu and S. Schippers and X. Ma}, doi = {10.1103/PhysRevA.111.042828}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042828}, shortjournal = {Phys. Rev. A}, title = {Exploring the enhancement of radiative recombination through field-induced recombination}, volume = {111}, year = {2025}, }
• (2025). Toward a full understanding of the physics of heavy-ion-induced inner-shell ionization. PRA, 111(4), 042827. (www)

  @article{ , abstract = {The complex physics of inner-shell ionization of target atoms by heavy-ion impact has remained only partially solved for decades. Recently, agreement between theory and experiment has been achieved by considering inner-shell ionization of target atoms due to projectile electron capture in addition to direct Coulomb ionization including multiple ionization effects. A thorough investigation exhibits such a picture only if the atomic parameters of the target atoms are correct. In fact, the theoretical approach is found to be right, but the problem arises with the faulty atomic parameters. Furthermore, we show that fluorescence yields play a major role among the atomic parameters. We explore such a powerful method that enables us to measure the correct and accurate fluorescence yields for almost every element in the periodic table. As per our present knowledge, this, in turn, not only solves the said complex issue fully but also makes the particle/proton-induced x-ray emission analysis more reliable and accurate using both light and heavy ions.}, archive = {J_PRA}, author = {Manpreet Kaur and Soumya Chatterjee and T. Nandi}, doi = {10.1103/PhysRevA.111.042827}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042827}, shortjournal = {Phys. Rev. A}, title = {Toward a full understanding of the physics of heavy-ion-induced inner-shell ionization}, volume = {111}, year = {2025}, }
• (2025). Influence of the impact parameter for ionization of argon by fast positrons and electrons on the postcollision kinematics and triply differential spectra. PRA, 111(4), 042826. (www)

  @article{ , abstract = {Classical trajectory Monte Carlo calculations for fast positron and electron impact ionization of argon are used to provide information about how the pre- and postcollision kinematics alter the triply differential spectra. It is shown that in addition to the scattering direction expected for a positive or negative projectile passing near a partially screened nuclear charge, scattering in the opposite direction also occurs. Independent of energy transfer, when the impact parameter is less than the mean radius of the electron cloud, the expected direction of scattering always occurs. In contrast, for scattering in the opposite direction, the impact parameter is larger than the mean radius for low energy transfer but decreases to values near the radius for large energy transfer. The change in impact parameter and direction of scattering are shown to influence the recoil to binary triply differential cross-section ratios and explains the unexpectantly large ratios that have been observed at higher emission energies and may explain the larger ratio observed for electron impact.}, archive = {J_PRA}, author = {R. D. DuBois and K. Tőkési}, doi = {10.1103/PhysRevA.111.042826}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042826}, shortjournal = {Phys. Rev. A}, title = {Influence of the impact parameter for ionization of argon by fast positrons and electrons on the postcollision kinematics and triply differential spectra}, volume = {111}, year = {2025}, }
• (2025). Exact closed-form unitary transformations of fermionic operators. PRA, 111(4), 042825. (www)

  @article{ , abstract = {Unitary transformations play a fundamental role in many-body physics, and except for special cases, they are not expressible in closed form. We present closed-form expressions for unitary transformations generated by a single fermionic operator for Hermitian and anti-Hermitian generators. We demonstrate the usefulness of these expressions in formal analyses of unitary transformations and numerical applications to Hamiltonian downfolding in quantum computing and Heisenberg dynamics. This work paves the way for new analytical treatments of unitary transformations and numerical many-body methods for fermions.}, archive = {J_PRA}, author = {Francesco A. Evangelista and Ilias Magoulas}, doi = {10.1103/PhysRevA.111.042825}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042825}, shortjournal = {Phys. Rev. A}, title = {Exact closed-form unitary transformations of fermionic operators}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic-coupling-mediated argon dimer dissociation by slow and low-charge-state ion collisions. PRA, 111(4), 042824. (www)

  @article{ , abstract = {Weakly bound systems provide possibilities to study nonlocal electronic decay processes, which present unique physical and chemical properties. Here we report the experimental observation of a nonlocal decay process, i.e., nonadiabatic-coupling-mediated charge transfer (NCMCT), in argon dimer. This process can be effectively produced and manipulated by the double electron capture in low-charge-state oxygen ion collisions. Compared to other common decay mechanisms of dication, the NCMCT process results in notably different kinetic energy releases for the channel. It is due, revealed by theoretical calculations, to the special potential energy curve of the responsible state that possesses many crossing points and thus nonadiabatically couples with the states in a wide internuclear distance range. Such an NCMCT process is expected to be a general process occurring in weakly bound systems when highly excited. The present work provides a prime collision system to explore the charge transfer in ion-molecule reactions and also brings insight into cluster dissociation mechanism.}, archive = {J_PRA}, author = {Yu Zhang and Jiarong Wang and Xiaoqing Hu and Baihui Ren and Tianming Meng and Pufang Ma and Yueying Qi and Yong Wu and Jianguo Wang and Yaming Zou and Bingsheng Tu and Amine Cassimi and Baoren Wei}, doi = {10.1103/PhysRevA.111.042824}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042824}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic-coupling-mediated argon dimer dissociation by slow and low-charge-state ion collisions}, volume = {111}, year = {2025}, }
• (2025). Theoretical determination of the ionization potentials of ScF, YF, LaF, and AcF. PRA, 111(4), 042823. (www)

  @article{ , abstract = {We present a comprehensive theoretical study of the ionization potentials of molecules using a state-of-the-art relativistic coupled-cluster approach with single, double, and perturbative triple excitations. We further correct our results for higher-order excitations (up to full triples), the QED self-energy, and vacuum-polarization contributions. We extensively investigate the effect of the various computational parameters on the calculated ionization potentials, allowing us to assign realistic uncertainties to our predictions.}, archive = {J_PRA}, author = {A. A. Kyuberis and L. F. Pašteka and E. Eliav and A. Sunaga and M. Au and S. G. Wilkins and A. Borschevsky}, doi = {10.1103/PhysRevA.111.042823}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042823}, shortjournal = {Phys. Rev. A}, title = {Theoretical determination of the ionization potentials of ScF, YF, LaF, and AcF}, volume = {111}, year = {2025}, }
• (2025). Theoretical investigation of the laser-induced three-dimensional vibration excitation of neutral N2Ar. PRA, 111(4), 042822. (www)

  @article{ , abstract = {In this paper, the laser-driven three-dimensional vibration excitation dynamics of dimer are simulated using the full time-dependent wave-packet simulation method. The three-dimensional vibrational wave functions are obtained first by solving the Schrödinger equation involving the rotation of , vibration of -Ar, and intermolecular interaction. The solved vibration wave functions have both the angular quantum number and the symmetric or antisymmetric properties with respect to the -Ar axis. The theoretical calculation shows that laser-induced molecular vibrational excitation needs to satisfy the selection rules of nonresonant Raman processes. Two modes of excitation are further distinguished as follows: (1) and the symmetry does not change; here, the van der Waals bond will be strengthened. (2) and the symmetry is reversed; here, the dimer will be partially excited into a linear structure. Our results point out that the initially located in the ground vibrational state mainly prefers the excitation of mode (1), but the one located in the first excited state will undergo two modes of excitation simultaneously.}, archive = {J_PRA}, author = {Ting Xu and YinSong Tang and Xiaoqing Hu and JinPeng Ma and SiQi Pei and CongCong Jia and Yong Wu and JianGuo Wang}, doi = {10.1103/PhysRevA.111.042822}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042822}, shortjournal = {Phys. Rev. A}, title = {Theoretical investigation of the laser-induced three-dimensional vibration excitation of neutral N2Ar}, volume = {111}, year = {2025}, }
• (2025). Testing relativistic atomic structure and bound-state quantum electrodynamics with co-like ions. PRA, 111(4), 042821. (www)

  @article{ , abstract = {Multiply charged ions with a single hole in closed shells are being extensively used to study relativistic and quantum electrodynamic (QED) effects due to the suppression of electron correlations in such systems. Here, we report measurements of the fine-structure splitting in the ground configuration of Co-like ions of Yb, Re, Os, and Ir performed with an electron beam ion trap. Extensive relativistic many-body perturbation theory and multiconfiguration Dirac-Hartree-Fock calculations were executed with account of high-order QED contributions. It is found that those advanced calculations very well agree with the present accurate measurements of the splittings. Comparisons with other theoretical works and experiments are presented as well.}, archive = {J_PRA}, author = {R. Silwal and S. A. Blundell and S. C. Sanders and Dipti and H. Staiger and A. Hosier and M. G. Fuller and Yu. Ralchenko and E. Takacs}, doi = {10.1103/PhysRevA.111.042821}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042821}, shortjournal = {Phys. Rev. A}, title = {Testing relativistic atomic structure and bound-state quantum electrodynamics with co-like ions}, volume = {111}, year = {2025}, }
• (2025). Two-loop electron self-energy with accelerated partial-wave expansion. PRA, 111(4), 042820. (www)

  @article{ , abstract = {Calculations of the two-loop electron self-energy for the and states of hydrogen-like ions are reported, performed to all orders in the nuclear binding strength parameter (where is the nuclear charge number and is the fine structure constant). The presented approach features an accelerated convergence of the partial-wave expansion and allows calculations to be accomplished for nuclear charges lower than previously possible and with a higher numerical accuracy.}, archive = {J_PRA}, author = {V. A. Yerokhin and Z. Harman and C. H. Keitel}, doi = {10.1103/PhysRevA.111.042820}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042820}, shortjournal = {Phys. Rev. A}, title = {Two-loop electron self-energy with accelerated partial-wave expansion}, volume = {111}, year = {2025}, }
• (2025). Revisiting the hyperfine interval for the 2s2p PJ3 state in be9. PRA, 111(4), 042819. (www)

  @article{ , abstract = {By using the relativistic multiconfiguration Dirac-Fock method, we calculate the hyperfine-structure properties of the 2 s 2 p P J 3 state in Be 9 . The hyperfine-structure properties encompass first-order hyperfine-structure parameters, as well as second-order and third-order corrections caused by the off-diagonal hyperfine interaction. Based on our theoretical results, we reanalyze the previously reported measurement of the hyperfine interval for the 2 s 2 p P 3 state in Be 9 [A. G. Blachman and A. Lurio, Phys. Rev. 153 , 164 (1967) ], yielding updated hyperfine-structure constants. Our results show that the hyperfine-structure constant B of 2 s 2 p P 1 3 is notably sensitive to second-order correction. Conversely, accurately determining the hyperfine-structure constant B of 2 s 2 p P 2 3 necessitates consideration of the magnetic octupole hyperfine interaction in the first-order hyperfine interaction equation. The updated hyperfine-structure constant B of the 2 s 2 p P 2 3 state is found to be 1.4542(67) MHz, which is approximately 1.7 % larger than the previous value of 1.427(9) MHz [A. G. Blachman and A. Lurio, Phys. Rev. 153 , 164 (1967) ]. By combining our theoretical results with the updated hyperfine-structure constant for the 2 s 2 p P 2 3 state, we extract the electric quadrupole moment Q of Be 9 nucleus to be 0.05320(50) b. This value is consistent with the most recent determination using the few-body precision calculation method [Puchalski et al. Phys. Rev. Res. 3 , 013293 (2021) ]. Additionally, we discuss the reasons for the discrepancy between the electric quadrupole moment Q obtained through few-body and previous many-body calculations.}, archive = {J_PRA}, author = {Yu-Shan Zhang and Wei Dang and Kai Wang and Yong-Bo Tang}, doi = {10.1103/PhysRevA.111.042819}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042819}, shortjournal = {Phys. Rev. A}, title = {Revisiting the hyperfine interval for the 2s2p PJ3 state in be9}, volume = {111}, year = {2025}, }
• (2025). Stepwise ionization of mo14+ ions in an electron-beam ion trap: The importance of the metastable level. PRA, 111(4), 042818. (www)

  @article{ , abstract = {The visible spectrum of Mo 15 + ions was measured using a room-temperature permanent magnet electron-beam ion trap at the Shanghai EBIT Laboratory, with an electron-beam energy E e = 400 eV , which is significantly below the ionization potential ( IP = 544.0 eV) of the Mo 14 + ions in the ground configuration 3 p 6 3 d 10 . To provide a detailed explanation of the experiment, we calculated the energy-level structure, radiative transition properties, electron-impact excitation, and electron-impact ionization cross sections for both the ground state and low-lying excited states of the Mo 14 + ions using the Dirac-Fock-Slater method with a local central potential and the distorted-wave approximation. The results show good agreement with both experimental and theoretical data available in the literature. Through an analysis of the relevant atomic processes of Mo 14 + ions, a scenario involving the stepwise ionization via the metastable configuration 3 p 6 3 d 9 4 s was proposed to explain the presence of the Mo 15 + ions for electron energies below the ionization threshold. The study confirms the importance of metastable states in ionization processes, and provides new insights into their ionization mechanisms, which will be valuable for future studies of EBIT and similar plasma environments.}, archive = {J_PRA}, author = {Cunqiang Wu and Xiaobin Ding and Qi Guo and Jialin Liu and Ke Yao and Yunqing Fu and Chenzhong Dong}, doi = {10.1103/PhysRevA.111.042818}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042818}, shortjournal = {Phys. Rev. A}, title = {Stepwise ionization of mo14+ ions in an electron-beam ion trap: The importance of the metastable level}, volume = {111}, year = {2025}, }
• (2025). Facilitating role of hydrogen migration in the fragmentation dynamics of acetonitrile dications. PRA, 111(4), 042817. (www)

  @article{ , abstract = {We investigate the electron-impact double ionization and subsequent fragmentation dynamics of acetonitrile using multiparticle coincident momentum spectroscopy. Through the measurements of the kinetic energy release for the two-body Coulomb explosion processes and the potential energy calculations in the reaction coordinate, we identify several fragmentation channels that are typically not accessible via direct Coulomb explosion, necessitating prior isomerization, which dominates over the direct Coulomb explosion channel. The potential energy calculations reveal that hydrogen migration reduces the energy barrier of C-C bond cleavage, thereby promoting the fragmentation of acetonitrile dications. Moreover, we find that, instead of transferring to the nitrogen atom yielding the double hydrogen migration channel, the roaming H 2 captures a proton or transfers an electron to the remaining moiety, leading to the formation of H 3 + and H 2 + cations. This work provides insight into the competitive interplay between hydrogen migration and Coulomb explosion mechanisms in molecular fragmentation.}, archive = {J_PRA}, author = {Qibo Ma and Jiaqi Zhou and Xiaorui Xue and Xintai Hao and Enliang Wang and Xueguang Ren}, doi = {10.1103/PhysRevA.111.042817}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042817}, shortjournal = {Phys. Rev. A}, title = {Facilitating role of hydrogen migration in the fragmentation dynamics of acetonitrile dications}, volume = {111}, year = {2025}, }
• (2025). Ultralong-range rydberg molecules of hg atoms. PRA, 111(4), 042816. (www)

  @article{ , abstract = {Ultralong-range Rydberg molecules, composed of an excited Rydberg atom and a ground-state atom, are characterized by large bond lengths, dipole moments, sensitivity to external fields, and an unusual binding mechanism based on low-energy elastic electron scattering. Although Rydberg molecules formed between alkali atoms have received the most attention, the additional complexity found in atoms with more than a single valence electron poses new theoretical challenges as well as new possibilities for control and design of the molecular structure. In this paper, we extend the theory of Rydberg molecules to include the additional spin coupling of the Rydberg states of a multivalent atom. We employ this theory to describe the properties of Rydberg molecules composed of mercury atoms. We calculate the potential energy curves of both heteronuclear ( Hg * Rb ) and homonuclear ( Hg * Hg ) molecules. In the former case, we propose the realization of long-range spin entanglement and remote spin flip. In the latter, we show how long-lived metastable molecular states of Hg * Hg exist as resonances above the dissociation threshold.}, archive = {J_PRA}, author = {Agata Wojciechowska and Michał Tomza and Matthew T. Eiles}, doi = {10.1103/PhysRevA.111.042816}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042816}, shortjournal = {Phys. Rev. A}, title = {Ultralong-range rydberg molecules of hg atoms}, volume = {111}, year = {2025}, }
• (2025). Electron emission in water molecules impacted by charged and neutral heq+ projectiles. PRA, 111(4), 042815. (www)

  @article{ , abstract = {The electron emission processes in charged and neutral helium projectiles colliding with water molecules are theoretically investigated. The individual reactions, namely, target ionization and projectile electron loss, are studied within the continuum distorted wave–eikonal initial state model. Comparison of theoretical predictions with experimental data will help to improve the accuracy of models that describe such collisions. This can have implications for a wide range of fields, including plasma physics, astrophysics, and radiation biology. The calculations presented here are shown in the form of differential cross sections, in the energy range from 300 keV/u to 10 MeV/u, which describe the energy and angular spectra of the electrons emitted. Also, the computed total cross sections are compared with available theoretical and experimental results in the energy range from 40 keV/u up to 50 MeV/u.}, archive = {J_PRA}, author = {M. A. Quinto and N. J. Esponda and R. D. Rivarola and J. M. Monti}, doi = {10.1103/PhysRevA.111.042815}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042815}, shortjournal = {Phys. Rev. A}, title = {Electron emission in water molecules impacted by charged and neutral heq+ projectiles}, volume = {111}, year = {2025}, }
• (2025). Alignment-transfer rate coefficients for excitation of o v by electrons with an anisotropic two-temperature maxwellian distribution. PRA, 111(4), 042814. (www)

  @article{ , abstract = {Alignment-transfer rate coefficients C 0 K K ′ , with nonzero even values of K and K ′ , enter in the population-alignment collisional-radiative model and are useful in anisotropic plasma diagnostics. Here, these coefficients are calculated for electron impact excitation of the Be-like ion O v from its metastable 2 s 2 p 3 P 1 , 2 levels in a nonthermal plasma with an anisotropic two-temperature Maxwellian electron velocity distribution. The calculations take into account coherences between magnetic sublevels within initial and final levels of the collisional transfer of alignment, via integration of linear combinations of alignment-transfer σ Q = 0 K K ′ and coherence-transfer σ Q ≠ 0 K K ′ cross sections. Computations of these cross sections are performed up to 1.8 keV of the scattered electron energy in the relativistic distorted-wave approximation using an extended version of the flexible atomic code . Selected results of C 0 22 and C 0 44 for 2 s 2 p 3 P 1 , 2 → 2 s 3 p 3 P 1 , 2 and 2 s 2 p 3 P 1 , 2 → 2 s 3 d 3 D 2 , 3 excitations are given to highlight the importance of coherences. Ignoring the coherence-transfer cross sections σ Q ≠ 0 K K ′ in the calculations may lead to underestimating the alignment-transfer rate coefficients by more than 80%. The present results could shed light on the discrepancies reported between theoretical predictions ignoring σ Q ≠ 0 K K ′ and measurements of the polarization of O v lines emitted from WT-3 tokamak plasma.}, archive = {J_PRA}, author = {A. F. Sekkal-Haddouche and M. K. Inal and M. Benmouna}, doi = {10.1103/PhysRevA.111.042814}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042814}, shortjournal = {Phys. Rev. A}, title = {Alignment-transfer rate coefficients for excitation of o v by electrons with an anisotropic two-temperature maxwellian distribution}, volume = {111}, year = {2025}, }
• (2025). Testing for isospin symmetry breaking by combining isotope shift measurements with precise calculations in potassium. PRA, 111(4), 042813. (www)

  @article{ , abstract = {Precise evaluation of the isotope shift (IS) factors for seven low-lying potassium states is achieved using relativistic coupled-cluster theory. The energies of these states are compared with the experimental data to confirm the accuracy of wave functions calculated at different approximations and to highlight the significance of many-body and relativistic effects. Various methods are used to compute the IS factors, with the finite-field (FF) approach yielding results that align with observed and semiempirical data. This is attributed to orbital relaxation effects that are present naturally in the FF method but emerge only through perturbation in other methods. Using results from the FF approach, we review the mean-square-radius difference between 38 m K and K 39 , which is combined with muonic atom x-ray spectroscopy and updated calculation of the nuclear polarizability effect to deduce the absolute radius of 38 m K . Finally, we evaluate the isospin symmetry breaking (ISB) in the isotriplet by integrating the radius of 38 m K with an updated radius of Ca 38 , concluding that the ISB is compatible with zero. This finding offers a stringent benchmark for nuclear models of ISB corrections in nuclear beta decay, which play a key role in determining the V u d matrix element.}, archive = {J_PRA}, author = {Vaibhav Katyal and A. Chakraborty and B. K. Sahoo and Ben Ohayon and Chien-Yeah Seng and Mikhail Gorchtein and John Behr}, doi = {10.1103/PhysRevA.111.042813}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042813}, shortjournal = {Phys. Rev. A}, title = {Testing for isospin symmetry breaking by combining isotope shift measurements with precise calculations in potassium}, volume = {111}, year = {2025}, }
• (2025). Experimentally determined interatomic potentials in low-energy atomic collisions relevant for nuclear fusion. PRA, 111(4), 042812. (www)

  @article{ , abstract = {Interatomic potentials were measured for combinations of chemical elements relevant for nuclear fusion. Angular scans of the scattering yield were performed on a W(110) and a Fe(100) single crystal using and beams with energies of 3 keV/atom using a time-of-flight low-energy ion scattering setup. Information on the interatomic potentials was deduced by reproducing width and intensity of minima and maxima in the angular scans in molecular dynamics simulations by adjusting the assumed screening length with a correction factor. Results from experiments were compared to common interatomic potential models and density functional theory predictions. Our measurements show that the uncorrected Thomas-Fermi-Molière and the Ziegler-Biersack-Littmark potentials overestimate the interatomic potential for the studied combinations. In contrast, the Yamamura-Takeuchi-Kawamura potential yields values slightly below our experimental result. At the same time, density functional theory predictions agree well with our experimental results for the He cases while differing significantly for the D cases.}, archive = {J_PRA}, author = {Philipp M. Wolf and Eduardo Pitthan and Daniel Primetzhofer}, doi = {10.1103/PhysRevA.111.042812}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042812}, shortjournal = {Phys. Rev. A}, title = {Experimentally determined interatomic potentials in low-energy atomic collisions relevant for nuclear fusion}, volume = {111}, year = {2025}, }
• (2025). Vacuum polarization in molecules. II. higher-order corrections. PRA, 111(4), 042811. (www)

  @article{ , abstract = {We outline a general formalism for treating vacuum polarization phenomena within an effective field expansion. The coupling between source charges and virtual fields is examined from the perspectives of electrostatic potentials, induced charge densities, and form factors in momentum space. A strategy for the efficient calculation of vacuum polarization potentials is outlined, implemented, and applied towards the construction of fitting potentials that are suitable for molecular electronic structure calculations, which enclose no overall charge by construction. The order- α ( Z α ) , - α ( Z α ) 3 , and - α 2 ( Z α ) effects of a Gaussian nuclear charge on the electron-positron field are applied variationally towards the E119F molecule, as well as the order- α ( Z α ) effects arising from the virtual muon and charged pion fields.}, archive = {J_PRA}, author = {D. J. Flynn and H. M. Quiney and I. P. Grant}, doi = {10.1103/PhysRevA.111.042811}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042811}, shortjournal = {Phys. Rev. A}, title = {Vacuum polarization in molecules. II. higher-order corrections}, volume = {111}, year = {2025}, }
• (2025). Vacuum polarization in molecules. i. uehling interaction. PRA, 111(4), 042810. (www)

  @article{ , abstract = {Radiative corrections to electronic structure are characterized by perturbative expansions in α and Z α , where α is the fine-structure constant and Z is the nuclear charge. A formulation of the leading-order α ( Z α ) Uehling contribution to the renormalized vacuum polarization is reported in a form that is convenient for implementation in computational studies of the relativistic electronic structures of molecules. Benchmark calculations based on these methods are reported that include the leading-order vacuum polarization effects within relativistic mean-field methods for the E 119 + ion and the closed-shell diatomic species E119F.}, archive = {J_PRA}, author = {D. J. Flynn and H. M. Quiney and I. P. Grant}, doi = {10.1103/PhysRevA.111.042810}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042810}, shortjournal = {Phys. Rev. A}, title = {Vacuum polarization in molecules. i. uehling interaction}, volume = {111}, year = {2025}, }
• (2025). Improved positron-molecule binding energies and estimations using molecular parameters. PRA, 111(4), 042809. (www)

  @article{ , abstract = {Positron-molecule binding energies ɛ B have been measured for over 100 molecules. They range from a few to greater than 300 meV. The complete set of ɛ B values is presented including, where necessary, updated analyses of previous data to provide more accurate values of ɛ B . The result is a dataset of 85 distinct hydrocarbon molecules and 29 deuterated analogs with ɛ B values ranging in precision from ± 3 to ± 20 meV. Linear regression analysis is used to estimate ɛ B using the global molecular parameters polarizability α , permanent dipole moment μ , and the number of π bonds N π associated aromatic molecules and those with unsaturated bonds. Use of an optimized expansion for the entire dataset predicts ɛ B to within a root-mean-square error of ≈ 30 meV. This expression can provide useful estimates of ɛ B for molecular species similar to those in the existing dataset but for which ɛ B has not been measured. Chemical species for which this regression analysis is not valid are discussed. Complementary analyses are made for restricted ranges of global parameters, and these empirical expressions provide additional insight into the underlying physical mechanisms for positron-molecule binding. The results are related to recent many-body theory calculations of the bound-state positron wave functions.}, archive = {J_PRA}, author = {J. R. Danielson and E. Arthur-Baidoo and C. M. Surko}, doi = {10.1103/PhysRevA.111.042809}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042809}, shortjournal = {Phys. Rev. A}, title = {Improved positron-molecule binding energies and estimations using molecular parameters}, volume = {111}, year = {2025}, }
• (2025). High-precision measurements of electric-dipole-transition amplitudes in excited states of pb208 using faraday rotation spectroscopy. PRA, 111(4), 042808. (www)

  @article{ , abstract = {We have completed measurements of two low-lying excited-state electric-dipole (E1) transition amplitudes in lead. Our measured reduced matrix elements of the ( 6 s 2 6 p 2 ) P 1 3 → ( 6 s 2 6 p 7 s ) P 0 3 transition at 368.3 nm and the 405.8-nm ( 6 s 2 6 p 2 ) P 2 3 → ( 6 s 2 6 p 7 s ) P 1 3 transition are 1.90(1) and 3.01(2) a.u., respectively, both measured to sub-1% precision and both in excellent agreement with the latest ab initio lead wave-function calculations. These measurements were completed by comparing the low-field Faraday optical rotation spectra of each E1 transition in turn with that of the ground-state P 0 3 − P 1 3 M1 transition under identical experimental conditions. Our spectroscopy technique involves polarization modulation and lock-in detection yielding microradian-level optical rotation resolution. At temperatures where direct absorption was significant for both E1 and M1 transitions, we also extracted matrix element values from a direct optical absorption depth comparison. As part of this work we designed an interaction region within our furnace which allows precise measurement of our quartz vapor cell sample temperature and thus accurate determination of the Boltzmann thermal population of the low-lying excited states that were studied.}, archive = {J_PRA}, author = {John H. Lacy and Abby C. Kinney and P. K. Majumder}, doi = {10.1103/PhysRevA.111.042808}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042808}, shortjournal = {Phys. Rev. A}, title = {High-precision measurements of electric-dipole-transition amplitudes in excited states of pb208 using faraday rotation spectroscopy}, volume = {111}, year = {2025}, }
• (2025). Ab initio calculations of electric dipole polarizabilities in the li, na, and k atoms. PRA, 111(4), 042807. (www)

  @article{ , abstract = {We carry out first-principle calculations of scalar and tensor components of the static electric dipole polarizabilities of six low-lying states of lithium (Li), sodium (Na) and potassium (K) alkali-metal atoms in the linear-response approach. Results are compared from the Dirac-Hartree-Fock (DHF) method, third-order many-body perturbation theory [MBPT(3) method], random-phase approximation (RPA) and singles and doubles approximated relativistic coupled-cluster theory (RCCSD method). We find the DHF and RPA results are close to each other, while the MBPT(3) and RCCSD results are close to each other. This suggests that pair-correlation effects play significant roles over core-polarization effects to determine these quantities accurately in the above alkali-metal atoms. We also compare contributions arising through the core, core-valence, and valence correlations through all the methods in Li, Na, and K, which show that the core-valence contributions are negligibly small in all the methods and there is no particular trends of the core and valence correlation contributions with the size of the atom. Uncertainties to the RCCSD results are estimated to quote the final values, and they are compared with the previous calculations and experimental results.}, archive = {J_PRA}, author = {A. Chakraborty and B. K. Sahoo}, doi = {10.1103/PhysRevA.111.042807}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042807}, shortjournal = {Phys. Rev. A}, title = {Ab initio calculations of electric dipole polarizabilities in the li, na, and k atoms}, volume = {111}, year = {2025}, }
• (2025). Quantum-logic spectroscopy of an electron or positron for precise tests of the standard model. PRA, 111(4), 042806. (www)

  @article{ , abstract = {We propose a scheme for quantum-logic spectroscopy of an electron or positron in a Penning trap. An electron or positron in a spectroscopy trap is coupled to a remote logic electron or positron via a wire to achieve motional entanglement. By separating the two traps, one can significantly improve magnetic field homogeneity, microwave characteristics, and detection sensitivity. The proposed scheme will improve the measurement precision of the electron's and positron's magnetic moments and charge-to-mass ratios, enabling precise tests of the standard model of particle physics.}, archive = {J_PRA}, author = {Xing Fan and Atsushi Noguchi and Kento Taniguchi}, doi = {10.1103/PhysRevA.111.042806}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042806}, shortjournal = {Phys. Rev. A}, title = {Quantum-logic spectroscopy of an electron or positron for precise tests of the standard model}, volume = {111}, year = {2025}, }
• (2025). Blockwise perturbative corrections in multiconfiguration calculations based on configuration-state-function generators: A revised analysis of the w xxxviii spectrum. PRA, 111(4), 042805. (www)

  @article{ , abstract = {A methodology based on configuration-state-function generators (CSFGs) has recently been implemented in the General-Purpose Relativistic Atomic Structure Package ( grasp ) to reduce the computational load of configuration-interaction (CI) calculations Y. T. Li et al. , Comput. Phys. Commun. 283 , 108562 (2023) . Large CI calculations can be performed if part of the interaction is treated perturbatively. Here, we present enhancements to the perturbative estimates by implementing blockwise methods, where the blocks are given by configuration-state-functions spanned by CSFGs. We compute excitation energies for 4 s 2 4 p 6 4 d , 4 s 2 4 p 6 4 f , and 4 s 2 4 p 5 4 d 2 states in Rb-like W 37 + and corresponding transition wavelengths and rates to evaluate the methods. The final relative difference between calculated and experimental wavelengths is 0.01%. Thus, the calculations provide highly accurate values for W 37 + properties useful for a variety of applications, including fusion applications.}, archive = {J_PRA}, author = {Yanting Li and Chaofan Shi and Ran Si and Kai Wang and Per Jönsson and Gediminas Gaigalas and Michel Godefroid and Chongyang Chen}, doi = {10.1103/PhysRevA.111.042805}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042805}, shortjournal = {Phys. Rev. A}, title = {Blockwise perturbative corrections in multiconfiguration calculations based on configuration-state-function generators: A revised analysis of the w xxxviii spectrum}, volume = {111}, year = {2025}, }
• (2025). Fragmentation dynamics through geometrical distortion in low-energy electron attachment to carbon disulfide. PRA, 111(4), 042804. (www)

  @article{ , abstract = {The dissociation dynamics of dissociative electron attachment to carbon disulfide is studied using the velocity map imaging technique. Ion yields of the S − and CS − fragments are measured as a function of incident electron energy between 2 and 12 eV. Energy and angle-differential yields of the S − fragments are analyzed to investigate the dynamics of the CS 2 − anion around the 3.8-eV peak. The resonances involved in this fragmentation are identified and characterized in calculations using the well-known R -matrix method. Based on our measurements and the geometry dependence of the calculated resonances, we propose that a geometrical distortion of the transient negative-ion state of CS 2 is necessary for S-CS bond dissociation to occur.}, archive = {J_PRA}, author = {Anirban Paul and Daniel S. Slaughter and Sylwia Ptasinska and Dhananjay Nandi and Ian Carmichael and Jimena D. Gorfinkiel and Dipayan Chakraborty}, doi = {10.1103/PhysRevA.111.042804}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042804}, shortjournal = {Phys. Rev. A}, title = {Fragmentation dynamics through geometrical distortion in low-energy electron attachment to carbon disulfide}, volume = {111}, year = {2025}, }
• (2025). Derivation of hierarchically correlated orbital functional theory: The role of hypercomplex orbitals. PRA, 111(4), 042803. (www)

  @article{ , abstract = {This work presents a detailed mathematical derivation of the hierarchically correlated orbital functional theory (HCOFT), a framework based on hypercomplex orbitals. Recent study [ Phys. Rev. Lett. 133 , 206402 (2024) ] has demonstrated that hypercomplex orbitals in a determinant are equivalent to a set of real-valued orbitals that allow fractional occupations, making them desirable fundamental descriptors for many-electron systems. The algebraic properties of Clifford algebra are rigorously applied to derive key quantities within HCOFT, addressing the complexities introduced by the hypercomplex representation. It is shown that, despite this added complexity, the resulting density and kinetic energy remain physically meaningful and satisfy essential properties, including the Pauli exclusion principle. To establish the uniqueness of HCOFT, alternative definitions of hypercomplex orbitals within Clifford algebra are explored. These alternatives can lead to the loss of physical meaning in fundamental quantities for many-electron systems. Overall, this work demonstrates that HCOFT not only preserves the desired physical properties but also provides a single-determinant framework capable of describing multireference systems.}, archive = {J_PRA}, author = {Ting Zhang and Neil Qiang Su}, doi = {10.1103/PhysRevA.111.042803}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042803}, shortjournal = {Phys. Rev. A}, title = {Derivation of hierarchically correlated orbital functional theory: The role of hypercomplex orbitals}, volume = {111}, year = {2025}, }
• (2025). Dielectronic recombination studies on fe2+. PRA, 111(4), 042802. (www)

  @article{ , abstract = {Dielectronic recombination resonance strengths, energy-differential cross sections, and recombination rate coefficients are calculated fully relativistically for Fe 2 + ions. The ground-state and resonance energies are determined using the multiconfiguration Dirac-Hartree-Fock method. Radiative and autoionization rates are computed with a relativistic configuration-interaction method. For the calculation of Auger widths and resonance strengths, the continuum electron is treated within the framework of the relativistic distorted-wave model. Notably, the calculated level energies for Fe 2 + not only align well with experimental results but also show improvements compared to earlier theoretical studies. These fully relativistic calculations provide a more accurate and comprehensive understanding of the recombination process. This is particularly important in astrophysics and plasma physics, especially for studying phenomena such as kilonova events.}, archive = {J_PRA}, author = {S. Singh and Z. Harman}, doi = {10.1103/PhysRevA.111.042802}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042802}, shortjournal = {Phys. Rev. A}, title = {Dielectronic recombination studies on fe2+}, volume = {111}, year = {2025}, }
• (2025). Influence of plasma ions on the stopping power and the energy straggling of charged particles traversing hot plasmas. PRA, 111(4), 042801. (www)

  @article{ , abstract = {A charged test particle moving through a plasma suffers the effects of collisions with the plasma particles. The effects of these interactions may be described in terms of the two main energy-loss parameters, namely, the stopping power and the energy-loss straggling; these are the main parameters that characterize the interaction of external particles with the plasma. Here we perform a comparative study of the ionic and electronic contributions to the stopping and the straggling for the hydrogen isotopes, alpha particles, positrons, and muons, traversing different types of plasmas: tokamak plasmas, the dense helium region of a giant star, and the solar interior. To calculate these parameters we apply a quantum approach to describe the interaction of charged particles with plasmas, based on one side on the quantum dielectric plasma model, which includes a full description of statistical effects on energy exchange processes together with a quantum treatment of electron excitations. In addition, we incorporate the effect of the plasma ions through a semiclassical dielectric function that combines a quantum description of plasma electrons with a classical dielectric model for plasma ions. Through various examples we analyze the partial (electronic and ionic) and total contributions to the stopping power and energy straggling for protons, positrons, and muons. The comparison between these cases provides insights into the effects of statistical fluctuations and ionic contributions to the energy-loss processes for each of these particles and different plasma media.}, archive = {J_PRA}, author = {C. D. Archubi and N. R. Arista}, doi = {10.1103/PhysRevA.111.042801}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042801}, shortjournal = {Phys. Rev. A}, title = {Influence of plasma ions on the stopping power and the energy straggling of charged particles traversing hot plasmas}, volume = {111}, year = {2025}, }
• (2025). Optical phase estimation via homodyne measurement in the presence of photodetector saturation. PRA, 111(4), 042629. (www)

  @article{ , abstract = {For optical phase estimation via homodyne measurement, we generalize the theory from detector's linear to nonlinear response regime, which accounts for the presence of saturation effect. For optical coherent light, we carry out analytic expressions for detector's current and estimate precision. Using specific device parameters, we illustrate the improved estimation after accounting for the saturation effect.}, archive = {J_PRA}, author = {Jialin Li and Yazhi Niu and Lupei Qin and Xin-Qi Li}, doi = {10.1103/PhysRevA.111.042629}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042629}, shortjournal = {Phys. Rev. A}, title = {Optical phase estimation via homodyne measurement in the presence of photodetector saturation}, volume = {111}, year = {2025}, }
• (2025). Quantum-enhanced sensing with variable-range interactions. PRA, 111(4), 042628. (www)

  @article{ , abstract = {The typical bound on parameter estimation, known as the standard quantum limit (SQL), can be surpassed by exploiting quantum resources such as entanglement. To estimate the magnetic probe field, we propose a quantum sensor based on a variable-range many-body quantum spin chain with a moderate transverse magnetic field. We report the threefold benefits of employing a long-range system as a quantum sensor. First, sensors with quasi-long-range interactions can always beat the SQL for all values of the coordination number, while a sensor with long-range interactions does not have this ubiquitous quantum advantage. Second, a long-range Hamiltonian outperforms a nearest-neighbor (NN) Hamiltonian in terms of both estimating precision and system-size scaling. Finally, we observe that the system with long-range interactions can go below the SQL in the presence of a high temperature of the initial state, while sensors having NN interactions cannot. Furthermore, a sensor based on the long-range Ising Hamiltonian proves to be robust against impurities in the magnetic field and when the time-inhomogeneous dephasing noise acts during interaction of the probe with the system.}, archive = {J_PRA}, author = {Monika Mothsara and Leela Ganesh Chandra Lakkaraju and Srijon Ghosh and Aditi Sen(De}, doi = {10.1103/PhysRevA.111.042628}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042628}, shortjournal = {Phys. Rev. A}, title = {Quantum-enhanced sensing with variable-range interactions}, volume = {111}, year = {2025}, }
• (2025). Microwave continuous-variable quantum key distribution in the open air. PRA, 111(4), 042627. (www)

  @article{ , abstract = {Continuous-variable quantum key distribution (CV-QKD) enables the efficient distribution of unconditionally secure keys for both communicating parties. Despite significant advancements in optical-based CV-QKD, a persistent challenge is the limited resilience of optical quantum signals to atmospheric noise in free-space channels. This susceptibility leads to considerable degradation in the performance of optical CV-QKD systems, particularly under adverse climatic conditions. Meanwhile, recent advancements in superconducting quantum computing have driven the demand for quantum communication between spatially separated superconducting processors operating at microwave frequencies. To solve the problems, we propose a Gaussian-modulated coherent-state protocol operating at microwave frequencies, utilizing traveling-wave parametric amplifiers to generate entangled states. Our numerical analysis demonstrates that CV-QKD at microwave frequencies enables secure communication in a free-space channel at room temperature. Furthermore, we show that this protocol outperforms the THz frequency protocol over a distance of 20 m and exhibits stronger immunity to interference. Finally, we consider the impact of microwave antenna gain on the protocol's performance, highlighting the decisive role of antenna gain in determining the maximum transmission distance in practical application scenarios.}, archive = {J_PRA}, author = {Yongxin Feng and Gang Xu and Xiu-Bo Chen and Ying Guo}, doi = {10.1103/PhysRevA.111.042627}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042627}, shortjournal = {Phys. Rev. A}, title = {Microwave continuous-variable quantum key distribution in the open air}, volume = {111}, year = {2025}, }
• (2025). Simulating quantum-classical interfaces via the lindblad master equation. PRA, 111(4), 042626. (www)

  @article{ , abstract = {In hybrid quantum systems, the interface between quantum and classical domains is essential for the generation, control, and measurement of quantum states. Quantum-classical interfaces (QCIs) are ubiquitous in devices such as optical modulators, quantum sensors, and signal processors, where classical signals influence quantum dynamics. In this paper, we employ the Lindblad master equation to simulate the evolution of a quantum system interacting with a classical control system. Our model captures both linear and nonlinear interactions by incorporating first- and second-order susceptibilities, and it quantifies the influence of externally applied control parameters on decoherence and state evolution. As an illustrative example, we analyze an optical modulator and demonstrate how variations in material response and drive conditions affect photon statistics, coherence, and phase-space distributions. The findings offer a path to an all-encompassing model for understanding and optimizing QCIs, with wide-ranging implications for the performance, design, and robustness of next-generation quantum devices.}, archive = {J_PRA}, author = {Ali Passian and Joel Dawson and Stacy Prowell and Warren Grice}, doi = {10.1103/PhysRevA.111.042626}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042626}, shortjournal = {Phys. Rev. A}, title = {Simulating quantum-classical interfaces via the lindblad master equation}, volume = {111}, year = {2025}, }
• (2025). High-order schemes for solving partial differential equations on a quantum computer. PRA, 111(4), 042625. (www)

  @article{ , abstract = {We explore the utilization of higher-order discretization techniques in optimizing the gate count needed for quantum computer based solutions of partial differential equations. To accomplish this, we present an efficient approach for decomposing -band diagonal matrices into Pauli strings that are grouped into mutually commuting sets. Using numerical simulations of the one-dimensional wave equation, we show that higher-order methods can reduce the number of qubits necessary for discretization, similar to the classical case, although they do not decrease the number of Trotter steps needed to preserve solution accuracy. This result has important consequences for the practical application of quantum algorithms based on Hamiltonian evolution.}, archive = {J_PRA}, author = {Boris Arseniev and Dmitry Guskov and Richik Sengupta and Igor Zacharov}, doi = {10.1103/PhysRevA.111.042625}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042625}, shortjournal = {Phys. Rev. A}, title = {High-order schemes for solving partial differential equations on a quantum computer}, volume = {111}, year = {2025}, }
• (2025). Smolyak-algorithm-assisted robust control of quantum systems with uncertainties. PRA, 111(4), 042624. (www)

  @article{ , abstract = {Efficient and systematic numerical methods for robust control design are crucial in quantum systems due to inevitable uncertainties or disturbances. We propose an approach that models uncertainties as random variables and quantifies robustness using the expectation of infidelity by reformulating it as a weighted tensor product quadrature. We employ the Smolyak algorithm to develop a parametric robust quantum control scheme, which balances the reduction of computational cost with the enhancement of estimation accuracy. We demonstrate the effectiveness of our proposed algorithm by incorporating the Smolyak sparse grids into conventional gradient-based quantum optimal control methods such as grape and goat . In robust control problems concerning quantum gate realization, low infidelity and strong robustness can be achieved. These results contribute to improving the reliability and security of quantum computing and communication systems in the presence of real-world imperfections.}, archive = {J_PRA}, author = {Zigui Zhang and Zibo Miao and Xiu-Hao Deng}, doi = {10.1103/PhysRevA.111.042624}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042624}, shortjournal = {Phys. Rev. A}, title = {Smolyak-algorithm-assisted robust control of quantum systems with uncertainties}, volume = {111}, year = {2025}, }
• (2025). Zeno-effect computation: Opportunities and challenges. PRA, 111(4), 042623. (www)

  @article{ , abstract = {Adiabatic quantum computing has demonstrated how the quantum Zeno effect can be used to construct quantum optimizers. However, much less work has been done to understand how more general Zeno effects could be used in a similar setting. We use a construction based on three-state systems rather than directly in qubits, so that a qubit can remain after projecting out one of the states. We find that our model of computing is able to recover the dynamics of a transverse field Ising model. Several generalizations are possible, but our methods allow for constraints to be implemented nonperturbatively and do not need tunable couplers, unlike simple transverse field implementations. We further discuss how to implement the protocol physically using methods building on stimulated Raman adiabatic passage (STIRAP) protocols for state transfer. We find a substantial challenge that settings defined exclusively by measurement or dissipative Zeno effects do not allow for frustration, and in these settings pathological spectral features arise leading to unfavorable runtime scaling. We discuss methods to overcome this challenge, for example including gain as well as loss as is often done in an optical setting.}, archive = {J_PRA}, author = {Jesse Berwald and Nicholas Chancellor and Raouf Dridi}, doi = {10.1103/PhysRevA.111.042623}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042623}, shortjournal = {Phys. Rev. A}, title = {Zeno-effect computation: Opportunities and challenges}, volume = {111}, year = {2025}, }
• (2025). Experimental study of time-dependent side channels in quantum key distribution. PRA, 111(4), 042622. (www)

  @article{ , abstract = {Quantum key distribution (QKD) allows remote parties to share secret keys with proven security. In practice, optical schemes based on the Faraday mirror and Sagnac loop are widely used in QKD systems to improve the stability of QKD systems. In these schemes, light transmits bidirectionally in the optical path, compensating the effects caused by the environment automatically. However, due to the finite extinction ratio of the light source, these schemes will modulate the leaked light between the signal pulses, resulting in time-dependent side channels. Here, we provide a comprehensive experimental study of the security for practical QKD with time-dependent side channels. We demonstrate the amount of information leakage from the encoding modules using a Faraday mirror and Sagnac loop in a high-speed QKD system. Based on experimental results, we analyze the security risks and the corresponding countermeasures.}, archive = {J_PRA}, author = {Hao Tan and Weiyang Zhang and Liying Han and Sheng-Kai Liao and Feihu Xu}, doi = {10.1103/PhysRevA.111.042622}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042622}, shortjournal = {Phys. Rev. A}, title = {Experimental study of time-dependent side channels in quantum key distribution}, volume = {111}, year = {2025}, }
• (2025). Optimal connectivity from idle-qubit residual-coupling crosstalk in a cavity-mediated entangling gate. PRA, 111(4), 042621. (www)

  @article{ , abstract = {Quantum processors operated through long-range interaction mediated by a microwave resonator have been envisioned to allow for high connectivity. The ability to selectively operate qubits rely on the possibility to dynamically suppress the coupling between each qubit and the resonator, however, there always remains a residual coupling. In this article, we investigate the effect of high processor connectivity on average two-qubit gate fidelity in a cavity-based architecture with tunable coupling. Via a perturbative approach, we quantify the crosstalk errors from transverse residual couplings and show that they scale as n m 2 where n is the number of idle qubits and m is the ratio between the transverse residual and active couplings. Setting an error threshold E thr , we demonstrate that crosstalks restrict the hardware topology and prevent the full use of all-to-all connectivity. We predict that the maximum number of qubits allowed by E thr scales as n ∝ E thr / m 2 .}, archive = {J_PRA}, author = {A. Mammola and M. M. Desjardins and Q. Schaeverbeke}, doi = {10.1103/PhysRevA.111.042621}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042621}, shortjournal = {Phys. Rev. A}, title = {Optimal connectivity from idle-qubit residual-coupling crosstalk in a cavity-mediated entangling gate}, volume = {111}, year = {2025}, }
• (2025). Expressibility, entangling power, and quantum average causal effect for causally indefinite circuits. PRA, 111(4), 042620. (www)

  @article{ , abstract = {Parameterized quantum circuits are the core of new technologies such as variational quantum algorithms and quantum machine learning, which makes studying its properties a valuable task. We implement parameterized circuits with definite and indefinite causal order and compare their performance under particular descriptors. One of these is the expressibility, which measures how uniformly a given quantum circuit can reach the whole Hilbert space. Another property that we focus on this work is the entanglement capability, more specifically the concurrence and the entangling power. We also find the causal relation between the qubits of our system with the quantum average causal effect measure. We have found that indefinite circuits offer expressibility advantages over definite ones while maintaining the level of entanglement generation. Our results also point to the existence of a correlation between the quantum average causal effect and the entangling power.}, archive = {J_PRA}, author = {Pedro C. Azado and Guilherme I. Correr and Alexandre Drinko and Ivan Medina and Askery Canabarro and Diogo O. Soares-Pinto}, doi = {10.1103/PhysRevA.111.042620}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042620}, shortjournal = {Phys. Rev. A}, title = {Expressibility, entangling power, and quantum average causal effect for causally indefinite circuits}, volume = {111}, year = {2025}, }
• (2025). Quantum trajectory approach to error mitigation. PRA, 111(4), 042619. (www)

  @article{ , abstract = {Quantum error mitigation (EM) is a collection of strategies to reduce errors on noisy intermediate scale quantum (NISQ) devices on which proper quantum error correction is not feasible. One of such strategies entails implementing the inverse of a known noise map of an environment by using a set of completely positive maps weighted by a quasiprobability distribution, i.e., a probability distribution with positive and negative values. This distribution is realized using classical postprocessing after final measurements of desired observables have been made. Here we make a connection with quasiprobability EM and recent results from quantum trajectory theory for open quantum systems. We show that the inverse of noise maps can be realized by performing classical postprocessing with a quasiprobability measure called the influence martingale on the quantum trajectories generated by an additional engineered reservoir coupled to the system. We demonstrate our result on a model relevant for current NISQ devices. Finally, we show the required quantum trajectories themselves can be simulated by coupling an ancillary qubit to the system. In this way, we can avoid the introduction of the engineered reservoir.}, archive = {J_PRA}, author = {Brecht I. C. Donvil and Rochus Lechler and Joachim Ankerhold and Paolo Muratore-Ginanneschi}, doi = {10.1103/PhysRevA.111.042619}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042619}, shortjournal = {Phys. Rev. A}, title = {Quantum trajectory approach to error mitigation}, volume = {111}, year = {2025}, }
• (2025). Robust phase estimation of the ground-state energy without controlled time evolution on a quantum device. PRA, 111(4), 042618. (www)

  @article{ , abstract = {Estimating the ground-state energy of Hamiltonians in quantum systems is an important task. In this work, we demonstrate that the ground-state energy can be accurately estimated without controlled time evolution by using adiabatic state preparation (ASP) and Ramsey-type measurement. By considering the symmetry of the Hamiltonian governing the time evolution during ASP, we can prepare a superposition of the ground state and reference state whose eigenvalue is known. This enables the estimation of the ground-state energy via a Ramsey-type measurement. Furthermore, our method is robust against nonadiabatic transitions, making it suitable for use with early fault-tolerant quantum computers and quantum annealing.}, archive = {J_PRA}, author = {Hiroki Kuji and Yuta Shingu and Tetsuro Nikuni and Takashi Imoto and Kenji Sugisaki and Yuichiro Matsuzaki}, doi = {10.1103/PhysRevA.111.042618}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042618}, shortjournal = {Phys. Rev. A}, title = {Robust phase estimation of the ground-state energy without controlled time evolution on a quantum device}, volume = {111}, year = {2025}, }
• (2025). Scaling of computational order parameters in rydberg-atom graph states. PRA, 111(4), 042617. (www)

  @article{ , abstract = {Graph states are computationally powerful quantum states with many applications, including use as resource states for measurement-based quantum computing (MBQC). We demonstrate construction of graph states on a Rydberg atom quantum analog simulator. We show how an always-on interaction can be used to simultaneously entangle all Rydberg atoms into a graph state. We construct and implement many-body computational order parameters for graph states using nonlocal measurement-based logic operations in the Clifford group. The order parameters measure the efficacy of entanglement to allow MBQC on graph states of any size. We parametrize finite-size scaling of these order parameters. Our results define a route to efficiently test computational power in quantum devices.}, archive = {J_PRA}, author = {Zhangjie Qin and V. W. Scarola}, doi = {10.1103/PhysRevA.111.042617}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042617}, shortjournal = {Phys. Rev. A}, title = {Scaling of computational order parameters in rydberg-atom graph states}, volume = {111}, year = {2025}, }
• (2025). Variational quantum compiling for three-qubit-gate design in quantum dots. PRA, 111(4), 042616. (www)

  @article{ , abstract = {Semiconductor quantum dots provide a promising platform for spin qubit manipulation and quantum logic gate implementation, which are essential for scalable quantum computing architectures. In this work we utilize a variational quantum compiling algorithm to design efficient three-qubit gates using a time-independent Hamiltonian composed of only physical interaction terms. The resulting gates, including the Toffoli and Fredkin gates, demonstrate high fidelity and robustness against both coherent and incoherent noise sources, including charge and nuclear spin noise. This method is applicable to a wide range of physical systems, such as superconducting qubits and trapped ions, paving the way for more resilient and universal quantum computing architectures.}, archive = {J_PRA}, author = {Yuanyang Zhou and Huaxin He and Fengtao Pang and Hao Lyu and Yongping Zhang and Xi Chen}, doi = {10.1103/PhysRevA.111.042616}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042616}, shortjournal = {Phys. Rev. A}, title = {Variational quantum compiling for three-qubit-gate design in quantum dots}, volume = {111}, year = {2025}, }
• (2025). From quantum-enhanced to quantum-inspired monte carlo. PRA, 111(4), 042615. (www)

  @article{ , abstract = {We perform a comprehensive analysis of the quantum-enhanced Monte Carlo method [ Nature (London) 619 , 282 (2023) ], aimed at identifying the optimal working point of the algorithm. We observe an optimal mixing Hamiltonian strength and analyze the scaling of the total evolution time with the size of the system. We also explore extensions of the circuit, including the use of time-dependent Hamiltonians and reverse digitized annealing. Additionally, we propose that classical, approximate quantum simulators can be used for the proposal step instead of the original real-hardware implementation. We observe that tensor-network simulators, even with unconverged settings, can maintain a scaling advantage over standard classical samplers. This may extend the utility of quantum-enhanced Monte Carlo as a quantum-inspired algorithm, even before the deployment of large-scale quantum hardware.}, archive = {J_PRA}, author = {Johannes Christmann and Petr Ivashkov and Mattia Chiurco and Guglielmo Mazzola}, doi = {10.1103/PhysRevA.111.042615}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042615}, shortjournal = {Phys. Rev. A}, title = {From quantum-enhanced to quantum-inspired monte carlo}, volume = {111}, year = {2025}, }
• (2025). Measurement and feedforward correction of the fast phase noise of lasers. PRA, 111(4), 042614. (www)

  @article{ , abstract = {Lasers are the workhorse of quantum engineering in the atomic-molecular-optic community. However, phase noise of the laser, which can be especially large in popular semiconductor-based lasers, can limit gate fidelity. Here we present a fully fiberized instrument detecting and correcting the fast, submicrosecond, phase fluctuations of lasers. We demonstrate a measurement noise floor of less than 0.1 Hz 2 /Hz and a noise suppression of more than 20 dB for Fourier frequencies in the 1–10 MHz region (reaching up to 30 dB at 3 MHz), where noise is critical for Rydberg-based quantum gates. We observe the improvement offered by this fast-phase-noise eater on a Raman transition driven by two such stabilized lasers. These measurement and correction techniques are important tools for high-fidelity manipulation of the excited electronic states of atoms and molecules.}, archive = {J_PRA}, author = {T. Denecker and Y. T. Chew and O. Guillemant and G. Watanabe and T. Tomita and K. Ohmori and S. de Léséleuc}, doi = {10.1103/PhysRevA.111.042614}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042614}, shortjournal = {Phys. Rev. A}, title = {Measurement and feedforward correction of the fast phase noise of lasers}, volume = {111}, year = {2025}, }
• (2025). Optimizing quantum transformation matrices: Block decomposition approach for efficient gate reduction. PRA, 111(4), 042613. (www)

  @article{ , abstract = {This paper introduces an algorithm designed to approximate quantum transformation matrix with a restricted number of gates by using the block decomposition technique. Addressing challenges posed by numerous gates in handling large qubit transformations, the algorithm provides a solution by optimizing gate usage while maintaining computational accuracy. Inspired by the block decompose algorithm, our approach processes transformation matrices in a blockwise manner, enabling users to specify the desired gate count for flexibility in resource allocation. Simulations validate the effectiveness of the algorithm in approximating transformations with significantly fewer gates, enhancing quantum computing efficiency for complex calculations.}, archive = {J_PRA}, author = {Kin Man Lai and Xin Wang}, doi = {10.1103/PhysRevA.111.042613}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042613}, shortjournal = {Phys. Rev. A}, title = {Optimizing quantum transformation matrices: Block decomposition approach for efficient gate reduction}, volume = {111}, year = {2025}, }
• (2025). Asymptotic errors in adiabatic evolution. PRA, 111(4), 042612. (www)

  @article{ , abstract = {The adiabatic theorem in quantum mechanics implies that if a system is in a discrete eigenstate of a Hamiltonian and the Hamiltonian evolves in time arbitrarily slowly, the system will remain in the corresponding eigenstate of the evolved Hamiltonian. Understanding corrections to the adiabatic result that arise when the evolution of the Hamiltonian is slow, but not arbitrarily slow, has become increasingly important, especially since adiabatic evolution has been proposed as a method of state preparation in quantum computing. This paper identifies two regimes, an adiabatic regime in which corrections are generically small and can depend on details of the evolution throughout the path and a hyperadiabatic regime in which the error is given by a form similar to an asymptotic expansion in the inverse of the evolution time with the coefficients depending principally on the behavior at the endpoints. However, the error in this hyperadiabatic regime is neither given by a true asymptotic series nor solely dependent on the endpoints: The coefficients combine the contributions from both endpoints, with relative phase factors that depend on the average spectral gaps along the trajectory, multiplied by the evolution time. The central result of this paper is to identify a quantity, referred to as the typical error, which is obtained by appropriately averaging the error over evolution times that are small compared to the evolution time itself. This typical error is characterized by an asymptotic series and depends solely on the endpoints of the evolution, remaining independent of the details of the intermediate evolution.}, archive = {J_PRA}, author = {Thomas D. Cohen and Hyunwoo Oh}, doi = {10.1103/PhysRevA.111.042612}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042612}, shortjournal = {Phys. Rev. A}, title = {Asymptotic errors in adiabatic evolution}, volume = {111}, year = {2025}, }
• (2025). High-precision many-body ramsey spectroscopy with composite pulses. PRA, 111(4), 042611. (www)

  @article{ , abstract = {Ramsey spectroscopy serves as a key tool for frequency measurement. Although entanglement can enhance the measurement precision, the atom-atom interaction required for entanglement generation may lead to a frequency shift. In addition, the spectra also suffer from light shift caused by the interaction between light and atoms. Thus, it is difficult to achieve high precision without inducing additional systematic errors. Here, we propose to realize high-precision entanglement-enhanced Ramsey spectroscopy with composite pulses. First, we utilize spin-squeezed states generated by one-axis twisting (OAT) dynamics to enhance the measurement precision. We find that by applying a suitable pulse after OAT, the resonant frequency can be inferred and the light shift can be reduced by using composite pulses. To increase the signal slope, we use anti-OAT dynamics to perform interaction-based readout after interrogation. By designing suitable composite pulses, it can significantly increase the signal response and further improve the measurement precision. Although both schemes can mitigate the light shift, it cannot be entirely eliminated. Thus, we develop the autobalanced entanglement-enhanced Ramsey spectroscopy. By using combination of different sequences with short and long interrogation times and feedback control, the light shift of both our protocols can be completely suppressed, which increases the measurement accuracy. Besides, we also investigate the effects of background atom-atom interaction and find that it only reduces the measurement precision without introducing additional frequency shift. Our study offers an alternative method for achieving precise frequency measurement, which has the potential to be of significant application in quantum sensors such as atomic clocks.}, archive = {J_PRA}, author = {Yuehua Pang and Yi Shen and Jiahao Huang and Chaohong Lee}, doi = {10.1103/PhysRevA.111.042611}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042611}, shortjournal = {Phys. Rev. A}, title = {High-precision many-body ramsey spectroscopy with composite pulses}, volume = {111}, year = {2025}, }
• (2025). Geometric two-qubit gates in silicon-based double quantum dots. PRA, 111(4), 042609. (www)

  @article{ , abstract = {Achieving high-fidelity two-qubit gates is crucial for spin qubits in silicon-based double quantum dots. However, these gates are sensitive to charge noise in experimental settings, which remains a significant challenge. Geometric gates, which utilize pure geometric phases for gate operations, are a promising approach to achieving robust control. In this work, we theoretically propose a feasible strategy to implement geometric two-qubit gates for silicon-based spin qubits considering experimental control environments. By operating in the suitable region where the local magnetic field gradient is significantly larger than the exchange interaction, we can implement both entangling and nonentangling geometric gates through analytical and numerical methods. It is found that the geometric gates obtained are highly compatible with existing experimental techniques using electric dipole spin resonance in silicon. Moreover, the implemented geometric controlled- Z (CZ) gates can achieve fidelities exceeding 99% under experimental noise levels and the gate times are as short as 20 ns. Our work paves the way for the realization of high-fidelity geometric two-qubit gates for spin qubits in silicon.}, archive = {J_PRA}, author = {Yong-Yang Lu and Kejin Wei and Chengxian Zhang}, doi = {10.1103/PhysRevA.111.042609}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042609}, shortjournal = {Phys. Rev. A}, title = {Geometric two-qubit gates in silicon-based double quantum dots}, volume = {111}, year = {2025}, }
• (2025). Unifying quantum spatial search, state transfer, and uniform sampling on graphs. PRA, 111(4), 042608. (www)

  @article{ , abstract = {In this article, we present a succinct algorithmic framework via alternating quantum walks, unifying quantum spatial search, state transfer, and uniform sampling on a large class of graphs. Using the framework, we can achieve exact uniform sampling over all vertices and perfect state transfer between any two vertices, provided that eigenvalues of Laplacian matrix of the graph are all integers. Furthermore, if the graph is vertex transitive as well, then we can achieve deterministic quantum spatial search that finds a marked vertex with probability 100 % . In contrast, existing quantum search algorithms generally have a certain probability of failure. Even if the graph is not vertex transitive, such as the complete bipartite graph, we can still adjust the algorithmic framework to obtain deterministic spatial search, which thus shows the flexibility of it. Besides unifying and improving plenty of previous results, our work provides results on more graphs. The approach is easy to use since it has a succinct formalism that depends only on the depth of the Laplacian eigenvalue set of the graph, and may shed light on the solution of more problems related to graphs.}, archive = {J_PRA}, author = {Qingwen Wang and Ying Jiang and Shiguang Feng and Lvzhou Li}, doi = {10.1103/PhysRevA.111.042608}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042608}, shortjournal = {Phys. Rev. A}, title = {Unifying quantum spatial search, state transfer, and uniform sampling on graphs}, volume = {111}, year = {2025}, }
• (2025). Qubits on programmable geometries with a trapped-ion quantum processor. PRA, 111(4), 042607. (www)

  @article{ , abstract = {Geometry and dimensionality have played crucial roles in our understanding of the fundamental laws of nature, with examples ranging from curved space time in general relativity to modern theories of quantum gravity. In quantum many-body systems, the entanglement structure can change if the constituents are connected differently, leading to altered bounds for correlation growth and difficulties for classical computers to simulate large systems. While a universal quantum computer can perform digital simulations, an analog-digital hybrid quantum processor offers advantages such as parallelism. Here, we engineer a class of high-dimensional Ising interactions using a linear one-dimensional ion chain with up to eight qubits through stroboscopic sequences of commuting Hamiltonians. In addition, we extend this method to noncommuting circuits and demonstrate the quantum XY and Heisenberg models using Floquet periodic drives with tunable symmetries. The realization of higher-dimensional spin models offers new opportunities ranging from studying topological phases of matter or quantum spin glasses to future fault-tolerant quantum computation.}, archive = {J_PRA}, author = {Qiming Wu and Yue Shi and Jiehang Zhang}, doi = {10.1103/PhysRevA.111.042607}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042607}, shortjournal = {Phys. Rev. A}, title = {Qubits on programmable geometries with a trapped-ion quantum processor}, volume = {111}, year = {2025}, }
• (2025). Controlled-squeeze gate in superconducting quantum circuits. PRA, 111(4), 042606. (www)

  @article{ , abstract = {We present a method to prepare nonclassical states of the electromagnetic field in a microwave resonator. It is based on a controlled gate that applies a squeezing operation on a SQUID-terminated resonator conditioned on the state of a dispersively coupled qubit. This controlled-squeeze gate, when combined with Gaussian operations on the resonator, is universal. We explore the use of this tool to map an arbitrary qubit state into a superposition of squeezed states. In particular, we target a bosonic code with well-defined superparity which makes photon losses detectable by nondemolition parity measurements. We analyze the possibility of implementing this using state-of-the-art circuit QED tools and conclude that it is within reach of current technologies.}, archive = {J_PRA}, author = {Nicolás F. Del Grosso and Rodrigo G. Cortiñas and Paula I. Villar and Fernando C. Lombardo and Juan Pablo Paz}, doi = {10.1103/PhysRevA.111.042606}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042606}, shortjournal = {Phys. Rev. A}, title = {Controlled-squeeze gate in superconducting quantum circuits}, volume = {111}, year = {2025}, }
• (2025). Entanglement-enhanced ac magnetometry in the presence of markovian noise. PRA, 111(4), 042605. (www)

  @article{ , abstract = {Entanglement is a resource to improve the sensitivity of quantum sensors. In an ideal case, using an entangled state as a probe to detect target fields, we can beat the standard quantum limit by which all classical sensors are bounded. However, since entanglement is fragile against decoherence, it is unclear whether entanglement-enhanced metrology is useful in a noisy environment. Its benefit is indeed limited when estimating the amplitude of dc magnetic fields under the effect of parallel Markovian decoherence, where the noise operator is parallel to the target field. In this paper, on the contrary, we show an advantage to using an entanglement over the classical strategy under the effect of parallel Markovian decoherence when we try to detect ac magnetic fields. We consider a scenario to induce a Rabi oscillation of the qubits with the target ac magnetic fields. Although we can, in principle, estimate the amplitude of the ac magnetic fields from the Rabi oscillation, the signal becomes weak if the qubit frequency is significantly detuned from the frequency of the ac magnetic field. We show that, by using the Greenberger-Horne-Zeilinger (GHZ) states, we can significantly enhance the signal of the detuned Rabi oscillation even under the effect of parallel Markovian decoherence. Our method is based on the fact that the interaction time between the GHZ states and ac magnetic fields scales as 1 / L to mitigate the decoherence effect, where L is the number of qubits, which contributes to improving the bandwidth of the detectable frequencies of the ac magnetic fields. Our results pave the way for new applications of entanglement-enhanced ac magnetometry.}, archive = {J_PRA}, author = {Thanaporn Sichanugrist and Hajime Fukuda and Takeo Moroi and Kazunori Nakayama and So Chigusa and Norikazu Mizuochi and Masashi Hazumi and Yuichiro Matsuzaki}, doi = {10.1103/PhysRevA.111.042605}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042605}, shortjournal = {Phys. Rev. A}, title = {Entanglement-enhanced ac magnetometry in the presence of markovian noise}, volume = {111}, year = {2025}, }
• (2025). Qudit-native measurement protocol for dynamical correlations using hadamard tests. PRA, 111(4), 042604. (www)

  @article{ , abstract = {Dynamical correlations reveal important out-of-equilibrium properties of the underlying quantum many-body system, yet they are notoriously difficult to measure in experiments. While measurement protocols for dynamical correlations based on Hadamard tests for qubit quantum devices exist, they do not straightforwardly extend to qudits. Here, we propose a modified protocol to overcome this limitation by decomposing qudit observables into unitary operations that can be implemented and probed in a quantum circuit. We benchmark our algorithm numerically at the example of quench dynamics in a spin-1 X X Z chain with finite shot noise and demonstrate advantages in terms of the signal-to-noise ratio over established protocols based on linear response. Our scheme can readily be implemented on various platforms and offers a wide range of applications like variational quantum optimization and probing thermalization in many-body systems.}, archive = {J_PRA}, author = {Pavel P. Popov and Kevin T. Geier and Valentin Kasper and Maciej Lewenstein and Philipp Hauke}, doi = {10.1103/PhysRevA.111.042604}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042604}, shortjournal = {Phys. Rev. A}, title = {Qudit-native measurement protocol for dynamical correlations using hadamard tests}, volume = {111}, year = {2025}, }
• (2025). Phases and phase transition in grover's algorithm with systematic noise. PRA, 111(4), 042603. (www)

  @article{ , abstract = {While limitations on quantum computation under Markovian environmental noise are well understood in generality, their behavior for different quantum circuits and noise realizations can be less universal. Here we consider a canonical quantum algorithm—Grover's algorithm for unordered search on L qubits—in the presence of systematic noise. This allows us to write the evolution as a random Floquet unitary, which we show is well characterized by random matrix theory (RMT). The RMT analysis enables analytical predictions for different regimes and critical disorders of the many-body dynamics. We find two critical disorders. At small disorder, finite-dimensional manifold remains nonergodic as long as the noise is smaller than an ergodicity-breaking transition, which scales as O ( L − 1 ) . Computational power is lost at a much smaller disorder that scales as O ( 2 − L / 2 ) . We comment on relevance to nonsystematic noise in realistic quantum computers, including cold atom, trapped ion, and superconducting platforms.}, archive = {J_PRA}, author = {Sasanka Dowarah and Chuanwei Zhang and Vedika Khemani and Michael Kolodrubetz}, doi = {10.1103/PhysRevA.111.042603}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042603}, shortjournal = {Phys. Rev. A}, title = {Phases and phase transition in grover's algorithm with systematic noise}, volume = {111}, year = {2025}, }
• (2025). Time-optimal single-scalar control on a qubit of unitary dynamics. PRA, 111(4), 042602. (www)

  @article{ , abstract = {Optimal control theory is applied to analyze the time-optimal solution with a single scalar control knob in a two-level quantum system without quantum decoherence. Emphasis is placed on the dependence on the maximum control strength u max . General constraints on the optimal protocol are derived and used to rigorously parametrize the time-optimal solution. Two concrete problems are investigated. For generic state preparation problems, both multiple bang-bang and bang-singular-bang are legitimate and should be considered. Generally, the optimal is bang-bang for small u max , and there exists a state-dependent critical amplitude above which singular control emerges. For the X-gate operation of a qubit, the optimal protocol is exclusively multiple bang-bang. The minimum gate time is about 80% of that based on the resonant Rabi π -pulse over a wide range of control strength; in the u max → 0 limit, this ratio is derived to be π / 4 . To develop practically feasible protocols, we present methods to smooth the abrupt changes in the bang-bang control while preserving perfect gate fidelity. The presence of bang-bang segments in the time-optimal protocol indicates that the high-frequency components and a full calculation (instead of the commonly adopted rotating wave approximation) are essential for the ultimate quantum speed limit.}, archive = {J_PRA}, author = {Chungwei Lin and Qi Ding and Petros T. Boufounos and Yanting Ma and Yebin Wang and Dries Sels and Chih-Chun Chien}, doi = {10.1103/PhysRevA.111.042602}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042602}, shortjournal = {Phys. Rev. A}, title = {Time-optimal single-scalar control on a qubit of unitary dynamics}, volume = {111}, year = {2025}, }
• (2025). Generalized photon-number-splitting attack on a coherent one-way quantum-key-distribution protocol. PRA, 111(4), 042601. (www)

  @article{ , abstract = {Quantum key distribution (QKD) offers an unprecedented level of security, which, unlike its classical analog, is not based on computational assumptions. But tight lower and upper security bounds are still not provided for some QKD protocols. Here, we propose an effective attack strategy for coherent one-way (COW) QKD protocol. It is a generalized photon-number splitting (PNS) attack combined with sequential unambiguous state discrimination (USD) attack. We discuss the possibility of a generalized PNS attack because this attack demonstrates efficiency and does not introduce error, while previously the COW protocol was considered secure against PNS attack. To our knowledge, it is the most efficient attack on the COW protocol to date, hence we sharpen the upper security bound for this protocol.}, archive = {J_PRA}, author = {A. S. Avanesov and D. A. Kronberg}, doi = {10.1103/PhysRevA.111.042601}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042601}, shortjournal = {Phys. Rev. A}, title = {Generalized photon-number-splitting attack on a coherent one-way quantum-key-distribution protocol}, volume = {111}, year = {2025}, }
• (2025). Binarization of multioutcome measurements in high-dimensional quantum correlation experiments. PRA, 111(4), 042433. (www)

  @article{ , abstract = {High-dimensional systems are an important frontier for photonic quantum correlation experiments. These correlation tests commonly prescribe measurements with many possible outcomes but they are often implemented through many individual binary-outcome measurements that use only a single-detector. Here, we discuss how this binarization procedure for multioutcome measurements can open a loophole, unless specific device-characterization assumptions are satisfied. We highlight that correlation tests designed for multioutcome measurements can be trivialized in binarized implementations and we then show how to accurately analyze binarized data to reveal their quantum features. For seminal types of correlation experiments, such as Bell inequality tests, steering tests and prepare-and-measure experiments, we find that binarization may incur a sizable cost in the magnitude of quantum advantages. This emphasizes the importance of both accurate data analysis and implementing genuinely multioutcome measurements in high-dimensional correlation experiments.}, archive = {J_PRA}, author = {Armin Tavakoli and Roope Uola and Jef Pauwels}, doi = {10.1103/PhysRevA.111.042433}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042433}, shortjournal = {Phys. Rev. A}, title = {Binarization of multioutcome measurements in high-dimensional quantum correlation experiments}, volume = {111}, year = {2025}, }
• (2025). Biasing quantum trajectories for enhanced sensing. PRA, 111(4), 042432. (www)

  @article{ , abstract = {Quantum continuous measurement strategies are an essential element in many modern sensing technologies, leading to potentially enhanced estimation of unknown physical parameters. In such schemes, continuous monitoring of the quantum system, which encodes the parameters of interest, gives rise to different quantum trajectories conditioned on the measurement outcomes which carry information on the parameters themselves. Importantly, different trajectories carry different amounts of information, i.e., they are more or less sensitive to the unknown parameters of interest. In this work, we propose an approach on how to systematically engineer the quantum open-system dynamics in order to increase the probability of obtaining trajectories of high sensitivity. We focus on the simplest case scenario of a single two-level system interacting with ancillas, which are in turn measured using the discretized version of continuous monitoring. We analyze the performance of our protocol and demonstrate that it may lead to a substantial enhancement of sensitivity, as quantified by the classical Fisher information, even when applied to such small system sizes, holding the promise of direct implementation in state-of-the-art experimental platforms and large, complex many-body systems.}, archive = {J_PRA}, author = {Theodoros Ilias}, doi = {10.1103/PhysRevA.111.042432}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042432}, shortjournal = {Phys. Rev. A}, title = {Biasing quantum trajectories for enhanced sensing}, volume = {111}, year = {2025}, }
• (2025). Dividing quantum circuits for the time evolution of stochastic processes by orthogonal-series-density estimation. PRA, 111(4), 042431. (www)

  @article{ , abstract = {Quantum Monte Carlo integration (QMCI) is a quantum algorithm to estimate expectations of random variables, with applications in various industrial fields such as financial derivative pricing. When QMCI is applied to expectations concerning a stochastic process , e.g., an underlying asset price in derivative pricing, the quantum circuit to generate the quantum state encoding the probability density of can have a large depth. With time discretized into points, using state-preparation oracles for the transition probabilities of , the state preparation for results in a depth of , which may be problematic for large . Moreover, if we estimate expectations concerning at time points, the total query complexity scales on as , which is worse than the complexity in the classical Monte Carlo method. In this paper, to improve this, we propose a method to divide based on orthogonal-series-density estimation. This approach involves approximating the densities of at time points with orthogonal series, where the coefficients are estimated as expectations of the orthogonal functions by QMCI. By using these approximated densities, we can estimate expectations concerning by QMCI without requiring deep circuits. Our error and complexity analysis shows that to obtain the approximated densities at time points, our method achieves the circuit depth and total query complexity scaling as and , respectively.}, archive = {J_PRA}, author = {Koichi Miyamoto}, doi = {10.1103/PhysRevA.111.042431}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042431}, shortjournal = {Phys. Rev. A}, title = {Dividing quantum circuits for the time evolution of stochastic processes by orthogonal-series-density estimation}, volume = {111}, year = {2025}, }
• (2025). Quantum dissipative search via lindbladians. PRA, 111(4), 042430. (www)

  @article{ , abstract = {Closed quantum systems follow a unitary time evolution that can be simulated on quantum computers. By incorporating nonunitary effects via, e.g., measurements on ancilla qubits, these algorithms can be extended to open-system dynamics, such as Markovian processes described by the Lindblad master equation. In this paper, we analyze the convergence criteria and speed of a Markovian, purely dissipative quantum random walk on an unstructured classical search space. Notably, we show that certain jump operators make the quantum process replicate a classical one, while others yield differences between open quantum (OQRW) and classical random walks. We also clarify a previously observed quadratic speedup, demonstrating that OQRWs are no more efficient than classical search. Finally, we analyze a dissipative discrete-time ground-state preparation algorithm with a lower implementation cost. This allows us to interpolate between the dissipative and the unitary domain and thereby illustrate the important role of coherence for the quadratic speedup.}, archive = {J_PRA}, author = {Peter J. Eder and Jernej Rudi Finžgar and Sarah Braun and Christian B. Mendl}, doi = {10.1103/PhysRevA.111.042430}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042430}, shortjournal = {Phys. Rev. A}, title = {Quantum dissipative search via lindbladians}, volume = {111}, year = {2025}, }
• (2025). Nonconvex entanglement monotone determining the characteristic length of entanglement distribution in continuous-variable quantum networks. PRA, 111(4), 042429. (www)

  @article{ , abstract = {Quantum networks (QNs) promise to enhance the performance of various quantum technologies in the near future by distributing entangled states over long distances. The first step towards this is to develop novel entanglement measures that are both informative and computationally tractable at large scales. While numerous such entanglement measures exist for discrete-variable (DV) systems, a comprehensive exploration for experimentally preferred continuous-variable (CV) systems is lacking. Here, we introduce a class of CV entanglement measures, among which we identify a nonconvex entanglement monotone—the ratio negativity, which possesses a simple, scalable form that determines the exponential decay of optimal entanglement swapping on a chain of pure Gaussian states. This characterization opens avenues for leveraging statistical physics tools to analyze swapping-protocol-based CV QNs.}, archive = {J_PRA}, author = {Yaqi Zhao and Jinchuan Hou and Kan He and Nicolò Lo Piparo and Xiangyi Meng}, doi = {10.1103/PhysRevA.111.042429}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042429}, shortjournal = {Phys. Rev. A}, title = {Nonconvex entanglement monotone determining the characteristic length of entanglement distribution in continuous-variable quantum networks}, volume = {111}, year = {2025}, }
• (2025). Suppressing gauge drift in quantum simulations with gauge transformations. PRA, 111(4), 042428. (www)

  @article{ , abstract = {The simulation of quantum lattice gauge theories faces the major challenge of maintaining gauge invariance because various errors in the simulation push the state of the system out of the physical subspace of the system's exponentially larger Hilbert space. This paper outlines a method, based off of previous work [ Phys. Rev. A 110 , 022417 (2024) ], that uses gauge transformations in two ways. First, the method exploits the Zeno effect by conducting frequent projections to suppress gauge drift. These projections utilize local gauge transformations to destructively interfere unphysical amplitudes via coupling to an ancillary qubit while the physical amplitudes are left untouched, up to a less than unity normalization factor. Second, gauge transformations are conducted throughout the time evolution of the system to hamper the speed of gauge drift. This paper demonstrates this method on a pure one-dimensional SU(2) toy model.}, archive = {J_PRA}, author = {Carter Ball}, doi = {10.1103/PhysRevA.111.042428}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042428}, shortjournal = {Phys. Rev. A}, title = {Suppressing gauge drift in quantum simulations with gauge transformations}, volume = {111}, year = {2025}, }
• (2025). Quantifying quantum-state texture. PRA, 111(4), 042427. (www)

  @article{ , abstract = {Quantum-state texture is a newly recognized quantum resource that has garnered attention with the advancement of quantum theory. In this work, we introduce several potential quantum-state texture measure schemes and check whether they satisfy the three fundamental conditions required for a valid quantum-state texture measure. Specifically, the measure induced by the norm serves as a vital tool for quantifying coherence, but we prove that it cannot be used to quantify quantum-state texture. Furthermore, we show that while relative entropy and robustness meet three fundamental conditions, they are not optimal for quantifying quantum-state texture. Fortunately, we still find that there are several measures that can be used as the measure standard of quantum-state texture. Among them, the trace distance measure and the geometric measure are two good measurement schemes. In addition, the two measures based on Uhlmann's fidelity are experimentally friendly and can serve as an ideal definition of quantum-state texture measures in nonequilibrium situations. All this research on quantum-state texture measure theory can enrich the resource theory framework of quantum-state texture.}, archive = {J_PRA}, author = {Yiding Wang and Hui Liu and Tinggui Zhang}, doi = {10.1103/PhysRevA.111.042427}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042427}, shortjournal = {Phys. Rev. A}, title = {Quantifying quantum-state texture}, volume = {111}, year = {2025}, }
• (2025). Experimental quantification of quantum coherence for a set of quantum states. PRA, 111(4), 042426. (www)

  @article{ , abstract = {We present direct experimental verification of quantum coherence for a set of quantum states in a basis-independent manner. We find that the theory of quantum coherence for a set of quantum states matches our experimental results perfectly and can be applied to protocols such as the 1984 protocol of Bennett and Brassard (BB84) and quantum secure direct communication. Using a Sagnac interferometer, we experimentally quantify the quantum coherence for two sets of experimental states. Moreover, we introduce an application of set coherence, illustrating that the states employed in the BB84 protocol exhibit maximal set coherence. Our results pave the way for wider applications of quantum coherence for a set of quantum states, including quantum key distribution protocols and probabilistic quantum cloning.}, archive = {J_PRA}, author = {Tianle Zheng and Liangsheng Li and Wenting Zhou and Chengjie Zhang}, doi = {10.1103/PhysRevA.111.042426}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042426}, shortjournal = {Phys. Rev. A}, title = {Experimental quantification of quantum coherence for a set of quantum states}, volume = {111}, year = {2025}, }
• (2025). Postselected amplification applied to the mach-zehnder interferometer for phase-shift measurement of optical coherent states. PRA, 111(4), 042425. (www)

  @article{ , abstract = {We propose a postselected amplification scheme for phase-shift measurement of optical coherent states when passing through the Mach-Zehnder interferometer (MZI). Different from the usual weak-value-amplification (WVA) formulation, the which-path states of the MZI cannot be described as subsystem states entangled with two optical coherent states. However, we obtain the same phase amplification result of the usual WVA in the Aharonov-Albert-Vaidman limit but, beyond this limit, the result is essentially different. We explicitly carry out the amplified phase shift, which can be extracted out from the field-quadrature measurement in the dark port of the MZI. We also evaluate the performance quality of the proposed scheme and analyze the technical advantages by considering possible errors in the quadrature measurement.}, archive = {J_PRA}, author = {Jialin Li and Yazhi Niu and Lupei Qin and Xin-Qi Li}, doi = {10.1103/PhysRevA.111.042425}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042425}, shortjournal = {Phys. Rev. A}, title = {Postselected amplification applied to the mach-zehnder interferometer for phase-shift measurement of optical coherent states}, volume = {111}, year = {2025}, }
• (2025). Topological blocking decoder for surface codes. PRA, 111(4), 042424. (www)

  @article{ , abstract = {Surface codes have gained widespread popularity as quantum error-correction codes due to their unique structural feature that encoders and decoders can be implemented by leveraging interactions between physically neighboring qubits. The implementational advantage of surface codes has driven extensive research into decoding algorithms for surface codes, aimed at improving error-rate performance and/or reducing decoding complexity. In this paper, we propose a low-complexity postprocessing algorithm that effectively resolves failures of a syndrome-based belief-propagation (SB-BP) decoder for surface codes. In particular, we carefully analyze the topological structure of surface codes and present a method for selecting reliable qubits, enabling efficient recovery operator identification through a simple syndrome matching technique with a lookup table. Furthermore, we present an efficient way to construct lookup tables tailored to the proposed postprocessing algorithm. Numerical results demonstrate that the proposed postprocessing algorithm requires substantially reduced complexity as compared to that of a competing postprocessing algorithm, the ordered statistics decoding in the depolarizing error model, while providing the same logical error-rate (LER) performance. It is also demonstrated that the combination of SB-BP decoding and the proposed postprocessing algorithm outperforms minimum weight perfect matching, a more computationally expensive decoding algorithm, in terms of LER and threshold at drastically reduced complexity.}, archive = {J_PRA}, author = {Hyunwoo Jung and Jeongseok Ha}, doi = {10.1103/PhysRevA.111.042424}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042424}, shortjournal = {Phys. Rev. A}, title = {Topological blocking decoder for surface codes}, volume = {111}, year = {2025}, }
• (2025). Quantum routing based on chiral state transfer in arbitrary N-node networks. PRA, 111(4), 042423. (www)

  @article{ , abstract = {The ability to route quantum states between arbitrary nodes in a multinode network is one of the many facets required to build future large-scale quantum computing devices. Quantum routing can be implemented based on chiral dynamics, while their related research stays in three-node networks. In this paper, we give the target Hamiltonian for realizing chiral dynamics in arbitrary N -node networks. Based on the derived Hamiltonian, we present key features of chiral state transfer in multinode spin and bosonic networks. For the realistic implementation of the required Hamiltonian, we propose a modulation scheme to generate the matched effective Floquet Hamiltonian. Furthermore, we numerically simulate the multinode chiral dynamics with realistic parameters in superconducting circuits, and the results clearly show multinode chiral state transfer. Our work provides a universal and fundamental framework for understanding chiral dynamics in multinode networks. These findings will stimulate quantum state transfer, quantum routing, and nonreciprocal circulators in multinode networks.}, archive = {J_PRA}, author = {Wei Feng and Zuyan Wei and Guo-Qiang Zhang and Jun-Yao Li and Jun-Xiang Zhang and Chui-Ping Yang}, doi = {10.1103/PhysRevA.111.042423}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042423}, shortjournal = {Phys. Rev. A}, title = {Quantum routing based on chiral state transfer in arbitrary N-node networks}, volume = {111}, year = {2025}, }
• (2025). Global restrictions under local state discrimination. PRA, 111(4), 042422. (www)

  @article{ , abstract = {We investigate how local distinguishability can restrict global properties of states shared between two parties. We begin exploring how nonlocality becomes limited by local state discrimination and observe a nontrivial tradeoff between Clauser-Horne-Shimony-Holt (CHSH) violation and success probability of local discrimination. We extend our findings to bounding the maximally entangled state fidelity and global observables such as the energy. Our results show that local state discrimination can become a powerful tool to limit global behaviors, e.g., from entangled adversaries in quantum cryptography.}, archive = {J_PRA}, author = {Carles Roch i Carceller and Alexander Bernal}, doi = {10.1103/PhysRevA.111.042422}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042422}, shortjournal = {Phys. Rev. A}, title = {Global restrictions under local state discrimination}, volume = {111}, year = {2025}, }
• (2025). Macroscopic quantum teleportation with ensembles of qubits. PRA, 111(4), 042421. (www)

  @article{ , abstract = {We develop methods for performing quantum teleportation of the total spin variables of an unknown state, using quantum nondemolition measurements, spin projection measurements, and classical communication. While, theoretically, teleportation of high-dimensional states can be attained with the assumption of generalized Bell measurements, this is typically experimentally nontrivial to implement. We introduce two protocols and show that on average, the teleportation succeeds in teleporting the spin variables of a spin coherent state with average zero angular error in the ideal case, beating classical strategies based on quantum state estimation. In a single run of the teleportation, there is an angular error at the level of ∼ 0.1 radians for large ensembles. A potential physical implementation for the scheme is with atomic ensembles and quantum nondemolition measurements performed with light. We analyze the decoherence of the protocols and find that the protocol is robust even in the limit of large ensemble sizes.}, archive = {J_PRA}, author = {Manish Chaudhary and Zhiyuan Lin and Shuang Li and Mohan Zhang and Yuping Mao and Valentin Ivannikov and Tim Byrnes}, doi = {10.1103/PhysRevA.111.042421}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042421}, shortjournal = {Phys. Rev. A}, title = {Macroscopic quantum teleportation with ensembles of qubits}, volume = {111}, year = {2025}, }
• (2025). Single-shot quantum machine learning. PRA, 111(4), 042420. (www)

  @article{ , abstract = {Quantum machine learning aims to improve learning methods through the use of quantum computers. If it is to ever realize its potential, many obstacles need to be overcome. A particularly pressing one arises at the prediction stage because the outputs of quantum learning models are inherently random. This creates an often considerable overhead, as many executions of a quantum learning model have to be aggregated to obtain an actual prediction. In this work, we analyze when quantum learning models can evade this issue and produce predictions in a near-deterministic way—paving the way to single-shot quantum machine learning. We give a rigorous definition of single shotness in quantum classifiers and show that the degree to which a quantum learning model is near deterministic is constrained by the distinguishability of the embedded quantum states used in the model. Opening the black box of the embedding, we show that if the embedding is realized by quantum circuits, a certain depth is necessary for single shotness to be even possible. We conclude by showing that quantum learning models cannot be single shot in a generic way and trainable at the same time.}, archive = {J_PRA}, author = {Erik Recio-Armengol and Jens Eisert and Johannes Jakob Meyer}, doi = {10.1103/PhysRevA.111.042420}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042420}, shortjournal = {Phys. Rev. A}, title = {Single-shot quantum machine learning}, volume = {111}, year = {2025}, }
• (2025). Quantum permutation puzzles with indistinguishable particles. PRA, 111(4), 042419. (www)

  @article{ , abstract = {Permutation puzzles, such as the Rubik's Cube and the 15 puzzle, are enjoyed by the general public and mathematicians alike. Here we introduce quantum versions of permutation puzzles where the pieces of the puzzles are replaced with indistinguishable quantum particles. The moves in the puzzle are achieved by swapping or permuting the particles. We show that simply permuting the particles can be mapped to a classical permutation puzzle, even though the identical particles are entangled. However, we obtain a genuine quantum puzzle by adding a quantum move: the square root of swap . The resulting puzzle cannot be mapped to a classical permutation puzzle. We focus predominately on the quantization of the 2 × 2 slide puzzle and briefly treat the 2 × 2 × 1 Rubik's Cube.}, archive = {J_PRA}, author = {Noah Lordi and Maedée Trank-Greene and Akira Kyle and Joshua Combes}, doi = {10.1103/PhysRevA.111.042419}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042419}, shortjournal = {Phys. Rev. A}, title = {Quantum permutation puzzles with indistinguishable particles}, volume = {111}, year = {2025}, }
• (2025). Nonequivalence between absolute separability and positive partial transposition in the symmetric subspace. PRA, 111(4), 042418. (www)

  @article{ , abstract = {The equivalence between absolutely separable states and absolutely positive partial transposed (PPT) states in general remains an open problem in quantum entanglement theory. In this work, we study an analogous question for symmetric multiqubit states. We show that symmetric absolutely PPT (SAPPT) states (symmetric states that remain PPT after any symmetry-preserving unitary evolution) are not always symmetric absolutely separable by providing explicit counterexamples. More precisely, we construct a family of entangled five-qubit SAPPT states. Similar counterexamples for larger odd numbers of qubits are identified.}, archive = {J_PRA}, author = {Jonathan Louvet and Eduardo Serrano-Ensástiga and Thierry Bastin and John Martin}, doi = {10.1103/PhysRevA.111.042418}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042418}, shortjournal = {Phys. Rev. A}, title = {Nonequivalence between absolute separability and positive partial transposition in the symmetric subspace}, volume = {111}, year = {2025}, }
• (2025). Geometry of sets of bargmann invariants. PRA, 111(4), 042417. (www)

  @article{ , abstract = {Certain unitary invariants, known as Bargmann invariants or multivariate traces of quantum states, have recently gained attention due to their applications in quantum information theory. However, determining the boundaries of sets of Bargmann invariants remains a theoretical challenge. In this study, we address the problem by developing a unified, dimension-independent formulation that characterizes the sets of the third and fourth Bargmann invariants. In particular, our result for the set of fourth Bargmann invariants confirms the conjecture given by Fernandes et al. [ Phys. Rev. Lett. 133 , 190201 (2024) ]. Based on the obtained results, we conjecture that the unified, dimension-independent formulation of the boundaries for sets of third- and fourth-order Bargmann invariants may extend to the general case of the n th -order Bargmann invariants. These results deepen our understanding of the fundamental physical limits within quantum mechanics and pave the way for novel applications of Bargmann invariants in quantum information processing and related fields.}, archive = {J_PRA}, author = {Lin Zhang and Bing Xie and Bo Li}, doi = {10.1103/PhysRevA.111.042417}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042417}, shortjournal = {Phys. Rev. A}, title = {Geometry of sets of bargmann invariants}, volume = {111}, year = {2025}, }
• (2025). Quantum variational autoencoder utilizing regularized mixed-state latent representations. PRA, 111(4), 042416. (www)

  @article{ , abstract = {A major challenge in near-term quantum computing is its application to large real-world datasets due to scarce quantum hardware resources. One approach to enabling tractable quantum models for such datasets involves finding low-dimensional representations that preserve essential information for downstream analysis. In classical machine learning, variational autoencoders (VAEs) facilitate efficient data compression, representation learning for subsequent tasks, and novel data generation. However, no quantum model has been proposed that exactly captures all of these features for direct application to quantum data on quantum computers. Some existing quantum models for data compression lack regularization of latent representations, thus preventing direct use for generation and control of generalization. Others are hybrid models with only some internal quantum components, impeding direct training on quantum data. To address this, we present a fully quantum framework, ζ -QVAE, which encompasses all the capabilities of classical VAEs and can be directly applied to map both classical and quantum data to a lower-dimensional space, while effectively reconstructing much of the original state from it. Our model utilizes regularized mixed states to attain optimal latent representations. It accommodates various divergences for reconstruction and regularization. Furthermore, by accommodating mixed states at every stage, it can utilize the full data density matrix and allow for a training objective defined on probabilistic mixtures of input data. Doing so, in turn, makes efficient optimization possible and has potential implications for private and federated learning. In addition to exploring the theoretical properties of ζ -QVAE, we demonstrate its performance on representative genomics and synthetic data. Our results indicate that ζ -QVAE consistently learns representations that better utilize the capacity of the latent space and exhibits similar or better performance compared with matched classical models.}, archive = {J_PRA}, author = {Gaoyuan Wang and Jonathan Warrell and Prashant S. Emani and Mark Gerstein}, doi = {10.1103/PhysRevA.111.042416}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042416}, shortjournal = {Phys. Rev. A}, title = {Quantum variational autoencoder utilizing regularized mixed-state latent representations}, volume = {111}, year = {2025}, }
• (2025). Waiting time statistics for a double quantum dot coupled to an optical cavity. PRA, 111(4), 042415. (www)

  @article{ , abstract = {A double quantum dot coupled to an optical cavity is a prototypical example of a nontrivial open quantum system. Recent experimental and theoretical studies show that this system is a candidate for single-photon detection in the microwave domain. This motivates studies that go beyond just the average current, and also take into account the full counting statistics of photon and electron detections. With this in mind, here we provide a detailed analysis of the waiting time statistics of this system within the quantum jump unraveling, which allows us to extract analytical expressions for the success and failure probabilities, as well as for the interdetection times. Furthermore, by comparing single- and multiphoton scenarios, we infer a hierarchy of occurrence probabilities for the different events, highlighting the role of photon interference events in the detection probabilities. Our results therefore provide a direct illustration of how waiting time statistics can be used to optimize a timely and relevant metrological task.}, archive = {J_PRA}, author = {Luis F. Santos and Gabriel T. Landi}, doi = {10.1103/PhysRevA.111.042415}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042415}, shortjournal = {Phys. Rev. A}, title = {Waiting time statistics for a double quantum dot coupled to an optical cavity}, volume = {111}, year = {2025}, }
• (2025). Degrees of entanglement in systems of three indistinguishable bosons: Revisiting the greenberger-horne-zeilinger state. PRA, 111(4), 042414. (www)

  @article{ , abstract = {While the concept of entanglement for distinguishable particles is well established, defining entanglement and nonlocality in systems of indistinguishable particles, which require the use of the (anti)symmetrization postulate, remains challenging, and multiple approaches have been proposed to address this issue. In this work we study the problem of detecting genuine tripartite entanglement among systems of indistinguishable bosons. A genuine entangled state is one that cannot be separable under any bipartition, where separability in the indistinguishable regime is defined by the existence of single-particle properties within each subsystem, without the possibility of knowing which property belongs to which subsystem. We use an algorithm that allows us to search for these single-particle properties and consequently rank states according to their degree of separability. In particular, we introduce a state of indistinguishable bosons with properties analogous to those of the standard Greenberger-Horne-Zeilinger state.}, archive = {J_PRA}, author = {P. Céspedes and F. H. Holik and A. P. Majtey}, doi = {10.1103/PhysRevA.111.042414}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042414}, shortjournal = {Phys. Rev. A}, title = {Degrees of entanglement in systems of three indistinguishable bosons: Revisiting the greenberger-horne-zeilinger state}, volume = {111}, year = {2025}, }
• (2025). Variational quantum eigensolver approach to prime factorization on IBM's noisy intermediate scale quantum computer. PRA, 111(4), 042413. (www)

  @article{ , abstract = {This paper presents a hybrid quantum-classical approach to prime factorization. The proposed algorithm is based on the variational quantum eigensolver (VQE), which employs a classical optimizer to find the ground state of a given Hamiltonian. A numerical study is presented, evaluating the performance of the proposed method across various instances on both IBM's real quantum computer and its classical simulator. The results demonstrate that the method is capable of successfully factorizing numbers up to 253 on a real quantum computer and up to 1 048 561 on a classical simulator. These findings show the potential of the approach for practical applications on near-term quantum computers.}, archive = {J_PRA}, author = {Mona Sobhani and Yahui Chai and Tobias Hartung and Karl Jansen}, doi = {10.1103/PhysRevA.111.042413}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042413}, shortjournal = {Phys. Rev. A}, title = {Variational quantum eigensolver approach to prime factorization on IBM's noisy intermediate scale quantum computer}, volume = {111}, year = {2025}, }
• (2025). Second moment of hafnians in gaussian boson sampling. PRA, 111(4), 042412. (www)

  @article{ , abstract = {Gaussian boson sampling is a popular method for experimental demonstrations of quantum advantage, but many subtleties remain in fully understanding its theoretical underpinnings. An important component in the theoretical arguments for approximate average-case hardness of sampling is anticoncentration, which is a second-moment property of the output probabilities. In Gaussian boson sampling these are given by hafnians of generalized circular orthogonal ensemble matrices. In a companion work by Ehrenberg et al. [ Phys. Rev. Lett. 134 , 140601 (2025) ], we develop a graph-theoretic method to study these moments and use it to identify a transition in anticoncentration. In this work, we find a recursive expression for the second moment using these graph-theoretic techniques. While we have not been able to solve this recursion by hand, we are able to solve it numerically exactly, which we do up to Fock sector 2 n = 80 . We further derive analytical results about the second moment. These results allow us to pinpoint the transition in anticoncentration and furthermore yield the expected linear cross-entropy benchmarking score for an ideal (error-free) device.}, archive = {J_PRA}, author = {Adam Ehrenberg and Joseph T. Iosue and Abhinav Deshpande and Dominik Hangleiter and Alexey V. Gorshkov}, doi = {10.1103/PhysRevA.111.042412}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042412}, shortjournal = {Phys. Rev. A}, title = {Second moment of hafnians in gaussian boson sampling}, volume = {111}, year = {2025}, }
• (2025). Entanglement determination with a deep multiscale entanglement renormalization ansatz. PRA, 111(4), 042411. (www)

  @article{ , abstract = {We study the deep multiscale entanglement renormalization Ansatz (DMERA) on quantum hardware and the causal cone of a subset of the qubits, which make up the Ansatz . This causal cone spans O ( M + log N ) physical qubits on a quantum device, where M and N are the subset size and the total number qubits in the Ansatz , respectively. This allows for the determination of the von Neumann entanglement entropy of the N -qubit wave function using O ( M + log N ) qubits by diagonalization of the reduced density matrix (RDM). We show this by randomly initializing a 16-qubit DMERA and diagonalizing the resulting RDM of the M -qubit subsystem using density-matrix simulation. As an example of practical interest, we also encode the variational ground state of the long-range transverse field Ising model (LRTIM) on eight spins using DMERA. We perform density-matrix simulation with and without noise to obtain entanglement entropies in separate experiments using only four qubits. Finally, we repeat the experiment on the IBM Kyoto back end reproducing simulation results.}, archive = {J_PRA}, author = {Kushagra Garg and Zeeshan Ahmed and Andreas Thomasen}, doi = {10.1103/PhysRevA.111.042411}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042411}, shortjournal = {Phys. Rev. A}, title = {Entanglement determination with a deep multiscale entanglement renormalization ansatz}, volume = {111}, year = {2025}, }
• (2025). Transfer of nonlocality between two- and three-qubit dissipative systems with counter-rotating-wave terms. PRA, 111(4), 042410. (www)

  @article{ , abstract = {We investigate the effect of counter-rotating-wave terms on nonlocality and entanglement for three qubits coupled to a common bath for strong- and ultrastrong-coupling regimes beyond the traditional treatment of Born-Markovian, perturbative, and rotating-wave approximations by employing the numerical hierarchical equations-of-motion approach. Our findings are as follows: (1) In the strong-coupling regime, the counter-rotating terms accelerate the decay of genuine three-party correlations, and the obvious sudden birth of Bell nonlocality is found. (2) In the ultrastrong-coupling regime, we observe a phenomenon in which nonlocality is consistently transferred between a three-qubit system and its subsystem. In addition, the inclusion of counter-rotating wave terms obviously enhances genuine tripartite nonlocality. (3) These counter-rotating terms cannot effectively generate genuine three-party correlations in zero-excitation cases, which differs from previous studies involving only two qubits. (4) A significant reduction in steady-state correlations for three- and two-party systems due to counter-rotating-wave terms is observed, which is not detectable under the rotating-wave approximation.}, archive = {J_PRA}, author = {Zi-Yu Xiong and Yong-Jun Xiao and Ye-Qi Zhang and Qi-Liang He}, doi = {10.1103/PhysRevA.111.042410}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042410}, shortjournal = {Phys. Rev. A}, title = {Transfer of nonlocality between two- and three-qubit dissipative systems with counter-rotating-wave terms}, volume = {111}, year = {2025}, }
• (2025). Selective continuous-variable quantum process tomography. PRA, 111(4), 042409. (www)

  @article{ , abstract = {Quantum process tomography is a useful tool for characterizing quantum processes. This task is essential for the development of different areas, such as quantum information processing. In this work, we present a protocol for selective continuous-variable quantum process tomography. Our proposal allows one to selectively estimate any element of an unknown continuous-variable quantum process in the position representation, without requiring the complete reconstruction of the process. By resorting to controlled squeezing and translation operations, and adaptatively discretizing the process, a direct measure of an estimate of any process element can be obtained. Furthermore, we show, supported by numerical simulations, how the protocol can be used to partially reconstruct on a region a continuous-variable quantum process.}, archive = {J_PRA}, author = {Virginia Feldman and Ariel Bendersky}, doi = {10.1103/PhysRevA.111.042409}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042409}, shortjournal = {Phys. Rev. A}, title = {Selective continuous-variable quantum process tomography}, volume = {111}, year = {2025}, }
• (2025). Detectors for local discrimination of sets of generalized bell states. PRA, 111(4), 042408. (www)

  @article{ , abstract = {A fundamental problem in quantum information processing is the discrimination among a set of orthogonal quantum states of a composite system under local operations and classical communication (LOCC). Corresponding to the LOCC indistinguishable sets of four ququad-ququad orthogonal maximally entangled states constructed by Yu et al. [ Phys. Rev. Lett. 109 , 020506 (2012) ], the maximum commutative sets were introduced as detectors for the local distinguishability of the set of generalized Bell states (GBSs) for which the detectors are sufficient to determine the LOCC distinguishability. In this work, we show how to determine all the detectors for a given GBS set. We also construct several four-GBS sets without detectors, most of which are one-way LOCC indistinguishable and only one of which is one-way LOCC distinguishable, indicating that the detectors are not necessary for LOCC distinguishability. Furthermore, we show that for four-GBS sets in the quantum system C 6 ⊗ C 6 , the detectors are almost necessary for one-way LOCC distinguishability, except for one set in the sense of local unitary equivalence. The problem of one-way LOCC discrimination of four-GBS sets in C 6 ⊗ C 6 is completely resolved.}, archive = {J_PRA}, author = {Cai-Hong Wang and Jiang-Tao Yuan and Ying-Hui Yang and Mao-Sheng Li and Shao-Ming Fei and Zhi-Hao Ma}, doi = {10.1103/PhysRevA.111.042408}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042408}, shortjournal = {Phys. Rev. A}, title = {Detectors for local discrimination of sets of generalized bell states}, volume = {111}, year = {2025}, }
• (2025). Frequency-entangled w states and quantum frequency translation protocols via forward brillouin interactions. PRA, 111(4), 042407. (www)

  @article{ , abstract = {Complex quantum states of light are not only central to advancing our understanding of quantum mechanics, but are also necessary for a variety of quantum protocols. High-dimensional, or multipartite, quantum states are of specific interest, as they can exhibit unique properties both fundamentally and in application. The synthesis of high-dimensional, entangled photonic states can take the form of various schemes, which result in varying forms of entanglement. Frequency entanglement is specifically attractive due to compatibility with integrated systems and resistance to decoherence in fiber transportation; however, increasing the dimension of frequency-entangled states requires a system that offers quantum interactions between a large set of distinct frequencies. Here, we show how the phonon-photon interactions of forward Brillouin scattering, which offer access to a ladder of optical resonances permitted by a single mechanical mode, can be used for fast synthesis of frequency-entangled, single-photon W states. In our proposed system, simultaneous laser pulses of different frequencies dynamically evolve either an injected single photon or a heralded single phonon, generating W states of selected dimension and output frequency. This method enables the synthesis of “perfect” W states by adjusting the pulse amplitudes. In addition, we show how this system can be used for quantum frequency translation.}, archive = {J_PRA}, author = {Andrew J. Shepherd and Ryan O. Behunin}, doi = {10.1103/PhysRevA.111.042407}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042407}, shortjournal = {Phys. Rev. A}, title = {Frequency-entangled w states and quantum frequency translation protocols via forward brillouin interactions}, volume = {111}, year = {2025}, }
• (2025). Phase-space analysis of bell inequalities for mixed gaussian states. PRA, 111(4), 042405. (www)

  @article{ , abstract = {We present a phase-space formalism to evaluate Bell inequality violations in continuous variable systems. By doing so we can generalize previous analyses (which have dealt only with pure states) to arbitrary mixed states. We leverage these results to analyze the effect of temperature on violations of Bell inequalities in a two-mode squeezed thermal state, which can become useful in tests of local realism in the presence of thermal noise. We also explore the nonmonotonic relationship between the violations of Bell inequalities and the amount of entanglement present in this family of mixed states. Additionally, we discuss the optimal choices of pseudospin operators for states beyond the two-mode squeezed vacuum.}, archive = {J_PRA}, author = {Gurpahul Singh and Kelly Wurtz and Eduardo Martín-Martínez}, doi = {10.1103/PhysRevA.111.042405}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042405}, shortjournal = {Phys. Rev. A}, title = {Phase-space analysis of bell inequalities for mixed gaussian states}, volume = {111}, year = {2025}, }
• (2025). Generally noise-resilient quantum gates for trapped ions. PRA, 111(4), 042404. (www)

  @article{ , abstract = {We present an entangling gate scheme that achieves high-fidelity operations with excited motional states, despite multiple error sources. While we demonstrate this approach for trapped-ion chains, the underlying principles are applicable to a wide range of quantum computing platforms. Our scheme incorporates all relevant motional modes and exhibits enhanced robustness against both motional heating effects and detuning errors, critical features for building robust and scalable quantum computers.}, archive = {J_PRA}, author = {Modesto Orozco-Ruiz and Wasim Rehman and Florian Mintert}, doi = {10.1103/PhysRevA.111.042404}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042404}, shortjournal = {Phys. Rev. A}, title = {Generally noise-resilient quantum gates for trapped ions}, volume = {111}, year = {2025}, }
• (2025). Quantum imaginary time evolution and the unit-disk maximum independent set problem. PRA, 111(4), 042403. (www)

  @article{ , abstract = {In this work we apply a procedure based on the quantum imaginary time evolution method to solve the unit-disk maximum independent set problem. Numerical simulations are performed for instances of six-, eight-, and ten-qubit graphs. We find that the failure probability of the procedure is relatively small and rapidly decreases with the number of shots. In addition, a theoretical upper bound for the failure probability of the procedure is obtained.}, archive = {J_PRA}, author = {Victor A. Penas and Marcelo Losada and Pedro W. Lamberti}, doi = {10.1103/PhysRevA.111.042403}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042403}, shortjournal = {Phys. Rev. A}, title = {Quantum imaginary time evolution and the unit-disk maximum independent set problem}, volume = {111}, year = {2025}, }
• (2025). Protecting entanglement witnesses with randomized measurements. PRA, 111(4), 042402. (www)

  @article{ , abstract = {Entanglement is one of the most prominent features of quantum mechanics and serves as an essential resource in quantum information science. Therefore, the certification of entanglement is crucial for quantum information processing tasks. While entanglement witnesses are the most frequently used method for entanglement certification in experiments, recent research shows that even tiny errors in measurements may significantly undermine the effectiveness of a witness. In this work, we propose a randomized-measurement-based method to solve this problem. Through this method, the errors in measurement results can be substantially suppressed, thereby restoring the certification capability of entanglement witnesses. Our method is not only applicable to general types of witnesses, including multiparty entanglement and high-dimensional entanglement witnesses, but also experimentally friendly in the sense that only slight modifications are needed to the original measurement settings.}, archive = {J_PRA}, author = {Jing-Tao Qiu and Wei-Jie Jiang and Xiao-Dong Yu}, doi = {10.1103/PhysRevA.111.042402}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042402}, shortjournal = {Phys. Rev. A}, title = {Protecting entanglement witnesses with randomized measurements}, volume = {111}, year = {2025}, }
• (2025). Recovery of resources through sequential noisy measurements. PRA, 111(4), 042401. (www)

  @article{ , abstract = {Noisy unsharp measurements incorporated in quantum information protocols may hinder performance, reducing the quantum advantage. However, we show that, unlike projective measurements which completely destroy quantum correlations between nodes in quantum networks, sequential applications of noisy measurements can mitigate the adverse impact of noise in the measurement device on quantum information processing tasks. We demonstrate this in the case of concentrating entanglement on chosen nodes in quantum networks via noisy measurements performed by assisting qubits. In the case of networks with a cluster of three or more qubits, we exhibit that sequentially performing optimal unsharp measurements on the assisting qubits yields localizable entanglement between two nodes akin to that obtained by optimal projective measurements on the same assisting qubits. Furthermore, we find that the proposed approach using consecutive noisy measurements can potentially be used to prepare desired states that are resource for specific quantum schemes. We also argue that assisting qubits have greater control over the qubits on which entanglement is concentrated via unsharp measurements, in contrast to sharp-measurement-based protocols, which may have implications for secure quantum communication.}, archive = {J_PRA}, author = {Sudipta Mondal and Pritam Halder and Amit Kumar Pal and Aditi Sen(De}, doi = {10.1103/PhysRevA.111.042401}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042401}, shortjournal = {Phys. Rev. A}, title = {Recovery of resources through sequential noisy measurements}, volume = {111}, year = {2025}, }
• (2025). Bayesian and frequentist estimators for the transition frequency of a driven two-level quantum system. PRA, 111(4), 042218. (www)

  @article{ , abstract = {The formalism of quantum estimation theory with a specific focus on classical data postprocessing is applied to a two-level system driven by an external gyrating magnetic field. We employed both Bayesian and frequentist approaches to estimate the unknown transition frequency. In the frequentist approach, we have shown that only reducing the distance between the classical and the quantum Fisher information does not necessarily mean that the estimators as functions of the data deliver an estimate with desirable accuracy, as the classical Fisher information takes small values. We have proposed and investigated a cost function to account for the maximization of the classical Fisher information and the minimization of the aforementioned distance. Due to the nonlinearity of the probability mass function of the data on the transition frequency, the minimum variance unbiased estimator may not exist. The maximum likelihood and the maximum a posteriori estimators often result in ambiguous estimates, which in certain cases can be made unambiguous upon changing the parameters of the external field. It is demonstrated that the minimum mean-square error estimator of the Bayesian statistics provides unambiguous estimates. In the Bayesian approach, we have also investigated the effects of noninformative and informative priors on the Bayesian estimates, including a uniform prior, Jeffrey's prior, and a Gaussian prior.}, archive = {J_PRA}, author = {Chun Kit Dennis Law and József Zsolt Bernád}, doi = {10.1103/PhysRevA.111.042218}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042218}, shortjournal = {Phys. Rev. A}, title = {Bayesian and frequentist estimators for the transition frequency of a driven two-level quantum system}, volume = {111}, year = {2025}, }
• (2025). Compatibility of quantum measurements and the emergence of classical objectivity. PRA, 111(4), 042217. (www)

  @article{ , abstract = {The study of measurements in quantum mechanics exposes many of the ways in which the quantum world is different. For example, one of the hallmarks of quantum mechanics is that observables may be incompatible, implying among other things that it is not always possible to find joint probability distributions which fully capture the joint statistics of multiple measurements. Instead, one must employ more general tools such as the Kirkwood-Dirac quasiprobability (KDQ) distribution, which may exhibit negative or nonreal values heralding nonclassicality. In this paper, we consider the KDQ distributions describing arbitrary collections of measurements on disjoint components of some generic multipartite system. We show that the system dynamics ensures that these distributions are classical if and only if the Hamiltonian supports quantum Darwinism. Thus, we demonstrate a fundamental relationship between these two notions of classicality and their emergence in the quantum world.}, archive = {J_PRA}, author = {Emery Doucet and Sebastian Deffner}, doi = {10.1103/PhysRevA.111.042217}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042217}, shortjournal = {Phys. Rev. A}, title = {Compatibility of quantum measurements and the emergence of classical objectivity}, volume = {111}, year = {2025}, }
• (2025). Efficient wireless charging of a quantum battery. PRA, 111(4), 042216. (www)

  @article{ , abstract = {We explore the wireless charging of a quantum battery (QB) via charging units, whose coupling is mediated by a common bosonic reservoir. We consider the general scenarios in which the charger energy is not maximal and the QB has residual ergotropy initially. It is found that the charging performance improves with the increase of the coupling strength. In the strong coupling regime, the charging time is insensitive to the charger energy, the number of charging units, and the residual ergotropy in the QB, while the ergotropy charged on the QB strongly depends on the charger energy and ergotropy, and the residual ergotropy in the QB does not help to enhance its performance. Moreover, the multiple charging units help to enhance the charging performance in the weak and moderate coupling regimes, while they are less efficient in the strong coupling regime.}, archive = {J_PRA}, author = {Ming-Liang Hu and Ting Gao and Heng Fan}, doi = {10.1103/PhysRevA.111.042216}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042216}, shortjournal = {Phys. Rev. A}, title = {Efficient wireless charging of a quantum battery}, volume = {111}, year = {2025}, }
• (2025). Spikes in poissonian quantum trajectories. PRA, 111(4), 042215. (www)

  @article{ , abstract = {We consider the dynamics of a continuously monitored qubit in the limit of strong measurement rate where the quantum trajectory is described by a stochastic master equation with Poisson noise. Such limits are expected to give rise to quantum jumps between the pointer states associated with the nondemolition measurement. A surprising discovery in earlier work [A. Tilloy et al. , Phys. Rev. A 92 , 052111 (2015) ] on quantum trajectories with Brownian noise was the phenomena of spikes observed in-between the quantum jumps. Here, we show that spikes are observed also for Poisson noise. We consider three cases where the nondemolition is broken by adding, to the basic strong measurement dynamics, either unitary evolution or thermal noise or additional measurements. We present a complete analysis of the spike and jump statistics for all three cases using the fact that the dynamics effectively corresponds to that of stochastic resetting. We provide numerical results to support our analytic results.}, archive = {J_PRA}, author = {Alan Sherry and Cedric Bernardin and Abhishek Dhar and Aritra Kundu and Raphael Chetrite}, doi = {10.1103/PhysRevA.111.042215}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042215}, shortjournal = {Phys. Rev. A}, title = {Spikes in poissonian quantum trajectories}, volume = {111}, year = {2025}, }
• (2025). Sixth-order time-convolutionless master equation and beyond: Late-time resummations, two types of divergences, and the limits of validity. PRA, 111(4), 042214. (www)

  @article{ , abstract = {Perturbative master equations are essential for modeling open quantum systems but often exhibit late-time divergences when environmental correlations decay algebraically. In this work, we analyze the time-convolutionless (TCL) master equation expanded to order and demonstrate that, while van Kampen's cumulants suppress early-time secular growth, they ultimately diverge at long times. To overcome this, we introduce a resummation technique based on the Hadamard trick, which incorporates time integrals directly into the bath's spectral density via elementwise multiplication. This approach establishes a maximum expansion order, and defines a precision limit of the asymptotic states of , where is the power-law exponent and is the weak-coupling constant. The resummed master equation features renormalized Bohr frequencies that capture decoherence and spectral overlap effects. In the unbiased spin-boson model, this results in an inflation of the generator at a temperature-independent rate equal to the decoherence rate and a finite validity time . For exponentially decaying correlations, the method recovers a proper Markovian limit below a critical coupling threshold.}, archive = {J_PRA}, author = {Lance Lampert and Srikar Gadamsetty and Shantanu Chaudhary and Yiting Pei and Jiahao Chen and Elyana Crowder and Dragomir Davidović}, doi = {10.1103/PhysRevA.111.042214}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042214}, shortjournal = {Phys. Rev. A}, title = {Sixth-order time-convolutionless master equation and beyond: Late-time resummations, two types of divergences, and the limits of validity}, volume = {111}, year = {2025}, }
• (2025). Quantum systems from random probabilistic automata. PRA, 111(4), 042213. (www)

  @article{ , abstract = {Probabilistic cellular automata with deterministic updating are discrete quantum systems. They are characterized by a probability distribution over initial configurations. We employ the quantum formalism for an investigation of random probabilistic cellular automata for which the properties of the deterministic updating are randomly distributed over space and time. We are interested in a possible continuum limit for a very large number of cells or space points. We consider bits with two colors, moving to the left or right on a linear chain. At randomly distributed scattering points they change direction and color. A numerical simulation reveals the typical features of quantum systems. We find particular initial probability distributions which reemerge periodically after a certain number of time steps, as produced by the periodic evolution of energy eigenstates in quantum mechanics. Using a description in terms of wave functions allows us to introduce statistical observables for momentum and energy. They characterize the probabilistic information without taking definite values for a given bit configuration, with a conceptual status similar to temperature in classical statistical thermal equilibrium. Conservation of energy and momentum are essential ingredients for the understanding of the evolution of the stochastic probabilistic automata. This evolution resembles in some aspects a single Dirac fermion in two dimensions with a generalized random potential.}, archive = {J_PRA}, author = {A. Kreuzkamp and C. Wetterich}, doi = {10.1103/PhysRevA.111.042213}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042213}, shortjournal = {Phys. Rev. A}, title = {Quantum systems from random probabilistic automata}, volume = {111}, year = {2025}, }
• (2025). Eternal non-markovianity of qubit maps. PRA, 111(4), 042212. (www)

  @article{ , abstract = {As is well known, unital Pauli maps can be eternally non-CP-divisible. In contrast, here we show that in the case of nonunital maps, eternal non-Markovianity in the nonunital part is ruled out. In the unital case, the eternal non-Markovianity can be obtained by a convex combination of two dephasing semigroups, but not all three of them. We study these results and ramifications arising from them.}, archive = {J_PRA}, author = {Vinayak Jagadish and R. Srikanth}, doi = {10.1103/PhysRevA.111.042212}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042212}, shortjournal = {Phys. Rev. A}, title = {Eternal non-markovianity of qubit maps}, volume = {111}, year = {2025}, }
• (2025). Expression for the decoherence rate due to air-molecule scattering in spatial qubits. PRA, 111(4), 042211. (www)

  @article{ , abstract = {We provide an expression for the decoherence rate in spatial superpositions due to scattering or collision with air molecules which is independent of the wavelength of the air molecules. This result reproduces the short- and long-wavelength limits known in the literature. We compare the decoherence rate with several existing interpolations in the literature and evaluate the decoherence rate and experimental parameters when creating macroscopic quantum spatial superpositions (i.e., in micron-size spheres). The interpolation regime is relevant in, e.g., matter-wave interferometry, where one might switch between the wavelength limits during the experimental protocol. Finally, we consider the decoherence rate's time dependence while creating and closing the spatial superposition in an interferometer setup.}, archive = {J_PRA}, author = {Martine Schut and Patrick Andriolo and Marko Toroš and Sougato Bose and Anupam Mazumdar}, doi = {10.1103/PhysRevA.111.042211}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042211}, shortjournal = {Phys. Rev. A}, title = {Expression for the decoherence rate due to air-molecule scattering in spatial qubits}, volume = {111}, year = {2025}, }
• (2025). Certifying quantum randomness with disturbance. PRA, 111(4), 042210. (www)

  @article{ , abstract = {A quantum measurement generates genuine quantum randomness if and only if it breaks coherence and disturbs the measured state (and a following incompatible measurement). Here, we establish a quantitative relation between the generated randomness and its disturbance effect and provide a source-independent randomness verification protocol. Our protocol employs a few assumptions: (I) independence between the source and the measurement devices and (II) the Lüders' rule for measurement devices. Without involving heavy mathematical machinery, the generated quantum randomness can be directly estimated with the disturbance effect. In addition to the previously mentioned basic assumptions about measurements, we can improve our estimation by integrating additional measurement information for further optimization. Our protocol shows a high efficiency and yields a higher randomness generation rate than the existing one based on the uncertainty relation [G. Vallone et al. , Phys. Rev. A 90 , 052327 (2014) ].}, archive = {J_PRA}, author = {Liang-Liang Sun and Xingjian Zhang and Xiang Zhou and Zheng-Da Li and Xiongfeng Ma and Jing-Yun Fan and Sixia Yu}, doi = {10.1103/PhysRevA.111.042210}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042210}, shortjournal = {Phys. Rev. A}, title = {Certifying quantum randomness with disturbance}, volume = {111}, year = {2025}, }
• (2025). Exploring quantum contextuality with the quantum möbius-escher-penrose hypergraph. PRA, 111(4), 042209. (www)

  @article{ , abstract = {This paper presents the quantum Möbius-Escher-Penrose hypergraph, drawing inspiration from paradoxical constructs such as the Möbius strip and Penrose's “impossible objects.” The hypergraph is constructed using faithful orthogonal representations in Hilbert space, thereby embedding the graph within a quantum framework. Additionally, a quasiclassical realization is achieved through two-valued states and partition logic, leading to an embedding within a Boolean algebra. This dual representation delineates the distinctions between classical and quantum embeddings, with a particular focus on contextuality, highlighted by violations of exclusivity and completeness, quantified through classical and quantum probabilities. The paper also examines violations of Boole's conditions of possible experience using correlation polytopes, underscoring the inherent contextuality of the hypergraph. These results offer deeper insights into quantum contextuality and its intricate relationship with classical logic structures.}, archive = {J_PRA}, author = {Mirko Navara and Karl Svozil}, doi = {10.1103/PhysRevA.111.042209}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042209}, shortjournal = {Phys. Rev. A}, title = {Exploring quantum contextuality with the quantum möbius-escher-penrose hypergraph}, volume = {111}, year = {2025}, }
• (2025). Disentangling connection between static and dynamical phase transitions. PRA, 111(4), 042208. (www)

  @article{ , abstract = {Dynamical quantum phase transition is a nonstationary analog of the equilibrium quantum phase transitions that may occur after global quenches across a quantum phase transition in systems. In this work, we investigate the quench dynamics of single-particle tight-binding quasiperiodic lattices, where the quenching process originates and terminates within the same phases. Intriguingly, the system under quench dynamics undergoes an energy-dependent dynamical quantum phase transition, characterized by the singularities of the Loschmidt echo in time scale. Specifically, we find disentangling behavior between static and dynamical quantum phase transitions for eigenenergies excluding band edges. Remarkably, the connection between static and dynamical quantum phase transitions does not hold generally for all eigenenergies. Our findings suggest the existence of dynamical phase transitions inside the band energies without crossing the critical point under certain conditions. Our results pave the way to a deeper understanding of the energy-dependent nonequilibrium quench dynamics.}, archive = {J_PRA}, author = {Shihao Ye and Niaz Ali Khan and Muhammad Sajid}, doi = {10.1103/PhysRevA.111.042208}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042208}, shortjournal = {Phys. Rev. A}, title = {Disentangling connection between static and dynamical phase transitions}, volume = {111}, year = {2025}, }
• (2025). Driving a quantum phase transition at an arbitrary rate: Exact solution of the transverse-field ising model. PRA, 111(4), 042207. (www)

  @article{ , abstract = {We study the crossing of the quantum phase transition in the transverse-field Ising model after modulating the magnetic field at an arbitrary rate, exploring the critical dynamics from the slow to the sudden-quench regime. We do so by analyzing the defect density, the complete kink-number distribution, and its cumulants upon completion of a linearized quench. Our analysis relies on the diagonalization of the model using the standard Jordan-Wigner and Fourier transformations, along with the exact solution of the time evolution in each mode in terms of parabolic cylinder functions. The free-fermion nature of the problem dictates that the kink-number distribution is associated with independent and distinguishable Bernoulli variables, each with a success probability p k . We employ a combination of convergent and asymptotic series expansions to characterize p k without restrictions on the driving rate. When the latter is approximated by the Landau-Zener formula, the kink density is described by the Kibble-Zurek mechanism, and higher-order cumulants follow a universal power-law behavior, as recently predicted theoretically and verified in the laboratory. By contrast, for moderate and sudden-driving protocols, the cumulants exhibit a nonuniversal behavior that is not monotonic on the driving rate and changes qualitatively with the cumulant order. The kink-number statistics remain sub-Poissonian for any driving rate, as revealed by an analysis of the cumulant ratios that vary nonmonotonically from the sudden- to the slow-driving regime. Due to the determination of p k for an arbitrary rate, our study provides a complete analytical understanding of kink-number statistics from the slow-driving regime to the sudden-quench limit.}, archive = {J_PRA}, author = {András Grabarits and Federico Balducci and Adolfo del Campo}, doi = {10.1103/PhysRevA.111.042207}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042207}, shortjournal = {Phys. Rev. A}, title = {Driving a quantum phase transition at an arbitrary rate: Exact solution of the transverse-field ising model}, volume = {111}, year = {2025}, }
• (2025). Robust micro-macro entangled states. PRA, 111(4), 042206. (www)

  @article{ , abstract = {Bipartite entangled states between a qubit and macroscopically distinct states of a mesoscopic system, known as micro-macro entangled states, are emerging resources for quantum information processing. One main challenge in generating such states in the laboratory is their fragility to environmental noise. We analyze this fragility in detail for single-particle noise by identifying what factors play a role in the robustness and quantifying their effect. There is a trade-off between the macroscopicity of a micro-macro entangled state and the robustness of its bipartite entanglement to environmental noise. We identify symmetric micro-macro entangled states as the most robust states to single-particle noise. We show that the robustness of bipartite entanglement of such states to single-particle noise decreases as the second order of macroscopicity, which identifies a regime where the bipartite entangled state is both robust and macroscopic. Our result is a step towards retaining quantum characteristics on large scales and experimental realization of micro-macro entangled spin states and their use for connecting separated qubits. Moreover, it advances our understanding of quantum to classical transition.}, archive = {J_PRA}, author = {Maryam Sadat Mirkamali and David G. Cory}, doi = {10.1103/PhysRevA.111.042206}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042206}, shortjournal = {Phys. Rev. A}, title = {Robust micro-macro entangled states}, volume = {111}, year = {2025}, }
• (2025). Pseudo-hermitian topology in multiband non-hermitian systems. PRA, 111(4), 042205. (www)

  @article{ , abstract = {The complex eigenenergies and nonorthogonal eigenstates of non-Hermitian systems exhibit unique topological phenomena that cannot appear in Hermitian systems. Representative examples are the non-Hermitian skin effect and exceptional points. In a two-dimensional parameter space, topological classifications of nonseparable bands in multiband non-Hermitian systems can be established by invoking a permutation group, where the product of the permutation represents state exchange due to exceptional points in the space. We unveil in this work the role of pseudo-Hermitian lines in non-Hermitian topology for multiple bands. In particular, the nonseparability of non-Hermitian multibands can be topologically nontrivial without exceptional points in two-dimensional space. As a physical illustration of the role of pseudo-Hermitian lines, we examine a multiband structure of a photonic crystal system with lossy materials. Our work builds on the fundamental and comprehensive understanding of non-Hermitian multiband systems and also offers versatile applications and realizations of non-Hermitian systems without the need to consider exceptional points.}, archive = {J_PRA}, author = {Jung-Wan Ryu and Jae-Ho Han and Chang-Hwan Yi and Hee Chul Park and Moon Jip Park}, doi = {10.1103/PhysRevA.111.042205}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042205}, shortjournal = {Phys. Rev. A}, title = {Pseudo-hermitian topology in multiband non-hermitian systems}, volume = {111}, year = {2025}, }
• (2025). Characterizing the yang-lee zeros of the classical ising model through dynamic quantum phase transitions. PRA, 111(4), 042204. (www)

  @article{ , abstract = {In quantum dynamics, the Loschmidt amplitude is analogous to the partition function in the canonical ensemble. Zeros in the partition function indicate a phase transition, while the presence of zeros in the Loschmidt amplitude indicates a dynamical quantum phase transition. Based on the classical-quantum correspondence, we demonstrate that the partition function of a classical Ising model is equivalent to the Loschmidt amplitude in non-Hermitian dynamics, thereby mapping an Ising model with variable system size to the non-Hermitian dynamics. It follows that the Yang-Lee zeros and the Yang-Lee edge singularity of the classical Ising model correspond to the critical times of the dynamic quantum phase transitions and the exceptional point of the non-Hermitian Hamiltonian, respectively. Our work reveals an inner connection between Yang-Lee zeros and non-Hermitian dynamics, offering a dynamic characterization of the former.}, archive = {J_PRA}, author = {Mingtao Xu and Wei Yi and De-Huan Cai}, doi = {10.1103/PhysRevA.111.042204}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042204}, shortjournal = {Phys. Rev. A}, title = {Characterizing the yang-lee zeros of the classical ising model through dynamic quantum phase transitions}, volume = {111}, year = {2025}, }
• (2025). Unified framework of unitarily residual measures for quantifying dissipation. PRA, 111(4), 042203. (www)

  @article{ , abstract = {Open quantum systems are governed by both unitary and nonunitary dynamics, with dissipation arising from the latter. Traditional quantum divergence measures, such as quantum relative entropy, fail to account for the nonunitary oriented dissipation as the divergence is positive even between unitarily connected states. We introduce a framework for quantifying the dissipation by isolating the nonunitary components of quantum dynamics. We define equivalence relations among Hermitian operators through unitary transformations and characterize the resulting quotient set. By establishing an isomorphism between this quotient set and a set of real vectors with ordered components, we induce divergence measures that are invariant under unitary evolution, which we refer to as the unitarily residual measures. These unitarily residual measures inherit properties such as monotonicity and convexity and, in certain cases, correspond to classical information divergences between sorted eigenvalue distributions. Our results provide a powerful tool for quantifying dissipation in open quantum systems, advancing the understanding of quantum thermodynamics.}, archive = {J_PRA}, author = {Tomohiro Nishiyama and Yoshihiko Hasegawa}, doi = {10.1103/PhysRevA.111.042203}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042203}, shortjournal = {Phys. Rev. A}, title = {Unified framework of unitarily residual measures for quantifying dissipation}, volume = {111}, year = {2025}, }
• (2025). Newton's laws of motion generating gravity-mediated entanglement. PRA, 111(4), 042202. (www)

  @article{ , abstract = {The interface between quantum theory and gravity represents still uncharted territory. Recently, a tabletop experiment has been proposed for witnessing quantum features of gravity: Two masses in an initial superposition of spatially localized states interact only through gravity and it is measured whether the final state is entangled. Here we show that one can generate the same amount of entanglement in this setup by using the time evolution given by Newton's laws of motion. We argue that theories of quantum gravity that can be approximated by the Newtonian potential and time evolution given by Newton's laws of motion will generate gravity-mediated entanglement.}, archive = {J_PRA}, author = {Marta M. Marchese and Martin Plávala and Matthias Kleinmann and Stefan Nimmrichter}, doi = {10.1103/PhysRevA.111.042202}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042202}, shortjournal = {Phys. Rev. A}, title = {Newton's laws of motion generating gravity-mediated entanglement}, volume = {111}, year = {2025}, }
• (2025). Anomalous bulk-edge correspondence of the nonlinear rice-mele model. PRA, 111(4), 042201. (www)

  @article{ , abstract = {Bulk-edge correspondence constitutes a fundamental concept within the domain of topological physics, elucidating the profound interplay between the topological invariants that characterize the bulk states and the emergent edge states. A recent highlight along this research line consists of establishing bulk-edge correspondence under the eigenvalue's nonlinearity in a linear Hamiltonian by introducing auxiliary eigenvalues [T. Isobe et al. , Phys. Rev. Lett. 132 , 126601 (2024) ]. The purpose of this work aims to extend Isobe's analysis to uncover bulk-edge correspondence of the eigenvalue's nonlinearity in intrinsic nonlinear Hamiltonians. To achieve this, we numerically solve the nonlinear Rice-Mele (RM) model and identify two distinct types of nonlinear eigenvalues: the intrinsically nonlinear eigenvalues and the eigenvalue's nonlinearity introduced through the incorporation of auxiliary eigenvalues. Furthermore, we establish a form of bulk-edge correspondence based on these auxiliary nonlinear eigenvalues, which we term the anomalous bulk-edge correspondence of a nonlinear physical system. The concept of the anomalous bulk-edge correspondence defined herein provides an alternative perspective on the intricate interplay between topology and nonlinearity in the context of bulk-edge correspondence.}, archive = {J_PRA}, author = {Chenxi Bai and Zhaoxin Liang}, doi = {10.1103/PhysRevA.111.042201}, journal = {Physical Review a}, month = {4}, number = {4}, pages = {042201}, shortjournal = {Phys. Rev. A}, title = {Anomalous bulk-edge correspondence of the nonlinear rice-mele model}, volume = {111}, year = {2025}, }
• (2025). Impact of chaos on the excited-state quantum phase transition of the kerr parametric oscillator. PRA, 111(3), L031502. (www)

  @article{ , abstract = {The driven Kerr parametric oscillator, of interest to fundamental physics and quantum technologies, exhibits an excited state quantum phase transition (ESQPT) originating in an unstable classical periodic orbit. The main signature of this type of ESQPT is a singularity in the level density in the vicinity of the energy of the classical separatrix that divides the phase space into two distinct regions. The quantum states with energies below the separatrix are useful for quantum technologies, because they show a catlike structure that protects them against local decoherence processes. In this work, we show how chaos arising from the interplay between the external drive and the nonlinearities of the system destroys the ESQPT and eventually eliminates the cat states. Our results demonstrate the importance of the analysis of theoretical models for the design of new parametric oscillators with ever larger nonlinearities.}, archive = {J_PRA}, author = {Ignacio García-Mata and Miguel A. Prado Reynoso and Rodrigo G. Cortiñas and Jorge Chávez-Carlos and Victor S. Batista and Lea F. Santos and Diego A. Wisniacki}, doi = {10.1103/PhysRevA.111.L031502}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L031502}, shortjournal = {Phys. Rev. A}, title = {Impact of chaos on the excited-state quantum phase transition of the kerr parametric oscillator}, volume = {111}, year = {2025}, }
• (2025). Redistributing the imaginary poynting momentum based on radially varying polarization. PRA, 111(3), L031501. (www)

  @article{ , abstract = {We present a theoretical study on the harnessing and redistribution of the imaginary Poynting momentum (IPM) by introducing a radial degree of freedom in polarization. For specific radial indices, we find that the azimuthal optical force exerted by the IPM on nanoparticles varies with the light wavelength, particle radius, and the initial phase of the vector optical field. This finding demonstrates the controllability of the azimuthal IPM density and its mechanical effects on nanoparticles, providing insights into the manipulation of optical forces. Importantly, the light-driven motion is not dependent on spin or orbital angular momentum, or the use of inhomogeneous particles. Our results offer an alternative method for optical micromanipulation, thereby enhancing the potential for applications in physical and biochemical systems.}, archive = {J_PRA}, author = {Qiang Wang and Jiafeng Zeng and Xiangsheng Xie and Chenghou Tu}, doi = {10.1103/PhysRevA.111.L031501}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L031501}, shortjournal = {Phys. Rev. A}, title = {Redistributing the imaginary poynting momentum based on radially varying polarization}, volume = {111}, year = {2025}, }
• (2025). Accelerated creation of NOON states with ultracold atoms via counterdiabatic driving. PRA, 111(3), L031301. (www)

  @article{ , abstract = {A quantum control protocol is proposed for the creation of NOON states with N ultracold bosonic atoms on two modes, corresponding to the coherent superposition | N , 0 〉 + | 0 , N 〉 . This state can be prepared by using a third mode where all bosons are initially placed and which is symmetrically coupled to the other two modes. Tuning the energy of this third mode across the energy level of the other modes allows the adiabatic creation of the NOON state. While this process normally takes too much time to be of practical use, due to the smallness of the involved spectral gap, it can be drastically boosted through counterdiabatic driving which allows for efficient gap engineering. We demonstrate that this process can be implemented in terms of static parameter adaptations that are experimentally feasible with ultracold quantum gases. Gain factors in the required protocol speed are obtained that increase exponentially with the number of involved atoms and thus counterbalance the exponentially slow collective tunneling process underlying this adiabatic transition. Besides optimizing the protocol speed, our NOON state preparation scheme achieves excellent fidelities that are competitive for practical applications.}, archive = {J_PRA}, author = {Simon Dengis and Sandro Wimberger and Peter Schlagheck}, doi = {10.1103/PhysRevA.111.L031301}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L031301}, shortjournal = {Phys. Rev. A}, title = {Accelerated creation of NOON states with ultracold atoms via counterdiabatic driving}, volume = {111}, year = {2025}, }
• (2025). Polarization-agnostic continuous-variable quantum key distribution. PRA, 111(3), L030601. (www)

  @article{ , abstract = {We introduce a polarization-agnostic method for Gaussian-modulated coherent-state (GCMS) continuous-variable quantum key distribution (CVQKD). Due to the random and continuous nature of the GCMS protocol, Alice, the transmitter, can encode two distinct quadratures in each of two orthogonal polarization modes, such that Bob, the receiver, measures valid GCMS quadratures in a single polarization mode even when polarization changes occur during transmission. This method does not require polarization correction in the optical domain, does not require monitoring both polarization modes, reduces loss by eliminating optical components, and avoids the noise injected by polarization correction algorithms.}, archive = {J_PRA}, author = {Brian P. Williams and Nicholas A. Peters}, doi = {10.1103/PhysRevA.111.L030601}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L030601}, shortjournal = {Phys. Rev. A}, title = {Polarization-agnostic continuous-variable quantum key distribution}, volume = {111}, year = {2025}, }
• (2025). Verifying energy-time entanglement via nonlocal dispersion cancellation. PRA, 111(3), L030403. (www)

  @article{ , abstract = {We study the direct experimental verification of continuous-variable (CV) energy-time entanglement, a crucial resource for long-distance quantum communication. Despite its potential advantages, including higher information capacity and robustness against noise, verifying energy-time CV entanglement under practical conditions has remained challenging. We find that nonlocal dispersion cancellation (NDC) provides an effective means to probe energy-time CV entanglement, successfully emulating photon propagation through a 379-km optical fiber at telecom wavelengths. By implementing NDC, we experimentally demonstrate that pairs of energy-time-entangled photons experience opposite dispersions, leaving the two-photon wave packet unbroadened, despite significant local dispersion acting individually on each photon. Our results show a violation of the separability criterion [ Phys. Rev. A 82 , 052120 (2010) ] by 32 standard deviations, confirming energy-time CV entanglement independently of entanglement in other degrees of freedom. This work establishes a practical method for robustly verifying CV energy-time entanglement, facilitating advances in quantum information processing and secure long-distance quantum communication.}, archive = {J_PRA}, author = {Jin-Woo Chae and Heebong Seo and U-Shin Kim and Yoon-Ho Kim}, doi = {10.1103/PhysRevA.111.L030403}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L030403}, shortjournal = {Phys. Rev. A}, title = {Verifying energy-time entanglement via nonlocal dispersion cancellation}, volume = {111}, year = {2025}, }
• (2025). Biased estimator channels for classical shadows. PRA, 111(3), L030402. (www)

  @article{ , abstract = {Extracting classical information from quantum systems is of fundamental importance, and classical shadows allow us to extract a large amount of information using relatively few measurements. Conventional shadow estimators are unbiased and thus agree with the true mean in expectation. In this Letter, we consider a biased scheme, intentionally introducing a bias in the expectation value by rescaling the conventional classical-shadow estimators to reduce the error in the finite-sample regime. The approach is straightforward to implement and requires no quantum resources. We analytically prove average-case as well as worst- and best-case scenarios, and rigorously prove that it is, in principle, always worth biasing the estimators. We illustrate our approach in a quantum simulation task of a 12-qubit spin-ring problem and demonstrate how estimating expected values of nonlocal perturbations can be significantly more efficient using our biased scheme.}, archive = {J_PRA}, author = {Zhenyu Cai and Adrian Chapman and Hamza Jnane and Bálint Koczor}, doi = {10.1103/PhysRevA.111.L030402}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L030402}, shortjournal = {Phys. Rev. A}, title = {Biased estimator channels for classical shadows}, volume = {111}, year = {2025}, }
• (2025). Error-mitigated photonic quantum circuit born machine. PRA, 111(3), L030401. (www)

  @article{ , abstract = {In this Letter, we study quantum circuit Born machines (QCBMs) in the context of photonic quantum computing. QCBMs are a popular choice of quantum generative machine learning models, and we present a QCBM designed for linear optics. We show that a recently developed error mitigation technique called recycling mitigation greatly improves the training of QCBMs in realistic scenarios with photon loss, which is the primary source of noise in photonic systems. We demonstrate this through numerical simulations and through an experiment on a quantum photonic integrated processor. We expect our work to pave the way towards more demonstrations of error mitigation techniques tailored to photonic devices which can enhance the performance of a quantum algorithm.}, archive = {J_PRA}, author = {Alexia Salavrakos and Tigran Sedrakyan and James Mills and Shane Mansfield and Rawad Mezher}, doi = {10.1103/PhysRevA.111.L030401}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {L030401}, shortjournal = {Phys. Rev. A}, title = {Error-mitigated photonic quantum circuit born machine}, volume = {111}, year = {2025}, }
• (2025). Erratum: Coherence from multiorbital tunneling ionization of molecules [Phys. rev. a 108, 023123 (2023)]. PRA, 111(3), 039904. (www)

  @article{ , abstract = {Phys. Rev. A 111, 039904 (2025)}, archive = {J_PRA}, author = {C. H. Yuen and C. D. Lin}, doi = {10.1103/PhysRevA.111.039904}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {039904}, shortjournal = {Phys. Rev. A}, title = {Erratum: Coherence from multiorbital tunneling ionization of molecules [Phys. rev. a 108, 023123 (2023)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Accurate determination of an alkali-vapor–inert-gas diffusion coefficient using coherent transient emission from a density grating [Phys. rev. a 103, 023112 (2021)]. PRA, 111(3), 039903. (www)

  @article{ , abstract = {Phys. Rev. A 111, 039903 (2025)}, archive = {J_PRA}, author = {A. Pouliot and G. Carlse and H. C. Beica and T. Vacheresse and A. Kumarakrishnan and U. Shim and S. B. Cahn and A. Turlapov and T. Sleator}, doi = {10.1103/PhysRevA.111.039903}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {039903}, shortjournal = {Phys. Rev. A}, title = {Erratum: Accurate determination of an alkali-vapor–inert-gas diffusion coefficient using coherent transient emission from a density grating [Phys. rev. a 103, 023112 (2021)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Observing the coulomb shifts of ionization times in high-order harmonic generation [Phys. rev. a 107, 063102 (2023)]. PRA, 111(3), 039902. (www)

  @article{ , abstract = {Phys. Rev. A 111, 039902 (2025)}, archive = {J_PRA}, author = {Shengjun Yue and Jin Liu and Shan Xue and Hongchuan Du and Manfred Lein}, doi = {10.1103/PhysRevA.111.039902}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {039902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Observing the coulomb shifts of ionization times in high-order harmonic generation [Phys. rev. a 107, 063102 (2023)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Cryptographic quantum bound on nonlocality [Phys. rev. a 95, 022108 (2017)]. PRA, 111(3), 039901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 039901 (2025)}, archive = {J_PRA}, author = {Satoshi Ishizaka}, doi = {10.1103/PhysRevA.111.039901}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {039901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Cryptographic quantum bound on nonlocality [Phys. rev. a 95, 022108 (2017)]}, volume = {111}, year = {2025}, }
• (2025). Reply to “Comment on ‘Modulational instability and frequency combs in whispering-gallery-mode microresonators with backscattering' ”. PRA, 111(3), 037502. (www)

  @article{ , abstract = {In this Reply, we address the points raised by Emmanuel Kengne in his Comment on our paper [ Phys. Rev. A 101 , 013816 (2020) ]. Dr. Kengne asserts that the linear stability analysis method applied in the original article is incorrect and proposes an alternative approach. Here, we demonstrate that his considerations are not entirely accurate as the final solution derived from both methods are, in fact, equivalent. Finally, we prove the validity of our method.}, archive = {J_PRA}, author = {Nikita M. Kondratiev and Valery E. Lobanov}, doi = {10.1103/PhysRevA.111.037502}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {037502}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Modulational instability and frequency combs in whispering-gallery-mode microresonators with backscattering' ”}, volume = {111}, year = {2025}, }
• (2025). Comment on “Modulational instability and frequency combs in whispering-gallery-mode microresonators with backscattering”. PRA, 111(3), 037501. (www)

  @article{ , abstract = {Some years ago, to investigate modulational instability using a linear stability analysis, Kondratiev and Lobanov [ Phys. Rev. A 101 , 013816 (2020) ] applied a method that consists of adding complex conjugate equations to a differential system to close up the system self-consistently. It is the aim of this Comment to note and correct the crucial inconsistency found in the method used to investigate the modulational instability in Kondratiev and Lobanov's work.}, archive = {J_PRA}, author = {Emmanuel Kengne}, doi = {10.1103/PhysRevA.111.037501}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {037501}, shortjournal = {Phys. Rev. A}, title = {Comment on “Modulational instability and frequency combs in whispering-gallery-mode microresonators with backscattering”}, volume = {111}, year = {2025}, }
• (2025). Engineering tunable decoherence-free subspaces with collective atom-cavity interactions. PRA, 111(3), 033718. (www)

  @article{ , abstract = {We propose schemes to design and control a time-dependent decoherence-free subspace (DFS) in a dissipative atom-cavity system. These schemes use atoms with three internal energy levels, which allows for the DFS to be multidimensional—a condition important for quantum sensing, simulation, and computation. We consider the use of tunable external driving lasers to transfer the system from a coherent spin state to a highly degenerate DFS. We find that the typical state in the DFS is highly entangled. Throughout evolution the state is kept in an instantaneous DFS, thereby allowing for pure states to be prepared. We develop adiabatic shortcuts to carry out this evolution with higher purity and fidelity than standard adiabatic and dissipative methods.}, archive = {J_PRA}, author = {Lyryl H. C. Vaecairn and Jarrod T. Reilly and John Drew Wilson and Simon B. Jäger and Murray Holland}, doi = {10.1103/PhysRevA.111.033718}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033718}, shortjournal = {Phys. Rev. A}, title = {Engineering tunable decoherence-free subspaces with collective atom-cavity interactions}, volume = {111}, year = {2025}, }
• (2025). Cat-state-like non-gaussian entanglement in magnon systems. PRA, 111(3), 033717. (www)

  @article{ , abstract = {Magnons can serve as a bridge between spin, phonon, and photon systems, which renders them suitable for constructing hybrid systems. An important application of such hybrid systems is generating entanglement between different platforms. As magnons can support a broad variety of states, e.g., Fock states, squeezed states, or coherent states, and hybrid states can be produced with cavities or spins, there are many different kinds of entangled states in magnon systems. In this paper, we consider the entanglement of cat-state-like throughout states, which can be generated in magnon systems with parametric pumps beyond the parametric stable intensities. However, estimating the entanglement in such states is challenging due to their multiphoton and non-Gaussian properties. Here, we apply a modular variable-based projection, which maps the catlike states to spin states, preserving the encoded information. After the projection, Bell's inequality is employed to detect the entanglement in the effective spin states. Our numerical analysis provides the conditions for generating catlike entanglement in magnon systems and can be conveniently extended to other entangled states that may be formed by magnon and spin systems.}, archive = {J_PRA}, author = {Zeyu Zhang and Clemens Gneiting and Zheng-Yang Zhou and Ai-Xi Chen}, doi = {10.1103/PhysRevA.111.033717}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033717}, shortjournal = {Phys. Rev. A}, title = {Cat-state-like non-gaussian entanglement in magnon systems}, volume = {111}, year = {2025}, }
• (2025). Dark-state-mediated topological response to coherence effects from two independent phases in single-photon transport. PRA, 111(3), 033716. (www)

  @article{ , abstract = {We unveil the inherent topological nature from a two-dimensional synthetic parameter space in a single-photon transport problem, with the simple configuration of one waveguide coupled with two four-level atoms driven by external fields. We find that, by tuning the system in the dark-state condition, the system holds two independent phase degrees of freedom from both the photon propagation and the atomic transition. As the direct output, the photon scattering characteristics show the total reflection with the frequency preservation or the complete frequency conversion at the specific choices of two phases. We uncover the underlying topological effect by analyzing the photon scattering amplitudes in the parameter space of two phases, which links to the singularity with nonzero winding numbers. Our results are verified by numerical simulations, and hence point to an alternative perspective for the research at the intersection of single-photon transport and topology, without using the topological geometric arrangement of atoms.}, archive = {J_PRA}, author = {Haohang Zhou and Luojia Wang and Rui-Yang Gong and Ze-Liang Xiang and Xianfeng Chen and Luqi Yuan}, doi = {10.1103/PhysRevA.111.033716}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033716}, shortjournal = {Phys. Rev. A}, title = {Dark-state-mediated topological response to coherence effects from two independent phases in single-photon transport}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal photon blockade via chiral cavity-atom interaction. PRA, 111(3), 033715. (www)

  @article{ , abstract = {We introduce a method to achieve nonreciprocal photon blockade in an optical resonator that is chirally coupled to a two-level atom. This approach enables single-excitation and two-excitation resonant conditions to be simultaneously satisfied. The atom-uncoupled optical mode can be blocked with eliminating its two-photon excitation by judiciously selecting parameters, e.g., the optical coupling strength. The chiral interaction between the resonator mode and the atom leads to different optimal parameter conditions for generating photon blockade in the two opposite drivings. This offers a natural way to realize nonreciprocal photon blockade. The nonreciprocity achieved by the chiral cavity-atom interaction diminishes the experimental difficulty by eliminating the need to rotate the resonator. The blockade mode achieves very high purity of single-photon excitation, as characterized by a second-order correlation function of g ( 2 ) ( 0 ) ∼ 10 − 4 . In particular, in the nonreciprocal regime, the mean number of photons is significantly higher where photon blockade occurs compared to the general Jaynes-Cummings case. Our findings are particularly relevant for the development of quantum nonreciprocal devices and their applications in quantum information processing, including chiral networks.}, archive = {J_PRA}, author = {Li-Li Zheng and Yuan Zhou and Jun Yang and Kun Chen and Xin-You Lü and Chang-Sheng Hu}, doi = {10.1103/PhysRevA.111.033715}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033715}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal photon blockade via chiral cavity-atom interaction}, volume = {111}, year = {2025}, }
• (2025). Single-photon trapping in a giant-atom cavity coupled to a one-dimensional waveguide. PRA, 111(3), 033714. (www)

  @article{ , abstract = {Giant atoms introduce promising avenues for enhancing light-matter interaction in waveguides, which plays a crucial role in quantum information processing and quantum state control. In this work, we study the dynamics of a system comprising a single-photon Gaussian pulse initially inside a cavity with giant-atom mirrors coupled to a one-dimensional waveguide. The decay rate of the photon pulse can be significantly minimized by using giant atoms instead of point atoms and by carefully selecting the spacing between the coupling points of the giant atom to the waveguide. The quality factor for the cavity is analyzed by varying the number of atoms, coupling points, and coupling point spacing in each mirror to find the optimal parameters for a high Q -factor cavity. Our work contributes to the design of more efficient, high-quality quantum devices such as integrated quantum photonic circuits.}, archive = {J_PRA}, author = {Amal Vijayalekshmi Sivakumar and Jiru Liu and M. Suhail Zubairy}, doi = {10.1103/PhysRevA.111.033714}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033714}, shortjournal = {Phys. Rev. A}, title = {Single-photon trapping in a giant-atom cavity coupled to a one-dimensional waveguide}, volume = {111}, year = {2025}, }
• (2025). Multimode gaussian state analysis with one bounded photon counter. PRA, 111(3), 033713. (www)

  @article{ , abstract = {Gaussian states are ubiquitous in quantum optics and information processing, and it is essential to have effective tools for their characterization. One such tool is a photon-number-resolving detector, and the simplest configuration involves counting the total number of photons in the state to be characterized. This motivates the following question: What properties of a multimode Gaussian state are determined by the signal from one detector that measures the total number of photons up to some bound? We find that if the Gaussian state occupies S modes and the probabilities of n photons for all n ≤ 8 S are known, then we can determine the spectrum of the Gaussian covariance matrix and the magnitude of the displacements in each eigenspace of the covariance matrix. Nothing more can be learned, even if all photon-number probabilities are known. When the state is pure, the covariance matrix spectrum determines the squeezing parameters of the state.}, archive = {J_PRA}, author = {Arik Avagyan and Emanuel Knill and Scott Glancy}, doi = {10.1103/PhysRevA.111.033713}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033713}, shortjournal = {Phys. Rev. A}, title = {Multimode gaussian state analysis with one bounded photon counter}, volume = {111}, year = {2025}, }
• (2025). Multipartite magnon entanglement and collective steering in cavity magnonics. PRA, 111(3), 033712. (www)

  @article{ , abstract = {In this paper, we propose a scalable scheme to prepare multipartite entanglement and collective steering of four magnons, which are placed into four separate transmission line resonators. When the four cavity modes are coupled to a common superconducting qubit, the strong coherent coupling between the magnons and qubit can be established through virtual photon exchange. In the dressed picture, it is of interest to explore two types of interaction under different frequency-matching conditions, being responsible for the continuous-variable quadripartite Greenberger-Horne-Zeilinger and cluster entanglement. Furthermore, the generation of collective steering originates from the dissipation channel of Bogoliubov mode rather than from the conventional asymmetry of the system parameters. The multipartite entanglement in this solid-state device may find potential applications in constructing macroscopic quantum networks and the collective steering may be useful in one-sided device-independent quantum secret sharing.}, archive = {J_PRA}, author = {Fei Wang and Jiang Liu and Deyi Kong and Xin-You Lü}, doi = {10.1103/PhysRevA.111.033712}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033712}, shortjournal = {Phys. Rev. A}, title = {Multipartite magnon entanglement and collective steering in cavity magnonics}, volume = {111}, year = {2025}, }
• (2025). Superradiance from nitrogen-vacancy centers coupled to an ultranarrow optical cavity. PRA, 111(3), 033711. (www)

  @article{ , abstract = {Nitrogen-vacancy (NV) centers in diamond have been successfully coupled to various optical structures to enhance their radiation by the Purcell effect. The participation of many NV centers in these studies may naturally lead to cooperative emission and superradiance, and our recent experimental study with a diamond membrane in a fiber-based ultranarrow optical cavity demonstrated nonlinear radiation and fast photon bunching as signatures of the collective effects. In this theoretical article, we go beyond the simple model used in the previous study to address more phenomena, such as the appearance of bunching shoulders in second-order correlation function, Rabi splitting in steady-state spectrum, and population dynamics on excited Dicke states, which for moderate pumping explains the observed collective effects. Overall, our results can guide further experiments with NV centers, and they are also relevant for other solid-state color centers, such as silicon-vacancy centers in diamond and silicon carbide, boron-vacancy centers, and carbon-related centers in hexagonal boron nitride.}, archive = {J_PRA}, author = {Yi-Dan Qu and Yuan Zhang and Peinan Ni and Chongxin Shan and David Hunger and Klaus Mølmer}, doi = {10.1103/PhysRevA.111.033711}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033711}, shortjournal = {Phys. Rev. A}, title = {Superradiance from nitrogen-vacancy centers coupled to an ultranarrow optical cavity}, volume = {111}, year = {2025}, }
• (2025). Dipole-induced transparency in a cavity-waveguide system with attractive cavity modes. PRA, 111(3), 033710. (www)

  @article{ , abstract = {Dipole-induced transparency (DIT) is one of the most well-known transparency effects in quantum optics and has wide applications in scalable quantum information processing and quantum computation. However, most of the existing literatures only focuses on the DIT effect with coherent dipole-cavity coupling, thus its universality in other types of coupling is still to be clarified. Here, we propose a feasible scheme to realize dissipative dipole-cavity coupling with the assistance of a highly dissipative microcavity, and explicitly exhibit cavity-mode attraction. We then investigate the DIT effect in a cavity-waveguide system with attractive cavity modes and find that it can still be achievable even though the probe light is resonant with two attractive cavity modes. Furthermore, we reveal its underlying transparency mechanism with eigenfrequencies and the effective susceptibility of the dipole-cavity system, and show that its transparency lies in the destructive interference of two attractive cavity modes with splitting damping rates instead of splitting resonance frequencies in coherent coupling. Moreover, we find that the attractive and repulsive phenomena of the effective susceptibility, which also plays an important role in the DIT effect, exist in the dipole-cavity system. Our findings may not only be of importance for gaining a more comprehensive understanding on the DIT effect, but also have potential applications in quantum networks.}, archive = {J_PRA}, author = {Zhao-Hui Peng and Chun-Xia Jia and Yu-Qing Zhang and Ying Yang and Xiang-Yun Fu and Wangjun Lu and Le-Man Kuang}, doi = {10.1103/PhysRevA.111.033710}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033710}, shortjournal = {Phys. Rev. A}, title = {Dipole-induced transparency in a cavity-waveguide system with attractive cavity modes}, volume = {111}, year = {2025}, }
• (2025). Optimization of two-photon absorption for a three-level atom. PRA, 111(3), 033709. (www)

  @article{ , abstract = {This work discusses the problem of optimal excitation of a three-level atom of ladder configuration by light in the two-photon state and coherent light carrying an average of two photons. The applied atom-light interaction model is based on the Wigner-Weisskopf approximation. We characterize the properties of the optimal two-photon state that excites an atom perfectly, i.e., with probability equal to one. We find that the spectrotemporal shape of the optimal state of light is determined by the lifetimes of the atomic states, with the degree of photonic entanglement in the optimal state depending on the lifetime ratio. In consequence, two distinct interaction regimes can be identified in which the entanglement of the input state of light has a qualitatively different impact. As the optimal states may be challenging to prepare in general, we compare the results with those obtained for photon pairs of selected experimentally relevant pulse shapes. As these shapes are optimized for maximal atomic excitation probability, the results can be interpreted in terms of the overlap between the optimal and investigated pulse shapes.}, archive = {J_PRA}, author = {Masood Valipour and Gniewomir Sarbicki and Karolina Słowik and Anita Dąbrowska}, doi = {10.1103/PhysRevA.111.033709}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033709}, shortjournal = {Phys. Rev. A}, title = {Optimization of two-photon absorption for a three-level atom}, volume = {111}, year = {2025}, }
• (2025). Dark-state-induced transparency and the ultranarrow spectrum. PRA, 111(3), 033708. (www)

  @article{ , abstract = {Ultranarrow scattering spectra have important applications in precision measurements. Here, we show that the dark state of two atoms coupled to a one-dimensional (1D) waveguide leads to an ultranarrow transparency window with a width significantly smaller than the spontaneous decay rate of the atoms. Specifically, the position of this transparency dip is linearly proportional to the atom-atom distance. This ultranarrow dip can measure the atom-atom distance with an accuracy of one percent of the resonant wavelength. Additionally, the dip depth is highly sensitive to the atom-atom detuning, which could be used to measure small magnetic-field gradients at the nanoscale. The sign of the detuning can be further determined by measuring the second-order correlation function of the reflected photons.}, archive = {J_PRA}, author = {Ting-Qian Zhou and Yue Chang and Li-Ping Yang}, doi = {10.1103/PhysRevA.111.033708}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033708}, shortjournal = {Phys. Rev. A}, title = {Dark-state-induced transparency and the ultranarrow spectrum}, volume = {111}, year = {2025}, }
• (2025). Giant-atom dephasing dynamics and entanglement generation in a squeezed vacuum reservoir. PRA, 111(3), 033707. (www)

  @article{ , abstract = {The study of atomic behaviors in a squeezed vacuum reservoir plays an important role in exploring quantum effect and quantum physics. We here propose a scheme to manipulate the dynamics of giant atoms coupled to a one-dimensional waveguide driven by a broadband squeezed field, which acts as a squeezed vacuum reservoir. By tuning the propagating phase of photons, the center-of-mass phase of the giant atom, and the squeezing parameter, both the dephasing dynamics and entanglement dynamics of giant atoms can be effectively controlled. In the single-giant-atom case, we obtain the expressions of the dephasing rates based on the Bloch equations derived from the quantum master equation of the giant atom. Adjusting these two phases enables the dephasing rates to be enhanced, suppressed, or reduced to zero, thereby changing the dephasing dynamics. For the two-giant-atom system, we find that the atomic individual and collective squeezing depend on these two phases simultaneously. The steady-state giant-atom population and entanglement are obtained by working in the collective state representation for the two atoms. Different from small atoms, the steady-state population and entanglement depend on not only the center-mass-of phase, but also the propagating phase. In addition, we identify the condition for achieving larger steady-state entanglement via analyzing the system parameters. This work will facilitate the study of light-matter interaction based on giant-atom waveguide QED systems driven by a squeezed vacuum reservoir and has potential applications in quantum information processing.}, archive = {J_PRA}, author = {Xian-Li Yin and Heung-wing Joseph Lee and Guofeng Zhang}, doi = {10.1103/PhysRevA.111.033707}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033707}, shortjournal = {Phys. Rev. A}, title = {Giant-atom dephasing dynamics and entanglement generation in a squeezed vacuum reservoir}, volume = {111}, year = {2025}, }
• (2025). Multilevel quantum routing of single photons with whispering-gallery resonators. PRA, 111(3), 033706. (www)

  @article{ , abstract = {Quantum routers determine the propagation of quantum signals in a quantum network. In a complex optical quantum network, the quantum signals should be routed to multilevel quantum channels, but how to modulate this quantum routing process is a challenge. We study the quantum routing of single photons with three-level quantum channels connected by two whispering-gallery resonators (WGRs). We find that single photons can be efficiently routed to a third level quantum channel, though the maximum probability is not higher than that to the second level quantum channel, which can reach 100 % . Moreover, we also investigate how the phase shift parameter and the dissipation rates influence the routing probability in a third level quantum channel. Our work provides a robust proposal for harvesting the potential of quantum networks in the future.}, archive = {J_PRA}, author = {Jiafeng Wu and Xingmin Li}, doi = {10.1103/PhysRevA.111.033706}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033706}, shortjournal = {Phys. Rev. A}, title = {Multilevel quantum routing of single photons with whispering-gallery resonators}, volume = {111}, year = {2025}, }
• (2025). Testing the coherent-state description of radiation fields. PRA, 111(3), 033705. (www)

  @article{ , abstract = {We propose simple quantitative criteria, based on counting statistics in resonant harmonic detectors, that probe the quantum mechanical character of radiation fields. They provide, in particular, practical means to test the null hypothesis that a given field is “maximally classical,” i.e., accurately described by a coherent state. We suggest circumstances in which that hypothesis plausibly fails, notably including gravitational radiation involving nonlinear or stochastic sourcing.}, archive = {J_PRA}, author = {Sreenath K. Manikandan and Frank Wilczek}, doi = {10.1103/PhysRevA.111.033705}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033705}, shortjournal = {Phys. Rev. A}, title = {Testing the coherent-state description of radiation fields}, volume = {111}, year = {2025}, }
• (2025). Temporal cavities as temporal mode filters for optical information processing. PRA, 111(3), 033704. (www)

  @article{ , abstract = {Broadband temporal modes of pulsed optical fields have been recently recognized as very promising for photonic information processing and time-frequency metrology. Exploiting their full potential demands efficient and flexible tools for their manipulation. Among the tools demonstrated, surprisingly the most basic, a single-mode temporal filter, is missing. In this paper, we propose an experimentally feasible approach to realize a genuine single-mode temporal filter that is based on the concept of temporal cavity , a device with temporal mode-dependent resonances in the basis of temporal broadband modes. This functionality is achieved as the temporal-domain analogy of spatial-mode cleaner cavities. This device will enable robust temporal mode filtering and detection, opening new prospects in time-frequency metrology and multidimensional classical and quantum information processing.}, archive = {J_PRA}, author = {B. Dioum and S. Srivastava and M. Karpiński and G. Patera}, doi = {10.1103/PhysRevA.111.033704}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033704}, shortjournal = {Phys. Rev. A}, title = {Temporal cavities as temporal mode filters for optical information processing}, volume = {111}, year = {2025}, }
• (2025). Spin dynamics and noise spectrum for alkali-metal atoms of arbitrary polarization in the spin-exchange-relaxation-free regime. PRA, 111(3), 033703. (www)

  @article{ , abstract = {Theoretical studies on the spin dynamics of hot alkali-metal vapors typically require numerical simulations of the density-matrix equation, which is nonlinear because of spin-exchange collisions. In this study we derive a set of effective hyperfine Bloch equations (EHBEs) for systems with arbitrary polarization in the spin-exchange-relaxation-free (SERF) regime. These EHBEs provide an intuitive framework for understanding the spin dynamics in the SERF regime and yield simple solutions that are in excellent agreement with the results of density-matrix simulations. A stochastic EHBE model is created by adding spin noise caused by fundamental quantum fluctuations. This yields an optical-spin-noise spectrum that includes the intrinsic spin-projection noise and the backaction light-shift noise from Faraday rotation measurements. The spectrum is a summation of several absorptive and dispersive components, each of which has a clear physical origin and a simple algebraic expression. This provides a benchmark for calibrating future spin-squeezing experiments in the SERF regime.}, archive = {J_PRA}, author = {Yang Li and Xiangyu Li and Tingxuan Guo and Kaifeng Zhao}, doi = {10.1103/PhysRevA.111.033703}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033703}, shortjournal = {Phys. Rev. A}, title = {Spin dynamics and noise spectrum for alkali-metal atoms of arbitrary polarization in the spin-exchange-relaxation-free regime}, volume = {111}, year = {2025}, }
• (2025). Advanced manipulation of surface plasmon resonance and the goos-hänchen shift in a coupler-free system. PRA, 111(3), 033702. (www)

  @article{ , abstract = {We present a surface plasmon resonance (SPR) system designed to operate without the need for a conventional coupler. The proposed SPR configuration consists of a simple two-layer structure with an upper metal layer and a lower atomic medium. Surface plasmon polaritons (SPPs) are readily excited when the real part of the permittivity of the atomic medium falls below unity, enabling an efficient and streamlined excitation process. The atomic medium dynamics is modulated by external fields, such as pump fields and microwaves, facilitating precise control over SPP excitation. We investigate the influence of the atomic medium, analyzing the lifetimes and propagation lengths for both gold and silver layers, while also addressing realistic factors such as dipole momenta, the potential for structural damage, and manufacturing imperfections. Additionally, we explore the Goos-Hänchen (GH) shift of the reflected light, noting an enhanced GH shift that aligns with optimal SPP excitation. Both negative and positive GH shifts are observed, with their directions and magnitudes modifiable through external parameters. This system provides a straightforward and viable method for SPP generation and controlled SPR and GH shift modulation, presenting significant potential for tunable optical devices in telecommunication. We expect these findings to contribute to the development of advanced systems with improved data transmission capabilities.}, archive = {J_PRA}, author = {Fazal Badshah and Aiman Sohrab and You-Lin Chuang and Ziauddin and Zeyun Shi and Shi-Hai Dong}, doi = {10.1103/PhysRevA.111.033702}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033702}, shortjournal = {Phys. Rev. A}, title = {Advanced manipulation of surface plasmon resonance and the goos-hänchen shift in a coupler-free system}, volume = {111}, year = {2025}, }
• (2025). Cavity-modified oscillating bound states with a Λ-type giant emitter in a linear waveguide. PRA, 111(3), 033701. (www)

  @article{ , abstract = {We study a system composed of a three-level giant atom (3GA), a waveguide initially in the vacuum state, and a single-mode cavity. The 3GA-cavity system is in a strong-coupling regime, and the distance between the coupling points is comparable to the coherent length of a spontaneously emitted photon. The dynamics of the 3GA and its radiative field in the waveguide for long times are analyzed in each subspace with only one excitation exchanged between the waveguide and the 3GA cavity. Besides the steady value, we also found an oscillatory character of the excited-state population, a signature of oscillating bound states which is generated by the superposition of two bound states in the continuum. The radiative field propagates in the cavitylike geometry formed by the coupling points. When one bound state is emergent, a sinelike interference pattern is visible for the emitted photon distribution in spacetime. An oscillatory character in time and a beat in space for the emitted photon distribution are observed when two bound states are emergent in a subspace. The wavelengths and the periods are controlled by the number of photons in the cavity.}, archive = {J_PRA}, author = {Ge Sun (孙葛 and Ya Yang (杨亚 and Jing Li (李静 and Jing Lu (卢竞 and Lan Zhou (周兰}, doi = {10.1103/PhysRevA.111.033701}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033701}, shortjournal = {Phys. Rev. A}, title = {Cavity-modified oscillating bound states with a Λ-type giant emitter in a linear waveguide}, volume = {111}, year = {2025}, }
• (2025). Categorizing coalescing quasinormal modes through far-field scattering patterns. PRA, 111(3), 033534. (www)

  @article{ , abstract = {Resonances in the form of quasinormal modes (QNMs) for open scattering systems can be generally identified in the far field through peaks of scattering spectra (e.g. cross sections of scattering, extinction, and absorption). Nevertheless, when the resonant frequencies of different QNMs are spectrally overlapped or sufficiently close, the scattering peaks merge and it then becomes extremely challenging to reveal the mode constituents underlying the scattering spectra solely in the far field. Here in this paper, we study open systems scattering electromagnetic plane waves, and reveal that spectrally close or even overlapped QNMs can be selectively excited through tuning incident directions and polarizations. Such a far-field technique can be further applied to categorize the nature of degenerate QNMs sharing identical complex eigenfrequencies (coalescent eigenvalues): at effectively Hermitian degeneracies (conical or Dirac points), the eigenvectors are not coalescent and thus the QNMs can still be selectively excited, producing distinct scattering patterns, while for non-Hermitian degeneracies (exceptional points) eigenvectors also coalesce and thus selective QNM excitation does not exist, leading to invariant scattering patterns. Our technique sheds light on the borderlands of Mie theory, QNMs, non-Hermitian photonics, and singular optics, which can empower new explorations and applications and cross-fertilize all those disciplines.}, archive = {J_PRA}, author = {Jingwei Wang and Yuntian Chen and Wei Liu}, doi = {10.1103/PhysRevA.111.033534}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033534}, shortjournal = {Phys. Rev. A}, title = {Categorizing coalescing quasinormal modes through far-field scattering patterns}, volume = {111}, year = {2025}, }
• (2025). Sampling the spatial coherence of light. PRA, 111(3), 033533. (www)

  @article{ , abstract = {We introduce an application of the Hartmann sensor, traditionally designed for wavefront sensing, to measure the coherence properties of optical signals. By drawing an analogy between the coherence matrix and the density matrix of a quantum system, we recast the sensor operation as a quantum estimation problem. We experimentally demonstrate its effectiveness in the regime where signals from different apertures significantly overlap, enabling information extraction beyond the reach of standard wavefront sensing.}, archive = {J_PRA}, author = {M. Vitek and M. Peterek and D. Koutný and M. Paúr and L. Motka and B. Stoklasa and Z. Hradil and J. Řeháček and L. L. Sánchez-Soto}, doi = {10.1103/PhysRevA.111.033533}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033533}, shortjournal = {Phys. Rev. A}, title = {Sampling the spatial coherence of light}, volume = {111}, year = {2025}, }
• (2025). Hybrid amplitude- and frequency-modulated mode locking of singly resonant optical parametric oscillators. PRA, 111(3), 033532. (www)

  @article{ , abstract = {We investigate a mode-locking regime in the singly resonant optical parametric oscillator (OPO) employing simultaneous amplitude and frequency modulation of the intracavity field. This OPO exhibits deterministic, “turn-key” formation of a stable, broadband, chirped frequency comb with high conversion efficiency. Comb-forming dynamics follow a simple phase-space dynamical model, governed by cavity dispersion and modulator chirp, which agrees closely with full numerical simulations. The comb exhibits fast, mode-hop-free tuning over the full gain window of the optical parametric amplification crystal, controlled by the modulator frequency. Conditions for comb stability, and techniques to enhance comb bandwidth through intentional phase mismatch and chirping, are investigated.}, archive = {J_PRA}, author = {Ryan Hamerly and Evan Laksono and Marc Jankowski and Edwin Ng and Noah Flemens and Myoung-Gyun Suh and Hideo Mabuchi}, doi = {10.1103/PhysRevA.111.033532}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033532}, shortjournal = {Phys. Rev. A}, title = {Hybrid amplitude- and frequency-modulated mode locking of singly resonant optical parametric oscillators}, volume = {111}, year = {2025}, }
• (2025). Multiangle lensless imaging based on spatial correlation. PRA, 111(3), 033531. (www)

  @article{ , abstract = {X-ray diffraction imaging is a powerful tool for exploring microscopic structures. However, conventional x-ray diffraction imaging using synchrotron radiation relies on high-brilliance sources, which hinders its wide application in laboratory scenarios. Here we propose a multiangle lensless imaging method that allows for the simultaneous measurement of the sample's Fourier information from different angles. The Fourier-transform diffraction pattern of the sample can be obtained through spatial correlation calculation. Benefiting from the multiangle strategy, a significant improvement in the quality of the diffraction pattern can be achieved. In proof-of-concept simulations, we have successfully extracted the sample's Fourier information and retrieved its spatial distribution with a radiation flux as low as 1 photon/ mrad 2 s . Our research may enrich the panel of laboratory-based x-ray diffraction imaging techniques.}, archive = {J_PRA}, author = {Qingyu Li and Zhijie Tan and De Wang and Hong Yu and Shensheng Han}, doi = {10.1103/PhysRevA.111.033531}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033531}, shortjournal = {Phys. Rev. A}, title = {Multiangle lensless imaging based on spatial correlation}, volume = {111}, year = {2025}, }
• (2025). Geometric phases in optics: Polarization of light propagating in helical optical fibers. PRA, 111(3), 033530. (www)

  @article{ , abstract = {The optical geometric phase (OGP) is directly associated with the polarization of light. We investigate the physical principles underlying the occurrence of the OGP for a single-mode light beam propagating in a single-mode optical fiber wound into a circular helix configuration, with and without stress-induced birefringence. The effects of the curvature and torsion of the helical fiber on the rotation of the polarization vector and the associated OGP are discussed. Analytic expressions are derived for the polarization vector and Stokes parameters for any initial polarization state of the light entering the helical fiber, as well as for the OGP of the light as a function of helix arclength. Additionally, the intensity of a superposition of the initial and final beams, which depends on the final OGP, is derived. Furthermore, the relationship between the OGP and the solid angle subtended by the tangent vector of the helix plotted on the Poincaré sphere is analyzed and the effects of fluctuations of the parameters specifying the geometry and the material characteristics of the helical fiber on the OGP are considered. We also point out that the OGP is a geometric phase and not a topological phase and therefore is not topologically protected against local perturbations which can adversely affect fault tolerance.}, archive = {J_PRA}, author = {Y. B. Band and Igor Kuzmenko and Yshai Avishai}, doi = {10.1103/PhysRevA.111.033530}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033530}, shortjournal = {Phys. Rev. A}, title = {Geometric phases in optics: Polarization of light propagating in helical optical fibers}, volume = {111}, year = {2025}, }
• (2025). Hartman effect and frequency-independent asymptote for the tunneling time of electromagnetic pulses through a plasma layer. PRA, 111(3), 033529. (www)

  @article{ , abstract = {Electromagnetic pulse propagation through a plasma layer below the plasma frequency is a genuine classical wave tunneling phenomenon strongly differing from tunneling in dielectric structures due to the specific dispersion of plasma. We consistently examine this phenomenon using direct numerical simulations of a time-dependent wave equation and show that in the low-frequency limit the tunneling time has the frequency-independent asymptotic 2 / ω p with ω p being the plasma frequency, in good correspondence with the analysis in stationary approximation. These results prove that radiation tunneling for plasma principally differs from the other electromagnetic tunneling phenomena which supposedly obey the inverse proportional dependence of the tunneling time on radiation frequency. The Hartman effect (saturation of the tunneling time with layer thickness) is demonstrated for pulse propagation as well with the saturated time getting closer to the asymptotic value as we move deeper into the tunneling regime. We also show that the reflected wave packet build-up gives an efficient tool for the tunneling problem and that reflection develops synchronously with transmission. Our theoretical calculations are supported by experiments with microwave tunneling through the electromagnetic band gap structure (electromagnetic crystal) based on gas discharge plasmas.}, archive = {J_PRA}, author = {Denis Novitsky and Maksim Usachonak and Leanid Simonchik and Sergey Gaponenko}, doi = {10.1103/PhysRevA.111.033529}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033529}, shortjournal = {Phys. Rev. A}, title = {Hartman effect and frequency-independent asymptote for the tunneling time of electromagnetic pulses through a plasma layer}, volume = {111}, year = {2025}, }
• (2025). Reservoir engineering for nonreciprocal photon coupling in three-dimensional helical waveguides. PRA, 111(3), 033528. (www)

  @article{ , abstract = {A three-dimensional (3D) photonic waveguide array is proposed to simulate the concept of reservoir-engineering-induced nonreciprocal transmission. The reservoir is offered by coupling two optical modes simultaneously to an additional mode with loss, yielding a jump operator, which is a coherent superposition of annihilation operators of these two modes. The waveguides are helically curved, leading to a synthetic gauge field for the propagating photons and consequently an adjustable phase factor for the jump operator. The unidirectional coupling is derived analytically and verified numerically, and an intuitive interpretation is provided. Furthermore, the model is extended to a periodic lattice, where asymmetric hopping arises and unidirectional hopping appears for certain Bloch wave vectors. Our design is based on real-experiment parameters, which can be readily implemented by femtosecond laser direct writing of 3D waveguides in silica.}, archive = {J_PRA}, author = {Yuan Liu and Shuyi Wang and Linhan Lin}, doi = {10.1103/PhysRevA.111.033528}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033528}, shortjournal = {Phys. Rev. A}, title = {Reservoir engineering for nonreciprocal photon coupling in three-dimensional helical waveguides}, volume = {111}, year = {2025}, }
• (2025). Influence of conjugated structure for tunable molecular plasmons in peropyrene and its derivatives. PRA, 111(3), 033527. (www)

  @article{ , abstract = {Advances in research have sparked an increasing curiosity in understanding the plasmonic excitation properties of molecular-scale systems. Polycyclic aromatic hydrocarbons, as the fundamental building blocks of graphene, have been documented to possess plasmonic properties through experimental observations, making them prime candidates for investigation. By doping different elements, the conjugated structure of the molecule can be altered. In this study, the plasmonic excitation properties influenced by conjugated structures in peropyrene and its derivatives are investigated through first-principles calculations that combine the plasmonicity index, generalized plasmonicity index, and transition contribution map. For molecular plasmonic excitation, the conjugated structure can influence the oscillation modes of valence electrons, which is pivotal in yielding distinct field enhancement characteristics. Furthermore, charge doping can lead to a certain degree of alteration in the conjugated structures, and the doping of elements will result in varying degrees of such alteration, thereby initiating different trends in the evolution of plasmonic resonance. This further enhances the tunability of molecular plasmonic resonance. The results provide novel insights into the development and utilization of molecular plasmonic devices in practical applications.}, archive = {J_PRA}, author = {Haoran Liu and Nan Gao and Yurui Fang}, doi = {10.1103/PhysRevA.111.033527}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033527}, shortjournal = {Phys. Rev. A}, title = {Influence of conjugated structure for tunable molecular plasmons in peropyrene and its derivatives}, volume = {111}, year = {2025}, }
• (2025). Ultrahigh-resolution angle sensing based on a laser-frequency measurement. PRA, 111(3), 033526. (www)

  @article{ , abstract = {Precision measurement of small angles is essential in both industrial applications and high-precision scientific research. Although a traditional angle interferometer is widely employed, its resolution is fundamentally constrained. In this paper, we introduce an innovative method for ultrahigh-resolution angle measurement based on the laser frequency measurement, directly converting angle measurement into frequency measurement, which can be traced to the most accurate frequency standards. The proposed scheme integrates a frequency selection element interference filter (IF) with a transparent solid or liquid medium, forming a highly sensitive measurement system. This system capitalizes on the sensitivity of laser frequency to changes in cavity length and the incidence angle of the IF. As a result, even minute angular rotations of the sensor induce detectable shifts in the laser's frequency. The angular displacement is inferred directly by analyzing the frequency difference between a test signal and a reference, with this difference arising from variations in the incident angle at the IF and the corresponding changes in cavity length due to medium rotation. Theoretical analysis suggests that this method can achieve a resolution better than 10 − 4 arcsecond ( 10 − 8 deg ), representing an order of magnitude improvement over existing techniques.}, archive = {J_PRA}, author = {Pengyuan Chang and Xufeng Ling and Haoran Zhong and Pengfei Guo and Xinrong Huang and Duo Pan and Jingbiao Chen}, doi = {10.1103/PhysRevA.111.033526}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033526}, shortjournal = {Phys. Rev. A}, title = {Ultrahigh-resolution angle sensing based on a laser-frequency measurement}, volume = {111}, year = {2025}, }
• (2025). Optical analogs of bloch-zener oscillations in binary waveguide arrays: Wave-number-evolution perspective. PRA, 111(3), 033525. (www)

  @article{ , abstract = {We study optical analogs of Bloch oscillations and Zener tunneling in binary waveguide arrays (BWAs) with the help of the wave-number-based approach. We analytically derive two very simple laws describing the evolution of the central wave numbers of beams in BWAs that help us analytically obtain the propagation distances where the Zener tunneling takes place due to the interband transition and the distances where beams reach the turning points and change direction. These distances just depend on the strength of the linear potential and the initial wave number of input beams. We also show that nonlinearity of the Kerr type has a detrimental influence on the Bloch-Zener oscillations.}, archive = {J_PRA}, author = {Minh C. Tran and Truong X. Tran}, doi = {10.1103/PhysRevA.111.033525}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033525}, shortjournal = {Phys. Rev. A}, title = {Optical analogs of bloch-zener oscillations in binary waveguide arrays: Wave-number-evolution perspective}, volume = {111}, year = {2025}, }
• (2025). Design of multifunctional nonlinear optical loop mirrors. PRA, 111(3), 033524. (www)

  @article{ , abstract = {A nonlinear optical loop mirror (NOLM) is an optical component commonly used to shape the temporal profile of guided light waves in a large number of optical systems. Although the NOLM is an inherently multifunctional device, in all its practical applications this device is still designed to provide a single functionality. Here we show that the NOLM can be designed to provide multiple functions and make a complex optical system more efficient and competitive. In particular, we show that in a mode-locked laser cavity the NOLM can be designed to serve as a mode-locking element in the transient regime of the laser, and as a power regulator in the stationary regime. While the conventional architecture of a NOLM is usually built from nontunable components, our multifunctional NOLM is built with tunable components offering great flexibility in setting the device's transfer function, and therefore the ability to access different types of optical functions such as pulse regeneration, power regulation, or mode locking in laser cavities.}, archive = {J_PRA}, author = {A. Malfondet and M. Deroh and P. Tchofo Dinda and G. Millot}, doi = {10.1103/PhysRevA.111.033524}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033524}, shortjournal = {Phys. Rev. A}, title = {Design of multifunctional nonlinear optical loop mirrors}, volume = {111}, year = {2025}, }
• (2025). Mode hitching in traveling-wave optical parametric amplification. PRA, 111(3), 033523. (www)

  @article{ , abstract = {Optical parametric amplifiers (OPAs) in traveling-wave configuration can generate localized spatial quantum correlations between a signal and an idler beam, a useful resource for quantum imaging. To characterize the spatial correspondence between the optical modes of the signal and those of the idler, we look at the classical transverse dynamics of these beams when they propagate in a generic thick OPA at a nominally small angle. In these conditions, the beams tend to copropagate while maintaining a fixed separation, a phenomenon that we term hitching. We develop a model for hitching, validated by a numerical simulation, and provide an experimental demonstration using four-wave mixing in a hot atomic vapor. They show that the OPA gain is the primary influence on the final hitching distance. These results have implications for the generation of multi-spatial-mode squeezed light for quantum imaging applications, where the exact spatial correlations between the quantum fluctuations of the signal and the idler are of prime importance.}, archive = {J_PRA}, author = {Joseph Kelly and Eleanor Fradgley and Lida Zhang (张理达 and Vincent Boyer}, doi = {10.1103/PhysRevA.111.033523}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033523}, shortjournal = {Phys. Rev. A}, title = {Mode hitching in traveling-wave optical parametric amplification}, volume = {111}, year = {2025}, }
• (2025). Antihyperbolic surface waves on hyperbolic metasurfaces. PRA, 111(3), 033522. (www)

  @article{ , abstract = {Hyperbolic metasurfaces exhibit the ability to support surface waves with hyperbolic isofrequency contours (i.e., hyperbolic eigenmodes), offering an exceptional platform for enhancing light-matter interactions. In addition to hyperbolic eigenmodes, hyperbolic metasurfaces can also support the propagation of surface-wave eigenmodes with an antihyperbolic isofrequency contour (i.e., antihyperbolic eigenmodes). In this work, we explore the lesser-known antihyperbolic eigenmodes, highlighting their unique polarization properties compared to hyperbolic eigenmodes. We find that the antihyperbolic eigenmodes at the vertices of the antihyperbolic isofrequency contour and the hyperbolic eigenmodes at the vertices of the hyperbolic isofrequency contour could have purely linear but opposite polarizations. Moreover, we reveal that the manipulation of metasurface's surface conductivity can provide a feasible route to realize the polarization conversion between these linearly polarized antihyperbolic and hyperbolic eigenmodes. That is, the s -polarized antihyperbolic eigenmodes would be changed to p -polarized ones, while the p -polarized hyperbolic eigenmodes are changed to s -polarized ones. These findings offer a pathway to selectively excite either hyperbolic or antihyperbolic eigenmodes, enabling control over subwavelength light propagation. Our results provide insights into polarization manipulation and potential applications in nano-optics and photonic devices.}, archive = {J_PRA}, author = {Chenxu Bian and Xinyan Zhang and Wenbo Ma and Xuhuinan Chen and Hongsheng Chen and Tony Low and Xiao Lin}, doi = {10.1103/PhysRevA.111.033522}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033522}, shortjournal = {Phys. Rev. A}, title = {Antihyperbolic surface waves on hyperbolic metasurfaces}, volume = {111}, year = {2025}, }
• (2025). Unbounded tellegen response in media with multiple resonances. PRA, 111(3), 033521. (www)

  @article{ , abstract = {The Tellegen response is a special type of nonreciprocal magnetoelectric coupling which has long remained elusive in photonics and is extremely weak in condensed matter. It is widely accepted that the Tellegen coefficient is restricted by χ 2 < ε μ , where ɛ and μ are the permittivity and permeability of the material. Here, we demonstrate that this restriction is lifted in the medium with several close resonances, which provides a theoretical foundation for a giant Tellegen response and enhanced nonreciprocal phenomena.}, archive = {J_PRA}, author = {Timur Z. Seidov and Maxim A. Gorlach}, doi = {10.1103/PhysRevA.111.033521}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033521}, shortjournal = {Phys. Rev. A}, title = {Unbounded tellegen response in media with multiple resonances}, volume = {111}, year = {2025}, }
• (2025). Operator scattering theory for multilayer cylinders comprising gyrotropic materials and its application to weyl semimetals. PRA, 111(3), 033520. (www)

  @article{ , abstract = {Weyl semimetals are prospective materials to tailor light-matter interaction due to their gyrotropic properties caused by a couple of chiral Weyl points. Here, we study electromagnetic scattering characteristics from infinitely long multilayer cylindrical particles containing Weyl semimetal layers. We develop a modification of operator scattering theory that uses evolution operators to describe a set of layers. We reveal asymmetry in differential scattering cross sections stemming from the axion term of Weyl semimetal permittivity tensor, trace the radiation pattern change for multilayer particles, analyze the interference of lower multipoles with perspective of generalizing the Kerker effect, and carry out multipolar decomposition of the scattered radiation. Both the scattering theory and the numerical results can be useful for device engineering in nanophotonics.}, archive = {J_PRA}, author = {Michael M. Kharton and Lei Gao and Dongliang Gao and Andrey Novitsky}, doi = {10.1103/PhysRevA.111.033520}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033520}, shortjournal = {Phys. Rev. A}, title = {Operator scattering theory for multilayer cylinders comprising gyrotropic materials and its application to weyl semimetals}, volume = {111}, year = {2025}, }
• (2025). Modulational instability induced by mode perturbation in normal-dispersion microresonators. PRA, 111(3), 033519. (www)

  @article{ , abstract = {Mode coupling has been proven to be an effective method for initiating modulational instability (MI) in a normal-dispersion microresonator. In various mode-coupling systems, mode loss perturbation occurs alongside mode frequency perturbation. In this study, we present a detailed analysis of MI induced by either loss or frequency perturbations added to the pump mode of a normal-dispersion cavity. By distinguishing the individual contributions of frequency and loss perturbations to MI gain, we demonstrate that, in addition to the widely studied frequency perturbation, the introduction of an additional loss to the pump mode can also induce MI even without frequency perturbation, enabling the spontaneous excitation of frequency combs. The effects of pump mode perturbations in various mode-coupling schemes are compared, revealing that loss perturbation has a more significant impact when the pump power is relatively low or when the auxiliary mode experiences a sufficiently higher loss than the main mode. Our findings provide an alternative perspective on illustrating the underlying mechanisms of normal-dispersion Kerr frequency combs generation aided by mode perturbation.}, archive = {J_PRA}, author = {Bofan Yang and Shangyuan Li and Xiaoping Zheng and Xiaoxiao Xue}, doi = {10.1103/PhysRevA.111.033519}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033519}, shortjournal = {Phys. Rev. A}, title = {Modulational instability induced by mode perturbation in normal-dispersion microresonators}, volume = {111}, year = {2025}, }
• (2025). Optomechanical non-gaussian quantum steering and remote preparation of large-size motional schrödinger cat states. PRA, 111(3), 033518. (www)

  @article{ , abstract = {In this paper, we present a scheme for remotely generating large-size motional Schrödinger cat states in cavity optomechanical (OM) systems with non-Gaussian quantum steering of continuous variables. We consider that the output field from the OM cavity undergoes three typical kinds of multiphoton operations: multiphoton subtraction, multiphoton addition, or multiphoton catalysis, followed by homodyne detection. We first demonstrate that these multiphoton operations can lead to non-Gaussian OM quantum steerable correlations, which are unveiled by the subsequent homodyne detection with a Fisher-information-based steering criterion. It is found that the non-Gaussian steering is obviously enhanced with an increasing number n of photons in the multiphoton operations, which, as we show, fails to be revealed with the well-known Reid's steering criterion. It therefore suggests that the Fisher-information-based criterion is more effective for witnessing non-Gaussian quantum steering. We next show that the strong OM steering enables the remote preparation of large-size Schrödinger odd or even cat states of the mechanical oscillator by the homodyne detection. Accordingly, the amplitudes of the cat states also increase significantly with the photon number n , particularly in the cases of multiphoton subtraction and addition. Our results reveal the properties of non-Gaussian steering generated by multiphoton operations, and the large cat states of macroscopic mechanical resonators hold promise for fundamental tests in quantum mechanics and practical applications in quantum science.}, archive = {J_PRA}, author = {Miaomiao Wei and Huatang Tan}, doi = {10.1103/PhysRevA.111.033518}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033518}, shortjournal = {Phys. Rev. A}, title = {Optomechanical non-gaussian quantum steering and remote preparation of large-size motional schrödinger cat states}, volume = {111}, year = {2025}, }
• (2025). Responsivity and stability of nonlinear exceptional point lasers with saturable gain and loss. PRA, 111(3), 033517. (www)

  @article{ , abstract = {The responsivity of perturbation sensing can be effectively enhanced by using higher-order exceptional points (EPs) due to their nonlinear response to frequency perturbations. However, experimental realization can be difficult due to the stringent parameter conditions associated with these points. In this work we study an EP laser composed of two coupled nonlinear resonators that uses nonlinearity to simplify these tuning requirements. This system demonstrates a distinct cube-root response in the steady-state lasing frequency, with a constant of proportionality that depends on the distribution of linear and saturable gain and loss. This design freedom enables several orders of magnitude higher responsivity than systems with a single nonlinear resonator, which have been previously explored. Maximizing responsivity also improves the robustness of sensing performance against parametric errors. These features are derived from coupled-mode theory and further supported by steady-state ab initio laser theory results at several nonlinear EPs. Through linear stability analysis, we also identify regions of instability within the class-A regime that arise due to mode competition, which can be induced by asymmetric passive losses. In the class-B regime, we show that the interplay between gain dynamics and detuning can lead to restabilization at slow relaxation rates or higher interresonator coupling rates. This regime could be used to increase the maximum achievable responsivity of the system.}, archive = {J_PRA}, author = {Todd Darcie and J. Stewart Aitchison}, doi = {10.1103/PhysRevA.111.033517}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033517}, shortjournal = {Phys. Rev. A}, title = {Responsivity and stability of nonlinear exceptional point lasers with saturable gain and loss}, volume = {111}, year = {2025}, }
• (2025). Bound states in the continuum via singular transfer matrices. PRA, 111(3), 033516. (www)

  @article{ , abstract = {Bound states in the continuum (BICs) in photonic crystal slabs are Bloch eigenstates with zero linewidth and infinite lifetimes, though practical devices exhibit quasi-BICs due to geometric imperfections and material losses. Despite these limitations, quasi-BICs still maintain high Q factors, enabling applications in lasing, high harmonic generation, and biosensing. The selection of specific geometrical or material parameters is essential to achieve devices that sustain BICs. Our work presents a framework for generating BICs by driving the transfer matrix of a device to a singular point, where it becomes noninvertible, thus defining the BIC states. This method applies to nonhomogeneous, tessellated structures and is supported by closed-form analytical expressions, facilitating efficient parametric exploration. The proposed framework aligns with the conjecture that the most robust BICs are associated with topological defects in specific parameter spaces. We identify regions in parameter space supporting BICs and validate our theoretical predictions through full-wave numerical simulations. The framework extends to a wide range of photonic structures, enabling robust design and optimization of devices for diverse applications.}, archive = {J_PRA}, author = {Ovidiu-Zeno Lipan and Aldo De Sabata}, doi = {10.1103/PhysRevA.111.033516}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033516}, shortjournal = {Phys. Rev. A}, title = {Bound states in the continuum via singular transfer matrices}, volume = {111}, year = {2025}, }
• (2025). Geometric-stair-shaped super-regular breathers induced by PT-symmetric nonlinearity. PRA, 111(3), 033515. (www)

  @article{ , abstract = {We numerically discover an alternative type of super-regular breather (SRB) that exhibits an asymmetric geometric stair structure in its spatiotemporal amplitude distribution. This kind of geometric-stair-shaped SRB is induced by the PT -symmetric nonlocal nonlinearity and is effectively excited by localized periodic perturbations on a plane wave. By adjusting the amplitude and phase differences of the initial perturbations, we can control the direction and rate of its ascent or descent. Interestingly, due to the presence of PT -symmetric nonlinearity, applying a spatial offset to the initial wave can excite an SRB with a significantly larger peak value, which can reach over 100 times the amplitude of the plane wave. Our results provide a method for exciting SRBs with spatial asymmetry and can offer different insights for the experimental observation of extremely asymmetric modulation instability phenomena.}, archive = {J_PRA}, author = {Xin Li and Peng Gao and Wenjun Liu}, doi = {10.1103/PhysRevA.111.033515}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033515}, shortjournal = {Phys. Rev. A}, title = {Geometric-stair-shaped super-regular breathers induced by PT-symmetric nonlinearity}, volume = {111}, year = {2025}, }
• (2025). Optical levitation of arrays of microspheres. PRA, 111(3), 033514. (www)

  @article{ , abstract = {Levitated optomechanical systems are rapidly becoming leading tools for precision sensing of forces and accelerations acting on particles in the femtogram to nanogram mass range. These systems enable a high level of control over the sensor's center-of-mass motion, rotational degrees of freedom, and electric charge state. For many sensing applications, extending these techniques to arrays of sensors enables rejection of correlated noise sources and increases sensitivity to interactions that may be too rare or weak to detect with a single particle. Here we present techniques capable of trapping defect-free, two-dimensional arrays of more than 25 microspheres in vacuum. These techniques provide independent control of the optical potential for each sphere. Simultaneous imaging of the motion of all spheres in the array is demonstrated using camera-based imaging, with optimized object tracking algorithms reaching a displacement sensitivity below 1 nm/ Hz . Such arrays of levitated microspheres may find applications ranging from inertial sensing to searches for weakly interacting particles such as dark matter.}, archive = {J_PRA}, author = {Benjamin Siegel and Gadi Afek and Cecily Lowe and Jiaxiang Wang and Yu-Han Tseng and T. W. Penny and David C. Moore}, doi = {10.1103/PhysRevA.111.033514}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033514}, shortjournal = {Phys. Rev. A}, title = {Optical levitation of arrays of microspheres}, volume = {111}, year = {2025}, }
• (2025). Exceptional-point restoration and fast-light edge states in photonic crystal waveguides with glide and time-reversal symmetries. PRA, 111(3), 033513. (www)

  @article{ , abstract = {Exceptional points (EPs) in propagation states induce intriguing properties as the group velocities. However, superluminal propagation near EPs is challenging due to the smoothing caused by symmetry breaking. In this study, we propose a photonic crystal waveguide design with glide and time-reversal symmetry and derive an effective Hamiltonian to realize fast-light edge states. We adopt a systematic method to generate EPs in edge states by introducing non-Hermitian perturbations to Dirac points guaranteed by glide symmetry, which ensures that EP modes are free from out-of-plane radiation losses. We identify the conditions for exact EP restoration and provide an analytical solution to offset the EP smoothing due to symmetry breaking, which significantly reduces the group velocity contrast. A glide symmetry of the photonic crystal waveguide allows us to derive the effective Hamiltonian in a simple form, and the EPs can be restored by adjusting the real part of the permittivity. Furthermore, we design a feasible photonic crystal slab waveguide incorporating graphene as the absorbing material, and numerically demonstrate a group velocity reaching v g = 3.3 c near the EP, which is up to 25 times that of the original structure. The proposed setup based on non-Hermitian photonics paves the way for the realization of superluminal devices in nanophotonics. In addition, the method for restoring EPs also addresses challenges in the phenomena arising from non-Hermitian properties.}, archive = {J_PRA}, author = {Takahiro Uemura and Taiki Yoda and Yuto Moritake and Shutaro Otsuka and Kenta Takata and Masaya Notomi}, doi = {10.1103/PhysRevA.111.033513}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033513}, shortjournal = {Phys. Rev. A}, title = {Exceptional-point restoration and fast-light edge states in photonic crystal waveguides with glide and time-reversal symmetries}, volume = {111}, year = {2025}, }
• (2025). Phase-controlled higher-order exceptional points and nonreciprocal transmission in an optomechanical system. PRA, 111(3), 033512. (www)

  @article{ , abstract = {The higher-order exceptional point (EP) and reconfigurable nonreciprocal transmission have been investigated in a four-mode optomechanical system, consisting of two passive cavities and two active mechanical modes. A phase diagram of multiple EPs including higher than third-order EP is divided into different regions with a certain EP pattern, the variation of which with the parameters are demonstrated by analyzing the eigenspectrum of the system. In particular, the emergence, coalescence, and separation of the multiple EPs are strongly dependent on the relative phase between different paths in the cavity optomechanics system. On the other hand, the optical nonreciprocity with a large isolation about 50 dB can be achieved by incorporating mechanical gain. It is shown that the optical nonreciprocity at the relative phase φ exhibits exchange symmetry with that in the case of the phase 2 π − φ . Additionally, the system presents a special nonreciprocal spectra at different EPs, which can provide a means to identify the type of multiple EPs. Our scenario shows that the optical nonreciprocity associated with the multiple EPs may provide a useful platform for realizing optical communications and exploring the physics related to the higher-order EPs.}, archive = {J_PRA}, author = {Yi-Bing Qian and Ya-Ya Deng and Lei Tang and Deng-Gao Lai and Bang-Pin Hou}, doi = {10.1103/PhysRevA.111.033512}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033512}, shortjournal = {Phys. Rev. A}, title = {Phase-controlled higher-order exceptional points and nonreciprocal transmission in an optomechanical system}, volume = {111}, year = {2025}, }
• (2025). Recovery of microcavity spectral readout distortion induced by fast scanning. PRA, 111(3), 033511. (www)

  @article{ , abstract = {Optical microcavities have attracted increasing attention for high-performance sensing, where a laser scans the resonance, providing high-resolution and time-sensitive measurements. However, rapid resonance scanning can lead to readout distortions, affecting the accuracy of high-speed sensing. Traditional methods have attempted to alleviate this distortion by examining the relationship between the ringing behavior and the scanning speed or by reconstructing the steady-state spectra. Yet the complexity of distorted readouts often obscures their correlation with well-established steady-state spectra, presenting a significant challenge for transient sensing. In this study, we revisit electromagnetic theory in microcavities and discover that ringing distortion stems from quadratic phase interference between light emitted from the microcavity and the input. Remarkably, this quadratic phase solely arises from the spectral scanning speed, indicating a universality across microcavity types. As a result, the proposed method enables the recovery of a complex steady-state spectrum from a distorted readout at an arbitrary scanning speed after compensating for the introduced phases. This method bridges the gap between transient and steady-state spectra by harnessing the dimensions of spectral scanning speed, offering a promising avenue for high-speed sensing, precision measurement, and advanced scientific research.}, archive = {J_PRA}, author = {Lei Chen and Bei-Bei Li and Yu Zhong and Weibin Zhong and Xiangyang Gong and Gui-Shi Liu and Yaofei Chen and Yunhan Luo and Zhe Chen}, doi = {10.1103/PhysRevA.111.033511}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033511}, shortjournal = {Phys. Rev. A}, title = {Recovery of microcavity spectral readout distortion induced by fast scanning}, volume = {111}, year = {2025}, }
• (2025). Frequency up-conversion of midinfrared signals from resonantly enhanced nonlinear spectroscopy. PRA, 111(3), 033510. (www)

  @article{ , abstract = {We experimentally demonstrated and thoroughly investigated the up-conversion of midinfrared signals from nonlinear spectroscopy in a molecular gas to the regime of shorter wavelength to improve the features and applicability of such sensitive techniques for the detection of molecular species. In particular, we apply sum-frequency mixing (SFM) of weak signals from resonantly enhanced third-harmonic-generation (THG) spectroscopy with strong nanosecond pump pulses, implemented in a conventional bulk nonlinear crystal. The conversion efficiency reaches 26%, i.e., a substantial fraction of the THG signal photons from the molecular sample at long midinfrared wavelength are converted to a SFM signal pulse at much shorter wavelength in the near-ultraviolet regime. This permits detection of the SFM signal beam on a standard photomultiplier tube with large amplification and aperture rather than detection of the midinfrared THG signal on an avalanche photodiode with much lower amplification and smaller aperture. The measure also considerably improves the signal-to-noise ratio by more than a factor of 20, which in turn pushes the particle detection limit by an order of magnitude towards much lower gas pressures.}, archive = {J_PRA}, author = {Benedikt Burger and Oskar Ernst and Thomas Halfmann}, doi = {10.1103/PhysRevA.111.033510}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033510}, shortjournal = {Phys. Rev. A}, title = {Frequency up-conversion of midinfrared signals from resonantly enhanced nonlinear spectroscopy}, volume = {111}, year = {2025}, }
• (2025). Decay rates of optical modes unveiling the island structures in mixed phase space. PRA, 111(3), 033509. (www)

  @article{ , abstract = {We explore the decay rates of optical modes in asymmetric microcavities with mixed phase space across a wide range of wavelengths that extend deep into the semiclassical, i.e., short-wavelength, limit. Implementing an efficient numerical method, we computed 10 6 eigenmodes and discovered that certain decay rates form sequential separate branches with increasing wave number that eventually merge into smooth curves. The analysis of the localization properties and Husimi distributions reveals that each branch corresponds to a periodic orbit in the closed classical system. Our findings show that these decay rates gradually resolve the structure of the islands in mixed phase space as we approach the short-wavelength limit. We present an effective semiclassical model incorporating wave-number-dependent localization, Fresnel reflection, and the Goos-Hänchen shift and demonstrate that these effects are crucial in accounting for the observed branches of decay rate curves.}, archive = {J_PRA}, author = {Chang-Hwan Yi and Barbara Dietz and Jae-Ho Han and Jung-Wan Ryu}, doi = {10.1103/PhysRevA.111.033509}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033509}, shortjournal = {Phys. Rev. A}, title = {Decay rates of optical modes unveiling the island structures in mixed phase space}, volume = {111}, year = {2025}, }
• (2025). Symmetry-protected lossless modes in dispersive time-varying media. PRA, 111(3), 033507. (www)

  @article{ , abstract = {We give an exact application of a recently developed, operator-based theory of wave propagation in dispersive, time-varying media. Using this theory, we find that the usual symmetry of complex conjugation plus changing the sign of the frequency, required for real-valued fields, implies that the allowed propagation constants in the medium are either real valued or come in conjugate pairs. The real-valued wave numbers are only present in time-varying media, implying that time variation leads to modes that are free from dissipation, even in a lossy medium. Moreover, these symmetry-unbroken waves lack a defined propagation direction. This can lead to a divergent transmission coefficient when waves are incident onto a finite, time-varying slab. The techniques used in this paper present a route toward further analytic applications of this operator formalism.}, archive = {J_PRA}, author = {Calvin M. Hooper and James R. Capers and Ian R. Hooper and Simon A. R. Horsley}, doi = {10.1103/PhysRevA.111.033507}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033507}, shortjournal = {Phys. Rev. A}, title = {Symmetry-protected lossless modes in dispersive time-varying media}, volume = {111}, year = {2025}, }
• (2025). Bifurcations of nonlinear dynamics in coupled twin spin masers. PRA, 111(3), 033506. (www)

  @article{ , abstract = {Spin masers are a prototype nonlinear dynamic system. They undergo a bifurcation at a critical amplification factor, transiting into a limit cycle phase characterized by a Larmor precession around the external bias magnetic field, thereby serving as a key frequency reference for precision measurements. Recently, a system of coupled twin spin masers placed in dual bias magnetic fields, involving simultaneously two intrinsic Larmor frequencies, has been studied in Commun. Phys. 8 , 41 (2025) . Compared with previous spin masers, this setup exhibits new attractors such as quasiperiodic orbits and chaos in addition to the usual limit cycles and the trivial no signal fixed point. The richer dynamic phases imply the existence of bifurcations, whose nature has not been fully analyzed. Here, to shed light on the nature of the bifurcations, we turn to a closely related system and systematically study the various bifurcations therein along different routes in parameter space. We identify the bifurcations as of the types including pitchfork, Hopf, homoclinic bifurcations, and saddle-node bifurcations of cycles. By both analytical and numerical methods, we reveal how various attractors interplay with each other and change their stability. We also quantitatively evaluate the locations where these bifurcations occur by tracking the both stable and even not easily detected unstable limit cycles. These findings deepen our understanding of the underlying mechanisms resulting in the rich dynamic phases in the coupled twin spin masers.}, archive = {J_PRA}, author = {Tishuo Wang and Zhenhua Yu}, doi = {10.1103/PhysRevA.111.033506}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033506}, shortjournal = {Phys. Rev. A}, title = {Bifurcations of nonlinear dynamics in coupled twin spin masers}, volume = {111}, year = {2025}, }
• (2025). Enhancing macroscopic multimode entanglement through many-body interactions in cavity magnomechanics. PRA, 111(3), 033505. (www)

  @article{ , abstract = {Coherent control of many-body interactions allows the possibility of generating complex quantum states for future quantum technology. Specifically, the quantum states of the center-of-mass motion of a trapped macroscopic particle, being highly isolated from the environment, in hybrid systems is a potential platform for testing macroscopic quantum mechanics. We present a many-body interaction platform to enhance multimode Gaussian entanglement where the center-of-mass motion is coupled to a magnon through a microwave field. The strong and ultrastrong cavity-magnon couplings allow the generation of simultaneous entanglement in all bipartitions, without any pairwise entanglement, through numerical optimization of parameters, akin to quantum phase transitions in spin systems. Moreover, the ultrastrong coupling facilitates the generation of such multimode entanglement for a low-frequency oscillator in the unresolved sideband. This scheme provides a potential platform to explore the quantum effects in a large massive oscillator and paves the way for creating complex states for quantum simulation, sensing, exploring exotic quantum phases, and quantum computing.}, archive = {J_PRA}, author = {Anil Kumar Chauhan and A. Kani and Jason Twamley}, doi = {10.1103/PhysRevA.111.033505}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033505}, shortjournal = {Phys. Rev. A}, title = {Enhancing macroscopic multimode entanglement through many-body interactions in cavity magnomechanics}, volume = {111}, year = {2025}, }
• (2025). Coupled-mode phase matching on a silicon chip. PRA, 111(3), 033504. (www)

  @article{ , abstract = {Phase matching lies at the heart of the classical nonlinear process for frequency conversion and all-optical processing, as well as the spontaneous parametric process for the quantum light sources generation. In this work, we experimentally demonstrate the coupled-mode phase-matching (CMPM) engineered by the two-paralleled-coupled waveguides on a silicon-on-insulator (SOI) chip, extending the converted beam and entangled photons to the S band and L band. We measure the spectrum and efficiency of wavelength conversion, which successfully validates the designed CMPM scheme. We further measure the pairs generation rate of the biphoton based on the spontaneous four-wave mixing, which features a narrow bandwidth consistent well with the theoretical simulations. Multiple CMPM conditions can be achieved by exploiting the combinations of even and odd supermodes of the coupled system and tuned by designing a proper coupling gap between the two waveguides. The CMPM can extend the FWM nonlinear process ranging from the O band to the U band and even the midinfrared, enriching the working wavelength to a large extent. In addition, the CMPM features a discrete-band narrow bandwidth, which will greatly enhance the encoding density of frequency and the spectral purity of generated photon. In addition, our methods can be easily extended to a wide range of materials such as silicon nitride, dispensing with the dispersion engineering for phase matching.}, archive = {J_PRA}, author = {Chao Wu and Pingyu Zhu and Miaomiao Yu and Weihong Luo and Qilin Zheng and Kaikai Zhang and Yingwen Liu and Ping Xu}, doi = {10.1103/PhysRevA.111.033504}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033504}, shortjournal = {Phys. Rev. A}, title = {Coupled-mode phase matching on a silicon chip}, volume = {111}, year = {2025}, }
• (2025). Enhanced electromechanical entanglement in a coupled optoelectromechanical system. PRA, 111(3), 033503. (www)

  @article{ , abstract = {Quantum entanglement, as a central concept in quantum theory, plays a crucial role in understanding the fundamentals of quantum mechanics and is widely studied in advanced practical technological applications. We study the behavior of bipartite and tripartite entanglement in a hybrid optoelectromechanical system consisting of a pair of coupled cavities, a large mass membrane, and a low-frequency L C resonator. Within the experimentally achievable parameters, we observe a significant enhancement of the electromechanical entanglement, which directly originates from the electromechanical coupling. We also show that entanglement between subsystems can be manipulated by tuning the cavity-cavity coupling rate. Furthermore, we significantly enhance the robustness of electromechanical entanglement against thermal noise. The enhancement of electromechanical entanglement in this system will facilitate the investigation of quantum theory applications on more macroscopic scales, such as medical imaging, quantum communication, and astronomical signal detection.}, archive = {J_PRA}, author = {Xuan Ma and Yikyung Yu and Xue Han and Hong-Fu Wang and Shou Zhang}, doi = {10.1103/PhysRevA.111.033503}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033503}, shortjournal = {Phys. Rev. A}, title = {Enhanced electromechanical entanglement in a coupled optoelectromechanical system}, volume = {111}, year = {2025}, }
• (2025). Breather dynamics in an optomechanical array with staggered coupling. PRA, 111(3), 033502. (www)

  @article{ , abstract = {We present an approach toward generating highly controllable breathers, using an array of staggered optomechanical cavities that feature alternating coupling strengths. Four different types of breather states as well as stable two-soliton states are demonstrated to form in such an optomechanical array, thanks to the interplay between the photon-hopping induced tunneling effect and the photon-phonon coupling in the optomechanical cell. It is seen that both their photonic and phononic wave components manifest quasi-periodic oscillatory patterns and coherent localization. We unveil that such breather dynamics can be well controlled by adjusting the coupling strength, the cavity field decay, and the number of array cells. As a result, we observe an unusual odd-even lattice effect in that stable breathers are only available when the cell number is even. We anticipate that these findings from the staggered optomechanical configuration may expand the realm of cavity optomechanics, yielding promising applications such as on-chip manipulation of light propagation.}, archive = {J_PRA}, author = {Yuan Zhao and Yiheng Hou and Yu Wang and Zhuo Fan and Wei Peng and Qin Zhou and Siliu Xu and Shihua Chen}, doi = {10.1103/PhysRevA.111.033502}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033502}, shortjournal = {Phys. Rev. A}, title = {Breather dynamics in an optomechanical array with staggered coupling}, volume = {111}, year = {2025}, }
• (2025). Electromagnetically induced transparency in first- and second-harmonic-generated extinction coefficients in plasmonic nanohybrids. PRA, 111(3), 033501. (www)

  @article{ , abstract = {We have developed a theory of the first- and second-harmonic-generated extinction coefficients in plasmonic nanohybrids. We consider that a nanohybrid is made of an ensemble of interacting metallic nanoparticles (MNPs). The surface plasmon polaritons (SPPs) for the MNPs and the dipole-dipole interaction (DDI) between nanoparticles are calculated. Using the quantum mechanical density matrix method, we have obtained analytical expressions for the first- and second-harmonic-generated extinction coefficients in the presence of the SPP and DDI fields. These analytical expressions can be useful for scientists and engineers to compare their experiments and make new plasmonic devices. We have predicted that there is a noticeable enhancement in the extinction coefficients due to an extra contribution from the SPPs present in the nanohybrid. We found that there are two types of contributions to the extinction coefficients. The first is called the photonic extinction coefficient induced by the probe field. The second is called the polaritonic extinction coefficient produced by the SPP field. The enhancement phenomenon can be used to fabricate the nanoamplifiers and nanosensors from plasmonic nanohybrids. Next, we have compared theory with experimental data of the Au-MNPs and Au/Ag core-shell metallic nanorods for the first harmonic extinction coefficient. Similarly, we have also compared our theory with experimental data of the Au/Ag core-shell MNPs for the second harmonic extinction coefficient. Good agreement between theory and experiments is found. Further, we predicted the phenomenon of the electromagnetically induced transparency in the first- and second-harmonic-generated extinction coefficients due to DDI coupling. In other words, the nanohybrid becomes transparent for the first- and second-harmonic-generated extinction processes. Additionally, we found that a peak in the extinction coefficient splits into two peaks due to DDI coupling. Due to the strong coupling between the exciton and DDI polaritons, the excitonic state splits into two states and produces two excitons. These two excitons are responsible for the two peaks. This finding can be used to fabricate nanoswitches (i.e., ON = one peak, OFF = two peaks) and nanosensors using plasmonic nanohybrids.}, archive = {J_PRA}, author = {Mahi R. Singh and Xintong Jiang}, doi = {10.1103/PhysRevA.111.033501}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033501}, shortjournal = {Phys. Rev. A}, title = {Electromagnetically induced transparency in first- and second-harmonic-generated extinction coefficients in plasmonic nanohybrids}, volume = {111}, year = {2025}, }
• (2025). Synthetic half-integer magnetic monopole and single-vortex dynamics in spherical bose-einstein condensates. PRA, 111(3), 033322. (www)

  @article{ , abstract = {Magnetic monopoles are crucial in explaining the quantization of electric charges and quantum Hall effects, while artificially creating a minimal magnetic monopole in experiments remains a challenge. Here we develop a flexible way to simulate a half-integer-type monopole in Bose gases and investigate the induced vortex dynamics on a sphere. We list the possible experiment parameter settings for different isotopes and discuss their experimental feasibility. With the assumption of a rigid monopole-vortex structure, we analytically predict the vortex trajectory in an external magnetic field. We then confirm the result by numerically solving the Gross-Pitaevskii equation, which employs two gauges simultaneously (the Wu-Yang approach) to prevent singularity in the one-gauge method when a monopole is present. The study offers significant insight into the characteristics of monopoles and vortices, facilitating avenues for experimental validation.}, archive = {J_PRA}, author = {Xi-Yu Chen and Lijia Jiang and Wen-Kai Bai and Tao Yang and Jun-Hui Zheng}, doi = {10.1103/PhysRevA.111.033322}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033322}, shortjournal = {Phys. Rev. A}, title = {Synthetic half-integer magnetic monopole and single-vortex dynamics in spherical bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Geometric phase and multipartite entanglement of rydberg atom chains. PRA, 111(3), 033321. (www)

  @article{ , abstract = {We investigate the behavior of geometric phase (GP) and geometric entanglement (GE), a multipartite entanglement measure, across quantum phase transitions in Rydberg atom chains. Using density-matrix renormalization-group calculations and finite-size scaling analysis, we characterize the critical properties of transitions between disordered and ordered phases. Both quantities exhibit characteristic scaling near transition points, with the disorder to the Z 2 ordered phase transition showing behavior consistent with the Ising universality class, while the disorder to the Z 3 phase transition displays distinct critical properties. We demonstrate that GP and GE serve as sensitive probes of quantum criticality, providing consistent critical parameters and scaling behavior. A unifying description of these geometric quantities from a quantum geometry perspective is explored, and an interferometric setup for their potential measurement is discussed. Our results provide insights into the interplay between geometric phase and multipartite entanglement near quantum phase transitions in Rydberg-atom systems, revealing how these quantities reflect the underlying critical behavior in these complex quantum many-body systems.}, archive = {J_PRA}, author = {Chang-Yan Wang}, doi = {10.1103/PhysRevA.111.033321}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033321}, shortjournal = {Phys. Rev. A}, title = {Geometric phase and multipartite entanglement of rydberg atom chains}, volume = {111}, year = {2025}, }
• (2025). Spatiotemporal chaos and extended self-similarity of bose-einstein condensates in a one-dimensional harmonic trap. PRA, 111(3), 033320. (www)

  @article{ , abstract = {We investigate spatiotemporal chaos in Bose-Einstein condensate (BEC) confined by a one-dimensional harmonic trap using Gross-Pitaevskii equation simulations. The chaos arises from nonlinear mixing of ground and excited states, confirmed by positive Lyapunov exponents. By sampling the density field at intervals matching the center-of-mass oscillation period, we analyze the density structure function. Both spatial and temporal density structure functions reveal Kolmogorov-type scaling through extended self-similarity (ESS). Our findings suggest that ESS and density structure functions provide experimentally accessible tools to explore spatiotemporal chaos and turbulencelike behavior in BECs.}, archive = {J_PRA}, author = {Mingshu Zhao}, doi = {10.1103/PhysRevA.111.033320}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033320}, shortjournal = {Phys. Rev. A}, title = {Spatiotemporal chaos and extended self-similarity of bose-einstein condensates in a one-dimensional harmonic trap}, volume = {111}, year = {2025}, }
• (2025). Haldane fractional statistics for a one-dimensional heisenberg spin XXX chain. PRA, 111(3), 033319. (www)

  @article{ , abstract = {Haldane's fractional exclusion statistics (FES) describe generalized Pauli exclusion statistics, which can be regarded as emergent quantum statistics induced by the intrinsic dynamical interaction. Nonmutual FES have been identified at the quantum criticality of the one-dimensional (1D) and 2D interacting Bose gas [ Nat. Sci. Rev. 9 , nwac027 (2022) ]. It is naturally asked if such nonmutual FES can be induced by the spin-spin interaction in the antiferromagnetic spin-1/2 X X X chain. In this article, we first represent the Bethe ansatz equations of spin strings in terms of the FES equations of different species. Then we show that the 1D spin X X X chain remarkably possesses nonmutual FES in the critical region. We observe that the equation of state in terms of the FES gives rises to full statistical properties of the model at quantum criticality, which are in good agreement with the results obtained from the thermodynamic Bethe ansatz (TBA) equations of the model. From the nonmutual FES, we also precisely determine the quantum scaling functions, which further agree well with the previous TBA results [ Phys. Rev. B 96 , 220401(R) (2017) ]. Finally, we also establish an exact mapping between the scaling functions of the Lieb-Liniger model and the spin Heisenberg spin chain at quantum criticality. Our method provides deep insights into the critical phase of matter from a quantum FES point of view.}, archive = {J_PRA}, author = {Wei-Jia Liu and Jia-Jia Luo and Xi-Wen Guan}, doi = {10.1103/PhysRevA.111.033319}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033319}, shortjournal = {Phys. Rev. A}, title = {Haldane fractional statistics for a one-dimensional heisenberg spin XXX chain}, volume = {111}, year = {2025}, }
• (2025). Characterizing the transition from topology to chaos in a kicked quantum system. PRA, 111(3), 033318. (www)

  @article{ , abstract = {This paper theoretically investigates the transition from topology to chaos in a periodically driven system consisting of a quantum top coupled to a spin-1/2 particle. The system is driven by two alternating interaction kicks per period. For small kick strengths, localized topologically protected bound states exist, and as the kick strengths increase, these states proliferate. However, at large kick strengths they gradually delocalize in stages, eventually becoming random orthonormal vectors as chaos emerges. We identify the delocalization of the bound states as a finite-size effect where their proliferation leads to their eventual overlap. This insight allows us to make analytic predictions for the onset and full emergence of chaos which are supported by numerical results of the quasienergy level spacing ratio and Rényi entropy. A dynamical probe is also proposed to distinguish chaotic from regular behavior.}, archive = {J_PRA}, author = {J. Mumford and H.-Y. Xie and R. J. Lewis-Swan}, doi = {10.1103/PhysRevA.111.033318}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033318}, shortjournal = {Phys. Rev. A}, title = {Characterizing the transition from topology to chaos in a kicked quantum system}, volume = {111}, year = {2025}, }
• (2025). One-body correlations and momentum distributions of trapped one-dimensional bose gases at finite temperature. PRA, 111(3), 033317. (www)

  @article{ , abstract = {We introduce a general approximate method for calculating the one-body correlations and the momentum distributions of one-dimensional Bose gases at finite interaction strengths and temperatures trapped in smooth confining potentials. Our method combines asymptotic techniques for the long-distance behavior of the gas (similar to Luttinger liquid theory) with known short-distance expansions. We derive analytical results for the limiting cases of strong and weak interactions and provide a general procedure for calculating one-body correlations at any interaction strength. A step-by-step explanation of the numerical method used to compute Green's functions (needed as input to our theory) is included. We benchmark our method against exact numerical calculations and compare its predictions to recent experimental results.}, archive = {J_PRA}, author = {Attila Takács and Yicheng Zhang and Pasquale Calabrese and Jerôme Dubail and Marcos Rigol and Stefano Scopa}, doi = {10.1103/PhysRevA.111.033317}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033317}, shortjournal = {Phys. Rev. A}, title = {One-body correlations and momentum distributions of trapped one-dimensional bose gases at finite temperature}, volume = {111}, year = {2025}, }
• (2025). Collective excitations and universal coarsening dynamics of a spin-orbit-coupled spin-1 bose-einstein condensate. PRA, 111(3), 033316. (www)

  @article{ , abstract = {We study the collective excitation spectrum of a Raman-induced spin-orbit-coupled spin-1 Bose-Einstein condensate confined in a quasi-one-dimensional harmonic trap while varying either the Raman coupling or quadratic Zeeman field strength by using the Bogoliubov approach. A few low-lying modes, which can be used to delineate the phase boundaries, are identified by exciting them with suitable perturbations. We also investigate the coarsening dynamics of a homogeneous quasi-two-dimensional spin-orbit-coupled spin-1 condensate by quenching from the zero momentum into the plane wave phase through a sudden change in Raman coupling or quadratic Zeeman field strength. We demonstrate that the correlation function of the order parameter displays dynamic scaling during the late-time dynamics, allowing us to determine the dynamic critical exponent.}, archive = {J_PRA}, author = {Rajat and Paramjeet Banger and Sandeep Gautam}, doi = {10.1103/PhysRevA.111.033316}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033316}, shortjournal = {Phys. Rev. A}, title = {Collective excitations and universal coarsening dynamics of a spin-orbit-coupled spin-1 bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Beyond the semiclassical approximation in atom interferometry. PRA, 111(3), 033315. (www)

  @article{ , abstract = {We describe a quantum perturbative approach to evaluating the phase shift of an atom interferometer in a weakly anharmonic trap. This provides a simple way to evaluate quantum corrections to the standard semiclassical approximation. The calculation benefits from the use of generalized coherent states for a basis. We find that the form of the semiclassical approximation remains valid to first order in the anharmonic perturbation, but that phase differences arise because the trajectory of a quantum wave packet will generally deviate from that of a classical particle. The quantum correction to the phase is a factor ℓ 2 / A 2 smaller than the semiclassical perturbation itself, where ℓ is the quantum harmonic-oscillator lengthscale, and A is the classical amplitude of the motion. We provide analytical results for one-dimensional perturbations of power 3 through 6 in the position coordinate.}, archive = {J_PRA}, author = {W. LaRow and M. Edwards and C. A. Sackett}, doi = {10.1103/PhysRevA.111.033315}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033315}, shortjournal = {Phys. Rev. A}, title = {Beyond the semiclassical approximation in atom interferometry}, volume = {111}, year = {2025}, }
• (2025). Modular quantum gas platform. PRA, 111(3), 033314. (www)

  @article{ , abstract = {We report on the development of a modular platform for programmable quantum simulation with atomic quantum gases. The platform is centered around exchangeable optical modules with versatile functionalities. The performance of each module is disentangled from all others, enabling individual validation and maintenance of its outputs. The relative spatial positioning of the modules with respect to the position of the atomic sample is set by a global reference frame. In this way, the platform simplifies reconfiguration and upgrading of existing setups and accelerates the design of new machines in a time- and cost-efficient manner. Furthermore, it facilitates collaborations between different experimental groups. This standardized hardware design framework, which we call Heidelberg Quantum Architecture , paves the way towards a new generation of on-demand and highly adaptable quantum simulation experiments.}, archive = {J_PRA}, author = {Tobias Hammel and Maximilian Kaiser and Daniel Dux and Philipp M. Preiss and Matthias Weidemüller and Selim Jochim}, doi = {10.1103/PhysRevA.111.033314}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033314}, shortjournal = {Phys. Rev. A}, title = {Modular quantum gas platform}, volume = {111}, year = {2025}, }
• (2025). Quench dynamics in topologically nontrivial quantum many-body systems. PRA, 111(3), 033313. (www)

  @article{ , abstract = {We investigate the nonequilibrium dynamics of a ground-state fermionic many-body gas subjected to a quench between parameter regimes of a topologically nontrivial Hamiltonian. By focusing on the role of the chiral edge states inherent in the system, we calculate the many-body overlap and show that the characteristic monotonic decay of the orthogonality catastrophe with increasing system size is notably altered. Specifically, we demonstrate that the dynamics are governed not solely by the total particle number but, rather, by the number of occupied single-particle edge states. This behavior is further explained through an analysis of the full work probability distribution, providing a deeper understanding of the system's dynamics.}, archive = {J_PRA}, author = {Sarika Sasidharan Nair and Giedrius Žlabys and Wen-Bin He and Thomás Fogarty and Thomas Busch}, doi = {10.1103/PhysRevA.111.033313}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033313}, shortjournal = {Phys. Rev. A}, title = {Quench dynamics in topologically nontrivial quantum many-body systems}, volume = {111}, year = {2025}, }
• (2025). Thermomagnetic anomalies in quantum magnon transport caused by tunable junction geometries in cold atomic systems. PRA, 111(3), 033312. (www)

  @article{ , abstract = {We study magnon-driven spin and heat transport in a magnetic linear junction (MLJ) formed by two ferromagnets in optical lattices linked via linearly aligned bonds. Using the Schwinger-Keldysh formalism, we uncover that under weak effective Zeeman fields, where Bose-Einstein statistics of magnons dominate, magnonic criticality dramatically enhances spin and thermal conductances. These singular transport properties depend on the junction geometry, and the transport properties qualitatively differ between the linear junction in this paper and the point contact in our previous work. The quantum-enhanced conductances result in the breakdown of the magnonic Wiedemann-Franz (WF) law. In the classical regime at temperatures much lower than magnon energy gaps, we find that a magnonic Lorenz number becomes independent of temperature yet dependent on junction geometry, sharply contrasting with the universal WF law for Fermi liquids. We also find that the interface geometry of the MLJ decouples spin and heat relaxations between ferromagnets with decay times insensitive to temperature and effective Zeeman fields. These dynamics reveal junction-geometry-sensitive magnon transport distinct from Fermi liquids, paving the way for new avenues in thermomagnetic research leveraging the tunability of cold atomic systems.}, archive = {J_PRA}, author = {Yuta Sekino and Yuya Ominato and Hiroyuki Tajima and Shun Uchino and Mamoru Matsuo}, doi = {10.1103/PhysRevA.111.033312}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033312}, shortjournal = {Phys. Rev. A}, title = {Thermomagnetic anomalies in quantum magnon transport caused by tunable junction geometries in cold atomic systems}, volume = {111}, year = {2025}, }
• (2025). Physics-guided weak-form discovery of reduced-order models for trapped ultracold hydrodynamics. PRA, 111(3), 033311. (www)

  @article{ , abstract = {We study the relaxation of a highly collisional, ultracold but nondegenerate gas of polar molecules. Confined within a harmonic trap, the gas is subject to fluid-gaseous coupled dynamics that lead to a breakdown of first-order hydrodynamics. An attempt to treat these higher-order hydrodynamic effects was previously made with a Gaussian ansatz and coarse-graining model parameter [R. R. W. Wang and J. L. Bohn, Phys. Rev. A 108 , 013322 (2023) ], leading to an approximate set of equations for a few collective observables accessible to experiments. Here we present substantially improved reduced-order models for these same observables, admissible beyond previous parameter regimes, discovered directly from particle simulations using the WSINDy algorithm (Weak-form Sparse Identification of Nonlinear Dynamics). The interpretable nature of the learning algorithm enables estimation of previously unknown physical quantities and discovery of model terms with candidate physical mechanisms, revealing new physics in mixed collisional regimes. Our approach constitutes a general framework for data-driven model identification leveraging known physics.}, archive = {J_PRA}, author = {Reuben R. W. Wang and Daniel A. Messenger}, doi = {10.1103/PhysRevA.111.033311}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033311}, shortjournal = {Phys. Rev. A}, title = {Physics-guided weak-form discovery of reduced-order models for trapped ultracold hydrodynamics}, volume = {111}, year = {2025}, }
• (2025). Excitation spectrum of a double supersolid in a trapped dipolar bose mixture. PRA, 111(3), 033310. (www)

  @article{ , abstract = {Dipolar Bose-Einstein condensates are excellent platforms for studying supersolidity, characterized by coexisting density modulation and superfluidity. The realization of dipolar mixtures opens intriguing new scenarios, most remarkably the possibility of realizing a double supersolid, composed of two interacting superfluids. We analyze the complex excitation spectrum of a miscible trapped dipolar Bose mixture, showing that it provides key insights about the double-supersolid regime. We show that this regime may be readily probed experimentally by monitoring the appearance of a doublet of superfluid compressional modes, linked to the different superfluid character of each component. Additionally, the dipolar supersolid mixture exhibits a nontrivial spin nature of the dipolar rotons, the Higgs excitation, and the low-lying Goldstone modes. Interestingly, the analysis of the lowest-lying modes allows for monitoring the transition of just one of the components into the incoherent-droplet regime, whereas the other remains coherent, highlighting their disparate superfluid properties.}, archive = {J_PRA}, author = {Daniel Scheiermann and Albert Gallemí and Luis Santos}, doi = {10.1103/PhysRevA.111.033310}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033310}, shortjournal = {Phys. Rev. A}, title = {Excitation spectrum of a double supersolid in a trapped dipolar bose mixture}, volume = {111}, year = {2025}, }
• (2025). Non-hermitian spin-orbit-coupling-induced unique dispersion relation and collective dynamics in nonuniform bose-einstein condensates. PRA, 111(3), 033309. (www)

  @article{ , abstract = {The interplay of non-Hermiticity and spin-orbit (SO) coupling has attracted great interest in condensed-matter physics, ultracold atomic physics, optics, and other fields. Here we study the ground states, collective modes, and free-expansion dynamics of non-Hermitian SO-coupled Bose-Einstein condensates (BECs) with momentum-dependent gain and loss in a harmonic trap. An efficient analytical method for revealing the impact of non-Hermiticity on the ground states and dynamics of SO-coupled BECs is proposed. A dispersion relation with effective mass m 2 that can be larger than 1, less than 1, or negative is engineered by the momentum-dependent gain and loss, which is distinct from the ordinary SO-coupled BECs, where m 2 > 1 always holds. Negative effective mass can lead to the self-interference effect of condensates, while m 2 < 1 means that condensates can gain a larger acceleration when they are subjected to a constant force. Interestingly, the high-order zero-point kinetic energies are derived analytically and confirmed numerically, establishing a link between the zero-point kinetic energy and dispersion relation. In particular, the second-order zero-point kinetic energy can be controlled by the effective mass m 2 , which has an important impact on many phenomena of ultracold atomic physics. In addition, another key result is that the frequencies of dipole and breathing modes can exceed the values of traditional BECs without SO coupling when the effective mass m 2 < 1 , showing that gain (loss) is a powerful tool for probing and controlling quantum systems. Moreover, the asymmetric free expansion and self-interference effect of the condensates caused by negative effective masses are observed, and it is found that the rate of expansion is controlled by the effective mass m 2 . Our results show that the controllable gain-loss engineering in SO-coupled BECs provides a prospect to explore novel quantum many-body physics.}, archive = {J_PRA}, author = {Jun-Cheng Liang and Ai-Xia Zhang and Ju-Kui Xue}, doi = {10.1103/PhysRevA.111.033309}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033309}, shortjournal = {Phys. Rev. A}, title = {Non-hermitian spin-orbit-coupling-induced unique dispersion relation and collective dynamics in nonuniform bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Two-particle tunneling and the impact of interaction. PRA, 111(3), 033308. (www)

  @article{ , abstract = {We analyze the tunneling of two bosons in a double-well potential, for contact, soft-, and hard-core Coulomb interaction of tunable strength. Transitions from correlated to uncorrelated tunneling of the left well's two-particle ground state are due to resonances with states with one particle in either well. Their abundance and dependence on the interaction strength is indicative of the interaction type.}, archive = {J_PRA}, author = {Jonathan Brugger and Christoph Dittel and Andreas Buchleitner}, doi = {10.1103/PhysRevA.111.033308}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033308}, shortjournal = {Phys. Rev. A}, title = {Two-particle tunneling and the impact of interaction}, volume = {111}, year = {2025}, }
• (2025). Microscopic theory of the hubbard interaction in low-dimensional optical lattices. PRA, 111(3), 033307. (www)

  @article{ , abstract = {The Hubbard model is a paradigmatic model of strongly correlated quantum matter, thus making it desirable to investigate with quantum simulators such as ultracold atomic gases. Here we consider the problem of two atoms interacting in a quasi-one- or quasi-two-dimensional optical lattice, geometries which are routinely realized in quantum-gas-microscope experiments. We perform an exact calculation of the low-energy scattering amplitude which accounts for the effects of the transverse confinement as well as all higher Bloch bands. This goes beyond standard perturbative treatments and allows us to precisely determine the effective Hubbard on-site interaction for arbitrary s -wave scattering length (see source code available at https://github.com/HaydnAdlong/Hubbard-Interaction-Optical-Lattices ). In particular, we find that the Hubbard on-site interaction displays lattice-induced resonances for scattering lengths on the order of the lattice spacing, which are well within reach of current experiments. Furthermore, we show that our results are in excellent agreement with spectroscopic measurements of the Hubbard interaction for a quasi-two-dimensional square optical lattice in a quantum-gas microscope. Our formalism is very general and may be extended to multiband models and other atomlike scenarios in lattice geometries, such as exciton-exciton and exciton-electron scattering in moiré superlattices.}, archive = {J_PRA}, author = {Haydn S. Adlong and Jesper Levinsen and Meera M. Parish}, doi = {10.1103/PhysRevA.111.033307}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033307}, shortjournal = {Phys. Rev. A}, title = {Microscopic theory of the hubbard interaction in low-dimensional optical lattices}, volume = {111}, year = {2025}, }
• (2025). Nonlinear topological pumping of edge solitons. PRA, 111(3), 033306. (www)

  @article{ , abstract = {We study how nonlinear strength affects topological pumping of edge solitons by using the Gross–Pitaevskii equation. For weak nonlinear strength, the introduction of nonlinearity breaks the symmetry of the energy spectrum, which makes the topological pumping from the left edge to the right edge differ from the inverse process. For moderate nonlinear strength, self-crossing structures appear in the spectrum, and the right-to-left adiabatic pumping channel is destroyed, only left-to-right topological pumping can be achieved under slow modulation. As the nonlinear strength further increases, although left-to-right topological pumping in one pumping cycle also breaks down, we find that a thin soliton, located at a single left edge, can be mixed with the bulk soliton, and hybridized topological pumping of edge and bulk solitons can be realized after multiple pumping cycles. For stronger nonlinear strength, edge solitons are self-trapped and all topological pumping channels are shut down. Our work could trigger further studies of the interplay between nonlinearity and topology.}, archive = {J_PRA}, author = {Xinrui You and Liaoyuan Xiao and Boning Huang and Yongguan Ke and Chaohong Lee}, doi = {10.1103/PhysRevA.111.033306}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033306}, shortjournal = {Phys. Rev. A}, title = {Nonlinear topological pumping of edge solitons}, volume = {111}, year = {2025}, }
• (2025). Real-time compensation scheme for the accurate measurement of the differential phase in a dual-atom-interferometer gyroscope. PRA, 111(3), 033305. (www)

  @article{ , abstract = {A dual-atom-interferometer gyroscope has high sensitivity for accurate rotation measurements because of its immunity to common-mode noise. However, a measurement error is induced as the common phase noise, e.g., vibration noise, increases. In this work, we demonstrated a real-time compensation (RTC) scheme to improve the accuracy of measurements of the differential phase in dual atom interferometers. The vibration noise was measured by two seismometers and its induced phase shift was fed back to the Raman lasers after this shift was calculated based on the sensitivity function of the atom interferometers. After the RTC module was applied, the interference signals obtained via the square modulation method were stabilized at their midfringe points, which caused the vibration-induced phase noise for each of the atom interferometers to decrease from 495 mrad to 165 mrad. The differential phase error obtained by the dual atom interferometers and two seismometers was reduced from 114.8 mrad to 49.6 mrad, which implies that the rotation measurement error was improved by a factor of 2.3. This work paves the way to accurately measuring the rotation signal and has promising applications in fields of precision measurements.}, archive = {J_PRA}, author = {Ze-Xi Lu and Zhan-Wei Yao and Hong-Hui Chen and Yin-Fei Mao and Si-Bin Lu and Min Jiang and Shao-kang Li and Min Ke and Jie Gu and An-Qing Zhang and Run-Bing Li and Jin Wang and Ming-Sheng Zhan}, doi = {10.1103/PhysRevA.111.033305}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033305}, shortjournal = {Phys. Rev. A}, title = {Real-time compensation scheme for the accurate measurement of the differential phase in a dual-atom-interferometer gyroscope}, volume = {111}, year = {2025}, }
• (2025). Selective rotation and attractive persistent currents in antidipolar ring supersolids. PRA, 111(3), 033304. (www)

  @article{ , abstract = {A repulsively interacting Bose-Einstein condensate on a ring is well known to show persistent currents. For attractive interactions, however, a bound state may form that renders the rotation classical. Here we show that in a multiply connected confinement, the strong in-plane attraction of an antidipolar condensate can form stacks of ring-shaped density lumps which may coherently overlap to form a supersolid along the azimuthal symmetry axis of the system. Intriguingly, the functional behavior of the energy–angular-momentum dispersion of the antidipolar ring condensate differs from that of a usual repulsive superfluid. The periodic maxima between persistent flow and the nonrotating ground state flatten significantly and the typical pronounced cusps in the energy dispersion also occur in the rotationally symmetric supersolid state. A weak link results in the reduction of this minimum, shifting it to smaller angular momenta. With an asymmetric link potential one can selectively induce superfluid and rigid-body rotation in different layers within the same system. This intriguing setup offers new perspectives for atomtronics applications.}, archive = {J_PRA}, author = {K. Mukherjee and T. Arnone Cardinale and S. M. Reimann}, doi = {10.1103/PhysRevA.111.033304}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033304}, shortjournal = {Phys. Rev. A}, title = {Selective rotation and attractive persistent currents in antidipolar ring supersolids}, volume = {111}, year = {2025}, }
• (2025). Exploring the strongly interacting regime of effective multibody interactions in a trapped ultracold-atom system. PRA, 111(3), 033303. (www)

  @article{ , abstract = {A two-body interaction or force between quantum particles is ubiquitous in nature, and the microscopic description in terms of the bare two-body interaction is the basis for quantitatively describing interacting few- and many-body systems. Alternatively, the effective description in terms of an effective two-body interaction successfully captures the essence of the systems. However, for several important observations, the explanation in terms of an effective two-body interaction is not satisfactory, and the effective three-body interaction has played an essential role in understanding the systems. In this study, we investigate a few-body system comprising of ultracold bosons tightly confined in a deep optical lattice site, which is effectively described as zero-dimensional bosons. By combining an occupancy-resolving high-resolution laser spectroscopy with an inter-orbital Feshbach resonance controlling the bare two-body interaction over a wide range, we experimentally reveal the behaviors of few-atom systems in a strongly interacting regime. Our results, for which perturbative calculations do not provide proper explanations, serve as a valuable and precise benchmark for theoretical approaches to strongly interacting few-body systems. As one important illustration, we obtain a clear signature of an effective four-body interaction evidenced by the binding energies of four and more atoms. This work is an important step for our deeper understanding of strongly interacting few-body systems.}, archive = {J_PRA}, author = {Kantaro Honda and Yosuke Takasu and Yuki Haruna and Yusuke Nishida and Yoshiro Takahashi}, doi = {10.1103/PhysRevA.111.033303}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033303}, shortjournal = {Phys. Rev. A}, title = {Exploring the strongly interacting regime of effective multibody interactions in a trapped ultracold-atom system}, volume = {111}, year = {2025}, }
• (2025). Spin structure of diatomic van der waals molecules of alkali-metal atoms. PRA, 111(3), 033302. (www)

  @article{ , abstract = {We theoretically investigate the spin structure of weakly bound diatomic van der Waals molecules formed by two identical bosonic alkali atoms. Our studies were performed using known Born-Oppenheimer potentials while developing a reduced interaction potential model. Such reduced potential models are currently a key for solving certain classes of few-body problems of atoms as they decrease the numerical burden on the computation. Although the reduced potentials are significantly shallower than actual Born-Oppenheimer potentials, they still capture the main properties of the near-threshold bound states, including their spin structure, and the scattering states over a broad range of magnetic fields. At zero magnetic field, we find that the variation in spin structure across different alkali species originates from the interplay between electronic spin exchange and hyperfine interactions. To characterize this competition we introduce a single parameter that is a function of the singlet and triplet scattering lengths, the atomic hyperfine splitting constant, and the molecular binding energy. We show that this parameter can be used to classify the spin structure of vdW molecules for each atomic species.}, archive = {J_PRA}, author = {Jing-Lun Li and Paul S. Julienne and Johannes Hecker Denschlag and José P. D'Incao}, doi = {10.1103/PhysRevA.111.033302}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033302}, shortjournal = {Phys. Rev. A}, title = {Spin structure of diatomic van der waals molecules of alkali-metal atoms}, volume = {111}, year = {2025}, }
• (2025). Topological chiral edge states in a synthetic dimension of atomic trap states. PRA, 111(3), 033301. (www)

  @article{ , abstract = {A key hallmark of quantum Hall physics is the existence of topological chiral states at the system boundary. Signatures of these edge states have been experimentally observed in cold atoms by using different approaches, including notably that of “synthetic dimensions” in which internal states are coupled together and reinterpreted as sites along an artificial spatial dimension. However, previous atomic synthetic dimension implementations have been limited to relatively small system sizes with inflexible boundaries. In this paper, we propose instead how to use a synthetic dimension of atomic trap states to observe chiral edge states in a large quantum Hall system with a tunable edge. We present numerical simulations for relevant experimental parameters, showing how this scheme may be used to probe the properties and robustness of the edge states to defects. Our work opens the way for future experiments in topological physics with synthetic dimensions, while also providing new ways to manipulate and control highly excited trap states.}, archive = {J_PRA}, author = {David G. Reid and Christopher Oliver and Patrick Regan and Aaron Smith and Thomas Easton and Grazia Salerno and Giovanni Barontini and Nathan Goldman and Hannah M. Price}, doi = {10.1103/PhysRevA.111.033301}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033301}, shortjournal = {Phys. Rev. A}, title = {Topological chiral edge states in a synthetic dimension of atomic trap states}, volume = {111}, year = {2025}, }
• (2025). Maximizing orientation of a three-state molecule in a cavity with analytically designed pulses. PRA, 111(3), 033119. (www)

  @article{ , abstract = {We theoretically explore the precise control of a molecular polariton by strongly coupling the lowest three rotational states of a single molecule with a single-mode cavity. We examine two distinct cavity resonance configurations: a fundamental frequency cavity with the rotational constant resonating with the lowest two rotational states, and a second harmonic cavity coupling with the first and second excited rotational states. We propose two control schemes based on the two polariton configurations and derive the corresponding pulse-area theorems to achieve a theoretical maximum orientation of 0.7746, identical to the molecule without the cavity. The control schemes are analyzed in carbonyl sulfide (OCS) molecules in their ground rotational state. Our numerical simulation results demonstrate the theoretical control schemes and analyze the sensitivity of the molecular polariton orientation degree to the control field bandwidth and phases. This work provides a valuable reference for achieving maximum field-free orientation of ultracold three-state molecules in a cavity using analytically designed pulses.}, archive = {J_PRA}, author = {Li-Bao Fan and Hai-Ji Li and Qi Chen and Hang Zhou and Heng Liu and Chuan-Cun Shu}, doi = {10.1103/PhysRevA.111.033119}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033119}, shortjournal = {Phys. Rev. A}, title = {Maximizing orientation of a three-state molecule in a cavity with analytically designed pulses}, volume = {111}, year = {2025}, }
• (2025). Probing attosecond dynamics of chiral bound wave packets with an attoclock. PRA, 111(3), 033118. (www)

  @article{ , abstract = {The coherent superposition of two current-carrying electronic states can form a chiral state in an atom. We study strong-field ionization of such a chiral electronic state in a few-cycle carrier-envelope-phase-stabilized circularly polarized laser field with an attoclock configuration by numerically solving the three-dimensional time-dependent Schrödinger equation. We find that the photoelectron momentum along the laser propagation direction reveals a high sensitivity to the photoelectron emission angle in the laser polarization plane. The time-to-angle mapping relation of the attoclock allows us to obtain a time-resolved photoelectron circular dichroism spectrum on the attosecond timescale. We reconstruct the temporal evolution of the chiral bound wave packet from the time-resolved photoelectron circular dichroism spectrum, which shows the phenomenon of the electronic chirality flips occurring on the attosecond timescale.}, archive = {J_PRA}, author = {Yang Liu and Weibin Liu and Yanan Qin and Peipei Ge and Min Li and Peixiang Lu}, doi = {10.1103/PhysRevA.111.033118}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033118}, shortjournal = {Phys. Rev. A}, title = {Probing attosecond dynamics of chiral bound wave packets with an attoclock}, volume = {111}, year = {2025}, }
• (2025). Temporal interference picture for subpeak structures between autler-townes doublets in photoelectron energy spectra. PRA, 111(3), 033117. (www)

  @article{ , abstract = {The existence of subpeak structures between the Autler-Townes (AT) doublet of the photoelectron spectrum during resonant ionization of an atom has been predicted in a large number of theoretical calculations, but a convincing physical explanation is still lacking. In this study we establish a temporal interference picture to elucidate the physical origin of these subpeaks. We derive an analytical estimation for the photoelectron spectra based on a three-level model, which agrees well with the numerical solution of the time-dependent Schrödinger equation at moderately strong pulse intensities. Our interpretation suggests that the interference of the photoelectron wave packet emitted during each Rabi cycle results in the subpeak structure between the AT doublet. By analyzing the phase difference between two temporally adjacent photoelectron wave packets, we successfully predict the interference minima in the photoelectron energy spectra.}, archive = {J_PRA}, author = {Wen-qin Wan and Guang-Yin Liu and Meng-Fei Xie and Qiu-Bo Meng and Wei-Chao Jiang}, doi = {10.1103/PhysRevA.111.033117}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033117}, shortjournal = {Phys. Rev. A}, title = {Temporal interference picture for subpeak structures between autler-townes doublets in photoelectron energy spectra}, volume = {111}, year = {2025}, }
• (2025). Photoelectron spectra calculated from absorption. PRA, 111(3), 033116. (www)

  @article{ , abstract = {We demonstrate a way to calculate photoelectron spectra on a numerical domain much smaller than the actual extension of the wave function. Specifically, a hydrogen atom exposed to a laser pulse in the moderately ultraviolet region is studied numerically within the dipole approximation. Outgoing waves are absorbed by means of a complex absorbing potential. The corresponding photoelectron spectra are calculated by aggregating the absorbed part of the outgoing particle. Via a density operator formulation and projections onto time-independent scattering states, we obtain convergent spectra using numerical domains for which a significant part of the unbound wave is absorbed during interaction with the time-dependent field. We compare this numerical approach with methods based on approximating time-dependent scattering states by Volkov states, which do not encompass the long-range nature of the Coulomb potential. This comparison demonstrates how the present method, which was introduced by Selstø [ Phys. Rev. A 106 , 042213 (2022) ], is able to account for Coulomb corrections to the photoelectron spectra.}, archive = {J_PRA}, author = {Bendik Steinsvåg Dalen and Sølve Selstø}, doi = {10.1103/PhysRevA.111.033116}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033116}, shortjournal = {Phys. Rev. A}, title = {Photoelectron spectra calculated from absorption}, volume = {111}, year = {2025}, }
• (2025). Observation of asymmetric sideband generation in strongly driven rydberg atoms. PRA, 111(3), 033115. (www)

  @article{ , abstract = {Improving the bandwidth of Rydberg-atom-based receivers is an ongoing challenge owing to the long-lived Rydberg state lifetimes that limit the refresh rate of ground-state atoms. In particular, the local-oscillator-based Rydberg mixer approach allows for bandwidths into the few-megahertz range. Here we use heterodyne detection of the Rydberg-atom receiver probe laser to separate the negative and positive sidebands that originate from distinct six-wave-mixing processes, in order to investigate their individual bandwidths. We experimentally confirm the prediction that the negative sideband exhibits a higher bandwidth than the positive sideband. We further explore the effect of coupling and probe laser Rabi frequency on the bandwidth, which we find to be in close agreement with our model. We achieve maximum experimental (and theoretical) bandwidths of 10.5 ± 0.4 (11.6) and 3.4 ± 0.2 (5.4) MHz for the negative and positive sidebands, respectively, from the − 3 dB roll-off point for optimized field parameters. This work provides insight into the bandwidth-limiting features of Rydberg-atom receivers and points the way towards further optimization of their response.}, archive = {J_PRA}, author = {Dangka Shylla and Nikunjkumar Prajapati and Andrew P. Rotunno and Noah Schlossberger and Dixith Manchaiah and William J. Watterson and Alexandra Artusio-Glimpse and Samuel Berweger and Matthew T. Simons and Christopher L. Holloway}, doi = {10.1103/PhysRevA.111.033115}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033115}, shortjournal = {Phys. Rev. A}, title = {Observation of asymmetric sideband generation in strongly driven rydberg atoms}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic laser-induced alignment dynamics of alkali-metal dimers on the surface of a helium droplet. PRA, 111(3), 033114. (www)

  @article{ , abstract = {Alkali-metal dimers, Ak 2 , located on the surface of a helium nanodroplet, are set into rotation through the polarizability interaction with a nonresonant 1-ps-long laser pulse. The time-dependent degree of alignment is recorded using femtosecond-probe-pulse-induced Coulomb explosion into a pair of Ak + fragment ions. The results, obtained for Na 2 , K 2 , and Rb 2 in both the ground state 1 1 Σ g + and the lowest-lying triplet state 1 3 Σ u + , exhibit distinct, periodic revivals with a gradually decreasing amplitude. The dynamics differ from that expected for dimers had they behaved as free rotors. Numerically, we solve the time-dependent rotational Schrödinger equation, including an effective mean-field potential to describe the interaction between the dimer and the droplet. The experimental and simulated alignment dynamics agree well and their comparison enables us to determine the effective rotational constants of the alkali dimers with the exception of Rb 2 ( 1 3 Σ u + ) that only exhibits a prompt alignment peak but no subsequent revivals. For Na 2 ( 1 3 Σ u + ), K 2 ( 1 1 Σ g + ), K 2 ( 1 3 Σ u + ), and Rb 2 ( 1 1 Σ g + ), the alignment dynamics are well described by a two-dimensional rotor model. We ascribe this to a significant confinement of the internuclear axis of these dimers, induced by the orientation-dependent droplet–dimer interaction, to the tangential plane of their residence point on the droplet.}, archive = {J_PRA}, author = {Henrik H. Kristensen and Lorenz Kranabetter and Areg Ghazaryan and Constant A. Schouder and Emil Hansen and Frank Jensen and Robert E. Zillich and Mikhail Lemeshko and Henrik Stapelfeldt}, doi = {10.1103/PhysRevA.111.033114}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033114}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic laser-induced alignment dynamics of alkali-metal dimers on the surface of a helium droplet}, volume = {111}, year = {2025}, }
• (2025). Modification of the saddle-point equation for strong-field ionization from atomic p orbitals. PRA, 111(3), 033113. (www)

  @article{ , abstract = {The saddle-point approximation (SPA) within the framework of strong-field approximation is extensively applied in strong-field physics because it offers clear physical insight into intense light-matter interactions. In this study, we introduce an -resolved saddle-point approximation ( -SPA), where is the magnetic quantum number, to analyze the ionization dynamics of atoms initially in orbitals subjected to an intense laser field. Our results reveal that influences not only the prefactor of the ionization rate but also the saddle-point equation itself, an effect overlooked in prior studies. The accuracy of the -SPA method is validated through comparisons with the backpropagation method and the strong-field approximation, showing its superiority over the conventional SPA approach. By employing the -SPA approach, we are able to extract more accurate distributions of the initial tunneling exit energy and position, thereby allowing for a more precise determination of the asymptotic photoelectron characteristics. Additionally, we extend the conservation law for angular momentum and energy of photoelectrons from orbitals to orbitals and from circularly polarized to elliptically polarized laser fields, both at the tunnel exit and in the asymptotic region. This work facilitates future research on strong-field ionization from arbitrary atomic orbitals.}, archive = {J_PRA}, author = {Xiaodan Mao and Kunlong Liu and Hongcheng Ni and Jian Wu}, doi = {10.1103/PhysRevA.111.033113}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033113}, shortjournal = {Phys. Rev. A}, title = {Modification of the saddle-point equation for strong-field ionization from atomic p orbitals}, volume = {111}, year = {2025}, }
• (2025). Doppler-free three-photon spectroscopy on narrow-line optical transitions. PRA, 111(3), 033112. (www)

  @article{ , abstract = {We demonstrate coherent Doppler-free three-photon excitation of the S 0 1 ↔ P 0 3 optical clock transition and the S 0 1 ↔ P 1 3 intercombination transition in free-space thermal clouds of Sr 88 atoms. By appropriate orientation of the wave vectors of three lasers incident on the atoms, the first-order Doppler shift can be eliminated for all velocity classes. Three-photon excitation of the S 0 1 ↔ P 1 3 transition enables high-contrast Ramsey spectroscopy with interrogation times comparable to the 21 µ s natural lifetime using a single near-resonant laser source. Three-photon spectroscopy on the S 0 1 ↔ P 0 3 clock transition, using only laser frequencies nearly resonant with the S 0 1 ↔ P 0 3 and S 0 1 ↔ P 1 3 transitions, enables a reduction in Doppler broadening by two orders of magnitude and a corresponding ∼ 470 Hz linewidth without a confining potential.}, archive = {J_PRA}, author = {Guglielmo Panelli and Shaun C. Burd and Erik J. Porter and Mark Kasevich}, doi = {10.1103/PhysRevA.111.033112}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033112}, shortjournal = {Phys. Rev. A}, title = {Doppler-free three-photon spectroscopy on narrow-line optical transitions}, volume = {111}, year = {2025}, }
• (2025). Measurement of the total spin angular momentum 〈Fz〉 of alkali-metal atoms. PRA, 111(3), 033111. (www)

  @article{ , abstract = {It is important to evaluate the total spin angular momentum of alkali-metal atoms if the atoms serve as a reservoir of angular momenta. We use an absorption-monitoring technique to measure 〈 F z 〉 , i.e., the expectation values of the quantization ( z ) axis components of the total angular momentum of Cs atoms in the electronic ground state in both uncoated and antirelaxation-coated vacuum cells at room temperature. Cs atoms are polarized via optical pumping and probed using their D 2 transitions. The probe laser frequency is varied across the Doppler-broadened D 2 transition; the 〈 F z 〉 values are derived using the integrated absorption coefficients. The largest 〈 F z 〉 is 2.5 for the coated cell. We then use a simple model of spin flow through vapor cells to estimate the atomic spin relaxation probabilities after a single surface collision.}, archive = {J_PRA}, author = {Runa Yasuda and Kei Ishii and Wolfgang Klassen and Jeffery W. Martin and Atsushi Hatakeyama}, doi = {10.1103/PhysRevA.111.033111}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033111}, shortjournal = {Phys. Rev. A}, title = {Measurement of the total spin angular momentum 〈Fz〉 of alkali-metal atoms}, volume = {111}, year = {2025}, }
• (2025). Three-body fragmentation of doubly ionized argon trimers in two-color femtosecond laser pulses. PRA, 111(3), 033110. (www)

  @article{ , abstract = {Using linearly polarized two-color femtosecond laser fields and coincidence measurements, we experimentally study the three-body fragmentation of the argon trimer following double ionization, resulting in two ionic fragments, A r + , and one neutral fragment, Ar. This three-body channel is distinguished from the raw data by analyzing the correlation between the sum momentum vectors of the two ionic fragments A r + versus their total kinetic energy releases. Two distinct fragmentation pathways, concerted and sequential, are confirmed by a detailed examination of the kinetic energy releases’ correlation spectra, Newton diagrams, and Dalitz plots of the fragments. The emission directions of the neutral fragments from the sequential pathway are manipulated by adjusting the relative phase of the two-color laser fields. The observed relative phase-dependent asymmetry patterns are attributed to the enhanced ionization induced asymmetric emission of residual A r 2 + in the first dissociation step. Our findings offer valuable insights into the dissociative ionization of argon trimers and are expected to stimulate further research into the ultrafast dynamics of clusters in femtosecond laser fields.}, archive = {J_PRA}, author = {Junyang Ma and Shuqi Li and Lei Xiong and Zhubin Hu and Haitao Sun and Yan Yang and Zhenrong Sun}, doi = {10.1103/PhysRevA.111.033110}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033110}, shortjournal = {Phys. Rev. A}, title = {Three-body fragmentation of doubly ionized argon trimers in two-color femtosecond laser pulses}, volume = {111}, year = {2025}, }
• (2025). Quantum effects of coulomb explosion simulations revealed by time-dependent density-functional theory. PRA, 111(3), 033109. (www)

  @article{ , abstract = {This study investigates the influence of quantum effects on Coulomb explosion dynamics using time-dependent density-functional theory (TDDFT) simulations in comparison to classical simulations. The goal is to elucidate how electron dynamics affect the kinetic energy, angular distribution, and final velocities of ejected ions. The results indicate that quantum effects result in lower kinetic energies of all ions, deviating from classical predictions. Furthermore, TDDFT simulations exhibit broader angular distributions and more diverse ion trajectories, aligning closely with experimental observations. The research also highlights the role of laser intensity and the resultant ionization in enhancing quantum effects, particularly in modifying ion velocities and distributions. These findings provide a deeper understanding of the role of electron dynamics in Coulomb explosions, offering valuable insights for both experimental and theoretical studies of molecular fragmentation.}, archive = {J_PRA}, author = {Samuel S. Taylor and Cody Covington and Kálmán Varga}, doi = {10.1103/PhysRevA.111.033109}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033109}, shortjournal = {Phys. Rev. A}, title = {Quantum effects of coulomb explosion simulations revealed by time-dependent density-functional theory}, volume = {111}, year = {2025}, }
• (2025). Measurements of diffusion coefficients for rubidium–inert-gas mixtures using coherent scattering from optically pumped population gratings. PRA, 111(3), 033108. (www)

  @article{ , abstract = {We present comprehensive determinations of the diffusion coefficients D at T = 24 ∘ C for trace amounts of naturally abundant Rb atoms in inert, naturally abundant He, Ne, N 2 , Ar, Kr, and Xe buffer gases using a single measurement technique. They have been measured by establishing a spatially periodic population grating in the Rb sample using two laser beams that intersect at a small angle θ of a few milliradians. The atomic population grating decays exponentially in time due to diffusive motion induced by momentum-changing elastic collisions between Rb and buffer gas atoms or molecules. This decay is monitored by observing the scattered field from a readout beam aligned along the direction of one of the excitation beams. We distinguish the contribution of diffusion from other collisional processes by measuring the characteristic θ 2 dependence of the decay rate. We also measure the systematic dependence of the decay rate on the buffer gas pressure over a range of 7000 to 90 000 Pa. In this manner, we obtain diffusion coefficients at standard atmospheric pressure of 101 325 Pa and at a temperature of 24.0 ( 5 ) ∘ C . We use two models to correct for systematic effects due to the transit time, one assuming a rectangular profile of the population distribution and a rectangular readout beam profile, and a second using Gaussian profiles. We obtain weighted averages of 0.33(5), 0.214(14), 0.132(7), 0.123(9), 0.093(9), and 0.073 ( 4 ) cm 2 /s for Rb in He, Ne, N 2 , Ar, Kr, and Xe, respectively. The number in parentheses represents one standard deviation of the combined statistical and systematic uncertainty. We also compare these data with diffusion coefficients obtained using quantum, classical, and semiclassical theoretical methods based on the most accurate interatomic interaction potentials from the literature. Near room temperature, simulations of D using classical and quantum methods agree within their intrinsic, sub-1% standard uncertainties. We find that the semiclassical model only gives the correct orders of magnitude for D . Our computed diffusion coefficients based on the quantum theory agree with the experimental determinations when systematic effects are taken into account. Our measurements and modeling are relevant to the optimization of magnetometers, biomedical imaging using spin-polarized noble gases, tests of collision models based on interatomic potentials, and the development of pressure sensors.}, archive = {J_PRA}, author = {Alexander Pouliot and Eduardo Chomen Ramos and Gehrig Carlse and Thomas Vacheresse and Jaskaran Randhawa and Louis Marmet and A. Kumarakrishnan and Jacek Kłos and Eite Tiesinga}, doi = {10.1103/PhysRevA.111.033108}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033108}, shortjournal = {Phys. Rev. A}, title = {Measurements of diffusion coefficients for rubidium–inert-gas mixtures using coherent scattering from optically pumped population gratings}, volume = {111}, year = {2025}, }
• (2025). Transition from rabi oscillations to dynamic interference: The multipeak pattern of the autler-townes doublet revisited. PRA, 111(3), 033107. (www)

  @article{ , abstract = {Recent studies have shown that both Rabi oscillations (ROs) and dynamic interference (DI) lead to pronounced multipeak patterns in the spectrum of ionized photoelectrons. These two prominent dynamical effects—characteristic of intense, short, and (near-)resonant laser pulses interacting with matter—usually coexist, and are thus hard to distinguish. Here, we revisit the multipeak pattern of the Autler-Townes doublet to uncover its physical origin, by calculating the photoelectron spectrum accurately. Our joint analytical and numerical analysis reveals that selectively populating the two emerging dynamically dressed states is key to an efficient balancing between ROs and DI. We demonstrate physical situations where either ROs or DI dictate the spectrum shape, and explore the transition between these regimes. The present work provides further insight into our results reported in a previous work [ Phys. Rev. A 108 , L061101 (2023) ].}, archive = {J_PRA}, author = {Ayoub Ait Elarabi and András Csehi}, doi = {10.1103/PhysRevA.111.033107}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033107}, shortjournal = {Phys. Rev. A}, title = {Transition from rabi oscillations to dynamic interference: The multipeak pattern of the autler-townes doublet revisited}, volume = {111}, year = {2025}, }
• (2025). Investigating the hyperfine systematic error and relative phase in low-spin-polarization alkali-metal free-induction-decay magnetometers. PRA, 111(3), 033106. (www)

  @article{ , abstract = {Alkali-metal optically pumped magnetometers that utilize vapor cells containing high buffer-gas pressure and operate at elevated temperatures are prone to inaccuracies arising from the overlap of the average F = I + 1 / 2 and F = I − 1 / 2 ground-state Zeeman resonances. We employ density-matrix simulations and experiments to investigate how this hyperfine systematic error varies with spin polarization in a Rb 87 free-induction-decay (FID) magnetometer. At low spin polarizations P ≤ 0.5 , this effect causes single-frequency magnetic-field-extraction techniques to exhibit inaccuracies up to approximately 3.5 nT. Density-matrix simulations reveal that this bias can be traced to the relative amplitude and phase between the F = I ± 1 / 2 hyperfine ground-state manifolds in the FID spin precession signal. We show that this systematic error can be mitigated using either a double-frequency fitting model that accounts for the relative amplitude and phase or synchronous-pulse pumping that minimizes the F = 1 contribution to the FID signal. Theoretical simulations predict accuracies within 0.5 nT for both techniques across a wide range of spin polarizations, suggesting a sevenfold enhancement over single-frequency extraction methods. Our experiments validate this, showcasing a variation in the extracted field below 1 nT, a 3.5-fold improvement compared to single-frequency extraction methods. Furthermore, the mitigation techniques demonstrate agreement of the extracted magnetic field within 1.5 nT.}, archive = {J_PRA}, author = {D. P. Hewatt and M. Ellmeier and C. Kiehl and T. S. Menon and J. W. Pollock and C. A. Regal and S. Knappe}, doi = {10.1103/PhysRevA.111.033106}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033106}, shortjournal = {Phys. Rev. A}, title = {Investigating the hyperfine systematic error and relative phase in low-spin-polarization alkali-metal free-induction-decay magnetometers}, volume = {111}, year = {2025}, }
• (2025). Advantages of polarization control in RABBITT. PRA, 111(3), 033105. (www)

  @article{ , abstract = {The reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) setup is theoretically studied for various combinations of extreme ultraviolet and infrared (IR) field components polarization: “ ,” “ ” with crossed propagation directions, and “ ” with parallel propagation directions. We examine the general properties of photoelectron angular distributions and their response to the variation of the IR pulse delay. Numerical simulations are performed for the neon valence shell ionization into the structureless continuum using two approaches: time-dependent perturbation theory and the solution of amplitude rate equations. To distinguish between “geometrical” governed by fields polarization and spectroscopic features, we provide an additional analysis for the case of -shell ionization.}, archive = {J_PRA}, author = {Maria M. Popova and Elena V. Gryzlova and Sergei N. Yudin and Alexei N. Grum-Grzhimailo}, doi = {10.1103/PhysRevA.111.033105}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033105}, shortjournal = {Phys. Rev. A}, title = {Advantages of polarization control in RABBITT}, volume = {111}, year = {2025}, }
• (2025). Frequency shifts in the electron paramagnetic resonance spectrum of k39 due to spin-exchange collisions with polarized he3 and precise he3 polarimetry. PRA, 111(3), 033104. (www)

  @article{ , abstract = {The Zeeman splittings and electron paramagnetic resonance frequencies of alkali-metal atoms are shifted in the presence of a polarized noble gas. For a spherical geometry, the shift is enhanced over what is expected classically by a dimensionless atomic parameter that is unique to each alkali-metal-atom–noble-gas pair. We present a precise measurement of for the system with a relative accuracy of better than 1%. A critical component of achieving subpercent accuracy involved characterizing the shape of our samples using both MRI and CT medical-imaging techniques. The parameter plays an important role in establishing the absolute polarization of in a variety of contexts, including polarized targets for electron-scattering experiments and MRI of the gas space of the lungs. Our measurement more than doubles the accuracy possible when using for polarimetry purposes. Just as important, the work presented here represents a direct measurement of for the system; previous values for in the system relied on a chain of measurements that were benchmarked by previous measurements of in the Rb- system.}, archive = {J_PRA}, author = {Sumudu Katugampola and Christopher Jantzi and David A. Keder and G. Wilson Miller and Vladimir Nelyubin and Huong Nguyen and Sina Tafti and William A. Tobias and Gordon D. Cates}, doi = {10.1103/PhysRevA.111.033104}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033104}, shortjournal = {Phys. Rev. A}, title = {Frequency shifts in the electron paramagnetic resonance spectrum of k39 due to spin-exchange collisions with polarized he3 and precise he3 polarimetry}, volume = {111}, year = {2025}, }
• (2025). Distinct role of electric field and vector potential in strong-field tunneling ionization. PRA, 111(3), 033103. (www)

  @article{ , abstract = {Light can be described either by its field or potential, which are often interchangeable. We theoretically investigate the distinct roles of the electric field and the vector potential of an ultrashort laser pulse in strong-field tunneling ionization, based on their distinct central frequencies. Employing the conservation law between the angular momentum and energy, we demonstrate that quantum tunneling dynamics is driven by the electric field, while the subsequent classical motion in the continuum is governed by the vector potential. Our work casts new light on the fundamental laser-matter interactions and offers a fresh perspective on the application of ultrashort laser pulses in strong-field physics.}, archive = {J_PRA}, author = {Yongzhe Ma and Xiaodan Mao and Lanhe Kong and Qingcao Liu and Hongcheng Ni and Jian Wu}, doi = {10.1103/PhysRevA.111.033103}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033103}, shortjournal = {Phys. Rev. A}, title = {Distinct role of electric field and vector potential in strong-field tunneling ionization}, volume = {111}, year = {2025}, }
• (2025). Realization of landau-zener rabi oscillations on an optical lattice clock. PRA, 111(3), 033102. (www)

  @article{ , abstract = {Manipulating quantum states is at the heart of quantum information processing and quantum metrology. Landau-Zener Rabi oscillation (LZRO), which arises from a quantum two-level system swept repeatedly across the avoided crossing point in the time domain, has been suggested for widespread use in manipulating quantum states. Cold atoms are one of the most prominent platforms for quantum computing and precision measurement. However, LZRO has never been observed in cold atoms due to its stringent requirements. By compensating for the linear drift of the clock laser and optimizing experimental parameters, we successfully measured LZRO on the strontium atomic optical clock platform under both fast- and slow-passage limits within four to six driving periods. Compared to previous results on other platforms, the duration of the plateau is times longer in the optical lattice clock. The experimental data also suggests that destructive Landau-Zener interference can effectively suppress dephasing effects in the optical lattice clock, paving the way for manipulating quantum states against various environmental effects in cold atomic systems.}, archive = {J_PRA}, author = {Wei Tan and Wei-Xin Liu and Ying-Xin Chen and Chi-Hua Zhou and Guo-Dong Zhao and Hong Chang and Jun Dai and Tao Wang}, doi = {10.1103/PhysRevA.111.033102}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033102}, shortjournal = {Phys. Rev. A}, title = {Realization of landau-zener rabi oscillations on an optical lattice clock}, volume = {111}, year = {2025}, }
• (2025). Enhanced accuracy of isotope-shift measurements of yb+ 369- and 935-nm transitions via sympathetic cooling. PRA, 111(3), 033101. (www)

  @article{ , abstract = {We report enhanced accuracy in isotope-shift (IS) measurement using sympathetic cooling, demonstrated with transitions at 369 and 935 nm. Considering only type-A uncertainties, sympathetic cooling achieves 30- and 200-fold improvements in IS measurement accuracy at 369 and 935 nm compared with previous single-ion results. Our measurements remain the most accurate to date including type-B uncertainties. King-plot analysis yields model-independent IS factors for these transitions [ GHz/ GHz u, GHz/ , and GHz u] and their ratio [ ] along with GHz u, representing a 17-fold improvement. More reliable nuclear charge radii for are also determined with an accuracy of 0.01 . This paper complements collinear laser spectroscopy, introduces a robust approach for researching unstable isotopes, and supports applications of sympathetic cooling in trapped-ion quantum computers and quantum frequency standards.}, archive = {J_PRA}, author = {Jize Han and Ying Zheng and Yanmei Yu and Jiguang Li and Zhiguo Huang and Jingwei Wen and Ling Qian and Lijun Wang}, doi = {10.1103/PhysRevA.111.033101}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {033101}, shortjournal = {Phys. Rev. A}, title = {Enhanced accuracy of isotope-shift measurements of yb+ 369- and 935-nm transitions via sympathetic cooling}, volume = {111}, year = {2025}, }
• (2025). Hyperfine structure and collisions in three-photon rydberg electromagnetically induced transparency. PRA, 111(3), 032821. (www)

  @article{ , abstract = {Multiphoton electromagnetically induced transparency (EIT) of atomic vapors involves several intermediate atomic levels. The substructure of these levels and their collisional interactions can drastically alter experimental EIT signals. Here we report on hyperfine structure and collision effects in three-photon Rydberg EIT on the cascade in a room-temperature vapor cell. In our measurements of EIT spectra, we identify two types of EIT signatures that correspond with distinct excitation pathways and atomic velocity classes in the atomic vapor. The hyperfine structure and Autler-Townes splittings lead to complex patterns in the EIT spectra, which we analyze with the aid of 10-level EIT simulations. Adding 50 mTorr of Ar gas alters the EIT spectra and induces an additional, third EIT mode. Based on our simulation results, we attribute these changes to hyperfine collisions in the Rb level. Our study may become useful in quantum technologies involving Rydberg EIT and hyperfine collisions in vapor cells, including noninvasive spatiotemporally resolved electric-field sensing of electric fields in low-pressure plasmas.}, archive = {J_PRA}, author = {Alisher Duspayev and Georg Raithel}, doi = {10.1103/PhysRevA.111.032821}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032821}, shortjournal = {Phys. Rev. A}, title = {Hyperfine structure and collisions in three-photon rydberg electromagnetically induced transparency}, volume = {111}, year = {2025}, }
• (2025). Recoil corrections with finite nuclear size in hydrogenic systems. PRA, 111(3), 032820. (www)

  @article{ , abstract = {Formulas for the combined nuclear-recoil and finite-nuclear-size effects of orders and are derived without any expansion in the nuclear-charge radius , making them applicable to both electronic and muonic atoms. The obtained results are particularly relevant for high-precision determinations of root-mean-square charge radii from muonic atom spectroscopy. We demonstrate that calculations of the atomic isotope shift based on the widely used Breit approximation give rise to an unphysical nuclear-size contribution that is linear in the nuclear-charge radius at order . This spurious term vanishes in a full QED treatment, leaving the correct contribution quadratic in . For electronic atoms, this quadratic term is significantly smaller than the spurious linear contribution.}, archive = {J_PRA}, author = {Krzysztof Pachucki and Vojtěch Patkóš and Vladimir A. Yerokhin}, doi = {10.1103/PhysRevA.111.032820}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032820}, shortjournal = {Phys. Rev. A}, title = {Recoil corrections with finite nuclear size in hydrogenic systems}, volume = {111}, year = {2025}, }
• (2025). Intramolecular scattering in dissociating multiply charged diiodoacetylene. PRA, 111(3), 032819. (www)

  @article{ , abstract = {The fragmentation dynamics of diiodoacetylene ( ), multiply ionized by low-energy collisions of , is studied by using a momentum imaging spectrometer. The kinetic energy releases of four-body fragmentation channels of are investigated for up to 10, in which generation of high- ions requires conversion of the projectile collision energy to the electronic energy. The experimentally observed momentum correlation in the four-body dissociation channels reveals the tendency that the direction of the emitted carbon and iodine ions are mutually perpendicular, in contrast to the intuitive prediction that the fragments of the linear molecule will align. The simulated trajectories of the fragments based on the pure (classical) Coulomb explosion model manifest that the fragmentation scheme can be well described by this model, taking into account the significant Coulombic interactions between dissociating carbon and iodine ions.}, archive = {J_PRA}, author = {Manisha Samal and Pragya Bhatt and H. Tezuka and G. Veshapidze and C. P. Safvan and J. Matsumoto and H. Shiromaru and Sankar De}, doi = {10.1103/PhysRevA.111.032819}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032819}, shortjournal = {Phys. Rev. A}, title = {Intramolecular scattering in dissociating multiply charged diiodoacetylene}, volume = {111}, year = {2025}, }
• (2025). Repulsive interatomic potentials calculated at three levels of theory. PRA, 111(3), 032818. (www)

  @article{ , abstract = {The high-energy repulsive interaction between nuclei at distances much smaller than the equilibrium bond length is the key quantity determining the nuclear stopping power and atom scattering in keV and MeV radiation events. This interaction is traditionally modeled within orbital-free density functional theory with frozen atomic electron densities, following the Ziegler-Biersack-Littmark (ZBL) model. In this work, we calculate atom pair-specific repulsive interatomic potentials with the ZBL model, and compare them to two kinds of quantum chemical calculations (second-order Møller-Plesset perturbation theory in flexible Gaussian basis sets as well as density functional theory with numerical atomic orbital basis sets) which go well beyond the limitations in the ZBL model, allowing the density to relax in the calculations. We show that the repulsive interatomic potentials predicted by the two quantum chemical models agree within for potential energies above 30 eV, while the ZBL pair-specific potentials and universal ZBL potentials differ much more from either of these calculations. We provide pair-specific fits of the screening functions in terms of three exponentials to the calculations for all pairs for , and show that they agree within % with the raw data. We use these potentials to simulate ion implantation depth profiles in single-crystalline Si and show very good agreement with experiment. However, we also show that under channeling conditions, the attractive part of the potential can affect the depth profiles.}, archive = {J_PRA}, author = {Kai Nordlund and Susi Lehtola and Gerhard Hobler}, doi = {10.1103/PhysRevA.111.032818}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032818}, shortjournal = {Phys. Rev. A}, title = {Repulsive interatomic potentials calculated at three levels of theory}, volume = {111}, year = {2025}, }
• (2025). Rovibrational quenching calculations of c2− in collision with h2. PRA, 111(3), 032817. (www)

  @article{ , abstract = {The molecular anion C 2 − has been of interest in the past few years as a candidate for laser cooling due to its electronic structure and favorable branching ratios to the ground electronic and vibrational states. Molecular hydrogen has been used by the Wester group at Innsbruck as a buffer gas to cool the molecule's internal rovibrational motion. In the present work we generate a five-dimensional (5D) interaction potential for the system by considering the H 2 as a rigid rotor and the C 2 − as a rotating-vibrating diatomic molecule. We then calculate the cross sections and rate coefficients for rovibrational inelastic collisions of C 2 − with both para- and ortho- H 2 on this 5D ab initio potential energy surface using quantum scattering theory for the dynamics. The rates for vibrational quenching are obtained over a range of temperatures that covers the single point measured by the experiments. A comparison is also made with earlier results which had used a simpler 3D interaction potential. Para- H 2 is found to be more efficient than ortho- H 2 (with or without also undergoing rotational excitation) in cooling C 2 − . The rate coefficients for cooling the anions have been computed by appropriately weighting the ortho- and para- H 2 and compared with the available experimental result at 20 K. The computed results are nearly two orders of magnitude larger than the single experimental point. When the vibrational deexcitation rate coefficients are employed without any concurrent rotational excitations in the final C 2 − anions (a situation considered to be nonphysical under the present experimental setup), the properly averaged results are found to get smaller and to become very close to the existing experimental measurements. The robustness of the present results is tested and confirmed. The implications of these results for laser cooling of C 2 − are analyzed and discussed.}, archive = {J_PRA}, author = {Kousik Giri and Barry Mant and Franco A. Gianturco and Roland Wester and Jan Franz and Rupayan Biswas and Upakarasamy Lourderaj and Narayanasami Sathyamurthy}, doi = {10.1103/PhysRevA.111.032817}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032817}, shortjournal = {Phys. Rev. A}, title = {Rovibrational quenching calculations of c2− in collision with h2}, volume = {111}, year = {2025}, }
• (2025). Beyond the phase stability in standard stark deceleration. PRA, 111(3), 032816. (www)

  @article{ , abstract = {Improving the number and number density of cold molecules is a longstanding goal in cold molecule research. Stark deceleration provides an important access to taming polar molecules and makes the collision and high-resolution spectroscopy a reality. However, the full deceleration efficiency of the traditional Stark decelerator has been impeded by its intrinsic loss mechanisms, which significantly limit its applications. In this paper, we introduce an interspersed guiding deceleration strategy that surpasses the periodic phase stability limitations of traditional Stark decelerator. Our approach is theoretically and experimentally validated using the molecule, achieving significant gains of for all final velocity ranges. Additionally, our method requires a lower operation number of switching that is beneficial for reducing the consumption of the high-voltage switches and suitable for controlling a large number of deceleration stages. This method is applicable to any traditional crossed-pin Stark decelerator and can stop a wider variety of molecular species with higher densities, including those with a small Stark shift-to-mass ratio. It is anticipated to become an essential tool for producing cold and dense molecular samples, offering promising prospects for cold collision studies and precision measurements.}, archive = {J_PRA}, author = {Qing Liu and Wenli Li and Shanwu Wang and Chenyue Pan and Du Wang and Tao Yang and Dongdong Zhang and Shunyong Hou and Jianping Yin}, doi = {10.1103/PhysRevA.111.032816}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032816}, shortjournal = {Phys. Rev. A}, title = {Beyond the phase stability in standard stark deceleration}, volume = {111}, year = {2025}, }
• (2025). Photon angular distribution in two-photon electron capture by H-like uranium. PRA, 111(3), 032815. (www)

  @article{ , abstract = {We present a comprehensive study of the angular distribution of photons emitted during resonant two-photon electron capture by H-like uranium ions. Focusing on the energies of incident electrons, for which the dielectronic recombination (DR) dominates, we analyze the angular emission spectrum of the most significant cascade transitions, which make the main contribution to the total cross section. In particular, we consider the cascade transitions that occur with the formation of ( 1 ⁢ 𝑠 ⁢ 2 ⁢ 𝑠 ) and ( 1 ⁢ 𝑠 ⁢ 2 ⁢ 𝑝 ) intermediate states. We investigate the angular distribution of the emitted photons beyond the single-photon approximation. We separately consider the contributions of the DR and the radiative recombination channels and demonstrate that the two-photon angular distribution shows strong interference between these channels.}, archive = {J_PRA}, author = {Konstantin N. Lyashchenko and Oleg Yu. Andreev and Deyang Yu}, doi = {10.1103/PhysRevA.111.032815}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032815}, shortjournal = {Phys. Rev. A}, title = {Photon angular distribution in two-photon electron capture by H-like uranium}, volume = {111}, year = {2025}, }
• (2025). Deciphering the coalescence behavior of coulomb-schrödinger atomic wave functions from an operator-product expansion. PRA, 111(3), 032814. (www)

  @article{ , abstract = {We revisit the coalescence behavior of the atomic Schrödinger wave functions from the angle of an operator-product expansion (OPE) within the nonrelativistic Coulomb-Schrödinger effective-field theory. We take the electron-nucleus coalescence as an explicit example to demonstrate our formalism, by proving an exact OPE relation to all orders in perturbation theory. As a consequence, the celebrated Kato's cusp condition can be readily reproduced. Our approach can be readily extended to ascertain the multiparticle coalescence behaviors of atomic wave functions, which are otherwise difficult to achieve from the conventional Schrödinger equation approach. Moreover, by incorporating relativistic effects, our OPE approach appears to be able to provide key insight for solving a 90-year-old puzzle concerning the peculiar coalescence behavior of the wave function for a Dirac hydrogen atom.}, archive = {J_PRA}, author = {Yingsheng Huang and Yu Jia and Rui Yu}, doi = {10.1103/PhysRevA.111.032814}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032814}, shortjournal = {Phys. Rev. A}, title = {Deciphering the coalescence behavior of coulomb-schrödinger atomic wave functions from an operator-product expansion}, volume = {111}, year = {2025}, }
• (2025). Optical-beat-frequency measurement of strong magnetic field using a cs micron-thick cell. PRA, 111(3), 032813. (www)

  @article{ , abstract = {Measuring strong magnetic fields with atoms holds promise for various scientific applications, yet enhancing measurement resolution remains a challenge. This paper demonstrates strong magnetic-field measurement using the saturated absorption spectrum of a cesium micron-thick cell (MC), where the magnetic-field strength is indicated by the Zeeman shift of spectral lines and assessed via beat-frequency measurements with two stabilized lasers. Theoretical calculations have been refined to better interpret the clear splitting of experimental saturated absorption spectra of the MC in inhomogeneous strong magnetic fields with suppressed crossover spectral lines, which facilitates the magnetic-field measurements. Our approach achieves a measurement resolution of 0.36 G in an ambient magnetic field of 610 G and can effectively track time-varying magnetic fields. The measurement scheme provides high measurement resolution, which is valuable for remotely monitoring nuclear reactors, characterizing particle accelerator magnets, and mapping the magnetic fields of sunspots.}, archive = {J_PRA}, author = {Junlong Han and Shuyuan Chen and Wei Xiao and Xiang Peng and Hong Guo}, doi = {10.1103/PhysRevA.111.032813}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032813}, shortjournal = {Phys. Rev. A}, title = {Optical-beat-frequency measurement of strong magnetic field using a cs micron-thick cell}, volume = {111}, year = {2025}, }
• (2025). Vacuum polarization corrections to hyperfine structure in many-electron atoms. PRA, 111(3), 032812. (www)

  @article{ , abstract = {We perform a theoretical study of vacuum polarization corrections to the hyperfine structure in many-electron atoms. Calculations are performed for systems of interest for precision atomic tests of fundamental physics belonging to the alkali-metal atoms and singly ionized alkaline earths. The vacuum polarization is considered in the Uehling approximation, and we study the many-body effects core relaxation, core polarization, and valence-core correlations in the relativistic framework. We find that for s states, the relative vacuum polarization correction may be well approximated by that for hydrogenlike ions, though for all other states an account of the many-body effects, in particular, the polarization of the core, is needed to obtain the correct sign and magnitude of the correction.}, archive = {J_PRA}, author = {J. C. Hasted and C. J. Fairhall and O. R. Smits and B. M. Roberts and J. S. M. Ginges}, doi = {10.1103/PhysRevA.111.032812}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032812}, shortjournal = {Phys. Rev. A}, title = {Vacuum polarization corrections to hyperfine structure in many-electron atoms}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic couplings as a stabilization mechanism in long-range rydberg molecules. PRA, 111(3), 032811. (www)

  @article{ , abstract = {Long-range Rydberg molecules are typically bound in wells formed in their oscillatory potential energy curves. In alkaline Rydberg molecules, bound vibrational states exist even when these potential wells are disrupted by level repulsion from the steep butterfly potential energy curve induced by a scattering shape resonance. The binding in this case is attributed to quantum reflection. However, the rapidly varying regions of the potential energy landscape where quantum reflection occurs often coincide with regions where nonadiabatic coupling becomes significant. By comparing the molecular states calculated within the Born-Oppenheimer approximation, where quantum reflection is the only binding mechanism, with those obtained from the full set of coupled channel equations, we assess the effects of nonadiabatic coupling on vibrational energies and lifetimes. Our findings show that these couplings can stabilize the molecule by providing an additional barrier which protects the vibrational states from predissociation and nonradiative transitions. There can also be extreme cases where nonadiabatic coupling completely dominates the binding and the molecular lifetimes saturate at the atomic Rydberg lifetime.}, archive = {J_PRA}, author = {Aileen A. T. Durst and Milena Simić and Neethu Abraham and Matthew T. Eiles}, doi = {10.1103/PhysRevA.111.032811}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032811}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic couplings as a stabilization mechanism in long-range rydberg molecules}, volume = {111}, year = {2025}, }
• (2025). Electron transfer and interatomic motion in two-center dielectronic recombination. PRA, 111(3), 032810. (www)

  @article{ , abstract = {The recombination of an incoming electron with an atomic cation , accompanied by energy transfer to a neighboring atom , which becomes electronically excited and subsequently relaxes radiatively, is investigated. The theory of this process, known as two-center dielectronic recombination (2CDR), is significantly extended to account for the interatomic motion between the two atoms involved. Additionally, the electron transfer mechanism, due to orbital overlap between the atoms, is incorporated into the model. Using the example reaction , we demonstrate that both interatomic motion and electron transfer have a substantial impact on the predicted efficiency of 2CDR. Our findings suggest that 2CDR can dominate over photorecombination across a much broader energy range of the incoming electron than previously estimated. Moreover, 2CDR is particularly efficient when the dimer dissociates during recombination, as this suppresses the energy transfer back to the captured electron, preventing its re-emission.}, archive = {J_PRA}, author = {Jan Philipp Drennhaus and Axel Molle and Jan Šenk and Elena Jahr and Elke Fasshauer and Federico M. Pont and Nicolas Sisourat}, doi = {10.1103/PhysRevA.111.032810}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032810}, shortjournal = {Phys. Rev. A}, title = {Electron transfer and interatomic motion in two-center dielectronic recombination}, volume = {111}, year = {2025}, }
• (2025). Lifetime measurement of the 5s5p1P1 state in strontium. PRA, 111(3), 032809. (www)

  @article{ , abstract = {We present a direct lifetime measurement of the state of strontium using time-correlated single-photon counting of laser-induced fluorescence in a hot atomic beam. To achieve fast switch-off times and a high signal-to-noise ratio, we excite the strontium atoms with a femtosecond pulsed laser at approximately 461 nm and collect the fluorescence onto a hybrid single-photon detector. Analysis of the measured exponential decay gives a lifetime of the state of ns, where all the systematic effects have been thoroughly considered.}, archive = {J_PRA}, author = {Ivana Puljić and Ana Cipriš and Damir Aumiler and Ticijana Ban and Neven Šantić}, doi = {10.1103/PhysRevA.111.032809}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032809}, shortjournal = {Phys. Rev. A}, title = {Lifetime measurement of the 5s5p1P1 state in strontium}, volume = {111}, year = {2025}, }
• (2025). D-electron contribution to the stopping power of transition metals. PRA, 111(3), 032808. (www)

  @article{ , abstract = {We present a nonperturbative model to describe the stopping power by ionization of the 𝑑 electrons of transition metals. These metals are characterized by the filling of the 𝑑 subshell and the promotion of some of the electrons to the conduction band. The contribution of 𝑑 electrons at low-impact energies has been noted experimentally in the past as a break of the linear dependence of the stopping power with the ion velocity. In this paper we describe the response of these electrons considering the atomic inhomogeneous momentum distribution. We focus on the transition metals of groups 10 and 11 in the Periodic Table: Ni, Pd, Pt, Cu, Ag, and Au. Results are shown to describe the low-energy stopping power, with good agreement with the experimental data and available time-dependent density-functional theory results. By combining the present nonperturbative model for the 𝑑 -subshell contribution with other approaches for the valence electrons and for the inner shells, we provide a coherent theoretical method capable of describing the stopping power of these transition metals from the very-low- to the high-energy region.}, archive = {J_PRA}, author = {J. P. Peralta and A. M. P. Mendez and D. M. Mitnik and C. C. Montanari}, doi = {10.1103/PhysRevA.111.032808}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032808}, shortjournal = {Phys. Rev. A}, title = {D-electron contribution to the stopping power of transition metals}, volume = {111}, year = {2025}, }
• (2025). Double and single K-shell-vacancy production of xenon atoms by 95–197-MeV/u xe54+-ion collisions. PRA, 111(3), 032807. (www)

  @article{ , abstract = {We probe the production of single and double -shell vacancies in xenon atoms during symmetric collisions with ions at 95, 146, and 197 MeV/u at the heavy-ion storage ring equipped with an internal gas-jet target. For each collision energy, the xenon x-ray spectra are measured at five observation angles, ranging from to with respect to the projectile beam. To resolve the measured Xe target x-ray spectra into four Gaussian peaks, including the hypersatellites and satellites of the lines, we develop a data-analysis method that reduces the fitting parameters from 12 to 6. The determined intensities of the hypersatellites and satellites, which shows no significant radiation anisotropy, are subsequently used to calculate the cross-section ratio for double-to-single -shell vacancy production in the Xe target atoms. The obtained values decrease from 0.286 0.036 to 0.176 0.021 as the collision energy increases. We compare these experimental results to relativistic time-dependent two-center calculations and find reasonable agreement between the theoretical predictions and the experimental data.}, archive = {J_PRA}, author = {Zhangyong Song and Caojie Shao and Deyang Yu and Yury S. Kozhedub and Kun Ma and Yingli Xue and Wei Wang and Mingwu Zhang and Junliang Liu and Bian Yang and Chenzhong Dong and Hongqiang Zhang and Xiaohong Cai}, doi = {10.1103/PhysRevA.111.032807}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032807}, shortjournal = {Phys. Rev. A}, title = {Double and single K-shell-vacancy production of xenon atoms by 95–197-MeV/u xe54+-ion collisions}, volume = {111}, year = {2025}, }
• (2025). Variational principles in ensemble and excited-state density- and potential-functional theories. PRA, 111(3), 032806. (www)

  @article{ , abstract = {Typical density-functional theory (DFT) and approximations thereto solve the many-electron ground-state problem by working from a numerically efficient noninteracting Kohn-Sham reference system and benefit from useful minimization conditions that allow iteration (i.e., self-consistency) to the optimal energy and density. This work reveals that ensembles of ground and excited states can also benefit from similar minimization conditions within ensemble DFT (EDFT) and potential functional theory (EPFT) frameworks. It then reveals that individual excited states also have state-specific stationary conditions that can be deduced from the ensemble solution and apply to EDFT and its EPFT counterpart. However, the state-specific stationary condition for the noninteracting Kohn-Sham EPFT is revealed to be more complicated than the ground-state problem, due in part to a contribution from density-driven correlations that are neglected in typical “ ” approaches. The importance of this term is scrutinized through exact and approximate examples. Some implications for self-consistency in exact theory and approximations are discussed.}, archive = {J_PRA}, author = {Tim Gould}, doi = {10.1103/PhysRevA.111.032806}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032806}, shortjournal = {Phys. Rev. A}, title = {Variational principles in ensemble and excited-state density- and potential-functional theories}, volume = {111}, year = {2025}, }
• (2025). One- and two-center effects in single ionization in high-energy collisions of protons and hydrogen molecules. PRA, 111(3), 032805. (www)

  @article{ , abstract = {Doubly differential and total cross sections for single ionization in collisions are evaluated in the continuum distorted wave with eikonal initial state model. One- and two-center models are used to represent the target molecule. In the two-center model, the initial orbitals are represented by Hartree-Fock (HF) or density functional methods, while the continuum wave function of the ejected electron is determined on the spherically averaged model potential derived from the ground-state configuration. In the one-center description of the molecule, both the initial and final orbitals are represented on the same potential. Cross sections evaluated with the HF description of the target are generally in good agreement with both experimental data and available theoretical calculations. Models describing the motion of the ejected electron in a potential field derived from a two-center description of the molecule underestimate the electron yield at backward emission angles. The inadequacy of these applications is related to the scattering of the electron by the target nucleus, which is more realistically considered in a calculation based on a one-center description of the molecule.}, archive = {J_PRA}, author = {L. Gulyás and S. Egri and T. Kirchner}, doi = {10.1103/PhysRevA.111.032805}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032805}, shortjournal = {Phys. Rev. A}, title = {One- and two-center effects in single ionization in high-energy collisions of protons and hydrogen molecules}, volume = {111}, year = {2025}, }
• (2025). Quantum-classical rate coefficients for o2 + n2 inelastic collisions with very high vibrational levels. PRA, 111(3), 032804. (www)

  @article{ , abstract = {Energy exchanges among internal energy modes in collisions directly affect the microscopic dynamical evolution of nonequilibrium phenomena in these gases. Quantum calculations of energy exchanges, especially those involving high molecular levels, are challenging due to their daunting computational costs. In this study, by capturing quantum effects associated with vibrational motions, we employ the improved mixed quantum-classical (MQC) method to obtain rate coefficients of both vibration-to-vibration (V-V) and vibration-to-translation or rotation (V-T–R) energy exchanges for collisions over a wide temperature range (100–9000 K). This approach permits the achievement of results up to vibrational levels close to the molecular dissociation limit. The adopted potential-energy surface (PES) is formulated using a proper representation of both intermolecular and intramolecular components to provide the dependence of the interaction energy on molecular separation distances and molecular deformations. Notably, the MQC calculations with the new PES yield vibrational relaxation rate coefficients consistent with experimental data. In addition to the comprehensive MQC data, we utilize Gaussian process regression to predict rates for processes not directly computed, thus completing the V-V and V-T–R datasets for selected processes across full vibrational levels of and . At low temperatures, notable anti-Arrhenius behavior is observed, which would enhance relaxation processes in cold environments typical of upper and planetary atmospheres. The extensive datasets are valuable for describing the kinetic behaviors of and across various vibrational levels and temperatures, aiding in addressing non-local thermodynamic equilibrium conditions where the influence of vibrationally excited air molecules cannot be ignored.}, archive = {J_PRA}, author = {Jiawei Yang and Qizhen Hong and Massimiliano Bartolomei and Fernando Pirani and Cecilia Coletti and Quanhua Sun and Jun Li}, doi = {10.1103/PhysRevA.111.032804}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032804}, shortjournal = {Phys. Rev. A}, title = {Quantum-classical rate coefficients for o2 + n2 inelastic collisions with very high vibrational levels}, volume = {111}, year = {2025}, }
• (2025). Fermi resonance in the radiative vibrational cooling dynamics of N2O+. PRA, 111(3), 032803. (www)

  @article{ , abstract = {Using time-resolved UV-laser spectroscopy up to a few seconds in a cryogenic ion storage ring, we observe that coupling of the stretching and bending modes via Fermi resonance considerably affects the vibrational radiative cooling process of the linear triatomic molecular ion isolated in vacuum. We state-selectively compare the cooling rates of vibrational states in the electronic ground states and , only one of which is under Fermi resonance. The vibrational radiative cooling rate of the vibrational state ( ) = (2 0 0) in the electronic ground state , which couples with (1 2 0) via Fermi resonance, is determined through the excitation to a predissociation channel. Here, and represent the vibrational quantum numbers of NN–O stretching, N–N–O bending, and N–NO stretching, respectively. We successfully find that the vibrational radiative cooling rate for the (2 0 0) state of is significantly slower than that of without the Fermi resonance coupling.}, archive = {J_PRA}, author = {S. Harayama and S. Kuma and N. Kimura and K. C. Chartkunchand and M. Baba and T. Murakami and T. Takayanagi and K. Yagi and T. Yamaguchi and Y. Nakano and T. Azuma}, doi = {10.1103/PhysRevA.111.032803}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032803}, shortjournal = {Phys. Rev. A}, title = {Fermi resonance in the radiative vibrational cooling dynamics of N2O+}, volume = {111}, year = {2025}, }
• (2025). Spectroscopy of electric dipole and quadrupole transitions in ra+224. PRA, 111(3), 032802. (www)

  @article{ , abstract = {We report on spectroscopy of the low-lying electronic transitions in . We measured the frequencies of the cooling transition, the clock transition, the electric dipole transition, and the cleanout transition. From these measurements we calculate the frequencies of the repump transition, the electric quadrupole transition, and the electric dipole transition. The ion's low charge-to-mass ratio and convenient wavelengths make a promising optical clock candidate.}, archive = {J_PRA}, author = {Spencer Kofford and Haoran Li and Robert Kwapisz and Roy A. Ready and Akshay Sawhney and Oi Chee Cheung and Mingyu Fan and Andrew M. Jayich}, doi = {10.1103/PhysRevA.111.032802}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032802}, shortjournal = {Phys. Rev. A}, title = {Spectroscopy of electric dipole and quadrupole transitions in ra+224}, volume = {111}, year = {2025}, }
• (2025). Application of general-order relativistic coupled-cluster theory to estimate electric-field-response clock properties of ca+ and yb+. PRA, 111(3), 032801. (www)

  @article{ , abstract = {Accurate calculations of electric dipole polarizabilities ( ), quadrupole moments ( ), and quadrupole polarizabilities ( ) for the clock states of the singly charged calcium ( ) and ytterbium ( ) ions are presented using the general-order relativistic coupled-cluster (RCC) theory. Precise knowledge of these quantities is immensely useful for estimating uncertainties caused by major systematic effects such as the linear and quadratic Stark shifts and black-body radiation shifts in the optical and clocks. A finite-field approach is adopted for estimating these quantities in which the first-order and second-order energy level shifts are analyzed by varying strengths of externally applied electric field and field- gradient. To achieve high-accuracy results in the heavier ion, we first calculate these properties in a relatively lighter clock candidate , which involves similar clock states. From these analyses, we learn that electron correlation effects arising from triple excitations in the RCC theory contribute significantly to the above properties, and are decisive factors in bringing the calculated values closer to the experimental results.}, archive = {J_PRA}, author = {YanMei Yu and B. K. Sahoo}, doi = {10.1103/PhysRevA.111.032801}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032801}, shortjournal = {Phys. Rev. A}, title = {Application of general-order relativistic coupled-cluster theory to estimate electric-field-response clock properties of ca+ and yb+}, volume = {111}, year = {2025}, }
• (2025). Photonic simulation of localization phenomena using boson sampling. PRA, 111(3), 032622. (www)

  @article{ , abstract = {Quantum simulation in its current state faces experimental overhead in terms of physical space and cooling. We propose boson sampling as an alternative compact synthetic platform performing at room temperature. Identifying the capability of estimating matrix permanents, we explore the applicability of boson sampling for tackling the dynamics of quantum systems without having access to information about the full state vector. By mapping the time-evolution unitary of a Hamiltonian onto an interferometer via continuous-variable gate decompositions, we present proof-of-principle results of localization characteristics of a single particle. We study the dynamics of one-dimensional tight-binding systems in the clean and quasiperiodic-disordered limits to observe Bloch oscillations and dynamical localization, and the delocalization-to-localization phase transition in the Aubry-André-Harper model, respectively. Our computational results obtained using boson sampling are in complete agreement with the dynamical and static results of noninteracting tight-binding systems obtained using conventional numerical calculations. Additionally, our study highlights the role of the number of sampling measurements or “shots” for simulation accuracy.}, archive = {J_PRA}, author = {Anuprita V. Kulkarni and Vatsana Tiwari and Auditya Sharma and Ankur Raina}, doi = {10.1103/PhysRevA.111.032622}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032622}, shortjournal = {Phys. Rev. A}, title = {Photonic simulation of localization phenomena using boson sampling}, volume = {111}, year = {2025}, }
• (2025). Quantum simulation of spin-1 XXZ heisenberg models and the haldane phase with dysprosium. PRA, 111(3), 032621. (www)

  @article{ , abstract = {Dysprosium atoms have proven to be a promising platform for quantum simulation due to their strong magnetic moment and high tunability of interactions. In this work, we propose dysprosium atoms for simulating the one-dimensional spin-1 XXZ Heisenberg model, which is known to have a rich phase diagram including the famous Haldane phase. To realize the model, we make use of the strong dipolar exchange interactions that naturally occur in the ground state of dysprosium due to its large electron angular momentum of J = 8. To implement spin-1 particles, we encode the spin degree of freedom into three Zeeman sublevels, which are energetically isolated by applying a magnetic field. Using the density-matrix renormalization group, we analyze the ground-state properties of the resulting effective model. We find that a chain of fermionic dysprosium atoms in a suitable magnetic field can form a Haldane state with the characteristic spin-1/2 edge modes. Furthermore, we discuss the use of AC Stark shifts and Raman-type schemes for bosonic dysprosium to isolate effective spin-1 systems and to increase the tunability of model parameters.}, archive = {J_PRA}, author = {Katharina Brechtelsbauer and Johannes Mögerle and Hans Peter Büchler}, doi = {10.1103/PhysRevA.111.032621}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032621}, shortjournal = {Phys. Rev. A}, title = {Quantum simulation of spin-1 XXZ heisenberg models and the haldane phase with dysprosium}, volume = {111}, year = {2025}, }
• (2025). Estimation of nuclear polarization via discrete measurement of nitrogen-vacancy-center spin evolution. PRA, 111(3), 032620. (www)

  @article{ , abstract = {We propose a method for the estimation of the initial polarization of spinful nuclei of the C 13 isotope in diamond via a measurement of the evolution of the coherence of a nitrogen-vacancy-center spin qubit. Existing polarization measurement methods are difficult to implement experimentally because they require direct interference in the environment of the qubit. Here, in order to obtain the information, it is necessary to measure the qubit coherence at certain points of time, which are unambiguously determined by the applied magnetic field. For sufficiently high magnetic fields, the minimum value of the measured coherence constitutes an upper bound on the product of the initial polarizations of each environmental spin. The most significant advantage of the method, which allows to infer initial values of nuclear polarizations without any direct access to the environment, lies in its simplicity and the small amount of experimental resources that it requires. We exemplify the operation of the scheme on a realistic, randomly generated environment of eight nuclear spins, obtaining a reasonably accurate estimation of the initial polarization.}, archive = {J_PRA}, author = {Mateusz Kuniej and Katarzyna Roszak}, doi = {10.1103/PhysRevA.111.032620}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032620}, shortjournal = {Phys. Rev. A}, title = {Estimation of nuclear polarization via discrete measurement of nitrogen-vacancy-center spin evolution}, volume = {111}, year = {2025}, }
• (2025). Enhancing the fidelity of stimulated raman transitions with simple phase shifts. PRA, 111(3), 032619. (www)

  @article{ , abstract = {We demonstrate that in stimulated Raman transitions introducing one or two simple phase shifts to the control fields significantly enhances the fidelity of state manipulation while simultaneously reducing leakage to the intermediate excited state. Our approach achieves high-fidelity quantum gate operations between the two target states under arbitrary detuning conditions. Notably, the average population in the intermediate excited state is approximately halved, without extending the overall evolution time. Additionally, our method exhibits greater robustness to static amplitude and detuning errors compared to conventional adiabatic elimination techniques, and maintains higher fidelity even in the presence of dissipation.}, archive = {J_PRA}, author = {Hua-Yang Wang and Xu-Yang Chen and Zhen-Yu Wang}, doi = {10.1103/PhysRevA.111.032619}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032619}, shortjournal = {Phys. Rev. A}, title = {Enhancing the fidelity of stimulated raman transitions with simple phase shifts}, volume = {111}, year = {2025}, }
• (2025). Efficient estimation of error bounds for quantum multiparametric imaging with constraints. PRA, 111(3), 032618. (www)

  @article{ , abstract = {Advanced superresolution imaging techniques require specific approaches for accurate and consistent estimation of the achievable spatial resolution. Fisher information supplied to the Cramér-Rao bound (CRB) has proved to be a powerful and efficient tool for resolution analysis and optical setups optimization. However, the standard CRB is not applicable to constrained problems violating the unbiasedness condition, while such models are frequently encountered in quantum imaging of complex objects. Complementary to the existing approaches based on modifying CRB, we propose a practical algorithm for approximate construction of a modified Fisher information matrix, which takes the constraints into account and enables accurate estimation of errors for constrained problems by the standard CRB. We demonstrate the efficiency of the proposed technique by applying it to one-, two-, and multiparameter model problems in quantum imaging. The approach provides quantitative explanation of previous results with successful experimental reconstruction of objects with the spatial scale smaller than the theoretical limit predicted by the standard CRB.}, archive = {J_PRA}, author = {Alexander Mikhalychev and Saif Almazrouei and Svetlana Mikhalycheva and Abdellatif Bouchalkha and Dmitri Mogilevtsev and Bobomurat Ahmedov}, doi = {10.1103/PhysRevA.111.032618}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032618}, shortjournal = {Phys. Rev. A}, title = {Efficient estimation of error bounds for quantum multiparametric imaging with constraints}, volume = {111}, year = {2025}, }
• (2025). Scalable and noise-robust communication advantage of multipartite quantum entanglement. PRA, 111(3), 032617. (www)

  @article{ , abstract = {Distributed computing, involving multiple servers collaborating on designated computations, faces a critical challenge in optimizing interserver communication—an issue central to the study of communication complexity. Quantum resources offer advantages over classical methods in addressing this challenge. In this work, we investigate a distributed computing scenario with multiple senders and a single receiver, establishing a scalable advantage of multipartite quantum entanglement in mitigating communication complexity. Specifically, we demonstrate that when the receiver and the senders share a multiqubit Greenberger-Horne-Zeilinger (GHZ) state—a quintessential form of genuine multipartite entanglement—certain global functions of the distributed inputs can be computed with only one bit of classical communication from each sender. In contrast, without entanglement, two bits of communication are required from all but one sender. Consequently, quantum entanglement reduces communication overhead by n − 1 bits for n senders, allowing for arbitrary scaling with an increasing number of senders. We also show that the entanglement-based protocol exhibits significant robustness under white noise, thereby establishing the potential for experimental realization of this quantum advantage.}, archive = {J_PRA}, author = {Ananya Chakraborty and Ram Krishna Patra and Kunika Agarwal and Samrat Sen and Pratik Ghosal and Sahil Gopalkrishna Naik and Manik Banik}, doi = {10.1103/PhysRevA.111.032617}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032617}, shortjournal = {Phys. Rev. A}, title = {Scalable and noise-robust communication advantage of multipartite quantum entanglement}, volume = {111}, year = {2025}, }
• (2025). Examination of the extended hong-ou-mandel effect and considerations for experimental detection. PRA, 111(3), 032616. (www)

  @article{ , abstract = {We investigate the recent multiphoton extension [Alsing et al. , Phys. Rev. A 105 , 013712 (2022) ] of the celebrated two-photon Hong-Ou-Mandel (HOM) effect [Hong, Ou, and Mandel, Phys. Rev. Lett. 59 , 2044 (1987) ] for the quantum interference of amplitudes that lead to complete destructive interference for coincident counts for the output of a balanced, lossless 50:50 beam splitter (BS). We examine the extended HOM (eHOM) effect by first investigating diagrammatically the multiphoton scattering of photons from the two input ports to the two output ports for Fock number basis states (FS) | n , m 〉 12 , and show that destructive interference occurs pairwise within the quantum amplitudes with many scattering components, generalizing the two-photon HOM effect. This analysis leads us to a general, simple analytical derivation of the eHOM effect for FS/FS inputs, which has profound implications for arbitrary bipartite photonic input states constructed from such basis states: if the input state to one input port of the BS is of odd parity, i.e., constructed only of odd numbers of photons, then regardless of the input state to the second 50:50 BS port, there will be a central nodal line (CNL) of zeros in the joint output probability distribution along the main diagonal for coincidence detection. We further examine the case of a single photon interacting with a coherent state (an idealized laser) and consider prospects for experimental detection by including additional effects such as imperfect detection efficiency and time delay between the detected output photons. This work highlights the importance of the nonclassicality of light, and in particular the interference effects stemming from the discreteness of photon quanta.}, archive = {J_PRA}, author = {Paul M. Alsing and Richard J. Birrittella}, doi = {10.1103/PhysRevA.111.032616}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032616}, shortjournal = {Phys. Rev. A}, title = {Examination of the extended hong-ou-mandel effect and considerations for experimental detection}, volume = {111}, year = {2025}, }
• (2025). Symmetry-protecting ansatz for the variational quantum eigensolver of mirror- and occupation-number-inversion-symmetrical systems. PRA, 111(3), 032615. (www)

  @article{ , abstract = {The variational quantum eigensolver (VQE) is considered one of the most powerful alternative approaches for near-term noisy intermediate-scale quantum devices. However, the successful implementation of the VQE is quite challenging, as the ansatz must be sufficiently expressive, yet, if it is overly expressive, it may hinder the optimization process of the VQE in finding the global minimum. To address this challenge of the VQE, a commonly used approach is to apply the symmetries of the system, which reduces the dimensionality of the parameter space for the VQE. Here, we propose a quantum circuit that can be used for systems with mirror symmetry and occupation-number-inversion symmetry. We demonstrate its usefulness by applying it to find the eigenenergies of the Anderson impurity model, a representative fundamental model for various quantum simulations. In addition, we demonstrate the usability of our quantum circuit by applying it to a quantum algorithm for Green's function, which plays a crucial role in understanding quantum systems of condensed matter physics.}, archive = {J_PRA}, author = {Gwangsu Yoo and Jaehyun Bae and Dae Sin Kim}, doi = {10.1103/PhysRevA.111.032615}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032615}, shortjournal = {Phys. Rev. A}, title = {Symmetry-protecting ansatz for the variational quantum eigensolver of mirror- and occupation-number-inversion-symmetrical systems}, volume = {111}, year = {2025}, }
• (2025). Two-dimensional topological effect in a transmon qubit array with tunable couplings. PRA, 111(3), 032614. (www)

  @article{ , abstract = {We investigate a square-lattice architecture of superconducting transmon qubits with interqubit interactions mediated by inductive couplers. Via periodically modulating the couplers, the Abelian gauge potential, termed effective magnetic flux, can be synthesized artificially, making the system an excellent platform for simulating two-dimensional topological physics. First, we focus on the three-leg ladder which only has three rows and investigate the chiral dynamics therein for the single-particle ground state when the effective magnetic flux varies. We find what we call the “staggered vortex-Meissner phase transition,” where the vortex number can typically stagger a few times between one (defined as “vortex phase”) and larger integers (defined as “Meissner phase”) when the effective magnetic flux changes between − π and π . This phenomenon, actually not a phase transition by definition, is quite different from the vortex-Meissner phase transition in the two-leg ladder that, in contrast, possesses only two rows and is usually treated as the quasi-two-dimensional model. Also, we find that the chiral current relies on the effective magnetic flux according to a squeezed sinusoidal function. Both the staggering of the vortex number and squeezing of the chiral current can be controllable by the coupling ratio, which is defined by the coupling-strength ratio between the column direction and row direction. Second, we continue to increase the number of rows beyond three, and the topological band structure to be anticipated at an infinite number of rows begins to occur even for a relatively small number (10 or so for typical parameters) of rows. This heralds a small circuit scale enough to observe the topological band. The behavior of the edge state in the band gap can be interpreted by the topological Chern number, which can be calculated through integrating the Berry curvature with respect to the first Brillouin zone. Last, we present a systematic method on how to measure the topological band structure based on time- and space-domain Fourier transformation of the wave function after properly exciting the qubits, which should be helpful for comprehensively analyzing the topological physics since all the topological properties are mainly contained in the band structure. Our results offer an avenue for simulating two-dimensional topological physics on the state-of-the-art superconducting quantum chips.}, archive = {J_PRA}, author = {Yan-Jun Zhao and Yu-Qi Wang and Yang Xue and Xun-Wei Xu and Yan-Yang Zhang and Wu-Ming Liu and Yu-xi Liu}, doi = {10.1103/PhysRevA.111.032614}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032614}, shortjournal = {Phys. Rev. A}, title = {Two-dimensional topological effect in a transmon qubit array with tunable couplings}, volume = {111}, year = {2025}, }
• (2025). Noise-resilient quantum random access codes. PRA, 111(3), 032613. (www)

  @article{ , abstract = {A quantum random access code (QRAC) is a communication task where Alice encodes classical bits into quantum states of dimension and transmits them to Bob, who performs appropriate measurements to recover the required bit with probability . In the presence of a noisy environment, the performance of a QRAC is degraded, losing the advantage over classical strategies. We propose a practical technique that enables noise tolerance in such scenarios, recovering the quantum advantage in retrieving the required bit. We perform a photonic implementation of a QRAC using polarization-encoded qubits under an amplitude-damping channel, where simple operations allow for noise robustness showing the revival of the quantum advantage when the noisy channel degrades the performance of the QRAC. This revival can be observed by violating a suitable dimension witness, which is closely related to the average success probability of the QRAC. This technique can be extended to other applications in the so-called prepare-and-measure scenario, enhancing the semi-device-independent protocol implementations.}, archive = {J_PRA}, author = {H. S. Karthik and S. Gómez and F. M. Quinteros and Akshata Shenoy H and M. Pawłowski and S. P. Walborn and G. Lima and E. S. Gómez}, doi = {10.1103/PhysRevA.111.032613}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032613}, shortjournal = {Phys. Rev. A}, title = {Noise-resilient quantum random access codes}, volume = {111}, year = {2025}, }
• (2025). Imaginary hamiltonian variational ansatz for combinatorial optimization problems. PRA, 111(3), 032612. (www)

  @article{ , abstract = {Obtaining exact solutions to combinatorial optimization problems using classical computing is computationally expensive. The current tenet in the field is that quantum computers can address these problems more efficiently. While promising algorithms require fault-tolerant quantum hardware, variational algorithms have emerged as viable candidates for near-term devices. The success of these algorithms hinges on multiple factors, with the design of the Ansatz being of the utmost importance. It is known that popular approaches such as the quantum approximate optimization algorithm (QAOA) and quantum annealing suffer from adiabatic bottlenecks, which lead to either larger circuit depth or evolution time. On the other hand, the evolution time of imaginary-time evolution is bounded by the inverse energy gap of the Hamiltonian, which is constant for most noncritical physical systems. In this work we propose an imaginary Hamiltonian variational Ansatz ( ) inspired by quantum imaginary-time evolution to solve the MaxCut problem. We introduce a tree arrangement of the parametrized quantum gates, enabling the exact solution of arbitrary tree graphs using the one-round . For randomly generated -regular graphs, we numerically demonstrate that the solves the MaxCut problem with a small constant number of rounds and sublinear depth, outperforming the QAOA, which requires rounds increasing with the graph size. Furthermore, our Ansatz solves the MaxCut problem exactly for graphs with up to 24 nodes and , whereas only approximate solutions can be derived by the classical near-optimal Goemans-Williamson algorithm. We validate our simulated results with hardware demonstrations on a graph with 67 nodes.}, archive = {J_PRA}, author = {Xiaoyang Wang and Yahui Chai and Xu Feng and Yibin Guo and Karl Jansen and Cenk Tüysüz}, doi = {10.1103/PhysRevA.111.032612}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032612}, shortjournal = {Phys. Rev. A}, title = {Imaginary hamiltonian variational ansatz for combinatorial optimization problems}, volume = {111}, year = {2025}, }
• (2025). Implementing transferable annealing protocols for combinatorial optimization on neutral-atom quantum processors: A case study on smart charging of electric vehicles. PRA, 111(3), 032611. (www)

  @article{ , abstract = {In the quantum optimization paradigm, variational quantum algorithms face challenges with hardware-specific and instance-dependent parameter tuning, which can lead to computational inefficiencies. The promising potential of parameter transferability across problem instances with similar local structures has been demonstrated in the context of the quantum approximate optimization algorithm. In this paper we build on these advancements by extending the concept to annealing-based protocols, employing Bayesian optimization to design robust quasiadiabatic schedules. Our study reveals that, for maximum independent set problems on graph families with shared geometries, optimal parameters naturally concentrate, enabling efficient transferability between similar instances and from smaller to larger ones. Experimental results on the Orion Alpha platform validate the effectiveness of our approach, scaling to problems with up to 100 qubits. We apply this method to address a smart-charging optimization problem on a real dataset. These findings highlight a scalable, resource-efficient path for hybrid optimization strategies applicable in real-world scenarios.}, archive = {J_PRA}, author = {Lucas Leclerc and Constantin Dalyac and Pascale Bendotti and Rodolphe Griset and Joseph Mikael and Loic Henriet}, doi = {10.1103/PhysRevA.111.032611}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032611}, shortjournal = {Phys. Rev. A}, title = {Implementing transferable annealing protocols for combinatorial optimization on neutral-atom quantum processors: A case study on smart charging of electric vehicles}, volume = {111}, year = {2025}, }
• (2025). Mixed-state quantum denoising diffusion probabilistic model. PRA, 111(3), 032610. (www)

  @article{ , abstract = {Generative quantum machine learning has gained significant attention for its ability to produce quantum states with desired distributions. Among various quantum generative models, quantum denoising diffusion probabilistic models (QuDDPMs) [Zhang et al. , Phys. Rev. Lett. 132 , 100602 (2024) ] provide a promising approach with stepwise learning that resolves the training issues. However, the requirement of high-fidelity scrambling unitaries in QuDDPMs poses a challenge to near-term implementation. We propose a mixed-state quantum denoising diffusion probabilistic model (MSQuDDPM) to eliminate the need for scrambling unitaries. Our approach focuses on adapting the quantum noise channels to the model architecture, which integrates depolarizing noise channels in the forward diffusion process and parameterized quantum circuits with projective measurements in the backward denoising steps. We also introduce several techniques to improve MSQuDDPM, including a cosine-exponent schedule of noise interpolation, the use of a single-qubit random ancilla, and superfidelity-based cost functions to enhance the convergence. We evaluate MSQuDDPM on quantum ensemble generation tasks, demonstrating its successful performance.}, archive = {J_PRA}, author = {Gino Kwun and Bingzhi Zhang and Quntao Zhuang}, doi = {10.1103/PhysRevA.111.032610}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032610}, shortjournal = {Phys. Rev. A}, title = {Mixed-state quantum denoising diffusion probabilistic model}, volume = {111}, year = {2025}, }
• (2025). Microwave-activated two-qubit gates for fixed-coupling and fixed-frequency transmon qubits. PRA, 111(3), 032609. (www)

  @article{ , abstract = {All-microwave control of fixed-frequency superconducting quantum systems offers the potential to reduce control circuit complexity and increase system coherence. Nevertheless, due to the limited control flexibility in qubit parameters, one has to address several issues, such as quantum crosstalk and frequency crowding, for scaling up qubit architecture with nontunable elements. This paper proposes a microwave-activated two-qubit gate scheme for two fixed-frequency transmon qubits coupled via a fixed-frequency transmon coupler. The protocol relies on applying a microwave pulse exclusively to the coupler, enabling the implementation of a controlled- gate. We show that the gate fidelity exceeding 0.999 can be achieved within 150 ns, excluding decoherence effects. Moreover, we also show that leakage from the computational subspace to noncomputational states can also be effectively suppressed.}, archive = {J_PRA}, author = {Ling Jiang and Peng Xu and Shengjun Wu and Jian-An Sun and Fu-Quan Dou}, doi = {10.1103/PhysRevA.111.032609}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032609}, shortjournal = {Phys. Rev. A}, title = {Microwave-activated two-qubit gates for fixed-coupling and fixed-frequency transmon qubits}, volume = {111}, year = {2025}, }
• (2025). Finite-key interfering-or-not-interfering quantum key distribution without intensity modulation. PRA, 111(3), 032608. (www)

  @article{ , abstract = {This paper presents an enhanced interfering-or-not-interfering quantum key distribution (INI-QKD) protocol incorporating a scheme without intensity modulation (IM), which circumvents the impulse correlation issue associated with IM. Based on the minimum smooth entropy, we derive the key rate for finite code lengths and estimate the phase bit error rate using a no-decoy state method. Simulation results show that the protocol achieves the maximum communication distance of 337 km with quantum bit error rate of approximately 0.36 % . Moreover, the feasibility of using fewer phase plates ( M = 6 , 8 ) to realize discrete random phases in INI-QKD is also verified. Notably, the INI-QKD without IM exhibits significant advantages under polarization misalignment and phase mismatch conditions, reflecting greater adaptability to complex environments. By simplifying experimental setups and reducing the technical challenges, the INI-QKD without IM provides an alternative realization idea in the field of quantum communication.}, archive = {J_PRA}, author = {Yue Li and Kaiyi Shi and Haoyang Wang and Chang Liu and Yujia Zhang and Duo Ma and Haiqiang Ma}, doi = {10.1103/PhysRevA.111.032608}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032608}, shortjournal = {Phys. Rev. A}, title = {Finite-key interfering-or-not-interfering quantum key distribution without intensity modulation}, volume = {111}, year = {2025}, }
• (2025). Cheaper and more noise-resilient quantum state preparation using eigenvector continuation. PRA, 111(3), 032607. (www)

  @article{ , abstract = {Subspace methods are powerful, noise-resilient methods that can effectively prepare ground states on quantum computers. The challenge is to get a subspace with a small condition number that spans the states of interest using minimal quantum resources. In this work, we will use eigenvector continuation to build a subspace from the low-lying states of a set of Hamiltonians. The basis vectors are prepared using truncated versions of standard state preparation methods such as imaginary-time evolution (ITE), adiabatic state preparation (ASP), and variational quantum eigensolver. By using these truncated methods combined with eigenvector continuation, we can directly improve upon them, obtaining more accurate ground-state energies at a reduced cost. We use several spin systems to demonstrate convergence even when methods like ITE and ASP fail, such as ASP in the presence of level crossings and ITE with vanishing energy gaps. We also showcase the noise resilience of this approach beyond the gains already made by having shallower quantum circuits. Our findings suggest that eigenvector continuation can be used to improve existing state preparation methods in the near term.}, archive = {J_PRA}, author = {Anjali A. Agrawal and João C. Getelina and Akhil Francis and A. F. Kemper}, doi = {10.1103/PhysRevA.111.032607}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032607}, shortjournal = {Phys. Rev. A}, title = {Cheaper and more noise-resilient quantum state preparation using eigenvector continuation}, volume = {111}, year = {2025}, }
• (2025). Universal control in bosonic systems with weak kerr nonlinearities. PRA, 111(3), 032606. (www)

  @article{ , abstract = {Resonators with weak single-photon self-Kerr nonlinearities can theoretically be used to prepare Fock states in the presence of a loss much larger than their nonlinearities. Two necessary ingredients are large displacements and a two-photon (parametric) drive. Here, we find that these systems can be controlled to achieve any desired gate operation in a finite-dimensional subspace (whose dimensionality can be chosen at will). Moreover, we show that the two-photon driving requirement can be relaxed and that full controllability is achievable with only one-photon (linear) drives. We make use of both Trotter-Suzuki decompositions and gradient-based optimization to find control pulses for a desired gate, which reduces the computational overhead by using a small blockaded subspace. We also discuss the infidelity arising from input power limitations in realistic settings, as well as from corrections to the rotating-wave approximation. Our universal control protocol opens the possibility for quantum information processing using a wide range of lossy systems with weak nonlinearities.}, archive = {J_PRA}, author = {Ming Yuan and Alireza Seif and Andrew Lingenfelter and David I. Schuster and Aashish A. Clerk and Liang Jiang}, doi = {10.1103/PhysRevA.111.032606}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032606}, shortjournal = {Phys. Rev. A}, title = {Universal control in bosonic systems with weak kerr nonlinearities}, volume = {111}, year = {2025}, }
• (2025). Momentum-entangled two-photon interference for quantum-limited transverse-displacement estimation. PRA, 111(3), 032605. (www)

  @article{ , abstract = {We propose a scheme achieving the ultimate quantum precision for the estimation of the transverse displacement between two interfering photons. Such a transverse displacement could be caused, for example, by the refracting properties of the propagation medium or by the orientation of a system of mirrors. By performing transverse-momentum sampling interference between polarization-entangled pairs of photons that propagate with different momenta, we show that it is possible to perform transverse-displacement estimation with a precision that increases with the difference of the transverse momenta of the photons. We show that the precision achieved with our scheme is independent of the value of the displacement, which is useful when tracking a variable displacement. Moreover, only for small displacements, we show that the estimation can be performed without the need for transverse-momentum-resolving detectors. More fundamentally, we demonstrate that it is the quantum interference arising from two-photon entanglement in the transverse momenta at the very heart of the foreseen quantum-limited sensitivity in the spatial domain.}, archive = {J_PRA}, author = {Danilo Triggiani and Vincenzo Tamma}, doi = {10.1103/PhysRevA.111.032605}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032605}, shortjournal = {Phys. Rev. A}, title = {Momentum-entangled two-photon interference for quantum-limited transverse-displacement estimation}, volume = {111}, year = {2025}, }
• (2025). Generation of arbitrary high-dimensional qudit-based entangled states. PRA, 111(3), 032604. (www)

  @article{ , abstract = {The generation of a high-dimensional quantum entangled state provides a crucial resource for achieving more complex and diverse quantum information processing tasks. In this paper, we present two deterministic protocols designed for the generation of a four-dimensional two-qudit Bell state and three-qudit Greenberger-Horne-Zeilinger (GHZ) state assisted by cross-Kerr nonlinearity, where the four-dimensional qudit is encoded in the hybrid polarization-spatial state of the single photon to conserve quantum resources and alleviate environmental noise. The proposed protocols for generating a four-dimensional two-qudit Bell state and three-qudit GHZ state are circuit concise, high success, robust fidelity, noise resistant, and resource saving. Moreover, the four-dimensional -qudit ( ) GHZ states can be generated with the help of the generating devices of the four-dimensional Bell state. Consequently, its efficiency and fidelity decay exponentially by a factor of . Further, the arbitrary high-dimensional qudit-encoded entangled states can be achieved with linear-optics four-dimensional single-qudit gates and gates. These protocols offer a reference for further advancements in high-dimensional state generation technology and providing insights for the practical implementations of metrological enhancement, quantum simulation, high-dimensional quantum computation, and quantum error correction.}, archive = {J_PRA}, author = {Fang-Fang Du and Ming Ma and Zhuo-Ya Bai and Qiu-lin Tan}, doi = {10.1103/PhysRevA.111.032604}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032604}, shortjournal = {Phys. Rev. A}, title = {Generation of arbitrary high-dimensional qudit-based entangled states}, volume = {111}, year = {2025}, }
• (2025). Cooperative sensing with impurities in a two-dimensional subwavelength array. PRA, 111(3), 032603. (www)

  @article{ , abstract = {We propose a versatile quantum sensing protocol based on two dissipatively coupled distant atoms embedded as impurities in a two-dimensional subwavelength atomic array. The array acts analogously to a waveguide or cavity for the emitter light, where a modified decay environment creates cooperative enhancement, allowing for more efficient population transfer. By measuring the population of one of the impurity atoms, it is possible to detect frequency shifts in the emitters' resonance frequencies. We analytically estimate achievable sensitivities as well as the dependence on various system parameters. The proposed protocol is robust against various environmental factors and perturbations, which enhances its applicability in real-world scenarios.}, archive = {J_PRA}, author = {Oliver August Dall'Alba Sandberg and Stefan Ostermann and Susanne F. Yelin}, doi = {10.1103/PhysRevA.111.032603}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032603}, shortjournal = {Phys. Rev. A}, title = {Cooperative sensing with impurities in a two-dimensional subwavelength array}, volume = {111}, year = {2025}, }
• (2025). Magnetic-field-independent spin-exchange relaxation-free magnetometer. PRA, 111(3), 032602. (www)

  @article{ , abstract = {Spin-exchange relaxation-free magnetometers based on dense ensembles of alkali-metal spins are precision quantum sensors that hold the record of measured and projected sensitivity to magnetic fields, in the microgauss to milligauss range. At geomagnetic fields however, these sensors quickly lose their magnetic sensitivity due to spin decoherence by random spin-exchange collisions. Here we discover that atoms with nuclear spin can operate in the spin-exchange relaxation-free regime even at high magnetic field. We counterintuitively show that frequent collisions between a dense and optically inaccessible gas with another optically accessible spin gas ( ) improve the fundamental magnetic sensitivity of the latter. We analyze the performance of a dual-species potassium and atomic hydrogen magnetometer and project a fundamental sensitivity of about at geomagnetic fields for feasible experimental conditions.}, archive = {J_PRA}, author = {Mark Dikopoltsev and Uriel Levy and Or Katz}, doi = {10.1103/PhysRevA.111.032602}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032602}, shortjournal = {Phys. Rev. A}, title = {Magnetic-field-independent spin-exchange relaxation-free magnetometer}, volume = {111}, year = {2025}, }
• (2025). Amplitude amplification and estimation using the atom-optics kicked rotor. PRA, 111(3), 032601. (www)

  @article{ , abstract = {The atom-optics realization of the quantum kicked rotor represents one of the most well-studied experimental platforms for the physics of Anderson localization. In this work, we show that the same platform can be used to implement a quantum algorithm to perform quantum amplitude amplification (AA), a generalization of Grover's search algorithm. This is done using the usual kick sequence in combination with the well established technique of Raman velocity selection. We argue that this platform is well suited to implement AA, as its characteristic property of localization can be exploited to enhance the performance of the amplitude amplification algorithm by reducing its average runtime. We also introduce a kick potential which asymptotically leads to the optimal quantum speedup, constituting a complementary approach. Finally, we demonstrate that the scheme is fairly robust to noise in the kicks and discuss the experimental feasibility of each component of our proposal}, archive = {J_PRA}, author = {Keshav V and M. S. Santhanam}, doi = {10.1103/PhysRevA.111.032601}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032601}, shortjournal = {Phys. Rev. A}, title = {Amplitude amplification and estimation using the atom-optics kicked rotor}, volume = {111}, year = {2025}, }
• (2025). Perfect chiral quantum routing. PRA, 111(3), 032439. (www)

  @article{ , abstract = {Routing classical and quantum information is a fundamental task for quantum information technologies and processes. Here, we consider information encoded in the position of a quantum walker on a graph, and we design an optimal structure to achieve perfect quantum routing, exploiting chirality and weighting of the edges. The topology, termed the lily graph , enables perfect (i.e., with fidelity one) and robust routing of classical (localized) or quantum (superposition) states of the walker to n different, orthogonal, spatial regions of the graph, corresponding to the n possible outputs of the device. The routing time is independent of the input signal and the number of outputs, making our scheme a robust and scalable solution for all quantum networks.}, archive = {J_PRA}, author = {Simone Cavazzoni and Giovanni Ragazzi and Paolo Bordone and Matteo G. A. Paris}, doi = {10.1103/PhysRevA.111.032439}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032439}, shortjournal = {Phys. Rev. A}, title = {Perfect chiral quantum routing}, volume = {111}, year = {2025}, }
• (2025). Noise-adapted qudit codes for amplitude-damping noise. PRA, 111(3), 032438. (www)

  @article{ , abstract = {Quantum error correction (QEC) plays a critical role in preventing information loss in quantum systems and provides a framework for reliable quantum computation. Identifying quantum codes with nice code parameters for physically motivated noise models remains an interesting challenge. While past work has primarily focused on qubit codes, here we identify a [4,1] qudit error correcting code tailored to protect against amplitude-damping noise. We show that this four-qudit code satisfies the error correction conditions for all single-qudit and a few two-qudit damping errors up to the leading order in the damping parameter γ . We devise a protocol to extract syndromes that unambiguously identify this set of errors, leading to a noise-adapted recovery scheme that achieves a fidelity loss of O ( γ 2 ) . For the d = 2 case, our QEC scheme is identical to the known example of the four-qubit code and the associated syndrome-based recovery. We also assess the performance of this code using the Petz recovery map and note some interesting deviations from the qubit case. Finally, we generalize this construction to a family of [ 2 M + 2 , M ] qudit codes that can approximately correct all the single-qudit and a few two-qudit amplitude-damping errors.}, archive = {J_PRA}, author = {Sourav Dutta and Debjyoti Biswas and Prabha Mandayam}, doi = {10.1103/PhysRevA.111.032438}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032438}, shortjournal = {Phys. Rev. A}, title = {Noise-adapted qudit codes for amplitude-damping noise}, volume = {111}, year = {2025}, }
• (2025). Braiding majorana zero modes in a two-dimensional grid structure. PRA, 111(3), 032437. (www)

  @article{ , abstract = {Constructing Majorana zero modes (MZMs) is one of the most promising schemes for achieving topological quantum computing. However, recent research primarily focuses on preparing stable materials that carry MZMs and detecting their existence. Further combining structures that carry MZMs for quantum computing would facilitate the synergistic development of material fabrication and quantum computing. Here, we take the T-junction structure carrying MZMs as the basic unit to construct a two-dimensional (2D) grid structure. Based on this structure, the protocols for performing braiding operations for single-qubit and two-qubit gates are defined. Furthermore, the Deutsch-Jozsa (D-J) algorithm is derived to demonstrate the vast application potential of the 2D grid structure in more complex quantum algorithms.}, archive = {J_PRA}, author = {Shilong Li and Linsheng Bao and Shipeng Huang and Jiayun Ning and Aoqian Shi and Peng Peng and Jianjun Liu}, doi = {10.1103/PhysRevA.111.032437}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032437}, shortjournal = {Phys. Rev. A}, title = {Braiding majorana zero modes in a two-dimensional grid structure}, volume = {111}, year = {2025}, }
• (2025). Enhanced compressive threshold quantum state tomography for qudit systems. PRA, 111(3), 032436. (www)

  @article{ , abstract = {We propose an efficient quantum state tomography method inspired by compressed sensing and threshold quantum state tomography that can drastically reduce the number of measurement settings to reconstruct the density matrix of an -qudit system. We validate our algorithm with demonstrations on IBMQ and show the efficient and accurate reconstruction of qubit systems, reproducing GHZ, and random states with , and settings.}, archive = {J_PRA}, author = {Giovanni Garberoglio and Maurizio Dapor and Diego Maragnano and Marco Liscidini and Daniele Binosi}, doi = {10.1103/PhysRevA.111.032436}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032436}, shortjournal = {Phys. Rev. A}, title = {Enhanced compressive threshold quantum state tomography for qudit systems}, volume = {111}, year = {2025}, }
• (2025). Nonconvex optimization strategy for computing convex-roof entanglement. PRA, 111(3), 032435. (www)

  @article{ , abstract = {We develop a numerical methodology for the computation of entanglement measures for mixed quantum states. Using the well-known Schrödinger-Hughston-Jozsa-Wootters theorem, the computation of convex-roof entanglement measures is reframed as a search for unitary matrices: a nonconvex optimization problem. To address this nonconvexity, we modify a genetic algorithm, known in the literature as differential evolution, constraining the search space to unitary matrices by using a QR factorization. We then refine results using a quasi-Newton method. We benchmark our method on simple test problems and, as an application, compute entanglement between a system and its environment over time for pure dephasing evolutions. We also study the temperature dependence of Gibbs state entanglement for a class of block-diagonal Hamiltonians to provide a complementary test scenario with a set of entangled states that are qualitatively different. We find that the method works well enough to reliably reproduce entanglement curves, even for comparatively large systems. The modified genetic algorithm is a derivative-free, nonconvex computational method that broadly applies to the computation of convex-roof entanglement measures.}, archive = {J_PRA}, author = {Jimmie Adriazola and Katarzyna Roszak}, doi = {10.1103/PhysRevA.111.032435}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032435}, shortjournal = {Phys. Rev. A}, title = {Nonconvex optimization strategy for computing convex-roof entanglement}, volume = {111}, year = {2025}, }
• (2025). Long-distance genuine multipartite entanglement between magnetic defects in spin chains. PRA, 111(3), 032434. (www)

  @article{ , abstract = {We investigate the emergence and properties of long-distance genuine multipartite entanglement, induced via three localized magnetic defects, in a one-dimensional transverse-field X X spin- 1 / 2 chain. Using both analytical and numerical techniques, we determine the conditions for the existence of bound states localized at the defects. We find that the reduced density matrix (RDM) of the defects exhibits long-distance genuine multipartite entanglement (GME) across the whole range of the Hamiltonian parameter space, including regions where the two-qubit concurrence is zero. We quantify the entanglement by using numerical lower bounds for the GME concurrence, as well as by analytically deriving the GME concurrence in regions where the RDM is of rank 2. Our work provides insights into generating multipartite entanglement in many-body quantum systems via local control techniques.}, archive = {J_PRA}, author = {Mirko Consiglio and Jovan Odavić and Riccarda Bonsignori and Gianpaolo Torre and Marcin Wieśniak and Fabio Franchini and Salvatore M. Giampaolo and Tony J. G. Apollaro}, doi = {10.1103/PhysRevA.111.032434}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032434}, shortjournal = {Phys. Rev. A}, title = {Long-distance genuine multipartite entanglement between magnetic defects in spin chains}, volume = {111}, year = {2025}, }
• (2025). Quantum pushforward designs. PRA, 111(3), 032433. (www)

  @article{ , abstract = {Designs, structures connected to averaging with respect to a given measure using finite sets of points, have proven themselves to be invaluable tools across the field of quantum information, finding their uses in state and process tomography, key distribution, and others. In this work, we introduce a concept of pushforward designs that allows us to obtain new structures from already existing ones by mapping them between the spaces, with specific examples including simplex designs and mixed state designs from complex projective designs. Based on the general concept, we put forward a structure called channel -design, allowing for averaging over space of quantum channels for systems in contact with an environment of dimension . Based on this notion, we introduce the concept of effective environment dimensionality , which we estimate for the IBM Kyoto quantum computer to be below 2.2 for times up to .}, archive = {J_PRA}, author = {Jakub Czartowski and Karol Życzkowski}, doi = {10.1103/PhysRevA.111.032433}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032433}, shortjournal = {Phys. Rev. A}, title = {Quantum pushforward designs}, volume = {111}, year = {2025}, }
• (2025). Symmetric measurement-induced lower bounds of concurrence. PRA, 111(3), 032432. (www)

  @article{ , abstract = {We provide a class of lower bounds for concurrence based on symmetric measurements. We show that our lower bounds estimate the quantum entanglement better than some existing lower bounds by detailed examples. Moreover, our lower bounds can be experimentally identified without state tomography.}, archive = {J_PRA}, author = {Hao-Fan Wang and Shao-Ming Fei}, doi = {10.1103/PhysRevA.111.032432}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032432}, shortjournal = {Phys. Rev. A}, title = {Symmetric measurement-induced lower bounds of concurrence}, volume = {111}, year = {2025}, }
• (2025). Generalized no-flipping theorem as a consequence of commutation of spacelike operations. PRA, 111(3), 032431. (www)

  @article{ , abstract = {A quantum flipping device is a theoretical apparatus designed to transform an input quantum state, represented by the density operator acting on a -dimensional Hilbert space , into an output state residing within the subspace orthogonal to . While the no-flipping theorem establishes the impossibility of such a device for qubits (two-dimensional systems), its extension to higher-dimensional systems ( ) allows for the possibility of such devices due to the increased space available for the output state. In this paper, we derive an impossibility theorem for generalized flipping devices, applicable to higher-dimensional systems, based on a causal principle, namely, commutation of spacelike operations. Given a bipartite quantum state shared between two parties Alice and Bob, this principle prohibits the resulting state from depending on the time order of Alice's and Bob's spacelike separated local operations applied on the respective parts of the bipartite systems. Importantly, unlike the argument applied to qubits, our approach does not rely on the unitary dynamics postulate of quantum theory. Furthermore, we investigate the implications of violating the principle of commutation of spacelike operations and demonstrate that such violations do not necessarily entail a violation of the no-signaling principle.}, archive = {J_PRA}, author = {Anandamay Das Bhowmik and Tathagata Gupta and Preeti Parashar and Guruprasad Kar and Manik Banik}, doi = {10.1103/PhysRevA.111.032431}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032431}, shortjournal = {Phys. Rev. A}, title = {Generalized no-flipping theorem as a consequence of commutation of spacelike operations}, volume = {111}, year = {2025}, }
• (2025). Quantum search with the signless laplacian. PRA, 111(3), 032430. (www)

  @article{ , abstract = {Continuous-time quantum walks are typically effected by either the discrete Laplacian or the adjacency matrix. In this paper, we explore a third option: the signless Laplacian, which has applications in algebraic graph theory and may arise in layered antiferromagnetic materials. We explore spatial search on the complete bipartite graph, which is generally irregular and breaks the equivalence of the three quantum walks for regular graphs, and where the search oracle breaks the equivalence of the Laplacian and signless Laplacian quantum walks on bipartite graphs without the oracle. We prove that a uniform superposition over all the vertices of the graph partially evolves to the marked vertices in one partite set, with the choice of set depending on the jumping rate of the quantum walk. We boost this success probability to 1 by proving that a particular nonuniform initial state completely evolves to the marked vertices in one partite set, again depending on the jumping rate. For some parameter regimes, the signless Laplacian yields the fastest search algorithm of the three, suggesting that it could be a new tool for developing faster quantum algorithms.}, archive = {J_PRA}, author = {Molly E. McLaughlin and Thomas G. Wong}, doi = {10.1103/PhysRevA.111.032430}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032430}, shortjournal = {Phys. Rev. A}, title = {Quantum search with the signless laplacian}, volume = {111}, year = {2025}, }
• (2025). Photonic parameter-shift rule: Enabling gradient computation for photonic quantum computers. PRA, 111(3), 032429. (www)

  @article{ , abstract = {We present a method for gradient computation in quantum algorithms implemented on linear optical quantum computing platforms. While parameter-shift rules have become a staple in qubit gate-based quantum computing for calculating gradients, their direct application to photonic platforms has been hindered by the infinite dimensionality of phase-shift operators in Fock space. We introduce a photonic parameter-shift rule that overcomes this limitation, providing an exact formula for gradient computation in linear optical quantum processors. Our method scales linearly with the number of input photons and utilizes the same parametrized photonic circuit with shifted parameters for each evaluation. This advancement bridges a crucial gap in photonic quantum computing, enabling efficient gradient-based optimization for variational quantum algorithms on near-term photonic quantum processors. We demonstrate the efficacy of our approach through numerical simulations in quantum chemistry and generative modeling tasks, showing superior optimization performance as well as robustness to noise from finite sampling and photon distinguishability compared to other gradient-based and gradient-free methods.}, archive = {J_PRA}, author = {Axel Pappalardo and Pierre-Emmanuel Emeriau and Giovanni de Felice and Brian Ventura and Hugo Jaunin and Richie Yeung and Bob Coecke and Shane Mansfield}, doi = {10.1103/PhysRevA.111.032429}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032429}, shortjournal = {Phys. Rev. A}, title = {Photonic parameter-shift rule: Enabling gradient computation for photonic quantum computers}, volume = {111}, year = {2025}, }
• (2025). Emergent non-markovianity and dynamical quantification of the quantum switch. PRA, 111(3), 032428. (www)

  @article{ , abstract = {We investigate the dynamical aspects of the quantum switch and find a particular form of quantum memory emerging out of the switch action. We first analyze the loss of information in a general quantum evolution subjected to a quantum switch and propose a measure to quantify the switch-induced memory. We then derive an uncertainty relation between information loss and switch-induced memory. We explicitly consider the example of depolarizing dynamics and show how it is affected by the action of a quantum switch. For a more detailed analysis, we consider both the control qubit and the final measurement on the control qubit as noisy and investigate the said uncertainty relation. Further, while deriving the Lindblad-type dynamics for the reduced operation of the switch action, we identify that the switch-induced memory actually leads to the emergence of non-Markovianity. Interestingly, we demonstrate that the emergent non-Markovianity can be explicitly attributed to the switch operation by comparing it with other standard measures of non-Markovianity. Our investigation thus paves the way forward to understanding the quantum switch as an emerging non-Markovian quantum memory.}, archive = {J_PRA}, author = {Vishal Anand and Ananda G. Maity and Subhadip Mitra and Samyadeb Bhattacharya}, doi = {10.1103/PhysRevA.111.032428}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032428}, shortjournal = {Phys. Rev. A}, title = {Emergent non-markovianity and dynamical quantification of the quantum switch}, volume = {111}, year = {2025}, }
• (2025). Improved performance of the bacon-shor code with steane's syndrome extraction method. PRA, 111(3), 032427. (www)

  @article{ , abstract = {We compare Steane's and Shor's syndrome extraction methods on the Bacon-Shor code. We propose a straightforward strategy based on postselection to prepare the logical | 0 〉 L and | + 〉 L states of the Bacon-Shor code by using flaglike qubits to verify their constituent Greenberger-Horne-Zeilinger states. We perform stabilizer simulations with a circuit-level, depolarizing Pauli error model and find that Steane's method significantly outperforms Shor's. Not only does Steane's method result in pseudothresholds that are about one order of magnitude higher than Shor's, but also its advantage increases monotonically as we go from a distance-3 to a distance-9 Bacon-Shor code. The advantage of Steane's method is the greatest in the regime where gate errors dominate over measurement errors. Some of the circuit constructions we propose for Steane's method are not formally fault tolerant yet outperform the formally fault-tolerant Shor's protocols for experimentally relevant physical error rates. This suggests that constructing formally fault-tolerant circuits that maintain the full code distance is not strictly necessary to guarantee the usefulness of a quantum error-correcting protocol. Despite relying on postselection, we find that our methods can be efficient. These protocols would be naturally implementable on a platform with long-range qubit interactions like trapped ions or neutral atoms.}, archive = {J_PRA}, author = {Guillermo Escobar-Arrieta and Mauricio Gutiérrez}, doi = {10.1103/PhysRevA.111.032427}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032427}, shortjournal = {Phys. Rev. A}, title = {Improved performance of the bacon-shor code with steane's syndrome extraction method}, volume = {111}, year = {2025}, }
• (2025). Measurement-device-independent entanglement witnesses with imprecise input states. PRA, 111(3), 032426. (www)

  @article{ , abstract = {Measurement-device-independent entanglement witnesses (MDI-EWs) enable the detection of entanglement without relying on characterized measurements. However, entanglement criteria for MDI-EWs typically assume the idealized condition that the laboratory input states are precisely the desired ones. In this work, we remove this idealization by considering the realistic scenario in which laboratory input states may be imprecise. We specify a class of MDI-EWs, termed sensitive MDI-EWs, whose entanglement criteria fail under any nonzero imprecision in the input states. We derive sufficient conditions for an MDI-EW to be classified as sensitive, revealing that a large class of MDI-EWs exhibit this sensitivity, consistent with the intuition that sensitive MDI-EWs are common. Additionally, we demonstrate that two well-known MDI-EWs for Werner states are sensitive according to our criteria, one of which recovers the result from a previous study [ Phys. Rev. A 104 , 012429 (2021) ]. Moreover, we clarify the concept of laboratory input states in a way that makes imprecisions experimentally measurable and propose a systematic approach for modifying the criterion of any MDI-EW to accommodate small imprecisions, thus enhancing experimental relevance. A simple MDI-EW example is provided, where our modified criterion is already optimal. This work bridges the gap between idealized theoretical models and practical experimental conditions, paving the way for more robust and accessible entanglement detection in real-world settings.}, archive = {J_PRA}, author = {Xing-Chen Guo and Mao-Sheng Li}, doi = {10.1103/PhysRevA.111.032426}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032426}, shortjournal = {Phys. Rev. A}, title = {Measurement-device-independent entanglement witnesses with imprecise input states}, volume = {111}, year = {2025}, }
• (2025). Analysis of the relationship between imaginarity and entanglement. PRA, 111(3), 032425. (www)

  @article{ , abstract = {Imaginary numbers play an important role in physics, especially in quantum physics. They are not only a part of describing the dynamic behavior of quantum systems, but also play a key role in the phase and interference phenomena of quantum states. Similar to coherence and entanglement, the imaginarity has been regarded as a quantum resource, further revealing the nonclassical properties of quantum systems and providing new research directions and applications for fields such as quantum computing and quantum communication. In our work, we mainly explore the quantitative relationship between imaginarity and entanglement. For an arbitrary quantum state, there exists a general quantitative relationship between imaginarity and entanglement. For a given class of quantum states, where the closest real states to them are diagonal states, there exists an imaginarity-entanglement inequality. We demonstrate that for these quantum states, any degree of imaginarity with respect to some reference basis can be transformed into entanglement through incoherent real operations. This discovery allows us to define an entanglement-based imaginarity quantifier for these states in quantum systems of arbitrary dimensions and to study their properties. It is shown that for these quantum states, imaginarity and entanglement are operationally equivalent. Our work provides a clear quantitative and operational link between imaginarity and entanglement.}, archive = {J_PRA}, author = {Yanna Sun and Ruonan Ren and Yiran Wang and Yongming Li}, doi = {10.1103/PhysRevA.111.032425}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032425}, shortjournal = {Phys. Rev. A}, title = {Analysis of the relationship between imaginarity and entanglement}, volume = {111}, year = {2025}, }
• (2025). Logical coherence in two-dimensional compass codes. PRA, 111(3), 032424. (www)

  @article{ , abstract = {Two-dimensional compass codes are a family of quantum error-correcting codes that contain the Bacon-Shor codes, the -Shor and -Shor codes, and the rotated surface codes. Previous numerical results suggest that the surface code has a constant accuracy and coherence threshold under uniform coherent rotation. However, having analytical proof supporting a constant threshold is still an open problem. It is analytically proven that the toric code can exponentially suppress logical coherence in the code distance . However, the current analytical lower bound on the threshold for the rotation angle is , which linearly vanishes in instead of being constant. We show that this lower bound is achievable by the -Shor code, which does not have a threshold under stochastic noise. Compass codes provide a promising direction to improve on the previous bounds. We analytically determine thresholds for two new compass code families that provide upper and lower bounds to the rotated surface code's numerically established infidelity threshold. Furthermore, using a Majorana mode-based simulator, we use random families of compass codes to smoothly interpolate between the -Shor codes and the -Shor codes.}, archive = {J_PRA}, author = {Balint Pato and J. Wilson Staples and Kenneth R. Brown}, doi = {10.1103/PhysRevA.111.032424}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032424}, shortjournal = {Phys. Rev. A}, title = {Logical coherence in two-dimensional compass codes}, volume = {111}, year = {2025}, }
• (2025). Entanglement of assistance as a measure of multiparty entanglement. PRA, 111(3), 032423. (www)

  @article{ , abstract = {Quantifying multipartite entanglement poses a significant challenge in quantum information theory, prompting recent advancements in methodologies to assess it. We introduce the notion of “volume of assistance” (VoA), which computes the geometric mean of entanglement of assistance across all potential parties. We demonstrate the feasibility of VoA for three-qubit pure states and certain classes of pure tripartite qudit states. We have extended this measure to four-qubit states and general multipartite scenarios. We have done a comparative analysis to illustrate VoA's distinctiveness from established entanglement measures, notably showing it serves as an upper bound for the much celebrated generalized geometric measure. Remarkably, VoA excels in distinguishing a broad class of states that elude differentiation by the recently proposed Minimum Pairwise Concurrence measure. Finally, VoA is applied to quantify genuine entanglement in the ground states of a three-qubit Heisenberg X Y model, which highlights its practical utility in quantum information processing tasks.}, archive = {J_PRA}, author = {Indranil Biswas and Atanu Bhunia and Subrata Bera and Indrani Chattopadhyay and Debasis Sarkar}, doi = {10.1103/PhysRevA.111.032423}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032423}, shortjournal = {Phys. Rev. A}, title = {Entanglement of assistance as a measure of multiparty entanglement}, volume = {111}, year = {2025}, }
• (2025). Hodge theory for entanglement cohomology. PRA, 111(3), 032422. (www)

  @article{ , abstract = {We explore and extend the application of homological algebra to describe quantum entanglement, initiated by Mainiero [ arXiv:1901.02011 ], focusing on the Hodge-theoretic structure of entanglement cohomology in finite-dimensional quantum systems. We construct analogs of the Hodge star operator, inner product, codifferential, and Laplacian for entanglement k -forms. We also prove that such k -forms obey versions of the Hodge isomorphism theorem and Hodge decomposition, and that they exhibit Hodge duality. As a corollary, we conclude that the dimensions of the k th and ( n − k ) − th cohomologies coincide for entanglement in n -partite pure states, which explains a symmetry property (“Poincaré duality”) of the associated Poincaré polynomials.}, archive = {J_PRA}, author = {Christian Ferko and Eashan Iyer and Kasra Mossayebi and Gregor Sanfey}, doi = {10.1103/PhysRevA.111.032422}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032422}, shortjournal = {Phys. Rev. A}, title = {Hodge theory for entanglement cohomology}, volume = {111}, year = {2025}, }
• (2025). Stabilizer testing and central limit theorem. PRA, 111(3), 032421. (www)

  @article{ , abstract = {In this paper we introduce the concept of stabilizer convolution and demonstrate that the only convolutions that can be used for stability testing are stabilizer convolutions. Moreover, using any stabilizer convolution yields similarly good results. Through the Choi-Jamiołkowski isomorphism, this method can also be applied to Clifford testing for quantum gates. Leveraging the invariance of circuit magic classes of mean states under stabilizer self-convolution, we formulate a central limit theorem for circuit magic classes of quantum states. Moreover, employing the Choi-Jamiołkowski correspondence, we generalize this finding to establish a central limit theorem for circuit magic classes of completely positive and trace-preserving channels.}, archive = {J_PRA}, author = {Wenlong Sun and Yuanfeng Jin and Gang Lu and Yang Liu}, doi = {10.1103/PhysRevA.111.032421}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032421}, shortjournal = {Phys. Rev. A}, title = {Stabilizer testing and central limit theorem}, volume = {111}, year = {2025}, }
• (2025). Qubit-state purity oscillations from anisotropic transverse noise. PRA, 111(3), 032420. (www)

  @article{ , abstract = {We explore the dynamics of qubit-state purity in the presence of transverse noise that is anisotropically distributed in the Bloch-sphere plane. We perform Ramsey experiments with noise injected along a fixed laboratory-frame axis and observe oscillations in the purity at twice the qubit frequency arising from the intrinsic qubit Larmor precession. We probe the oscillation dependence on the noise anisotropy, orientation, and power spectral density, using a low-frequency fluxonium qubit. Our results elucidate the impact of transverse noise anisotropy on qubit decoherence and may be useful for disentangling charge and flux noise in superconducting quantum circuits.}, archive = {J_PRA}, author = {David A. Rower and Kotaro Hida and Lamia Ateshian and Helin Zhang and Junyoung An and Max Hays and Sarah E. Muschinske and Christopher M. McNally and Samuel C. Alipour-Fard and Réouven Assouly and Ilan T. Rosen and Bethany M. Niedzielski and Mollie E. Schwartz and Kyle Serniak and Jeffrey A. Grover and William D. Oliver}, doi = {10.1103/PhysRevA.111.032420}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032420}, shortjournal = {Phys. Rev. A}, title = {Qubit-state purity oscillations from anisotropic transverse noise}, volume = {111}, year = {2025}, }
• (2025). Machine learning meeting the clauser-horne-shimony-holt scenario. PRA, 111(3), 032419. (www)

  @article{ , abstract = {In this work we perform a comprehensive study of the machine learning (ML) methods for the purpose of characterizing the quantum set of correlations. As our main focus is on assessing the usefulness and effectiveness of the ML approach, we focus exclusively on the Clauser-Horne-Shimony-Holt scenario, both the four-dimensional variant, for which an analytical solution is known, and the eight-dimensional variant, for which no analytical solution is known but numerical approaches are relatively well understood. We consider a wide selection of approaches, ranging from simple data science models to dense neural networks. The two classes of models that perform well are support vector machines and dense neural networks, and they are the main focus of this work. We conclude that while it is relatively easy to achieve good performance on average, it is hard to train a model that performs well on the hard cases, i.e., points in the vicinity of the boundary of the quantum set, which are precisely the cases that are interesting from the academic point of view. In order to improve performance on hard cases we must, especially for the eight-dimensional problem, resort to a tailored choice of training data, which means that we are implicitly feeding our intuition and biases into the model. We feel that this is an important and often overlooked aspect of applying ML models to academic problems, where data generation or data selection is performed according to some implicit subjective criteria. In this way, it is possible to unconsciously steer our model so that it exhibits features that we are interested in seeing. Hence, special care must be taken while determining whether ML methods can be considered objective and unbiased in the context of academic problems.}, archive = {J_PRA}, author = {Gabriel Pereira Alves and Nicolas Gigena and Jędrzej Kaniewski}, doi = {10.1103/PhysRevA.111.032419}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032419}, shortjournal = {Phys. Rev. A}, title = {Machine learning meeting the clauser-horne-shimony-holt scenario}, volume = {111}, year = {2025}, }
• (2025). Impact of reservoir squeezing on quantum-memory-assisted entropic uncertainty relations. PRA, 111(3), 032418. (www)

  @article{ , abstract = {The entropic uncertainty principle imposes a limit on how precisely two incompatible observables can be measured, which can be reduced when quantum memory is involved. We theoretically investigate the dynamics of the quantum-memory-assisted entropic uncertainty relation when either quantum memory alone or both the measured particle and the quantum memory interact with a squeezed-vacuum bath through energy-preserving interactions. We show that in both scenarios, the squeezing phase of the reservoir decreases the entropic uncertainty (EU), whereas the squeezing strength increases the EU. In addition, we find that EU can be significantly reduced when both the measured particle and quantum memory are subjected to a common squeezed-vacuum bath. Furthermore, we explore the key factors controlling the behavior of EU by exploring the competition between quantum discord and minimal missing information. Moreover, we examine the tightness of the entropic uncertainty bound (EUB) in both system-environment setups and observe that the EUB is less tight when both the measured particle and quantum memory are coupled to a common squeezed-vacuum bath.}, archive = {J_PRA}, author = {Hamad Ali and Abdul Basit and Peng-Bo Li}, doi = {10.1103/PhysRevA.111.032418}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032418}, shortjournal = {Phys. Rev. A}, title = {Impact of reservoir squeezing on quantum-memory-assisted entropic uncertainty relations}, volume = {111}, year = {2025}, }
• (2025). Topological quantum state transfer beyond the single-excitation assumption. PRA, 111(3), 032417. (www)

  @article{ , abstract = {As is well known, within the single-excitation subspace, the Su-Schrieffer-Heeger (SSH) model exhibits a remarkable ability to transfer an excitation from one end of the lattice to the other. In this work, by relaxing the restriction of the single excitation, we find that a topological channel formed by the topological edge modes of the SSH model can also realize the transfer of arbitrary Gaussian states. Specifically, we investigate the state transfer process within a one-dimensional (1D) optomechanical lattice, which can be mapped to the SSH model with tunable coupling strength. By initially preparing the first optical mode in a squeezed vacuum state and adiabatically varying the system parameters over a full cycle, the squeezed vacuum state can be transferred to the mechanical mode. Furthermore, we extend our investigation to the transfer of arbitrary Gaussian states. Since Gaussian states can be described by the covariance matrix of the system, we reformulate the evolution equation of the covariance matrix in a Schrödinger-type equation. This reformulation provides us with an intuitive way to show how an arbitrary Gaussian state is transferred. Our work broadens the application of topological systems for quantum state transfer, demonstrating that not only single-excitation states but also arbitrary Gaussian states, which include multiple excitations and quantum coherence, can be efficiently transferred, with potential implications for quantum information processing.}, archive = {J_PRA}, author = {X. Z. Hao and X. Y. Zhang and X. X. Yi}, doi = {10.1103/PhysRevA.111.032417}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032417}, shortjournal = {Phys. Rev. A}, title = {Topological quantum state transfer beyond the single-excitation assumption}, volume = {111}, year = {2025}, }
• (2025). Exploring non-markovianity in ergodic channels: Measuring memory retention through ergotropy. PRA, 111(3), 032416. (www)

  @article{ , abstract = {In this work, we introduce and characterize a broad class of quantum operations with a unique fixed point, termed quantum ergodic channels. We derive Lindblad-type master equations for these channels in arbitrary finite dimensions and analyze their non-Markovian dynamics using established measures. When the fixed point is a passive state, the channels exhibit ergotropy dynamics with notable thermodynamic implications. Specifically, under Markovian processes, ergotropy (a measure of the extractable work from a system under unitary evolution) monotonically decreases. However, in non-Markovian dynamics, ergotropy fluctuates, leading to a backflow effect that highlights memory-induced resource recovery. Our findings suggest that this ergotropy backflow could serve as an operationally meaningful indicator of non-Markovianity, offering new perspectives on the interplay between memory effects and thermodynamic behavior in open quantum systems. This study enhances the theoretical framework for understanding energy dynamics under ergodic channels and highlights new avenues for exploring the implications of memory effects in quantum batteries.}, archive = {J_PRA}, author = {Ritam Basu and Anish Chakraborty and Himanshu Badhani and Mir Alimuddin and Samyadeb Bhattacharya}, doi = {10.1103/PhysRevA.111.032416}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032416}, shortjournal = {Phys. Rev. A}, title = {Exploring non-markovianity in ergodic channels: Measuring memory retention through ergotropy}, volume = {111}, year = {2025}, }
• (2025). Observation of collective einstein-podolsky-rosen steering in three-qubit systems. PRA, 111(3), 032415. (www)

  @article{ , abstract = {Collective Einstein-Podolsky-Rosen (EPR) steering is a unique multipartite resource that enables the realization of more secure communication protocols. However, due to the lack of suitable experimental criteria, research on collective EPR steering has so far been limited to continuous variable systems. Here, we employ the coherence-based collective EPR steering criteria proposed by Mondal et al. [ Phys. Rev. A 99 , 012312 (2019) ] and develop a semidefinite programming method to find the optimal measurement settings. Experimentally, we take the three-qubit generalized Greenberger-Horne-Zeilinger states and generalized states as examples, demonstrating that collective EPR steering can be observed by detecting the average norm of coherence of the steered subsystem. We also explored the effect of measurement settings on complementarity relations between different collective steering criteria, and established a connection between collective steering and coherence complementarity. Our paper fills a gap in the verification of collective steerability in discrete variable systems and reveals a profound connection between EPR steering and quantum coherence.}, archive = {J_PRA}, author = {Wen-Qi Fan and Yong-Jian Gu and Ya Xiao}, doi = {10.1103/PhysRevA.111.032415}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032415}, shortjournal = {Phys. Rev. A}, title = {Observation of collective einstein-podolsky-rosen steering in three-qubit systems}, volume = {111}, year = {2025}, }
• (2025). Continuous-time quantum optimization without the adiabatic principle. PRA, 111(3), 032414. (www)

  @article{ , abstract = {Continuous-time quantum algorithms for combinatorial optimization problems, such as quantum annealing, have previously been motivated by the adiabatic principle. A number of continuous-time approaches exploit dynamics, however, and therefore are no longer physically motivated by the adiabatic principle. In this work, we take Planck's principle as the underlying physical motivation for continuous-time quantum algorithms. Planck's principle states that the energy of an isolated system cannot decrease as the result of a cyclic process. We use this principle to justify monotonic schedules in quantum annealing, which are not adiabatic. This approach also highlights the limitations of reverse quantum annealing in an isolated system.}, archive = {J_PRA}, author = {Robert J. Banks and Georgios S. Raftis and Dan E. Browne and P. A. Warburton}, doi = {10.1103/PhysRevA.111.032414}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032414}, shortjournal = {Phys. Rev. A}, title = {Continuous-time quantum optimization without the adiabatic principle}, volume = {111}, year = {2025}, }
• (2025). X+y floquet code: A simple example for topological quantum computation in the path-integral approach. PRA, 111(3), 032413. (www)

  @article{ , abstract = {The path-integral approach to topological quantum error correction provides a unified way to construct and analyze fault-tolerant circuits in spacetime. In this work, we demonstrate its utility and versatility at hand of a simple example: We construct a fault-tolerant circuit for the toric-code phase by traversing its path integral on a cubic lattice in the direction. The circuit acts on qubits on a square lattice, and alternates between horizontal nearest-neighbor gates and vertical nearest-neighbor and measurements. We show how to incorporate boundaries and corners into the fault-tolerant circuit and how to perform topologically protected logic gates. As a specific example, we consider performing a fault-tolerant logical measurement via lattice surgery of two spatial rectangular blocks of our fault-tolerant circuit.}, archive = {J_PRA}, author = {Andreas Bauer}, doi = {10.1103/PhysRevA.111.032413}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032413}, shortjournal = {Phys. Rev. A}, title = {X+y floquet code: A simple example for topological quantum computation in the path-integral approach}, volume = {111}, year = {2025}, }
• (2025). Entanglement entropy dynamics of non-gaussian states in free boson systems: Random sampling approach. PRA, 111(3), 032412. (www)

  @article{ , abstract = {We develop a random sampling method for calculating the time evolution of the Rényi entanglement entropy after a quantum quench from an insulating state in free boson systems. Because of the non-Gaussian nature of the initial state, calculating the Rényi entanglement entropy calls for the exponential cost of computing a matrix permanent. We numerically demonstrate that a simple random sampling method reduces the computational cost of a permanent; for an 𝑁 s × 𝑁 s matrix corresponding to 𝑁 s sites at half filling, the sampling cost becomes 𝑂 ⁡ ( 2 𝛼 ⁢ 𝑁 s ) with a constant 𝛼 ≪ 1 , in contrast to the conventional algorithm with the 𝑂 ⁡ ( 2 𝑁 s ) number of summations requiring the exponential time cost. Although the computational cost is still exponential, this improvement allows us to obtain the entanglement entropy dynamics in free boson systems for more than 100 sites. We present several examples of the entanglement entropy dynamics in low-dimensional free boson systems.}, archive = {J_PRA}, author = {Ryui Kaneko and Daichi Kagamihara and Ippei Danshita}, doi = {10.1103/PhysRevA.111.032412}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032412}, shortjournal = {Phys. Rev. A}, title = {Entanglement entropy dynamics of non-gaussian states in free boson systems: Random sampling approach}, volume = {111}, year = {2025}, }
• (2025). Quantum combinatorial optimization beyond the variational paradigm: Simple schedules for hard problems. PRA, 111(3), 032411. (www)

  @article{ , abstract = {Advances in quantum algorithms suggest a tentative scaling advantage on certain combinatorial optimization problems. Recent work, however, has also reinforced the idea that barren plateaus render variational algorithms ineffective on large Hilbert spaces. Hence, finding annealing protocols by variation ultimately appears to be difficult. Similarly, the adiabatic theorem fails on hard problem instances with first-order quantum phase transitions. Here we show how to use the spin coherent-state path integral to shape the geometry of quantum adiabatic evolution, leading to annealing protocols at polynomial overhead that provide orders-of-magnitude improvements in the probability to measure optimal solutions, relative to linear protocols. These improvements are not obtained on a controllable toy problem but on randomly generated hard instances (Sherrington-Kirkpatrick and maximum 2-satisfiability), making them generic and robust. Our method works for large systems and may thus be used to improve the performance of state-of-the-art quantum devices.}, archive = {J_PRA}, author = {Tim Bode and Krish Ramesh and Tobias Stollenwerk}, doi = {10.1103/PhysRevA.111.032411}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032411}, shortjournal = {Phys. Rev. A}, title = {Quantum combinatorial optimization beyond the variational paradigm: Simple schedules for hard problems}, volume = {111}, year = {2025}, }
• (2025). Quantum coherence: A fundamental resource for establishing genuine multipartite correlations. PRA, 111(3), 032410. (www)

  @article{ , abstract = {We establish the profound equivalence between the coherence measures defined via the convex roof method and two classes of genuine multipartite entanglement (GME) under certain conditions. Initially we construct two distinct classes of measures for genuine multipartite entanglement utilizing real symmetric concave functions and the convex roof technique. We then demonstrate that all coherence measures for any qudit states, defined through the convex roof approach, are identical to our two classes of GME measures of the states combined with an incoherent ancilla under an incoherent unitary operation. This relationship implies that genuine multipartite entanglement can be generated from the coherence incoherent in an initial state through the incoherent unitary operations. Furthermore, we conduct a preliminary exploration into the interplay between coherence and genuine quantum correlations such as genuine multipartite steering and genuine multipartite nonlocality. We show that the coherence exists in a qubit state if and only if genuine multipartite nonlocality is present for the special three-qubit states, obtained by performing unitary incoherent operations on the tensor product of the qubit state and the incoherent ancilla. Moreover, under the above process, we prove that the coherence of the qubit state exists if and only if the corresponding special state is genuinely multipartite steerable.}, archive = {J_PRA}, author = {Zong Wang and Zhihua Guo and Zhihua Chen and Ming Li and Zihang Zhou and Chengjie Zhang and Shao-Ming Fei and Zhihao Ma}, doi = {10.1103/PhysRevA.111.032410}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032410}, shortjournal = {Phys. Rev. A}, title = {Quantum coherence: A fundamental resource for establishing genuine multipartite correlations}, volume = {111}, year = {2025}, }
• (2025). Tensor networks and efficient descriptions of classical data. PRA, 111(3), 032409. (www)

  @article{ , abstract = {We investigate the potential of tensor-network-based machine-learning methods to scale to large image and text datasets. We study how the mutual information between a subregion and its complement scales with the subsystem size , similarly to approaches used in quantum many-body physics. Using various mutual information (MI) estimation methods, including an autoregressive network-based estimator, we find that simple image datasets exhibit area law scaling, suggesting efficient representation by two-dimensional tensor networks. More complex image datasets exceed the area law, indicating the need for generalized tensor network states or hybrid models. For Wikipedia text data, we observe power-law scaling with , approaching a volume law. This implies that one-dimensional tensor networks with area law entanglement may not efficiently capture the structure of text. We introduce two models to reproduce this scaling: a quantum-inspired random pair toy model and a linguistically motivated Markovian dependency tree model. In the latter model, matching the observed MI scaling allows us to infer the word-word correlation length distribution in text.}, archive = {J_PRA}, author = {Sirui Lu and Márton Kanász-Nagy and Ivan Kukuljan and J. Ignacio Cirac}, doi = {10.1103/PhysRevA.111.032409}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032409}, shortjournal = {Phys. Rev. A}, title = {Tensor networks and efficient descriptions of classical data}, volume = {111}, year = {2025}, }
• (2025). Tradeoff between noise and banding in a quantum adder with qudits. PRA, 111(3), 032408. (www)

  @article{ , abstract = {Quantum addition based on the quantum Fourier transform can be an integral part of a quantum circuit and proved to be more efficient than the existing classical ripple carry adder. Our study includes identifying the quantum resource required in a quantum adder in any arbitrary dimension and its relationship with the performance indicator in the presence of local noise acting on the circuit and when a limited number of controlled rotation operations is permitted, a procedure known as banding. We analytically prove an upper bound on the number of the controlled rotation gates required to accomplish the quantum addition up to an arbitrary defect in the fidelity between the desired and imperfect output. When the environment interacts with individual qudits, we establish a connection between quantum coherence and fidelity of the output. Interestingly, we demonstrate that when banding is employed in the presence of noise, approximate circuits of constant depth outperform circuits with a higher number of controlled rotations, establishing a complementary relationship between the approximate quantum adder and the strength of the noise. We exhibit that utilizing magnetic fields to prepare an initial state that evolves according to a one-dimensional spin chain for a specific amount of time can be a potential technique to implement quantum addition circuits in many-body systems.}, archive = {J_PRA}, author = {Gaurang Agrawal and Tanoy Kanti Konar and Leela Ganesh Chandra Lakkaraju and Aditi Sen(De}, doi = {10.1103/PhysRevA.111.032408}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032408}, shortjournal = {Phys. Rev. A}, title = {Tradeoff between noise and banding in a quantum adder with qudits}, volume = {111}, year = {2025}, }
• (2025). Sub-shot-noise sensitivity via superpositions of two deformed kitten states. PRA, 111(3), 032407. (www)

  @article{ , abstract = {In the present work we explore nonclassical effects in the phase space of two superposed kitten states induced by photon addition and subtraction operations applied in different sequences. We investigate two scenarios: In the first, photon addition is applied to the state, followed by photon subtraction, while in the second, the order of operations is reversed. We demonstrate that applying multiphoton operations to the state results in notable nearly isotropic sub-Planck structures, with the characteristics of these structures being influenced by the photon addition and subtraction. Increasing the number of added photons compresses the sub-Planck structures in both cases. Photon subtraction, however, has the opposite effect on the sub-Planck structures in the first case and no effect in the second. Furthermore, we observe that the optimal choices of multiphoton operations lead to improved isotropy of sub-Planck structures in our cases. The presence of the sub-Planck structures in our states leads to improved sensitivity to displacements, exceeding the standard quantum limit, as verified across all the depicted scenarios.}, archive = {J_PRA}, author = {Naeem Akhtar and Xiaosen Yang and Jia-Xin Peng and Inaam Ul Haq and Yuee Xie and Yuanping Chen}, doi = {10.1103/PhysRevA.111.032407}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032407}, shortjournal = {Phys. Rev. A}, title = {Sub-shot-noise sensitivity via superpositions of two deformed kitten states}, volume = {111}, year = {2025}, }
• (2025). Efficient detection of nonclassicality using moments of the wigner function. PRA, 111(3), 032406. (www)

  @article{ , abstract = {States with a negative Wigner function, a significant subclass of nonclassical states, serve as a valuable resource for various quantum information processing tasks. Here we provide a criterion for detecting such quantum states characterized by a negative Wigner function. Our method relies on evaluating moments of the Wigner function, which involves computing simple functionals and can be implemented in a real experiment without the need for full state tomography or Wigner function reconstruction. We provide explicit examples to support our detection scheme. Further, we propose an experimental method utilizing the mode swap operator to realize these moments in a real experiment.}, archive = {J_PRA}, author = {Bivas Mallick and Sudip Chakrabarty and Saheli Mukherjee and Ananda G. Maity and A. S. Majumdar}, doi = {10.1103/PhysRevA.111.032406}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032406}, shortjournal = {Phys. Rev. A}, title = {Efficient detection of nonclassicality using moments of the wigner function}, volume = {111}, year = {2025}, }
• (2025). Quantum hypothesis testing for composite alternative hypotheses. PRA, 111(3), 032405. (www)

  @article{ , abstract = {Much of the research in quantum hypothesis testing has focused on simple hypotheses. In practical situations, though, we need to consider more complex, or composite, hypotheses. This paper introduces an approach for testing these composite hypotheses in quantum systems. It combines repeating projective measurements with the quantum Neyman-Pearson test including quantum correlations, which improves the effectiveness of the tests. We also clarify theoretically how the type-II error (false negative) probability of the proposed test behaves asymptotically and show that the proposed test is better at distinguishing hypotheses than traditional approaches. In addition, through numerical calculation, we demonstrate that the proposed test enhances performance in quantum statistical models, where we usually use the classical binomial test. This result shows the practical benefits of applying quantum correlations in hypothesis testing scenarios.}, archive = {J_PRA}, author = {Daichi Fujiki and Fuyuhiko Tanaka and Tatsuya Sakashita}, doi = {10.1103/PhysRevA.111.032405}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032405}, shortjournal = {Phys. Rev. A}, title = {Quantum hypothesis testing for composite alternative hypotheses}, volume = {111}, year = {2025}, }
• (2025). Entanglement between dependent degrees of freedom: Quasiparticle correlations. PRA, 111(3), 032404. (www)

  @article{ , abstract = {Common notions of entanglement are based on well-separated subsystems. However, obtaining such independent degrees of freedom is not always possible because of physical constraints. In this work, we explore the notion of entanglement in the context of dependent degrees of freedom. As a physically relevant application, we specifically study quantum correlation features for quasiparticle descriptions. Those are paramount for interacting light-matter systems, utilizing excitations of fermion-boson hybrid modes. By comparing independent and dependent degrees of freedom, we uncover that certain states are nonentangled although they would be entangled when only focusing on the common, independent description, and vice versa. Therefore, insight is provided into the resourcefulness of quantum correlations within the rarely discussed context of dependent degrees of freedom for light-matter links in quantum information applications.}, archive = {J_PRA}, author = {Franziska Barkhausen and Laura Ares and Stefan Schumacher and Jan Sperling}, doi = {10.1103/PhysRevA.111.032404}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032404}, shortjournal = {Phys. Rev. A}, title = {Entanglement between dependent degrees of freedom: Quasiparticle correlations}, volume = {111}, year = {2025}, }
• (2025). Self-supervised representation learning for bayesian quantum architecture search. PRA, 111(3), 032403. (www)

  @article{ , abstract = {Quantum architecture search (QAS) has shown significant promise in automating quantum circuit design for variational quantum algorithms (VQAs). However, a central challenge remains in the high computational cost of evaluating the ground-truth performance of numerous circuit architectures during the search process. This challenge is further complicated by factors such as inefficient gradient computation, the barren plateau phenomenon, and frequent data exchange between classical and quantum systems within VQAs, all of which restrict the scalability of QAS for increasingly complex VQAs. In this study, we propose an enhanced QAS framework that integrates a performance predictor trained through self-supervised learning with Bayesian optimization to overcome these computational barriers. To address the challenges of circuit performance evaluation, we develop a graph-isomorphism-network-based predictor pretrained using expressibility prediction, an intrinsic measure of a circuit's capacity to explore the Hilbert space uniformly. This pretraining process creates a structured and smooth latent space, significantly improving the predictor's accuracy and generalizability with minimal labeled data. Furthermore, Bayesian optimization is integrated into the QAS framework to refine the predictor iteratively, concentrating the search on regions containing high-performance circuits and thus accelerating the search process. Simulation results for VQAs involving the variational quantum eigensolver and quantum approximate optimization algorithm demonstrate that the proposed framework achieves faster convergence to optimal circuits and substantially reduces computational costs compared to existing QAS methods.}, archive = {J_PRA}, author = {Zhimin He and Hongxiang Chen and Yan Zhou and Haozhen Situ and Yongyao Li and Lvzhou Li}, doi = {10.1103/PhysRevA.111.032403}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032403}, shortjournal = {Phys. Rev. A}, title = {Self-supervised representation learning for bayesian quantum architecture search}, volume = {111}, year = {2025}, }
• (2025). Coherent information for calderbank-shor-steane codes under decoherence. PRA, 111(3), 032402. (www)

  @article{ , abstract = {Stabilizer codes lie at the heart of modern quantum-error-correcting codes (QECCs). Of particular importance is a class called Calderbank-Shor-Steane (CSS) codes, which includes many important examples such as toric codes, color codes, and fractons. Recent studies have revealed that the decoding transition for these QECCs could be intrinsically captured by calculating information-theoretic quantities from the mixed state. Here we perform a simple analytic calculation of the coherent information for general CSS codes under local incoherent Pauli errors via diagonalization of the density matrices and mapping to classical statistical mechanical (SM) models. Our result establishes a rigorous connection between the decoding transition of the quantum code and the phase transition in the random classical SM model. It is also directly confirmed for CSS codes that exact error correction is possible if and only if the maximum-likelihood decoder always succeeds in the thermodynamic limit. Thus, the fundamental threshold is saturated by the optimal decoder.}, archive = {J_PRA}, author = {Ryotaro Niwa and Jong Yeon Lee}, doi = {10.1103/PhysRevA.111.032402}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032402}, shortjournal = {Phys. Rev. A}, title = {Coherent information for calderbank-shor-steane codes under decoherence}, volume = {111}, year = {2025}, }
• (2025). Entanglement and fidelity across quantum phase transitions in locally perturbed topological codes with open boundaries. PRA, 111(3), 032401. (www)

  @article{ , abstract = {We investigate the topological-to-nontopological quantum phase transitions (QPTs) occurring in the Kitaev code under local perturbations in the form of a local magnetic field and spin-spin interactions of the Ising-type using fidelity susceptibility (FS) and entanglement as the probes. We assume the code to be embedded on the surface of a wide cylinder of height and circumference with . We demonstrate a power-law divergence of FS across the QPT and determine the quantum critical points via a finite-size-scaling analysis. We verify these results by mapping the perturbed Kitaev code to the two-dimensional Ising model with nearest- and next-nearest-neighbor interactions and computing the single-site magnetization as the order parameter using the quantum Monte Carlo technique. We also demonstrate a finite-size odd-even dichotomy in the occurrence of the QPT in the Kitaev ladder with respect to the odd and even values of , when the system is perturbed with only Ising interaction. Our results also indicate a higher robustness of the topological phase of the Kitaev code against local perturbations if the boundary is made open along one direction. We further consider a local entanglement witness operator designed specifically to capture a lower bound to the localizable entanglement on the vertical nontrivial loop of the code. We show that the first derivative of the expectation value of the witness operator exhibits a logarithmic divergence across the QPT and perform the finite-size-scaling analysis. We demonstrate similar behavior of the expectation value of the appropriately constructed witness operator also in the case of a locally perturbed color code with open boundaries.}, archive = {J_PRA}, author = {Harikrishnan K J and Amit Kumar Pal}, doi = {10.1103/PhysRevA.111.032401}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032401}, shortjournal = {Phys. Rev. A}, title = {Entanglement and fidelity across quantum phase transitions in locally perturbed topological codes with open boundaries}, volume = {111}, year = {2025}, }
• (2025). Subwavelength quantum battery based on an atomic ring array coupled with an incoherently driven atom. PRA, 111(3), 032221. (www)

  @article{ , abstract = {Many-body quantum batteries composed of N two-level systems benefit from collective effects, demonstrating excellent charging performance. In this paper, we consider a charging scheme where an atomic ring array serves as the quantum battery system, coupled to a central charger atom that is pumped by an incoherent thermal source. Assuming no interactions among the atoms on the ring, the system can be described using the Dicke model, where collective coupling results in a significant initial charging power. When dipole-dipole interactions among the atoms are taken into account, the charging power of the battery decreases due to the introduction of intricate collective dissipation. However, the symmetric coherent interactions facilitate the rapid relaxation of the system's dynamics to the eigenstates, thereby increasing the proportion of useful work within the battery. Moreover, we investigate the impact of the ring size and the detuning of the charger atom on the steady-state ergotropy of the quantum battery. Our findings indicate that, at zero detuning, the system exhibits a larger effective charging ring size. As the magnitude of the detuning increases, the effective charging ring size decreases. By analyzing the radiation properties of the system in its steady state, we also explain why the steady-state ergotropy is higher when the charger atom is positively detuned.}, archive = {J_PRA}, author = {Yu-xiang Han and Zhengquan Pan and Hong-rong Li}, doi = {10.1103/PhysRevA.111.032221}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032221}, shortjournal = {Phys. Rev. A}, title = {Subwavelength quantum battery based on an atomic ring array coupled with an incoherently driven atom}, volume = {111}, year = {2025}, }
• (2025). Queued quantum collision models. PRA, 111(3), 032220. (www)

  @article{ , abstract = {Collision models describe the sequential interactions of a system with independent ancillas. Motivated by recent advances in neutral atom arrays, here we investigate a model where the ancillas are governed by a classical controller that allows them to queue up while they wait for their turn to interact with the system. The ancillas can undergo individual open dynamics while they wait, which could cause them to, e.g., decohere. The system, which plays the role of the server in the queue, can also undergo its own open dynamics whenever it is idle. We show that this framework greatly generalizes existing approaches for quantum collision models, recovering the deterministic and stochastic formulations in the appropriate limits. Next, we show how the combination of queueing dynamics with quantum collisions introduces rich dynamical phenomena, including phase transitions and a sharp dependence on the queue statistics.}, archive = {J_PRA}, author = {Guilherme Fiusa and Gabriel T. Landi}, doi = {10.1103/PhysRevA.111.032220}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032220}, shortjournal = {Phys. Rev. A}, title = {Queued quantum collision models}, volume = {111}, year = {2025}, }
• (2025). Deriving propagators with stochastic quantum evolution. PRA, 111(3), 032219. (www)

  @article{ , abstract = {Quantum evolution was recently shown to be equivalent to the mathematical expectation of the stochastic motion described by the Schrödinger equation with momentum-coupled white noise [J. Shao, J. Chem. Phys. 159 , 024128 (2023) ]. The stochastic formulation provides a convenient means of evaluating quantum propagators because the involved kinetic and potential contributions are disentangled. With the help of the auxiliary functional averaging technique, we apply this scheme to the derivation of the quantum propagators for systems of exponential, linear, harmonic, and δ -function potentials. Notably, our work presents a truly workable expression of the quantum propagator for the exponential potential problem. To demonstrate the features and advantages of this propagator, we use it to calculate the wave-packet dynamics and compare it to the split-operator method.}, archive = {J_PRA}, author = {Yun-An Yan and Jiushu Shao}, doi = {10.1103/PhysRevA.111.032219}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032219}, shortjournal = {Phys. Rev. A}, title = {Deriving propagators with stochastic quantum evolution}, volume = {111}, year = {2025}, }
• (2025). Toward superstrong fields with a relativistic curved plasma mirror. PRA, 111(3), 032218. (www)

  @article{ , abstract = {The laser pulse reflected and focused by the relativistically moving curved plasma mirror can exceed the laser intensity obtained by focusing high-power laser pulses with conventional physical optics. In the ultrarelativistic limit where the Lorentz γ factor is large ( γ ≫ 1 ), the general field configuration focused by the relativistic curved plasma mirror is calculated using the 4 π -spherical focusing scheme in the boosted frame of reference. The calculated field strength and distribution can be applied to investigate nonlinear quantum electrodynamic effect (electron-positron pair creation from the vacuum via the Schwinger mechanism) under the two-beam colliding scheme, in which a high-intensity laser pulse collides with a focused field by the relativistic mirror. The benefit of using the relativistic mirror has been discussed in terms of the invariant field. Taking advantage of the mathematical expression for the focused field, the spatial distributions of the pair creation rate have been calculated as functions of time and the carrier envelope phase of the laser pulse. The calculation predicts that creating ≈ 2.2 × 10 6 electron-positron pairs is possible by colliding a 25 PW laser pulse with a reflected and focused field by the relativistic mirror with γ = 100 . This attributes to the field enhancement by the double Doppler effect, a large geometrical factor of the relativistic mirror, and the increase in the reflectivity due to the oblique incidence.}, archive = {J_PRA}, author = {Tae Moon Jeong and Sergei V. Bulanov and Rashid Shaisultanov and Prokopis Hadjisolomou and Timur Zh. Esirkepov}, doi = {10.1103/PhysRevA.111.032218}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032218}, shortjournal = {Phys. Rev. A}, title = {Toward superstrong fields with a relativistic curved plasma mirror}, volume = {111}, year = {2025}, }
• (2025). Measurement time of weak measurements on large entangled systems. PRA, 111(3), 032217. (www)

  @article{ , abstract = {It is well established that starting only with strong, projective quantum measurements, experiments can be designed to allow weak measurements, which lead to a random walk between the possible final measurement outcomes. However, one can ask the reverse question: starting with only weak measurements, can all the results of standard strong measurements be recovered? Prior work has shown that some results can be, such as the Born rule for the probability of measurement outcomes as a function of wave intensity. In this paper, we show that another crucial result can be reproduced by purely weak measurements, namely, the collapse of a many-body, nonlocally entangled wave function on a timescale comparable to the characteristic time of a single, local measurement. For an entangled state of a single excitation among qubits, we find the collapse time scales as a double logarithm of . This result affirms the self-consistency of the hypothesis that spontaneous weak measurements lie at the base of all physical measurements, independent of human observers.}, archive = {J_PRA}, author = {Truong-Son P. Văn and Andrew N. Jordan and David W. Snoke}, doi = {10.1103/PhysRevA.111.032217}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032217}, shortjournal = {Phys. Rev. A}, title = {Measurement time of weak measurements on large entangled systems}, volume = {111}, year = {2025}, }
• (2025). Complex-phase extensions of the szegedy quantum walk on graphs. PRA, 111(3), 032216. (www)

  @article{ , abstract = {This work introduces a graph-phased Szegedy's quantum walk, which incorporates link phases and local arbitrary phase rotations (APR), unlocking new possibilities for quantum algorithm efficiency. We demonstrate how to adapt quantum circuits to these advancements, allowing phase patterns that ensure computational practicality. The graph-phased model broadens the known equivalence between coined quantum walks and Szegedy's model, accommodating a wider array of coin operators. Through illustrative examples, we reveal intriguing disparities between classical and quantum interpretations of walk dynamics. Remarkably, local APR phases emerge as powerful tools for marking graph nodes, optimizing quantum searches without altering graph structure. We further explore the surprising nuances between single and double operator approaches, highlighting a greater range of compatible coins with the latter. To facilitate these advancements, we present an improved classical simulation algorithm, which operates with superior efficiency. This study not only refines quantum walk methodologies but also paves the way for future explorations, including potential applications in quantum search and PageRank algorithms. Our findings illuminate the path towards more versatile and powerful quantum computing paradigms.}, archive = {J_PRA}, author = {Sergio A. Ortega and Miguel A. Martin-Delgado}, doi = {10.1103/PhysRevA.111.032216}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032216}, shortjournal = {Phys. Rev. A}, title = {Complex-phase extensions of the szegedy quantum walk on graphs}, volume = {111}, year = {2025}, }
• (2025). Dynamical formulation of low-frequency scattering in two and three dimensions. PRA, 111(3), 032215. (www)

  @article{ , abstract = {The transfer matrix of scattering theory in one dimension can be expressed in terms of the time-evolution operator of an effective nonunitary quantum system. In particular, it admits a Dyson series expansion which turns out to facilitate the construction of the low-frequency series expansion of the scattering data. In two and three dimensions, there is a similar formulation of stationary scattering in which the scattering properties of the scatterer are extracted from the evolution operator for a corresponding effective quantum system. We explore the utility of this approach to scattering theory in the study of the scattering of low-frequency time-harmonic scalar waves , with satisfying the Helmholtz equation, ; and being, respectively, the angular frequency and wave number of the incident wave; and denoting the relative permittivity of the carrier medium, which, in general, takes complex values. We obtain explicit formulas for low-frequency scattering amplitude, examine their effectiveness in the study of a class of exactly solvable scattering problems, and outline their application in devising a low-frequency cloaking scheme.}, archive = {J_PRA}, author = {Farhang Loran and Ali Mostafazadeh}, doi = {10.1103/PhysRevA.111.032215}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032215}, shortjournal = {Phys. Rev. A}, title = {Dynamical formulation of low-frequency scattering in two and three dimensions}, volume = {111}, year = {2025}, }
• (2025). Steady-state correlation function beyond the standard weak-coupling limit and consistency with the kubo-martin-schwinger relation. PRA, 111(3), 032214. (www)

  @article{ , abstract = {Thermalization of a system when interacting with a thermal bath is an interesting problem. If a system eventually reaches a thermal state in the long time limit, it's expected that its density matrix would resemble the mean-force Gibbs state. Moreover, the correlation function must satisfy the Kubo-Martin-Schwinger (KMS) condition, or equivalently, the fluctuation-dissipation relation (FDR). In this paper, we derive a formal expression for the non-Markovian two-point function within the context of the weak coupling limit. Using this expression, we explicitly compute the two-point function for specific models, demonstrating their adherence to the KMS. In addition, we formulate a nonperturbative approach in the form of a self-consistent approximation that includes a partial resummation of perturbation theory. This approach can capture strong coupling phenomena while still relying on simple equations. Notably, we verify that the two-point function obtained through this method also satisfies the KMS condition.}, archive = {J_PRA}, author = {Sakil Khan and Lokendra Singh Rathore and Sachin Jain}, doi = {10.1103/PhysRevA.111.032214}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032214}, shortjournal = {Phys. Rev. A}, title = {Steady-state correlation function beyond the standard weak-coupling limit and consistency with the kubo-martin-schwinger relation}, volume = {111}, year = {2025}, }
• (2025). Characterizing topological pumping of charges in exactly solvable rice-mele chains of the non-hermitian variety. PRA, 111(3), 032213. (www)

  @article{ , abstract = {We address the nature of the Thouless charge pumping for a non-Hermitian (NH) generalization of the one-dimensional (1D) Rice-Mele model, considering a variety which allows closed-form analytical solutions for the eigensystems. The two-band system is subjected to an “adiabatic” time-periodic drive, which effectively gives us a closed two-dimensional (2D) manifold in the momentum-frequency space, mimicking a 2D Brillouin zone (BZ) for periodic boundary conditions. For open boundary conditions, we formulate the non-Bloch generalized Brillouin zone (GBZ). All these allow us to compute the Chern numbers of the 2D manifolds emerging for various parameter values, using the BZ or GBZ, which are well-defined integers in the gapped regions of the spectra. If Thouless pumping still holds for NH situations, the expectation values of the net displacement for the particles occupying a given band within a cycle, calculated using the right and left eigenvectors of a biorthogonal basis for the complex Hamiltonians, would coincide with the Chern numbers. However, we find that there are deviations from the expected quantized values whenever the spectra exhibit strongly fluctuating magnitudes of the imaginary parts of the (generically) complex eigenvalues. This implies that we need to address the question of how to meaningfully define time evolution, as well as adiabaticity, in the context of NH systems.}, archive = {J_PRA}, author = {Ipsita Mandal}, doi = {10.1103/PhysRevA.111.032213}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032213}, shortjournal = {Phys. Rev. A}, title = {Characterizing topological pumping of charges in exactly solvable rice-mele chains of the non-hermitian variety}, volume = {111}, year = {2025}, }
• (2025). Geometric monotones of violations of quantum realism. PRA, 111(3), 032212. (www)

  @article{ , abstract = {Quantum realism, as introduced by Bilobran and Angelo [ Europhys. Lett. 112 , 40005 (2015) ], states that projective measurements in quantum systems establish the reality of physical properties, even in the absence of a revealed outcome. This framework provides a nuanced perspective on the distinction between classical and quantum notions of realism, emphasizing the contextuality and complementarity inherent in quantum systems. While prior works quantified violations of quantum realism (VQRs) using measures based on entropic distances, here we extend the theoretical framework to geometric distances. Building on an informational approach, we derive geometric monotones of VQRs using trace distance, Hilbert-Schmidt distance, Schatten distances, and Bures and Hellinger distances. We identify Bures and Hellinger distances as uniquely satisfying all minimal criteria for a bona fide VQR monotone. Remarkably, these distances can be expressed in terms of symmetric Rényi and sandwiched Rényi divergences, aligning geometric and entropic approaches. Our findings suggest that the realism-information relation implies a deep connection between geometric and entropic frameworks, with only those geometric distances expressible as entropic quantities qualifying as valid monotones of VQRs. This work highlights the theoretical and practical advantages of geometric distances, particularly in contexts where computational simplicity or symmetry is important.}, archive = {J_PRA}, author = {Alexandre C. Orthey, Jr and Alexander Streltsov}, doi = {10.1103/PhysRevA.111.032212}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032212}, shortjournal = {Phys. Rev. A}, title = {Geometric monotones of violations of quantum realism}, volume = {111}, year = {2025}, }
• (2025). Quantum simulation of a qubit with a non-hermitian hamiltonian. PRA, 111(3), 032211. (www)

  @article{ , abstract = {Modeling non-Hermitian Hamiltonians is increasingly important in classical and quantum domains, especially when studying open systems, parity-time ( ) symmetry, and resonances. However, the quantum simulation of these models has been limited by the extensive resources necessary in iterative methods with exponentially small postselection success probability. Here we employ a fixed-depth variational circuit to circumvent these limitations, enabling simulation deep into the -broken regime surrounding an exceptional point. Quantum simulations are carried out using IBM superconducting qubits. The results underscore the potential for variational quantum circuits and machine learning to push the boundaries of quantum simulation, offering new methods for exploring quantum phenomena with near-term intermediate-scale quantum technology.}, archive = {J_PRA}, author = {Anastashia Jebraeilli and Michael R. Geller}, doi = {10.1103/PhysRevA.111.032211}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032211}, shortjournal = {Phys. Rev. A}, title = {Quantum simulation of a qubit with a non-hermitian hamiltonian}, volume = {111}, year = {2025}, }
• (2025). Leading correction to the relativistic foldy-wouthuysen hamiltonian. PRA, 111(3), 032210. (www)

  @article{ , abstract = {For Dirac particles interacting with external fields, we use the exact operator of the Foldy-Wouthuysen transformation obtained by Eriksen and rigorously derive a leading correction in the weak-field approximation to the known relativistic Foldy-Wouthuysen Hamiltonian. For this purpose, we carry out the operator extraction of a square root in the Eriksen operator. The derived correction is important for the scattering of relativistic particles. Since the description of this scattering by a relativistic wave equation of the second order is more convenient, we determine a general connection between relativistic wave equations of the first and second orders. For Dirac particles, the relativistic wave equation of the second order is obtained with a correction similar to that of the Foldy-Wouthuysen Hamiltonian.}, archive = {J_PRA}, author = {Alexander J. Silenko}, doi = {10.1103/PhysRevA.111.032210}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032210}, shortjournal = {Phys. Rev. A}, title = {Leading correction to the relativistic foldy-wouthuysen hamiltonian}, volume = {111}, year = {2025}, }
• (2025). Characterizing the lipkin-meshkov-glick excited-state spectrum through the quantum coherence spectrum. PRA, 111(3), 032209. (www)

  @article{ , abstract = {Excited-state quantum phase transitions extend the quantum phase transition concept beyond the ground state and offer insights into the complex behavior of quantum systems. In the present work we assess the use of the multiple quantum coherence spectrum as a valid tool to probe excited-state quantum phase transitions within the framework of the Lipkin-Meshkov-Glick model. The time dependence and the long-time average of the multiple quantum coherence spectrum reveal the intricate dynamics that stems from the existence of singularities in the excited-state spectrum of a quantum many-body system.}, archive = {J_PRA}, author = {Qian Wang and Jamil Khalouf-Rivera and Francisco Pérez-Bernal}, doi = {10.1103/PhysRevA.111.032209}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032209}, shortjournal = {Phys. Rev. A}, title = {Characterizing the lipkin-meshkov-glick excited-state spectrum through the quantum coherence spectrum}, volume = {111}, year = {2025}, }
• (2025). Quantum circuit complexity for linearly polarized light. PRA, 111(3), 032208. (www)

  @article{ , abstract = {In this study, we explore a form of quantum circuit complexity that extends to open systems. To illustrate our methodology, we focus on a basic model where the projective Hilbert space of states is depicted by the set of orientations in the Euclidean plane. Specifically, we investigate the dynamics of mixed quantum states as they undergo interactions with a sequence of gates. The latter aim to accurately adjust the path from referent to target, aligning it as closely as possible with the path we have chosen. Our approach involves the analysis of sequences of real density matrices. This mathematical model is physically exemplified by the Stokes density matrices, which delineate the linear polarization of a quasimonochromatic light beam, and the gates, which are viewed as quantum polarizers, whose states are also real density matrices. The interaction between polarizer-linearly polarized light is construed within the context of this quantum formalism. Each density matrix for the light evolves in an approach analogous to a Gorini-Kossakowski-Lindblad-Sudarshan (GKLS) process during the time interval between consecutive gates. Notably, when considering an upper limit for the tolerance or accuracy, we unearth that the number of gates follows a power-law relationship which gives an upper bound of the complexity.}, archive = {J_PRA}, author = {Evaldo M. F. Curado and Sofiane Faci and Jean-Pierre Gazeau and Tomoi Koide and Alan C. Maioli and Diego Noguera}, doi = {10.1103/PhysRevA.111.032208}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032208}, shortjournal = {Phys. Rev. A}, title = {Quantum circuit complexity for linearly polarized light}, volume = {111}, year = {2025}, }
• (2025). Self-interaction-induced phase modulation for directed current, energy diffusion, and quantum scrambling in a floquet ratchet system. PRA, 111(3), 032207. (www)

  @article{ , abstract = {We investigate the wave-packet dynamics in an interacting Floquet system described by the Gross-Pitaevskii equation with a ratchet potential. Under the quantum resonance condition, we thoroughly examine the exotic dynamics of directed current, mean energy, and quantum scrambling based on the exact expression of a time-evolving wave packet. The directed current is controlled by the phase of the ratchet potential. Interestingly, the phase modulation induced by self-interaction dominates the quadratic growth of both mean energy and out-of-time-ordered correlators (OTOCs). Under the quantum nonresonance condition, the disorder in momentum space, induced by the pseudorandom feature of the free evolution operator, suppresses the directed current at all times. Meanwhile, the disorder also leads to the dynamical localization of the mean energy and the freezing of quantum scrambling for an initially finite-time interval. The dynamical localization can be effectively manipulated by the phase, with underlying physics rooted in the different quasieigenenergy spectrum modulated by ratchet potential. Both the mean energy and OTOCs exponentially increase after long-time evolution, which is governed by the classically chaotic dynamics dependent on the self-interaction. Possible applications of our findings for quantum control are discussed.}, archive = {J_PRA}, author = {Jiejin Shi and Lihao Hua and Wenxuan Song and Wen-Lei Zhao}, doi = {10.1103/PhysRevA.111.032207}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032207}, shortjournal = {Phys. Rev. A}, title = {Self-interaction-induced phase modulation for directed current, energy diffusion, and quantum scrambling in a floquet ratchet system}, volume = {111}, year = {2025}, }
• (2025). Energy backflow in tightly focused hybrid vector beams with noncircular polarization-mapping tracks on the poincaré sphere. PRA, 111(3), 032206. (www)

  @article{ , abstract = {We report the formation of on-axis energy backflow in the focus of tightly focused hybrid vector beams featuring noncircular mapping tracks on the Poincaré sphere for azimuthal polarization states. Using the Richards-Wolf vectorial diffraction integral, we give the general expressions for all components of the electric and magnetic fields, as well as the expression for the longitudinal component of the Poynting vector in the focal plane under basis vectors. We reveal that the on-axis energy backflow will appear when the amplitude modulation factor and the topological charge of the vortex phase carried by basis vectors satisfy the condition . And, we show that the longitudinal Poynting vector is not circularly symmetric but related to the azimuthal angle in the focal plane for the hybrid vector beams with nonzero and . Furthermore, it is found that the on-axis energy backflow can also be observed in the focus of the hybrid vector beams under other basis vectors beyond the case. More intriguingly, we additionally uncover that there is on-axis energy backflow in the focus of a linearly polarized optical vortex with the topological charge , where the near-axis energy flows spirally along the optical axis. The numerical simulation results are in good agreement with the theoretical analyses.}, archive = {J_PRA}, author = {Lei Han and Chuchu Gao and Jiale Qi and Fuli Li}, doi = {10.1103/PhysRevA.111.032206}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032206}, shortjournal = {Phys. Rev. A}, title = {Energy backflow in tightly focused hybrid vector beams with noncircular polarization-mapping tracks on the poincaré sphere}, volume = {111}, year = {2025}, }
• (2025). Asymmetry amplification by a nonadiabatic passage through a critical point. PRA, 111(3), 032205. (www)

  @article{ , abstract = {We propose and solve a minimal model of dynamic passage through a second-order phase transition in the presence of symmetry-breaking interactions and no dissipation. Our model generalizes the Hamiltonian dynamics of the Painlevé-2 equation to the case with many degrees of freedom, while maintaining the integrability property. The evolution eventually leads to a highly asymmetric state, no matter how weak the symmetry-breaking parameter of the Hamiltonian is. This suggests a potential mechanism for strong asymmetry in the production of quasiparticles with nearly identical characteristics. The model's integrability also yields exact exponents for the scaling of the density of the nonadiabatically excited quasiparticles.}, archive = {J_PRA}, author = {Bhavay Tyagi and Fumika Suzuki and Vladimir A. Chernyak and Nikolai A. Sinitsyn}, doi = {10.1103/PhysRevA.111.032205}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032205}, shortjournal = {Phys. Rev. A}, title = {Asymmetry amplification by a nonadiabatic passage through a critical point}, volume = {111}, year = {2025}, }
• (2025). Inequality-free proof of bell's theorem. PRA, 111(3), 032204. (www)

  @article{ , abstract = {Bell's theorem supposedly demonstrates an irreconcilable conflict between quantum mechanics and local realistic hidden-variable theories. Most proofs of Bell's theorem, are based on inequalities. In this paper we present an alternative proof which does not involve inequalities, but only a direct comparison between correlation functions calculated using quantum mechanics on the one hand, and those calculated according to local realistic hidden-variable theories on the other. Our proof is based on a physically motivated use of Fourier series for periodic functions, and confirms that local realistic hidden-variable theories are incompatible with quantum mechanics.}, archive = {J_PRA}, author = {Andrea Aiello}, doi = {10.1103/PhysRevA.111.032204}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032204}, shortjournal = {Phys. Rev. A}, title = {Inequality-free proof of bell's theorem}, volume = {111}, year = {2025}, }
• (2025). Enhanced response at exceptional points in multiqubit systems for sensing. PRA, 111(3), 032203. (www)

  @article{ , abstract = {Exceptional points featuring enhanced energy response to perturbation hold significant potential in detection and measurement of weak signals. Of particular interest is the existence and property of high-order exceptional points in quantum systems, owing to the capability to provide high-order response to perturbations. We investigate the exceptional points in a system of identical qubits possessing parity-time-reversal symmetry. We prove that owing to an incomplete coalescence of eigenstates, the highest possible order of exceptional point is , which is also the upper bound of the order of energy response to perturbation. More interestingly, by considering an Ising-type interaction, we analytically prove that to achieve an order response for any , the system must acquire a nontrivial -body interaction. Finally, we propose a Floquet driving scheme to implement an effective multibody Ising-type interaction, which can be realized in trapped ions or superconducting qubits.}, archive = {J_PRA}, author = {Tingting Shi and Vasilii Smirnov and Kaiye Shi and Wei Zhang}, doi = {10.1103/PhysRevA.111.032203}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032203}, shortjournal = {Phys. Rev. A}, title = {Enhanced response at exceptional points in multiqubit systems for sensing}, volume = {111}, year = {2025}, }
• (2025). Impact of chiral transitions in quantum friction. PRA, 111(3), 032202. (www)

  @article{ , abstract = {We theoretically investigate the role of chiral transitions in the quantum friction force that acts on a two-level atom that moves with relative velocity v parallel to a planar metallic surface. We find that the friction force has a component that is sensitive to the handedness of the atomic transition dipole moment. In particular, we show that the friction force can be enhanced by an atomic transition with a dipole moment with a certain handedness and can almost be suppressed by the dipole moment with the opposite handedness. Curiously, the handedness of the transition dipole moment that boosts the ground-state friction force is the opposite of what is classically expected from the spin-momentum locking. We explain this discrepancy in terms of the interaction between positive- and negative-frequency oscillators.}, archive = {J_PRA}, author = {Muzzamal I. Shaukat and Mário G. Silveirinha}, doi = {10.1103/PhysRevA.111.032202}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032202}, shortjournal = {Phys. Rev. A}, title = {Impact of chiral transitions in quantum friction}, volume = {111}, year = {2025}, }
• (2025). Evolution of expected values in open quantum systems. PRA, 111(3), 032201. (www)

  @article{ , abstract = {We derive a generalization of the Ehrenfest theorem valid for open quantum systems. From this result, we identify three contributions to the evolution of expected values: (i) the explicit time dependence of the observable, (ii) the incompatibility between the observable and an operator which plays the role of an effective Hamiltonian, and (iii) entropy changes. Considering the local Hamiltonian as the observable, and adopting a specific interpretation of the nature of thermal interactions, we obtain an alternative version of the first law of thermodynamics. Within this framework, we show that in some cases the power performed by the system can be considered as a quantum observable. As an application, the pure-dephasing process is reinterpreted from this perspective.}, archive = {J_PRA}, author = {Andrés Vallejo and Alejandro Romanelli and Virginia Feldman and Raúl Donangelo}, doi = {10.1103/PhysRevA.111.032201}, journal = {Physical Review a}, month = {3}, number = {3}, pages = {032201}, shortjournal = {Phys. Rev. A}, title = {Evolution of expected values in open quantum systems}, volume = {111}, year = {2025}, }
• (2025). Velocimetry using free-induction decay of matter-wave lattices. PRA, 111(2), L021304. (www)

  @article{ , abstract = {We demonstrate a matter-wave velocimeter which probes the free-induction decay of an atomic lattice formed by interaction with an optical standing wave in the reference frame of the laser-cooled sample. During the drop time of the atoms in a gravitational field, we ensure lattice formation by changing the relative detuning of counterpropagating components of the standing wave. The contrast of the lattice, which is sensitive to the first-order Doppler shift, is measured by backscattering a near-resonant traveling-wave electric field. We infer the center-of-mass velocity by determining the line center of the backscattered spectrum. By varying the drop time, we also measure the gravitational acceleration of the falling lattice. We find that the spectrum can be considerably narrowed by imprinting a Ramsey fringe using two time-separated excitation pulses. We demonstrate these ideas using a sample of rubidium atoms with a temperature of ∼ 10 µ K , achieving a precision of 600 µ m / s for measurements of velocity and 2 mm / s 2 for determinations of gravity. Since the primary limitation in precision relates to the thermal coherence length of the sample, we show that the most precise atomic velocimeter can be realized by applying these techniques to a typical Bose gas.}, archive = {J_PRA}, author = {Gehrig Carlse and Jaskaran Randhawa and Eduardo Ramos and Thomas Vacheresse and Alex Pouliot and A. Kumarakrishnan}, doi = {10.1103/PhysRevA.111.L021304}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L021304}, shortjournal = {Phys. Rev. A}, title = {Velocimetry using free-induction decay of matter-wave lattices}, volume = {111}, year = {2025}, }
• (2025). Raman-type absolute atom gravimeter assisted by a degenerate optical cavity. PRA, 111(2), L021303. (www)

  @article{ , abstract = {Cavity-assisted atom interferometry has been proposed for gravity measurement in the past decade due to its promising advantages such as low laser power consumption, high beam quality, and strong atom-photon interactions. However, the previous cavity-related works have difficulties measuring the absolute gravitational acceleration g due to their limited cavity design and locking methods. We experimentally demonstrate a Raman-type absolute atom gravimeter assisted by a newly designed degenerate optical cavity. The gravimeter achieves a decent sensitivity of about 28.5 ( 9 ) × 10 − 8 g Hz − 1 / 2 under our noisy laboratory conditions and without magnetic shielding of the atom interference area. The accuracy reaches 20 µ Gal within half an hour of continuous measurement. We also systematically measure and analyze the main noises affecting the g -measure sensitivity, indicating no physical obstacles to achieving higher sensitivity. Our cavity scheme is compatible and can be easily integrated with current free-space atom interferometers. By fully utilizing the cavity's advantages, it will benefit many areas in future fundamental research and fieldable applications.}, archive = {J_PRA}, author = {Liang Yuan and Bin Chen and Yu-Hang Li and Chen Yao and Sheng-Jun Yang}, doi = {10.1103/PhysRevA.111.L021303}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L021303}, shortjournal = {Phys. Rev. A}, title = {Raman-type absolute atom gravimeter assisted by a degenerate optical cavity}, volume = {111}, year = {2025}, }
• (2025). Violation of the leggett-garg inequality for dynamics of a bose-einstein condensate in a double-well potential. PRA, 111(2), L021302. (www)

  @article{ , abstract = {The Leggett-Garg inequality (LGI) serves as a criterion to determine the adherence of macroscopic system dynamics to macrorealism, as introduced by Leggett and Garg. A violation of this inequality implies either the absence of a realistic description of the system or the impossibility of noninvasive measurement. In this Letter, we investigate the violation of the LGI for the system of bosons in a double-well potential. Specifically, we explore the violation of the LGI in the dynamics of bosons in a double-well potential in the Bose-Einstein-condensation (BEC) regime, where the system can be considered as two weakly coupled Bose condensates, and in the single-particle regime to establish the conditions under which the violation of the LGI occurs. Our analysis reveals that the LGI is violated due to Josephson oscillations, while it remains unviolated in the strong-coupling regime, attributed to the self-trapping phenomena. Notably, we observe that the violation of the LGI becomes increasingly significant as the particle number increases. These findings provide valuable insights into the macrorealistic behavior of Bose condensates and highlight the effect of measurements on the dynamics of a macroscopic system.}, archive = {J_PRA}, author = {Tsubasa Sakamoto and Ryosuke Yoshii and Shunji Tsuchiya}, doi = {10.1103/PhysRevA.111.L021302}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L021302}, shortjournal = {Phys. Rev. A}, title = {Violation of the leggett-garg inequality for dynamics of a bose-einstein condensate in a double-well potential}, volume = {111}, year = {2025}, }
• (2025). Anomalous landau damping and algebraic thermalization in two-dimensional superfluids far from equilibrium. PRA, 111(2), L021301. (www)

  @article{ , abstract = {We present a quantitative description of the thermalization dynamics of two-dimensional (2D) Bose superfluids far from equilibrium. Our analysis leverages a quantum kinetic formalism and allows us to identify two successive regimes of relaxation: an initial damping of quasiparticles due to Landau scattering processes, followed by the slower establishment of equilibrium at long time. For an initial state far from equilibrium, we find that Landau damping differs from the conventional picture of exponentially relaxing quasiparticles. Moreover, our results showcase a pronounced mechanism of slow algebraic transport at late times, rooted in energy conservation. Using theoretical and numerical arguments, we construct a detailed dynamical portrait of thermal equilibration in 2D superfluids.}, archive = {J_PRA}, author = {Clément Duval and Nicolas Cherroret}, doi = {10.1103/PhysRevA.111.L021301}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L021301}, shortjournal = {Phys. Rev. A}, title = {Anomalous landau damping and algebraic thermalization in two-dimensional superfluids far from equilibrium}, volume = {111}, year = {2025}, }
• (2025). Effect of rabi dynamics in resonant x-ray scattering of intense attosecond pulses. PRA, 111(2), L021101. (www)

  @article{ , abstract = {We theoretically study the effects of Rabi oscillations on resonant x-ray scattering in Ne + using intense attosecond and few-femtosecond pulses. The total photon yield strongly depends on the pulse area and has an upper bound at high intensities. Resonant scattering yields with attosecond pulses can be an order of magnitude higher than those far from resonances. Interference between resonance fluorescence and elastic scattering channels depends on the pulse area and initial state. Our results suggest that resonant x-ray scattering can be exploited for high-resolution, site-specific imaging.}, archive = {J_PRA}, author = {Akilesh Venkatesh and Phay J. Ho}, doi = {10.1103/PhysRevA.111.L021101}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L021101}, shortjournal = {Phys. Rev. A}, title = {Effect of rabi dynamics in resonant x-ray scattering of intense attosecond pulses}, volume = {111}, year = {2025}, }
• (2025). Correlation between acid dissociation states and average dipole moments of HCl-water clusters realized by a strong electric field. PRA, 111(2), L020802. (www)

  @article{ , abstract = {The dissociation of an acidic molecule in water clusters is a captivating and important subject. This paper employs hybrid density-functional theory to optimize HCl ( H 2 O ) n = 1 – 8 structures under electric fields ( E F = 0 − 50 MV / cm ) . It finds that strong E F greatly enhances the average dipole moments (ADMs) of dissociated clusters ( n ≥ 4 ) , while undissociated clusters, including n ≤ 3 , remain undissociated and exhibit negligible ADM changes. This means that the correlation between HCl dissociation and ADMs can be realized by increasing the E F strength, without changing the requirement of four water molecules for one HCl dissociation. A physical model elucidates this correlation, and beam deflection method is shown to operate effectively under significant E F s (∼40 MV/cm), challenging the conventional assumption of lower field strengths.}, archive = {J_PRA}, author = {Chuanfu Huang and Lei Zhuang and Jing Wang and Jianguo Wan}, doi = {10.1103/PhysRevA.111.L020802}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020802}, shortjournal = {Phys. Rev. A}, title = {Correlation between acid dissociation states and average dipole moments of HCl-water clusters realized by a strong electric field}, volume = {111}, year = {2025}, }
• (2025). Spin dependence in core-valence double photoionization of neon. PRA, 111(2), L020801. (www)

  @article{ , abstract = {We have studied core-valence double photoionization (DPI) of Ne leading to the 1 s − 1 2 s − 1 S 1 , 3 and 1 s − 1 2 p − 1 P 1 , 3 states of Ne 2 + over a range of photon energy extending up to approximately 200 eV above the thresholds using a multielectron coincidence technique. Each DPI process is distinctly identified in the energy correlation between two photoelectrons. The ratios of singlet-to-triplet cross sections exhibit variation with photon energy, indicating a spin dependence in the DPI dynamics. The state-resolved DPI probabilities have been investigated by an incoherent sum of the knock-out (KO) and shake-off (SO) contributions, revealing a significant disparity in the dynamics of the KO mechanism between the DPI into the P 1 and P 3 states.}, archive = {J_PRA}, author = {Takeshi Odagiri and Yuma Sugawara and Tatsuo Kaneyasu and Jun-ichi Adachi and Hirokazu Tanaka and Isao H. Suzuki and Sakura Suzuki and Yasumasa Hikosaka}, doi = {10.1103/PhysRevA.111.L020801}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020801}, shortjournal = {Phys. Rev. A}, title = {Spin dependence in core-valence double photoionization of neon}, volume = {111}, year = {2025}, }
• (2025). Long-lived metastable-qubit memory. PRA, 111(2), L020601. (www)

  @article{ , abstract = {Coherent storage of quantum information is crucial to many quantum technologies. Long coherence times have been demonstrated in trapped-ion qubits, typically using the hyperfine levels within the ground state of a single ion. However, recent research suggests qubits encoded in metastable states could provide architectural benefits for quantum information processing, such as the possibility of effective dual-species operation in a single-species system and erasure-error conversion for fault-tolerant quantum computing. Here, we demonstrate long-lived encoding of a quantum state in the metastable states of a trapped ion. By sympathetically cooling with another ion of the same species, employing a tuned CPMG dynamical-decoupling sequence, and constantly monitoring for leakage errors, we demonstrate a coherence time of 136(42) s with a qubit encoded in the metastable 5 D 5 / 2 state of a single 137 Ba + ion. In agreement with a model based on empirical results from dynamical-decoupling-based noise spectroscopy, we find that dephasing of the metastable levels is the dominant source of error once leakage errors are removed.}, archive = {J_PRA}, author = {Xiaoyang Shi and Jasmine Sinanan-Singh and Kyle DeBry and Susanna L. Todaro and Isaac L. Chuang and John Chiaverini}, doi = {10.1103/PhysRevA.111.L020601}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020601}, shortjournal = {Phys. Rev. A}, title = {Long-lived metastable-qubit memory}, volume = {111}, year = {2025}, }
• (2025). Imprecision plateaus in quantum steering. PRA, 111(2), L020404. (www)

  @article{ , abstract = {We study tests of quantum steering in which the trusted party does not have perfect control of their measurements. We report on steering inequalities that remain unaffected when introducing up to a threshold magnitude of measurement imprecision. This phenomenon, which we call an imprecision plateau, thus permits a departure from the standard assumption of idealized measurements without incurring any cost to the detection power of steering experiments. We provide an explanation for why imprecision plateaus are possible, a simple criterion for their existence, and tools for analyzing their properties. We also demonstrate that these plateaus have natural applications when the assumption of perfect measurements is relaxed: They allow for maintaining both the noise robustness and loss robustness of standard steering tests and the performance rate of idealized one-sided device-independent random number generators.}, archive = {J_PRA}, author = {Elna Svegborn and Nicola d'Alessandro and Otfried Gühne and Armin Tavakoli}, doi = {10.1103/PhysRevA.111.L020404}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020404}, shortjournal = {Phys. Rev. A}, title = {Imprecision plateaus in quantum steering}, volume = {111}, year = {2025}, }
• (2025). Universal time scalings of sensitivity in markovian quantum metrology. PRA, 111(2), L020403. (www)

  @article{ , abstract = {Assuming Markovian time evolution of a quantum sensing system, we study the general characterization of the optimal sensitivity scalings with time, under most general quantum control protocols. We allow the estimated parameter to influence both the Hamiltonian as well as the dissipative part of the quantum master equation and focus on the asymptotic-time along with the short-time sensitivity scalings. We find that via simple algebraic conditions (in terms of the Hamiltonian, the jump operators as well as their parameter derivatives), one can characterize the four classes of metrological models that represent: quadratic-linear, quadratic-quadratic, linear-linear, and linear-quadratic time scalings. We also investigate the relevant time scales on which the transition between the two regimes appears. Additionally, we provide universal numerical methods to obtain quantitative bounds on sensitivity that are the tightest that exist in the literature. Simplicity and universality of our results make it suitable for diverse applications in quantum metrology.}, archive = {J_PRA}, author = {Arpan Das and Wojciech Górecki and Rafał Demkowicz-Dobrzański}, doi = {10.1103/PhysRevA.111.L020403}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020403}, shortjournal = {Phys. Rev. A}, title = {Universal time scalings of sensitivity in markovian quantum metrology}, volume = {111}, year = {2025}, }
• (2025). Metrological usefulness of entanglement and nonlinear hamiltonians. PRA, 111(2), L020402. (www)

  @article{ , abstract = {A central task in quantum metrology is to exploit quantum correlations to outperform classical sensitivity limits. Metrologically useful entanglement is identified when the quantum Fisher information (QFI) exceeds a separability bound for a given parameter-encoding Hamiltonian. However, so far, only results for linear Hamiltonians are well established. Here, we characterize metrologically useful entanglement for nonlinear Hamiltonians, presenting separability bounds for collective angular momenta. Also, we provide a general expression for entangled states maximizing the QFI, which can be written as the superposition between the Greenberger-Horne-Zeilinger-like and singlet states. Finally, we compare the metrological usefulness of linear and nonlinear cases, in terms of entanglement detection and random symmetric states.}, archive = {J_PRA}, author = {Satoya Imai and Augusto Smerzi and Luca Pezzè}, doi = {10.1103/PhysRevA.111.L020402}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020402}, shortjournal = {Phys. Rev. A}, title = {Metrological usefulness of entanglement and nonlinear hamiltonians}, volume = {111}, year = {2025}, }
• (2025). Optimal limits of continuously monitored thermometers and their hamiltonian structure. PRA, 111(2), L020401. (www)

  @article{ , abstract = {We investigate the fundamental and practical precision limits of thermometry in bosonic and fermionic environments by coupling an N -level probe to them and continuously monitoring it. Our findings show that the ultimate precision limit, quantified by the Fisher information, scales linearly with N , offering an exponential improvement over equilibrium thermometry, where the scaling is only log 2 N . For a fixed Hamiltonian structure, we develop a maximum-likelihood estimation strategy that maps the observed continuously monitored trajectories of the probe into temperature estimates with minimal error. By optimizing over all possible Hamiltonian structures, we discover that the optimal configuration is an effective two-level system, with both levels exhibiting degeneracy that increases with N —a stark contrast to equilibrium thermometry, where the ground state remains nondegenerate. Our results have practical implications. First, continuous monitoring is experimentally feasible on several platforms and accounts for the preparation time of the probe, which is often overlooked in other approaches such as prepare and reset. Second, the linear scaling is robust against deviations from the effective two-level structure of the optimal Hamiltonian. Additionally, this robustness extends to cases of initial ignorance about the temperature. Thus, in global estimation problems, the linear scaling remains intact even without adaptive strategies.}, archive = {J_PRA}, author = {Mohammad Mehboudi and Florian Meier and Marcus Huber and Harry J. D. Miller}, doi = {10.1103/PhysRevA.111.L020401}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020401}, shortjournal = {Phys. Rev. A}, title = {Optimal limits of continuously monitored thermometers and their hamiltonian structure}, volume = {111}, year = {2025}, }
• (2025). Correlated and critical phenomena in multipartite quantum non-markovianity. PRA, 111(2), L020204. (www)

  @article{ , abstract = {We study non-Markovianity in the exact dynamics of two two-level atoms in a resonant cavity. We find a critical behavior in the form of a Markovian to non-Markovian transition at a finite interatomic distance and a discontinuity in the limit of infinitely close atoms. Actually, in this highly correlated regime, we find that non-Markovianity always arises if the system size exceeds a critical threshold. To this end, a nonsingular, additive non-Markovian measure with appropriate asymptotic behavior is formulated. These results show how inter-subsystem distance and system size can act as precise controls for modulating memory effects in multipartite open quantum systems.}, archive = {J_PRA}, author = {Ignacio González and Ángel Rivas}, doi = {10.1103/PhysRevA.111.L020204}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020204}, shortjournal = {Phys. Rev. A}, title = {Correlated and critical phenomena in multipartite quantum non-markovianity}, volume = {111}, year = {2025}, }
• (2025). Improved bounds on collapse models from rotational noise of the laser interferometer space antenna pathfinder mission. PRA, 111(2), L020203. (www)

  @article{ , abstract = {We study spontaneous wave-function collapse models, which modify the Schrödinger equation with nonlinear and stochastic terms offering a solution to the quantum measurement problem. We find that constraints on the phenomenological parameters of the continuous spontaneous localization (CSL) model can be tightened using the recent analysis of the Laser Interferometer Space Antenna Pathfinder mission's angular motion data. We derived a stronger constraint on the CSL model than previously achieved with translational motion. Additionally, we identify general conditions under which rotational measurements provide an advantage over translational ones in testing collapse models. These results enhance the experimental strategies for probing fundamental modifications of quantum mechanics.}, archive = {J_PRA}, author = {Davide Giordano Ario Altamura and Andrea Vinante and Matteo Carlesso}, doi = {10.1103/PhysRevA.111.L020203}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020203}, shortjournal = {Phys. Rev. A}, title = {Improved bounds on collapse models from rotational noise of the laser interferometer space antenna pathfinder mission}, volume = {111}, year = {2025}, }
• (2025). Crypto-nonlocality in arbitrarily dimensional systems. PRA, 111(2), L020202. (www)

  @article{ , abstract = {According to Bell's theorem, any physical theory based on local variables cannot fully reproduce quantum correlations. A critical question arises whether it is possible to develop an alternative framework based on nonlocal variables that can reproduce quantum correlations. Leggett proposed a nonlocal model, termed crypto-nonlocality, grounded in considerations of the reality of photon polarization. However, this model is inherently restricted to two dimensions. In this Letter, we extend the framework to higher dimensions and propose a method for constructing experimentally testable Leggett-type inequalities in arbitrary dimensions. From an information-theoretic perspective, our exploration of models that predict outcomes exceeding the scope of quantum mechanics is particularly intriguing and expected to deepen our understanding of quantum correlations.}, archive = {J_PRA}, author = {Jianqi Sheng and Dongkai Zhang and Lixiang Chen}, doi = {10.1103/PhysRevA.111.L020202}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020202}, shortjournal = {Phys. Rev. A}, title = {Crypto-nonlocality in arbitrarily dimensional systems}, volume = {111}, year = {2025}, }
• (2025). SU(N) fermi-hubbard model on two sites: Bethe ansatz solution and quantum phase transition of the lipkin-meshkov-glick model in the large-N limit. PRA, 111(2), L020201. (www)

  @article{ , abstract = {We show that the SU ( N ) Fermi-Hubbard model (FHM) on two sites, where N is the number of flavors of each fermion, corresponds to an exactly solvable two-level many-boson model that Richardson [ J. Math. Phys. 9 , 1327 (1968) ] analytically solved long ago. We express the Bethe ansatz solutions as a function of the physical parameters of the SU ( N ) FHM, and recast its eigenvalues and eigenstates in terms of the Richardson pair energies and creation operators. In this context, the connection with the well-studied Lipkin-Meshkov-Glick (LMG) model, known as equivalent to the Richardson model, is established and serves as a guideline to the prediction of some N -body physics phenomena in the two-site SU ( N ) FHM with N particles. In particular, the LMG second-order quantum phase transition (QPT) is shown to occur in the SU ( N ) FHM for an attractive density-density interaction U equal to U c = − 1 / ( 2 N ) , in units of the (absolute value of the) tunneling amplitude between the two sites. We show the finite-size energies, the gap, and the kinetic energy, which all reveal the transition, as a function of U for values of N from N = 3 to N = 36 , suggesting that the QPT could be experimentally achieved with current technologies involving SU ( N ) ultracold atoms or molecules. Finally, we show the entanglement entropy of the first site with respect to the second, and it scales like N at the transition, in contrast with several two-mode models.}, archive = {J_PRA}, author = {Pierre Nataf}, doi = {10.1103/PhysRevA.111.L020201}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {L020201}, shortjournal = {Phys. Rev. A}, title = {SU(N) fermi-hubbard model on two sites: Bethe ansatz solution and quantum phase transition of the lipkin-meshkov-glick model in the large-N limit}, volume = {111}, year = {2025}, }
• (2025). Erratum: Spin-noise-induced synchronization between non-overlapping laser beams [Phys. rev. a 110, 033105 (2024)]. PRA, 111(2), 029902. (www)

  @article{ , abstract = {Phys. Rev. A 111, 029902 (2025)}, archive = {J_PRA}, author = {Shiming Song and Min Jiang and Yushu Qin and Ze Wu and Haowen Su and Ren-bao Liu and Dieter Suter and Xinhua Peng}, doi = {10.1103/PhysRevA.111.029902}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {029902}, shortjournal = {Phys. Rev. A}, title = {Erratum: Spin-noise-induced synchronization between non-overlapping laser beams [Phys. rev. a 110, 033105 (2024)]}, volume = {111}, year = {2025}, }
• (2025). Erratum: Deorbitalization strategies for meta-generalized-gradient-approximation exchange-correlation functionals [Phys. rev. a 96, 052512 (2017)]. PRA, 111(2), 029901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 029901 (2025)}, archive = {J_PRA}, author = {Daniel Mejía-Rodríguez and S. B. Trickey}, doi = {10.1103/PhysRevA.111.029901}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {029901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Deorbitalization strategies for meta-generalized-gradient-approximation exchange-correlation functionals [Phys. rev. a 96, 052512 (2017)]}, volume = {111}, year = {2025}, }
• (2025). Measuring state-multipole moments in coherent-population-trapping experiments. PRA, 111(2), 023715. (www)

  @article{ , abstract = {The traditional Coherent-Population-Trapping (CPT) approach to atomic signal generation in chip-scale atomic clocks (CSACs) requires circularly polarized light, which creates spin polarization in the vapor and leads to reduced CSAC signal-to-noise ratios. Though various strategies have been developed to mitigate this problem, there is only a superficial and/or empirical understanding of these strategies’ efficacies due to the difficulty of measuring ground-state population distributions among hyperfine Zeeman sublevels. Here, we demonstrate an optical technique to measure the first three (density-matrix) state multipole moments of a single ground-state hyperfine manifold. Using this technique, we have discovered that ground-state angular momentum alignment (i.e., the quadrupole moment) can play an important role in CPT signal-to-noise ratios.}, archive = {J_PRA}, author = {Andrew Householder and Nate Ristoff and James Camparo}, doi = {10.1103/PhysRevA.111.023715}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023715}, shortjournal = {Phys. Rev. A}, title = {Measuring state-multipole moments in coherent-population-trapping experiments}, volume = {111}, year = {2025}, }
• (2025). Efficient characterization of spatial schmidt modes of multiphoton entangled states produced from high-gain parametric down-conversion. PRA, 111(2), 023714. (www)

  @article{ , abstract = {The ability to efficiently characterize the spatial correlations of entangled states of light is critical for applications of many quantum technologies such as quantum imaging. Here, we demonstrate highly efficient theoretical and experimental characterization of the spatial Schmidt modes and the Schmidt spectrum of bright multiphoton entangled states of light produced from high-gain parametric down-conversion. In contrast to previous studies, we exploit the approximate quasihomogeneity and isotropy of the signal field and dramatically reduce the numerical computations involved in the experimental and theoretical characterization procedures. In our particular case where our experimental datasets consist of 5000 single-shot images of 256 × 256 pixels each, our method reduced the overall computation time by 2 orders of magnitude. This speedup would be even more dramatic for larger input sizes. Consequently, we are able to rapidly characterize the Schmidt modes and the Schmidt spectrum for a range of pump amplitudes and study their variation with increasing gain. Our results clearly reveal the broadening of the Schmidt modes and the narrowing of the Schmidt spectrum for increasing gain with agreement between theory and experiment.}, archive = {J_PRA}, author = {Mahtab Amooei and Girish Kulkarni and Jeremy Upham and Robert W. Boyd}, doi = {10.1103/PhysRevA.111.023714}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023714}, shortjournal = {Phys. Rev. A}, title = {Efficient characterization of spatial schmidt modes of multiphoton entangled states produced from high-gain parametric down-conversion}, volume = {111}, year = {2025}, }
• (2025). On-demand acoustic shaping of mössbauer γ-ray photons. PRA, 111(2), 023713. (www)

  @article{ , abstract = {We propose a technique that makes it possible to transform the intensity of a quasimonochromatic single-photon wave packet, emitted by a radioactive Mössbauer γ-ray source, into a sequence of short bursts with an arbitrary number of bursts, including a single burst. In addition, the technique allows one to individually and independently control, on demand, the moments of the burst appearance, as well as the peak intensity, duration, and shape of each burst in the sequence. The technique is based on the transmission of Mössbauer (recoilless) photons through a resonantly absorbing medium, which is rapidly displaced at some moments of time relative to the source (or vice versa) along the photon propagation direction at a distance less than the photon wavelength, and returned to its original position. The burst duration can be comparable to the duration of the single-photon pulses that are produced by synchrotrons but have the controlled spectral-temporal characteristics. We show that the proposed technique can be implemented on the basis of currently available equipment with the use of 14.4-keV recoilless photons, emitted by a Co 57 source and a Fe 57 absorber, which opens up prospects for its applications in Mössbauer spectroscopy and x-ray quantum optics.}, archive = {J_PRA}, author = {I. R. Khairulin and Y. V. Radeonychev}, doi = {10.1103/PhysRevA.111.023713}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023713}, shortjournal = {Phys. Rev. A}, title = {On-demand acoustic shaping of mössbauer γ-ray photons}, volume = {111}, year = {2025}, }
• (2025). Simulating and probing many-body quantum states in waveguide-QED systems with giant atoms. PRA, 111(2), 023712. (www)

  @article{ , abstract = {Waveguide quantum electrodynamics (wQED) with giant atoms provides a distinctive opportunity to quantum simulation of many-body physics through its unique decoherence-free interactions. This study presents a theoretical framework for simulating the diagonal Aubry-André-Harper (AAH) model in the context of giant-atom wQED. The proposed scheme employs photonic modes in the waveguide to not only mediate interactions between atoms but also to detect the energy spectrum of the atom array. To illustrate the effectiveness of this approach, we present a simulation of the Hofstadter butterfly spectrum with high precision. Furthermore, for an incommensurate AAH atomic chain, we demonstrate that the photon transmission spectrum can accurately distinguish between the many-body localized phase and the extended phase. The method presented here is also applicable to the simulation of other types of 1D atomic chains based on giant-atom wQED.}, archive = {J_PRA}, author = {C. L. Yang and W. Z. Jia}, doi = {10.1103/PhysRevA.111.023712}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023712}, shortjournal = {Phys. Rev. A}, title = {Simulating and probing many-body quantum states in waveguide-QED systems with giant atoms}, volume = {111}, year = {2025}, }
• (2025). Single-photon scattering in giant-atom topological-waveguide-QED systems. PRA, 111(2), 023711. (www)

  @article{ , abstract = {The giant-atom topological-waveguide-QED systems have recently emerged as a promising platform for manipulating light-matter interactions. The combination of the multiple-point couplings and topological phase effect could lead to rich physical phenomena and effects. Here, we study single-photon scattering in a Su-Schrieffer-Heeger (SSH) waveguide coupled to either one or two two-level giant atoms. We assume that each giant atom is coupled to the waveguide via two coupling points and hence there exist four and sixteen coupling configurations for the single-giant-atom case and two-giant-atom separate coupling case, respectively. By solving the single-photon scattering problem in the real space, we obtain the exact expressions of the single-photon scattering amplitudes. It is found that a single photon in the SSH waveguide can be completely reflected or transmitted by choosing proper coupling configurations, coupling-point distances, atomic resonance frequency, and dimerization parameter. In addition, under proper parameter conditions, the scattering spectra are periodically modulated by the coupling-point distances. We also find that the collective behavior of the two giant atoms can be adjusted by quantum interference effect and topological effect and that the single-photon scattering spectra can exhibit the Lorentzian, super-Gaussian, electromagnetically induced transparencylike, and asymmetric Fano line shapes for some coupling configurations. This work will inspire the development of controllable single-photon devices based on the giant-atom topological-waveguide-QED systems.}, archive = {J_PRA}, author = {Hai Zhu and Xian-Li Yin and Jie-Qiao Liao}, doi = {10.1103/PhysRevA.111.023711}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023711}, shortjournal = {Phys. Rev. A}, title = {Single-photon scattering in giant-atom topological-waveguide-QED systems}, volume = {111}, year = {2025}, }
• (2025). Entanglement and steering in a three-dimensional cavity magnomechanics system. PRA, 111(2), 023710. (www)

  @article{ , abstract = {We investigate steady-state entanglement and steering in a three-dimensional cavity magnomechanics system. From the system's equations of motion, we derive the linearized Lyapunov equation for steady states, introduce logarithmic negativity to quantify entanglement, and apply a quantization method for Gaussian states with continuous variables to measure steering. Numerical simulations reveal that steady-state entanglement and steering can be established between various system components—such as the two cavity modes, the cavity mode and magnon mode, and the cavity mode and phonon mode—by selecting experimentally feasible detunings, dissipation rates, and coupling rates. We develop a three-dimensional cross-cavity model to study bipartite and tripartite entanglement and explore parameter adjustments to achieve both one-way and two-way steering. Additionally, we confirm the system's strong robustness to temperature variations. This work provides a platform for studying entanglement and steering beyond squeezed optical drives and has potential applications in quantum information processing and quantum sensing.}, archive = {J_PRA}, author = {Xin Ge and Jia-Xin Peng and Yue-Yue Chen}, doi = {10.1103/PhysRevA.111.023710}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023710}, shortjournal = {Phys. Rev. A}, title = {Entanglement and steering in a three-dimensional cavity magnomechanics system}, volume = {111}, year = {2025}, }
• (2025). Quantum correlations in integrated waveguide structures with disorder and next-nearest-neighbor coupling. PRA, 111(2), 023709. (www)

  @article{ , abstract = {We theoretically investigate the quantum correlations of nonclassical states in disordered optical waveguides with next-nearest-neighbor (second-order) coupling. We find that single-particle states from different initial positions exhibit similar behavior at specific second-order coupling strengths. At the same time, entangled bosons display correlations that are either analogous to or mirror-symmetric to those of bosons and fermions. We numerically calculate the interparticle distance probabilities of both planar and circular structures and show that their distinct boundary conditions produce unique correlation patterns. In certain cases, bosons are less likely to occupy the same site and single-particle states show asymmetric probability distributions. The effects of second-order coupling and disorder act to cancel out these nontrivial features. Nonclassical states have found numerous applications in integrated quantum photonics. Furthermore, in practical scenarios, disorder is unavoidable, and second-order coupling becomes crucial for light-matter interactions, polymer chains, magnetic materials, non-Hermitian Hamiltonians, topologically nontrivial systems, spin chains, and so on. Their combined effects across diverse physical systems and experimental platforms signify the broader importance of our work.}, archive = {J_PRA}, author = {Ankan Das Roy and Amit Rai and Gautam Vemuri}, doi = {10.1103/PhysRevA.111.023709}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023709}, shortjournal = {Phys. Rev. A}, title = {Quantum correlations in integrated waveguide structures with disorder and next-nearest-neighbor coupling}, volume = {111}, year = {2025}, }
• (2025). Controlling the superradiant phase transition in the quantum rabi model. PRA, 111(2), 023708. (www)

  @article{ , abstract = {In the ultrastrong-coupling regime, the quantum Rabi model can exhibit quantum phase transition (QPT) when the ratio of the qubit transition frequency to the frequency of the cavity field approaches infinity. However, it is challenging to control the QPT in few-body systems because of the limited coupling strength and the term. Here, we propose a practical scheme to manipulate the QPT of quantum Rabi model in the strong-coupling regime. By applying a periodic frequency modulation to the two-level system in a quantum Rabi model in the strong-coupling regime, an anisotropic quantum Rabi model with ultrastrong and tunable coupling strengths for rotating and counterrotating terms is obtained. The ground state and excitation energy of this model, in terms of the modulation parameters, are studied. We find that the QPT of the quantum Rabi model can be observed in the strong-coupling regime and externally controlled by the modulation.}, archive = {J_PRA}, author = {Xuan Xie and Cheng Liu and Lin-Lin Jiang and Jin-Feng Huang}, doi = {10.1103/PhysRevA.111.023708}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023708}, shortjournal = {Phys. Rev. A}, title = {Controlling the superradiant phase transition in the quantum rabi model}, volume = {111}, year = {2025}, }
• (2025). Tunable photon scattering by an atom dimer coupled to a band edge of a photonic crystal waveguide. PRA, 111(2), 023707. (www)

  @article{ , abstract = {Quantum emitters trapped near photonic crystal waveguides have recently emerged as an exciting platform for realizing novel quantum matter-light interfaces. Here, we study tunable photon scattering in a photonic crystal waveguide coupled to an atom dimer with an arbitrary spatial separation. In the weak-excitation regime, we give the energy levels and their decay rates into the waveguide modes in the dressed basis, which both depend on the distance between the two atoms. We focus on the Bragg case and anti-Bragg case, where subradiant and superradiant states are produced and perfect transmission with a phase shift may occur on resonance. We observe quantum beats in the photon-photon correlation function of the reflected field in the anti-Bragg case. Moreover, the frequencies of quantum beats can be controlled due to the tunability of the bound states via the dispersion engineering of the structure. We also observe directional photon emission in the anti-Bragg case and give the dynamic mechanism of the perfect transmission. We quantify the effects of the system imperfections, including the deviation in the distance between the two atoms and the asymmetry in the atomic decay rates into the waveguide modes. With recent experimental advances in the superconducting microwave transmission lines, our results should soon be realizable.}, archive = {J_PRA}, author = {Guo-Zhu Song and Lin-Xiong Wang and Jing-Xue Zhang and Hai-Rui Wei}, doi = {10.1103/PhysRevA.111.023707}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023707}, shortjournal = {Phys. Rev. A}, title = {Tunable photon scattering by an atom dimer coupled to a band edge of a photonic crystal waveguide}, volume = {111}, year = {2025}, }
• (2025). Quantum-optimal hypothesis testing for discriminating partially coherent optical sources. PRA, 111(2), 023706. (www)

  @article{ , abstract = {Discriminating a weak optical source that may be hidden near a known optical source is a fundamental and challenging task for quantum imaging, especially for small spatial separations. Previous works in this regard focused on two incoherent sources. Here, we complement this subject by extending the application scenario to two partially coherent sources. The lower limit on the error probability is investigated through analytical calculation of the quantum Bhattacharyya bound. We present two quantum-optimal detection strategies of which error probabilities decided by likelihood ratio test can approach the quantum Bhattacharyya bound. For practical purposes, we propose a simplified decision rule for these two strategies, which can greatly reduce the complexity of the discrimination task. In addition, the effects originating from spatial coherence and relative brightness are discussed. Our work provides insights into quantum imaging and opens a promising avenue for real-world imaging.}, archive = {J_PRA}, author = {Jian-Dong Zhang and Mei-Ming Zhang and Fan Jia and Chuang Li and Shuai Wang}, doi = {10.1103/PhysRevA.111.023706}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023706}, shortjournal = {Phys. Rev. A}, title = {Quantum-optimal hypothesis testing for discriminating partially coherent optical sources}, volume = {111}, year = {2025}, }
• (2025). Photon-pair generation via down-conversion in III-V semiconductor microrings: Modal dispersion and quasi-phase-matching. PRA, 111(2), 023705. (www)

  @article{ , abstract = {We explore how III-V semiconductor microring resonators can efficiently generate photon pairs and squeezed vacuum states via spontaneous parametric down-conversion by utilizing their built-in quasi-phase-matching and modal dispersion. We present an analytic expression for the biphoton wave function of photon pairs generated by weak pump pulses and characterize the squeezed states that result under stronger pumping conditions. Our model includes loss and captures the statistics of the scattered photons. A detailed sample calculation shows that for low pump power conversion efficiencies of , corresponding to a rate of 39 MHz for a pump power of , are attainable for rudimentary structures such as a simple microring coupled to a waveguide, in both the continuous-wave and pulsed-excitation regimes. Our results suggest that high levels of squeezing and pump depletion are attainable, possibly leading to the deterministic generation of non-Gaussian states.}, archive = {J_PRA}, author = {Samuel E. Fontaine and Colin Vendromin and Trevor J. Steiner and Amirali Atrli and Lillian Thiel and Joshua Castro and Galan Moody and John Bowers and Marco Liscidini and J. E. Sipe}, doi = {10.1103/PhysRevA.111.023705}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023705}, shortjournal = {Phys. Rev. A}, title = {Photon-pair generation via down-conversion in III-V semiconductor microrings: Modal dispersion and quasi-phase-matching}, volume = {111}, year = {2025}, }
• (2025). Correlations in circular quantum cascades. PRA, 111(2), 023704. (www)

  @article{ , abstract = {We introduce a one-way, one-quantum cascade, whereby a single excitation proceeds one-direction-wise in a ladder of energy levels. This makes a variation from more famous two-way cascades where the excitation can go up and down following its excitation or relaxation in the ladder. We provide closed-form solutions for two-photon correlation functions between any transitions in such circular cascades. We discuss how the rich correlations that result from what appears to be an extremely simple implementation are essentially those which have been obtained from complex architectures relying on strongly correlated, many-body physics or cavity QED effects, and might constitute the liquid phase of the new family of time materials.}, archive = {J_PRA}, author = {Miguel Ángel Palomo Marcos and Eduardo Zubizarret Casalengua and Elena del Valle and Fabrice P. Laussy}, doi = {10.1103/PhysRevA.111.023704}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023704}, shortjournal = {Phys. Rev. A}, title = {Correlations in circular quantum cascades}, volume = {111}, year = {2025}, }
• (2025). Local-photon model of the momentum of light. PRA, 111(2), 023703. (www)

  @article{ , abstract = {Recently we introduced a local photon approach for modeling the quantized electromagnetic field in position space. Using this approach, we define the momentum of light in this paper as in quantum mechanics as the generator for spatial translation. Afterward, we analyze the momentum dynamics of photonic wave packets which transition from air into a denser dielectric medium. Our analysis shines new light onto the Abraham-Minkowski controversy, which highlights the intricacies involved in the characterization of the momentum of the electromagnetic field. Although our results align with Minkowski's theory and with the definition of the canonical momentum of light in quantum electrodynamics, there are also some crucial differences.}, archive = {J_PRA}, author = {Gabriel Waite and Daniel Hodgson and Ben Lang and Varghese Alapatt and Almut Beige}, doi = {10.1103/PhysRevA.111.023703}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023703}, shortjournal = {Phys. Rev. A}, title = {Local-photon model of the momentum of light}, volume = {111}, year = {2025}, }
• (2025). Chiral-cat-state generation via the sagnac-fizeau effect. PRA, 111(2), 023702. (www)

  @article{ , abstract = {Chiral quantum state generation is an interesting topic in quantum physics and quantum information science. Here we propose an approach for generating chiral cat states in a spinning resonator supporting both the clockwise (CW) and counterclockwise (CCW) traveling modes, which are dispersively coupled to a two-level atom. The physical mechanism for the chiral-cat-state generation is based on the Sagnac-Fizeau effect. Concretely, when the resonator is rotating, the CW and CCW modes have different frequency detuning with respect to the atomic transition frequency and hence the atomic-state-dependent rotating angular velocities for the CW and CCW modes in phase space are different. This mode-dependent evolution leads to a chirality mechanism in the state generation. Based on the mode-dependent conditional rotation evolution and atomic projection measurement at proper time, we achieve the separate generation of cat states in the CW mode and coherent states in the CCW mode. We also investigate quantum coherence properties of the generated states by examining their Wigner functions. In addition, the influence of the system dissipations on the state generation in the open-system case is investigated. Our work will provide some insights into the development of chiral optical devices and nonreciprocal photonics.}, archive = {J_PRA}, author = {Yu-Hong Liu and Xian-Li Yin and Hui Jing and Le-Man Kuang and Jie-Qiao Liao}, doi = {10.1103/PhysRevA.111.023702}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023702}, shortjournal = {Phys. Rev. A}, title = {Chiral-cat-state generation via the sagnac-fizeau effect}, volume = {111}, year = {2025}, }
• (2025). Directional emission of a broadband squeezed microwave field. PRA, 111(2), 023701. (www)

  @article{ , abstract = {Broadband squeezed light is a valuable resource in the quantum information science community. Here, we propose an appealing method for the directional generation of broadband microwave squeezing based on hybrid magnonics, where multiple chiral cavity-magnonic subsystems are connected together through a bidirectional waveguide in a cascading way. The chirality arises from the selective coupling between the Kittel mode in the ferrimagnetic yttrium iron garnet sphere and one of the two degenerate counter-rotating microwave modes in a ring-shaped cavity. By introducing Floquet engineering to simultaneously induce red and blue sidebands in the photon-magnon coupling, the chiral squeezing-type interaction can be engineered in each cavity-magnonic subsystem. Considering all the photon-magnon couplings in the cascaded system with the same chirality, we show that a broadband squeezed microwave field can be emitted on demand to either of the two output ports along the waveguide. Compared with a single chiral cavity-magnonic system, both the squeezing amount and the bandwidth can be significantly enhanced through the cumulative effect of the cascaded system.}, archive = {J_PRA}, author = {Rong-teng Cao and Ji-kun Xie and Ya-long Ren and Shao-yan Gao and Sheng-li Ma}, doi = {10.1103/PhysRevA.111.023701}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023701}, shortjournal = {Phys. Rev. A}, title = {Directional emission of a broadband squeezed microwave field}, volume = {111}, year = {2025}, }
• (2025). Entanglement characteristics of levitated magnomechanical systems. PRA, 111(2), 023522. (www)

  @article{ , abstract = {We theoretically propose a cavity magnomechanical system with a levitated yttrium iron garnet sphere to study the entanglement characteristics between subsystems. The system consists of microwave photon, magnon, and mechanical phonon modes, where the photon and magnon modes can be driven by external microwave sources. We find that with the appropriate choice of the suspension position, the effective couplings between the cavity field and the magnon and phonon modes can be established, thus inducing the generation of bipartite entanglement and genuine tripartite entanglement in the system. Further, we also analyze in detail the influences of the radius of the sphere, the detunings of the cavity and magnon modes, the driving power, the frequency of the phonon mode, and the environment temperature on the characteristics of the quantum entanglement. The results obtained here indicate that the bipartite and tripartite entanglements can be manipulated by changing the radius and the oscillation frequency of the sphere in addition to changing the parameters of the cavity field, and therefore, the levitated magnomechanical system has a potential application in the study of macroscopic quantum phenomena.}, archive = {J_PRA}, author = {Huiya Zhan and Aixi Chen and Wenjie Nie}, doi = {10.1103/PhysRevA.111.023522}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023522}, shortjournal = {Phys. Rev. A}, title = {Entanglement characteristics of levitated magnomechanical systems}, volume = {111}, year = {2025}, }
• (2025). Optimizing attosecond-pulse generation in solids by modulating electronic dynamics with a monochromatic laser field. PRA, 111(2), 023521. (www)

  @article{ , abstract = {A practical approach is proposed for efficiently generating ultrashort attosecond pulses from realistic solid-state materials, aiming to optimize pulse width effectively. By adjusting the photon energy while maintaining a constant peak electric field, this strategy modulates the peak vector potential and laser field period, thereby controlling the high harmonic cutoff energy and the time-domain emission characteristics of the harmonics. The field-driven electronic dynamics lead to a nonmonotonic variation in both the intensity and the duration of the generated attosecond pulses. The light field frequency can be adjusted to yield the optimal pulse. Beyond the primary demonstration with hexagonal boron nitride as a prototypical material, significant pulse width optimization has been achieved across a range of different materials. This straightforward and versatile strategy shows promise for application in solid-state materials, offering new pathways to promote high harmonic performance.}, archive = {J_PRA}, author = {Xinyuan Zhang and Shiqi Hu and Mengxue Guan and Sheng Meng}, doi = {10.1103/PhysRevA.111.023521}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023521}, shortjournal = {Phys. Rev. A}, title = {Optimizing attosecond-pulse generation in solids by modulating electronic dynamics with a monochromatic laser field}, volume = {111}, year = {2025}, }
• (2025). Observing the influence of second-harmonic tangential surface source in gold plasmonic nanostructures. PRA, 111(2), 023520. (www)

  @article{ , abstract = {The origin of the second harmonic generation (SHG) from plasmonic structures remains a subject of debate. Here, we investigate SHG from gold plasmonic nanostructures by scanning nanostructures at the single-particle level to acquire two-dimensional (2D) SHG maps which are qualitatively and quantitatively compared with numerically simulated SHG maps. This approach allows us to discriminate the role played by the surface and bulk contributions to SHG. Our findings reveal that the tangential surface source contribution, often neglected in the literature, plays a dominant role and is affected by surface roughness. This is evident when comparing the SHG maps obtained from identically sized gold nanoparticles that are fabricated using physical and chemical techniques. Additionally, the normal surface source is not found to significantly impact SHG in these configurations.}, archive = {J_PRA}, author = {Sandy Mathew and Maëliss Ethis de Corny and Nicolas Chauvet and Laureen Moreaud and Erik Dujardin and Gilles Nogues and Guillaume Bachelier}, doi = {10.1103/PhysRevA.111.023520}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023520}, shortjournal = {Phys. Rev. A}, title = {Observing the influence of second-harmonic tangential surface source in gold plasmonic nanostructures}, volume = {111}, year = {2025}, }
• (2025). Spontaneous PT-symmetry-breaking transitions under the influence of noise in an optomechanical system. PRA, 111(2), 023519. (www)

  @article{ , abstract = {Spontaneous symmetry breaking is a phenomenon of an alteration of a state symmetry without a change in the system symmetry. A transition from a state with unbroken symmetry to a state with broken symmetry leads to a qualitative change in system properties and respective states are called symmetric and nonsymmetric phases of the system. Usually, the change in the system parameters is necessary for the transition between symmetric and nonsymmetric phases. In this paper, we consider the behavior of an optomechanical system with an exceptional point under the influence of noise. We demonstrate that below the exceptional point, -symmetric and non- -symmetric phases can coexist. In this regime, a noise can lead to random transitions between the symmetric and nonsymmetric phases. These transitions are accompanied by the abrupt changes in the intensities of photon and phonon modes. The predicted phenomenon opens up the possibility of studying the kinetics of phase transitions caused by spontaneous breaking of symmetry.}, archive = {J_PRA}, author = {A. R. Mukhamedyanov and E. S. Andrianov and A. A. Zyablovsky}, doi = {10.1103/PhysRevA.111.023519}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023519}, shortjournal = {Phys. Rev. A}, title = {Spontaneous PT-symmetry-breaking transitions under the influence of noise in an optomechanical system}, volume = {111}, year = {2025}, }
• (2025). Geometric phase self-focusing from optical spin angular momentum transfer to matter. PRA, 111(2), 023518. (www)

  @article{ , abstract = {Liquid crystals are well-known for their nonlinear orientational optical properties, in particular self-focusing as a result of optically induced reorientation magnitude, which relies on dynamic phase spatial modulation. Here we report on optical self-focusing of a purely geometric nature. The effect is demonstrated using a uniformly oriented liquid crystal half-wave plate illuminated by a fully polarized collimated beam. The effect is shown to be driven by spin angular momentum deposition and its magnitude scales with the amount of spin angular momentum carried by the incident beam. The experimental and modeling results encompass both material and wave aspects as well as the optomechanical process that drives the phenomenon, thus enriching the nonlinear spin-orbit photonics toolbox.}, archive = {J_PRA}, author = {Samlan Chandran Thodika and Etienne Brasselet}, doi = {10.1103/PhysRevA.111.023518}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023518}, shortjournal = {Phys. Rev. A}, title = {Geometric phase self-focusing from optical spin angular momentum transfer to matter}, volume = {111}, year = {2025}, }
• (2025). Multiple temporal compression as a method to control the generation of bright and dark solitons. PRA, 111(2), 023517. (www)

  @article{ , abstract = {Recently published works have shown that the multiple temporal compression (MTC) method is a more efficient approach for generation of multiple bright solitons in stacked waveguides, in comparison to the traditional soliton-fission technique. In the present paper, we performed systematic computer simulations of the appropriate generalized nonlinear Schrödinger equation to extend the MTC method for generation of dark solitons through controlled interactions of bright solitons in waveguiding systems with the normal group-velocity dispersion. Further, the generated dark solitons are demonstrated to be useful for accurately governing the dynamics of bright solitons generation in complex systems based on stacked waveguides. Therefore, we report scenarios that provide mitigation or switching of the energy transfer during bright-soliton collisions, along with the ability of the cascaded MTC processes to increase the number of generated solitons. These results underscore the potential of the MTC as a versatile method for managing the propagation dynamics of multiple temporal bright and dark solitons produced by a single input pulse, with possible applications for the design of optical devices.}, archive = {J_PRA}, author = {André C. A. Siqueira and Palacios G and Mario B. Monteiro and Albert S. Reyna and Boris A. Malomed and Edilson L. Falcão-Filho and Cid B. de Araújo}, doi = {10.1103/PhysRevA.111.023517}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023517}, shortjournal = {Phys. Rev. A}, title = {Multiple temporal compression as a method to control the generation of bright and dark solitons}, volume = {111}, year = {2025}, }
• (2025). Theoretical framework for enhancing or enabling cooling of a mechanical resonator via the anti-stokes or stokes interaction and zero-photon detection. PRA, 111(2), 023516. (www)

  @article{ , abstract = {We develop a theoretical framework to describe how zero-photon detection may be utilized to enhance optomechanical laser cooling via the anti-Stokes interaction and, somewhat surprisingly, enable cooling via the Stokes interaction commonly associated with heating. Our description includes both pulsed and continuous measurements as well as optical detection efficiency and open-system dynamics. For both cases, we discuss how the cooling depends on the system parameters such as detection efficiency and optomechanical cooperativity, and we study the continuous-measurement-induced dynamics, contrasting with single-photon-detection events. For the Stokes case, we explore the interplay between cooling and heating via optomechanical parametric amplification, and we find the minimum efficiency required to cool a mechanical oscillator via zero-photon detection. This work serves as a companion article to our recent experiment [E. A. Cryer-Jenkins et al. , Phys. Rev. Lett. 134 , 073601 (2025) ], which demonstrated enhanced laser cooling of a mechanical oscillator via zero-photon detection on the anti-Stokes signal. The cooling techniques developed here can be applied to a wide range of areas including nonclassical state preparation, quantum thermodynamics, and avoiding the often unwanted heating effects of parametric amplification.}, archive = {J_PRA}, author = {Jack Clarke and Evan A. Cryer-Jenkins and Arjun Gupta and Kyle D. Major and Jinglei Zhang and Georg Enzian and Magdalena Szczykulska and Anthony C. Leung and Harsh Rathee and Andreas Ø. Svela and Anthony K. C. Tan and Almut Beige and Klaus Mølmer and Michael R. Vanner}, doi = {10.1103/PhysRevA.111.023516}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023516}, shortjournal = {Phys. Rev. A}, title = {Theoretical framework for enhancing or enabling cooling of a mechanical resonator via the anti-stokes or stokes interaction and zero-photon detection}, volume = {111}, year = {2025}, }
• (2025). Cross-phase-modulation-induced nonlinear diffraction wave. PRA, 111(2), 023515. (www)

  @article{ , abstract = {We present and discuss a type of nonlinear diffraction wave (NLDW) induced by the strong cross-phase-modulation (XPM) effect between the femtosecond pump wave (FW) and its second-harmonic wave (SHW), observed experimentally in periodically poled lithium niobate (PPLN) nonlinear gratings. We develop a modified femtosecond pulse propagation model that describes the evolution of FW and SHW under the participation of the XPM effect. This model is numerically solved using the split-step Fourier transformation method, and the results successfully explain the experimentally observed XPM-NLDW phenomenon. The discovery and analysis of XPM-NLDW will provide a deeper insight into the synergic nonlinear effects arising from the interaction of a femtosecond laser pulse with the PPLN crystal and stimulate the exploration of many other unknown phenomena existing in this regime of nonlinear optics.}, archive = {J_PRA}, author = {Yuanyuan Liu and Lihong Hong and Zhi-Yuan Li}, doi = {10.1103/PhysRevA.111.023515}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023515}, shortjournal = {Phys. Rev. A}, title = {Cross-phase-modulation-induced nonlinear diffraction wave}, volume = {111}, year = {2025}, }
• (2025). Spatiotemporal force-density evolution in resonant structures with ultrafast optics. PRA, 111(2), 023514. (www)

  @article{ , abstract = {The temporal evolution of the optical force density in structured membranes under ultrafast optical illumination is investigated for illustrative situations. Based on this work, it appears that it is possible to exert a pulling force on resonant structures using pulsed light. A combination of optical pulse control and nanostructured material design enables optomechanical device paradigms that allow temporal control of mechanical modes. This is of relevance in several existing areas, such as sensing and computation, and could lead to special opportunities for mechanical metamaterial concepts. This work provides insight into interactions between pulsed light and condensed matter, and motivates optomechanics experiments using ultrafast light.}, archive = {J_PRA}, author = {Farhan I. Zahin and Adam W. Behnke and Thomas J. Pollei and Kevin J. Webb}, doi = {10.1103/PhysRevA.111.023514}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023514}, shortjournal = {Phys. Rev. A}, title = {Spatiotemporal force-density evolution in resonant structures with ultrafast optics}, volume = {111}, year = {2025}, }
• (2025). Laser beam tight focusing: Optimal algorithm for focal-region field computation within a plane perpendicular to the objective axis. PRA, 111(2), 023513. (www)

  @article{ , abstract = {We suggest an objective-axis-expansion single-integral algorithm based on the Richards-Wolf vectorial diffraction theory to calculate tight focusing of a collimated continuous-wave coherent laser beam by a high-numerical-aperture microscope objective into a planar layered microcavity. The mathematical basis of the algorithm is formed by (i) expansion of a focused beam into a linear superposition of circularly polarized vortex vector beams and (ii) expansion of the focal amplitudes of the circularly polarized vortex vector beams into power series of the focal distance coordinate . The algorithm's computational speed is from four to seven orders of magnitude greater than that of the direct double-integral Richards-Wolf algorithm and up to two orders of magnitude greater than that of the Bluestein-method-based algorithm [ Light: Sci. Appl. 9 , 119 (2020) ], the fastest existing method, for typical focal-plane field calculations. We show that such computational speeds are the fastest possible for focal field calculations in planes perpendicular to the microscope objective axis. These speeds are able to allow for the real-time prediction of focal fields. The accuracy of the suggested algorithm is completely controllable and unlimited. The reported computational speed enhancement is valid for three-dimensional focal field calculations as well because a three-dimensional region can be scanned slice by slice in the longitudinal direction.}, archive = {J_PRA}, author = {Stepan Boichenko}, doi = {10.1103/PhysRevA.111.023513}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023513}, shortjournal = {Phys. Rev. A}, title = {Laser beam tight focusing: Optimal algorithm for focal-region field computation within a plane perpendicular to the objective axis}, volume = {111}, year = {2025}, }
• (2025). Transient coherent phase modulation of nuclear states via a high-repetition-rate laser. PRA, 111(2), 023512. (www)

  @article{ , abstract = {Advancements in x-ray sources extend the scope of light-matter interactions into the x-ray-nuclear regime. Precise temporal control of quantum phases provides fundamental insights into quantum systems and serves as a cornerstone for numerous quantum technologies. Nevertheless, achieving phase control of quantum systems with high temporal and spatial resolution remains a substantial challenge in the realm of hard x-ray quantum optics due to the ultrashort oscillation periods of photons. In this study, we propose to manipulate the magnetic properties of a thin film using near-infrared (NIR) pulses characterized by a high repetition rate. By calculating the evolution of quantum beats, we can theoretically extract the phase information of the nuclear response. Coherence within the nuclear ensemble is preserved throughout the entire process. This control scheme achieves quantum shifts with zeptosecond precision and modulates the spectral line shape within the frequency domain. Our proposal introduces a high-resolution method for rapidly manipulating nuclear states using optical laser pulses.}, archive = {J_PRA}, author = {Nan Xue and Haohan Shi and Kailin Zhang and Zuoye Liu}, doi = {10.1103/PhysRevA.111.023512}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023512}, shortjournal = {Phys. Rev. A}, title = {Transient coherent phase modulation of nuclear states via a high-repetition-rate laser}, volume = {111}, year = {2025}, }
• (2025). Optical bistability and rabi oscillations in a driven two-level semiconductor quantum dot: Effect of dynamical coulomb interaction between two electrons. PRA, 111(2), 023511. (www)

  @article{ , abstract = {We theoretically investigate the influence of dynamic Coulomb interaction on optical bistability and Rabi oscillations in a driven two-level semiconductor quantum dot system under laser irradiation. Using density matrix equations derived from the Coulomb-interaction model proposed by Lu et al. [ Phys. Rev. A 103 , 043504 (2021) ], we obtain analytical solutions for population inversion under the rotating wave approximation. Our analysis shows that the Coulomb interaction induces optical bistability, governed by a cubic equation. The thresholds and the shapes of the hysteresis loops are tunable and can be controlled by various parameters, including electron density, confinement potential, detuning, and dephasing. Additionally, our numerical simulations demonstrate the potential for achieving high-efficiency population inversion and predicting bifurcation and anharmonic regimes in Rabi oscillations under monochromatic excitation.}, archive = {J_PRA}, author = {İbrahim Karabulut}, doi = {10.1103/PhysRevA.111.023511}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023511}, shortjournal = {Phys. Rev. A}, title = {Optical bistability and rabi oscillations in a driven two-level semiconductor quantum dot: Effect of dynamical coulomb interaction between two electrons}, volume = {111}, year = {2025}, }
• (2025). Optical nonreciprocity using light shifts. PRA, 111(2), 023510. (www)

  @article{ , abstract = {Hot atoms have been demonstrated to be a promising platform for the manipulation of optical fields. However, the thermal motion of atoms results in the broadening of spectral lines, which is accompanied by a reduction in the light-atom interaction. In this study we propose a nonreciprocal optical system that significantly enhances the strength of the light-atom interaction by unidirectionally compensating for the broadening associated with two-photon processes, employing inhomogeneous light shifts in a system. Utilizing the density matrix formalism, we provide a detailed description of the dynamics and examine the nonreciprocity in two distinct detuned regions. In the far-detuned region, a room-temperature nonreciprocity with an isolation of and a transmission of 0.99 can be achieved. Furthermore, in the near-resonance region, the ultrabroad bandwidth of the nonreciprocal window can reach gigahertz. Our findings pave the way for the realization of high-performance optical nonreciprocity and present opportunities for applications in integrated optics and quantum networks.}, archive = {J_PRA}, author = {Yifan Zhan and Shicheng Zhang and Shangqing Gong and Yueping Niu}, doi = {10.1103/PhysRevA.111.023510}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023510}, shortjournal = {Phys. Rev. A}, title = {Optical nonreciprocity using light shifts}, volume = {111}, year = {2025}, }
• (2025). Filamentation of femtosecond vector beams. PRA, 111(2), 023509. (www)

  @article{ , abstract = {We numerically study the filamentation of femtosecond vector beams with spatially varying polarization profiles in air. The vector beams include azimuthal, radial, and spiral cylindrical vector beams (CVBs), as well as low-order full Poincaré beams (FPBs) with star and lemon polarization topologies. Comparing the filamentation of CVBs to that of a circularly polarized Laguerre-Gaussian (LG) beam, we found that CVBs undergo filamentation more easily due to their more effective nonlinear focusing, in contrast with LG beams. In the case of low-order FPBs, we examined the role of the constituent orthogonally polarized spatial modes in their filamentation process. Our findings reveal that the Gaussian mode within these beams primarily contributes to their filamentation. Additionally, when compared with a linearly polarized Gaussian beam, star and lemon FPBs displayed greater resistance to filamentation. In all comparisons, the vector beams and their counterparts are initialized with equal physical powers to isolate the role of polarization and beam structure on filamentation dynamics. Furthermore, we investigated the evolution of polarization profiles of the beams during filamentation. We observed that the polarization profiles of CVBs remained largely unchanged. In contrast, the polarization profiles of the FPBs underwent significant nonuniform changes due to differences in accumulated nonlinear phase and Gouy phase among the constituent modes.}, archive = {J_PRA}, author = {Amirreza Sadeghpour and Daryoush Abdollahpour}, doi = {10.1103/PhysRevA.111.023509}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023509}, shortjournal = {Phys. Rev. A}, title = {Filamentation of femtosecond vector beams}, volume = {111}, year = {2025}, }
• (2025). Spectral asymmetry effect in terahertz generation by two-color ionizing femtosecond pulses. PRA, 111(2), 023508. (www)

  @article{ , abstract = {Ultrabroadband intense terahertz (THz) radiation generated by two-color femtosecond pulses is a promising tool for applications in many areas involving linear and nonlinear terahertz spectroscopy and light-matter interactions. The essential challenge is to understand and control the THz spectrum in order to optimize it for specific applications. Here we study the frequency-dependent modulation of the THz spectrum with the relative phase between the second-harmonic and fundamental-field components of the linearly polarized femtosecond pulse. Analytical consideration reveals the physical reason for the suppression of the spectral modulation, which is local (induced by the local ionization dynamics and electron motion and not related to propagation effects such as phase slippage) and coherent (associated only with the phase-dependent coherent THz waveforms). The spectral modulation is sensitive to the frequency detuning, both its absolute value and the sign. Having this asymmetric dependence on the detuning, the suppressed modulation can be observed even in commensurate two-color pulses with the effect enhanced additionally by the ionization blueshift. The theoretical findings are confirmed by the experiment, where we employed chirped two-color pulses with a variable time delay between their components, effectively enabling a scan over the detuning. The obtained results show that not only the THz yield but also the spectral shape can be effectively controlled by the relative phase and may be very sensitive to a small frequency detuning arising naturally during two-color pulse propagation.}, archive = {J_PRA}, author = {Zhiwen Zhang and Vasily A. Kostin and Alexander A. Silaev and Zefu Liu and Shixiang Wang and Chenhui Lu and Zhengquan Fan and Yi Liu}, doi = {10.1103/PhysRevA.111.023508}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023508}, shortjournal = {Phys. Rev. A}, title = {Spectral asymmetry effect in terahertz generation by two-color ionizing femtosecond pulses}, volume = {111}, year = {2025}, }
• (2025). Unitary control of multiport wave transmission. PRA, 111(2), 023507. (www)

  @article{ , abstract = {Controlling wave transmission is crucial for various applications. In this work we apply the concept of unitary control to manipulate multiport wave transmission. Unitary control aims to control the behaviors of a set of orthogonal waves simultaneously. The approach fully harnesses the capability of wavefront shaping techniques, with promising applications in communication, imaging, and photonic integrated circuits. Here we present a detailed theory of unitary control of wave transmission, focusing on two key characteristics: total (power) transmittance and direct (field) transmission. The total transmittance for an input port represents the fraction of total transmitted power with respect to the input power for a wave incident from an input port. The direct transmission for an input port denotes the complex transmission amplitude from that input port to its corresponding output port. We address two main questions: (i) the achievable total transmittance and direct transmission for each port and (ii) the configuration of unitary control to attain desired transmission values for each port. Our theory illustrates that unitary control enables uniform total transmittance and direct transmission across any medium. Furthermore, we show that reciprocity and energy conservation enforce direct symmetry constraints on wave transmission in both the forward and backward directions under unitary control.}, archive = {J_PRA}, author = {Cheng Guo and David A. B. Miller and Shanhui Fan}, doi = {10.1103/PhysRevA.111.023507}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023507}, shortjournal = {Phys. Rev. A}, title = {Unitary control of multiport wave transmission}, volume = {111}, year = {2025}, }
• (2025). Orbital-angular-momentum-controlled laser pulses with near-relativistic intensity. PRA, 111(2), 023506. (www)

  @article{ , abstract = {The spiral phase plate is an essential optical component for the generation of Laguerre-Gaussian laser pulses with doughnut intensity profiles and helical wavefronts. This is due to its extraordinary ability to create and manipulate polarization distributions and orbital angular momentum of laser pulses. Here, we show that Gaussian laser pulses with near-relativistic intensity can acquire orbital angular momentum directly through a fixed-thickness plasma transmission spiral phase plate, whose density increases proportionally to the azimuthal angle around the plasma center. We propose the design for a plasma spiral phase plate and outline how the thickness and density distribution of the plasma determine the orbital angular momentum. We also use three-dimensional particle-in-cell simulations to examine the properties of plasma transmission spiral phase plates, such as orbital angular momentum generation and high-intensity laser pulses manipulation. The simulations suggest that Gaussian laser pulses could be turned into Laguerre-Gaussian laser pulses carrying orbital angular momentum through a plasma plate, with the conversion efficiency above 90% at high light intensity exceeding . Our scheme offers a method for producing near-relativistic intensity vortex laser pulses with controlled orbital angular momentum, which could significantly advance the development of intense twisted laser pulses in high-field physics. Potential applications include the rotational dynamics of particle clumps, the generation of high-energy particles in plasma accelerators, and the radiation of attosecond pulses radiation with orbital angular momentum.}, archive = {J_PRA}, author = {Jiajun Li and Xianzhi Wang and Zhaohua Wang and Zhiyi Wei}, doi = {10.1103/PhysRevA.111.023506}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023506}, shortjournal = {Phys. Rev. A}, title = {Orbital-angular-momentum-controlled laser pulses with near-relativistic intensity}, volume = {111}, year = {2025}, }
• (2025). Generation of ultracollimated polarized attosecond γ-rays via beam instabilities. PRA, 111(2), 023505. (www)

  @article{ , abstract = {Polarized ultrashort high-energy sources of electromagnetic radiation are widely applied in nuclear physics, astrophysics, high-energy physics, etc. However, generation of a feasible and easy-to-deploy source, especially reaching the attosecond scale in the time-domain and MeV energy levels, is still a great challenge. Here, we put forward a method for producing ultracollimated high-brilliance polarized attosecond -rays via the interaction of an unpolarized electron beam with a solid-density plasma. As a relativistic electron beam enters a solid-density plasma, it can be modulated into high-density clusters via the self-modulation instability of itself and further into attosecond slices due to its own hosing instability. This is accompanied by the generation of similar pulse-width photon slices via synchrotron radiation. The severe hosing instability breaks symmetry of the excited electromagnetic fields, resulting in net linear polarization of the photon slices, which challenges the conventional perception that interaction of an axially symmetric unpolarized electron beam with a uniform plasma cannot generate radiation with net polarization. This paper provides new ideas for the generation of ultrashort, high-energy pulses with reduced dependence on the ultraintense peak power of the laser pulse.}, archive = {J_PRA}, author = {Li-Jie Cui and Ke-Jia Wei and Chong Lv and Feng Wan and Yousef I. Salamin and Lei-Feng Cao and Jian-Xing Li}, doi = {10.1103/PhysRevA.111.023505}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023505}, shortjournal = {Phys. Rev. A}, title = {Generation of ultracollimated polarized attosecond γ-rays via beam instabilities}, volume = {111}, year = {2025}, }
• (2025). Ground-state cooling of mechanical motion via phase-controlled dissipative optomechanical coupling. PRA, 111(2), 023504. (www)

  @article{ , abstract = {We study static behavior and mechanical cooling of a dissipative optomechanical system by considering a phase-controlled coupling strength. We find that the static displacement of the mechanical oscillator vanishes when the dissipative coupling strength becomes purely imaginary, while a real coupling strength gives rise to a driving power-dependent static mechanical displacement. The absence of static displacement sustains the resonance linewidth of the effective Fabry-Pérot cavity and guarantees the approximation of a linear dissipative coupling. In this case, we show that the membrane can be cooled from the cryogenic temperature to its quantum ground state outside the resolved-sideband limit with a moderately strong driving operating at the red-detuned regime, where the optomechanical cooling rate can be competitive with typical schemes that utilize a real coupling strength and a blue-detuned laser drive. The dissipative optomechanical system with a phase-controlled coupling strength offers the flexibility to investigate fundamental optomechanical effects and may find potential applications in high-sensitive position transduction.}, archive = {J_PRA}, author = {Ye Liu and Guang-Zheng Ye and Chang-Sheng Hu and Yong Li and Huaizhi Wu}, doi = {10.1103/PhysRevA.111.023504}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023504}, shortjournal = {Phys. Rev. A}, title = {Ground-state cooling of mechanical motion via phase-controlled dissipative optomechanical coupling}, volume = {111}, year = {2025}, }
• (2025). Theoretical description and experimental observation of multisoliton attractors. PRA, 111(2), 023503. (www)

  @article{ , abstract = {Several dissipative solitons or soliton attractors have been investigated in dissipative nonlinear systems, but the quantitative theoretical frame for multisoliton attractors is still lacking, which hinders the quantitative investigation of soliton attractors. We provide a method to obtain a theoretical frame for multisoliton attractors in mode-locked fiber lasers with various initial states. These results provide possibilities for realizing controllable generation of soliton attractors. We further propose that the properties of soliton attractors can be used to calculate dissipation strengths. We perform experiments to observe the generation of multisoliton attractors in a mode-locked fiber laser and demonstrate the effectiveness of the calculation method for the dissipation strengths. Our results provide possibilities for studying the dynamics of localized waves quantitatively in nonlinear non-Hermitian systems.}, archive = {J_PRA}, author = {Ning Mao and Xiankun Yao and Chong Liu and Zhan-Ying Yang and Wen-Li Yang and Li-Chen Zhao}, doi = {10.1103/PhysRevA.111.023503}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023503}, shortjournal = {Phys. Rev. A}, title = {Theoretical description and experimental observation of multisoliton attractors}, volume = {111}, year = {2025}, }
• (2025). Magnetic quadrupole dichroism in an isotropic medium. PRA, 111(2), 023502. (www)

  @article{ , abstract = {For isotropic media, the magnetic field applied across the light propagation direction affects their optical properties only in the second order, and its effect proves to be much weaker than in the longitudinal field. In this work, we show that, under resonant excitation well beyond the linear regime, the situation changes drastically: A small magnetic linear anisotropy considerably increases, and an even stronger new quadrupole dichroism emerges. The latter manifests itself as the -periodic azimuthal dependence of the transmission and anisotropic rotation of the probe polarization plane. These effects are described microscopically in a toy model, and their symmetry analysis is presented. Both are observed experimentally on the resonance of cesium vapor and agree with the theoretical predictions. The large magnitude of the quadrupole dichroism makes it promising for magnetometric applications and for studying the effects of anisotropic bleaching.}, archive = {J_PRA}, author = {A. A. Fomin and G. G. Kozlov and M. Yu. Petrov and D. S. Smirnov and M. V. Petrenko and V. S. Zapasskii}, doi = {10.1103/PhysRevA.111.023502}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023502}, shortjournal = {Phys. Rev. A}, title = {Magnetic quadrupole dichroism in an isotropic medium}, volume = {111}, year = {2025}, }
• (2025). Polarization-entanglement dynamics in optical fibers: Mitigating decay in the non-markovian regime with dynamical decoupling. PRA, 111(2), 023501. (www)

  @article{ , abstract = {Future distributed quantum systems and networks are likely to rely, at least in part, on the existing fiber infrastructure for entanglement distribution; hence, a precise understanding of the adverse effects of imperfections in optical fibers on entanglement is essential to their operation. Here, we consider maximally entangled polarization qubits and study the decay of the entanglement caused by spatial fluctuations in the refractive index of optical fibers. We study this entanglement dynamics using the spin-boson model and numerically solve our system of equations using the hierarchical equations of motion (HEOM) formalism. We show that within the range of practically relevant system parameters, our developed model exhibits both Markovian and non-Markovian entanglement decay behavior. Further, to counter the observed entanglement decay, we propose the implementation of dynamical decoupling in optical fibers using spaced half waveplates. In particular, we numerically model the time-dependent Hamiltonians of the Carr-Purcell-Meiboom-Gill and Uhrig dynamical decoupling schemes and show a reduced rate of entanglement decay even with sparsely spaced half waveplates along the length of optical fiber. Finally, we evaluate the performance of these two schemes in multiple system configurations.}, archive = {J_PRA}, author = {Pratik J. Barge and Arshag Danageozian and Manish K. Gupta and Brian T. Kirby and Hwang Lee}, doi = {10.1103/PhysRevA.111.023501}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023501}, shortjournal = {Phys. Rev. A}, title = {Polarization-entanglement dynamics in optical fibers: Mitigating decay in the non-markovian regime with dynamical decoupling}, volume = {111}, year = {2025}, }
• (2025). Transport of vector solitons in spin-dependent nonlinear thouless pumps. PRA, 111(2), 023329. (www)

  @article{ , abstract = {In nonlinear topological physics, Thouless pumping of nonlinear excitations is a central topic, often illustrated by scalar solitons. Vector solitons, with the additional spin degree of freedom, exhibit phenomena absent in scalar solitons due to the enriched interplay between nonlinearity and topology. Here, we theoretically investigate Thouless pumping of vector solitons in a two-component Bose-Einstein condensate confined in spin-dependent optical superlattices, using both numerical solutions of the Gross-Pitaevskii equation and the Lagrangian variational approach. The spin-up and spin-down components experience superlattice potentials that are displaced by a tunable distance , leading to a vector soliton state with a relative shift between its components. We demonstrate that , as an independent degree of freedom, offers a novel control parameter for manipulating the nonlinear topological phase transition of vector solitons. Specifically, when , both components are either pumped or arrested, depending on the interaction strength. When fixing the interaction strength and varying , remarkably, we find that an arrested vector soliton can reenter the pumped regime and exhibits a quantized shift. As continues to increase, the vector soliton transitions into a dynamically arrested state; however, with further increases in , the quantized shift revives. Our work paves new routes for engineering nonlinear topological pumping of solitons in spinor systems by utilizing the relative motion degrees of freedom between different spin components.}, archive = {J_PRA}, author = {Xuzhen Cao and Chunyu Jia and Hao Lyu and Ying Hu and Zhaoxin Liang}, doi = {10.1103/PhysRevA.111.023329}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023329}, shortjournal = {Phys. Rev. A}, title = {Transport of vector solitons in spin-dependent nonlinear thouless pumps}, volume = {111}, year = {2025}, }
• (2025). Floquet scattering resonances in two dimensions. PRA, 111(2), 023328. (www)

  @article{ , abstract = {In this work we establish a general scattering theory for two-dimensional quantum systems with periodically modulated interactions. We show that scattering quantities, such as the scattering cross section, effective scattering length, and effective-range parameter, can be defined in a manner analogous to conventional scattering theory, even in the presence of modulation. Unlike systems with static interactions, the incident wave in our setup can be scattered inelastically into different Floquet channels, absorbing or emitting quanta from the modulation field. A family of Floquet resonances is identified, at which universal recurrence relations are derived for the Floquet scattering amplitudes. These relations are equivalent to a discrete Schrödinger equation describing a pointlike source trapped by an effective potential. The resonance mechanism is explained as the coincidence of the point source's energy with the bound states of the effective potential. We discuss the scattering properties both at and near the resonances, finding that the resonance width and the ratio of the inelastic to elastic cross sections can be effectively controlled through the modulation of the interaction. Our results provide a pathway to precisely manipulate many-body interactions in periodically driven quantum systems.}, archive = {J_PRA}, author = {Cai-Xia Zhang and Shi-Guo Peng and Guo-Qing Zhang and Hui Yan}, doi = {10.1103/PhysRevA.111.023328}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023328}, shortjournal = {Phys. Rev. A}, title = {Floquet scattering resonances in two dimensions}, volume = {111}, year = {2025}, }
• (2025). Feshbach spectroscopy of ultracold mixtures of li6 and dy164 atoms. PRA, 111(2), 023327. (www)

  @article{ , abstract = {We report on the observation of Feshbach resonances in ultracold mixtures, where atoms are respectively prepared in their three lowest spin states and atoms are prepared in their lowest-energy state. We observe 21 interspecies scattering resonances over a magnetic-field range from 0 to 702 G using atom loss spectroscopy, three of which exhibit relatively broad widths. These broad resonances provide precise control over the interspecies interaction strength, enabling the study of strongly interacting effects in mixtures. Additionally, we observe a well-isolated interspecies resonance at 700.1 G, offering a unique platform to explore novel impurity physics, where heavy dipolar atoms are immersed in a strongly interacting Fermi superfluid of atoms.}, archive = {J_PRA}, author = {Ke Xie and Xi Li and Yu-Yang Zhou and Ji-Hong Luo and Shuai Wang and Yu-Zhao Nie and Hong-Chi Shen and Yu-Ao Chen and Xing-Can Yao and Jian-Wei Pan}, doi = {10.1103/PhysRevA.111.023327}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023327}, shortjournal = {Phys. Rev. A}, title = {Feshbach spectroscopy of ultracold mixtures of li6 and dy164 atoms}, volume = {111}, year = {2025}, }
• (2025). Impurities in a trapped one-dimensional bose gas of arbitrary interaction strength: Localization-delocalization transition and absence of self-localization. PRA, 111(2), 023326. (www)

  @article{ , abstract = {We discuss impurities in a one-dimensional Bose gas with arbitrary boson-boson and boson-impurity interactions. To fully account for quantum effects, we employ numerical simulations based on the density-matrix renormalization group (DMRG) and—in the regime of strong boson-boson interactions—the mapping to weakly interacting fermions. A mean-field description of the Bose polaron based on coupled Gross–Pitaevskii Schrödinger equations predicts the existence of a self-localized polaron. We here show that such a solution does not exist and is an artifact of the underlying decoupling approximation. To this end we consider a mobile impurity in a box potential. Our work demonstrates that correlations between the impurity position and the bosons are important even in the limit where mean-field approaches are expected to work well. Furthermore, we derive analytical approximations for the energy of a single polaron formed by a heavy impurity for arbitrary interaction strengths and large but finite boson-boson couplings which accurately reproduce DMRG results. This demonstrates that the polaron problem of a heavy impurity in a one-dimensional Bose gas can be accurately approximated by a proper mean-field description plus a linearized treatment of quantum fluctuations for arbitrary boson-boson and impurity-boson couplings. Finally, we determine the polaron-polaron interaction potential in the Born-Oppenheimer approximation for small and intermediate distances , which in the Tonks gas limit is oscillatory due to Friedel oscillations in the Bose gas.}, archive = {J_PRA}, author = {Dennis Breu and Eric Vidal Marcos and Martin Will and Michael Fleischhauer}, doi = {10.1103/PhysRevA.111.023326}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023326}, shortjournal = {Phys. Rev. A}, title = {Impurities in a trapped one-dimensional bose gas of arbitrary interaction strength: Localization-delocalization transition and absence of self-localization}, volume = {111}, year = {2025}, }
• (2025). Solitons in bose-einstein condensates with attractive self-interaction on a möbius strip. PRA, 111(2), 023325. (www)

  @article{ , abstract = {We study the matter-wave solitons in Bose-Einstein condensate (BEC) trapped on a Möbius st rip (MS), based on the respective Gross-Pitaevskii (GP) equation with the mean-field theory. In the linear regime, vortex states are characterized by quantum numbers, 𝑛 and 𝑚 , corresponding to the transverse and circumferential directions, with the phase structure determined by the winding number (WN) 𝑚 . Odd and even values of 𝑛 must associate, respectively, with integer and half-integer values of 𝑚 , the latter ones requiring two cycles of motion around MS for returning to the initial phase. Using variational and numerical methods, we solve the GP equation with the attractive nonlinearity, producing a family of ground-state (GS) solitons for values of the norm below the critical one, above which the collapse sets in. Vortex solitons with 𝑛 = 1 , 𝑚 = 1 and 𝑛 = 2 , 𝑚 = 1 / 2 are obtained in a numerical form. The vortex solitons with 𝑛 = 1 , 𝑚 = 1 are almost uniformly distributed in the azimuthal direction, while ones with 𝑛 = 2 , 𝑚 = 1 / 2 form localized states. The Vakhitov-Kolokolov criterion and linear-stability analysis for the GS soliton solutions and vortices with 𝑛 = 1 , 𝑚 = 1 demonstrates that they are completely stable, while the localized states with 𝑛 = 2 , 𝑚 = 1 / 2 are completely unstable. Finally, the motion of solitons on the MS and the collision of two solitons are discussed.}, archive = {J_PRA}, author = {Huan-Bo Luo and Guilong Li and Fu-Quan Dou and Bin Liu and Boris A. Malomed and Josep Batle and Yongyao Li}, doi = {10.1103/PhysRevA.111.023325}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023325}, shortjournal = {Phys. Rev. A}, title = {Solitons in bose-einstein condensates with attractive self-interaction on a möbius strip}, volume = {111}, year = {2025}, }
• (2025). Out-of-equilibrium dynamics in the two-component bose-hubbard model. PRA, 111(2), 023324. (www)

  @article{ , abstract = {We study the out-of-equilibrium dynamics of the Bose-Hubbard model for two-component bosons using a strong-coupling approach within the closed-time-path formalism and develop an effective theory for the action of this problem. We obtain equations of motion for the superfluid order parameters of both boson species for both the superfluid and Mott-insulating phases and study these in the low-frequency, long-wavelength limit during a quantum quench for various initial conditions. We find that an additional degree of freedom for bosons leads to a richer phase diagram and out-of-equilibrium dynamics than the single-component situation.}, archive = {J_PRA}, author = {Florian R. Bär and Malcolm P. Kennett}, doi = {10.1103/PhysRevA.111.023324}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023324}, shortjournal = {Phys. Rev. A}, title = {Out-of-equilibrium dynamics in the two-component bose-hubbard model}, volume = {111}, year = {2025}, }
• (2025). Chiral raman coupling for spin-orbit coupling in ultracold atomic gases. PRA, 111(2), 023323. (www)

  @article{ , abstract = {Spin-orbit coupling (SOC) in ultracold atoms is engineered by light-atom interaction, such as two-photon Raman transitions between two Zeeman spin states. In this paper, we propose and experimentally realize chiral Raman coupling to generate SOC in ultracold atomic gases, which exhibits high quantization axis direction dependence. Chiral Raman coupling for SOC is created by chiral light-atom interaction, in which a circularly polarized electromagnetic field generated by two Raman lasers interacts with two Zeeman spin states (chiral transition). We present a simple scheme of chiral one-dimensional (1D) Raman coupling by employing two Raman lasers at an intersecting angle with the proper polarization configuration. In this case, Raman coupling for SOC exists in one direction of the magnetic quantization axis and disappears in the opposite direction. Then we extend this scheme into a chiral two-dimensional (2D) optical square Raman lattice configuration to generate the 1D SOC. There are two orthogonal 1D SOCs, which exist in the positive and negative directions of the magnetic quantization axis respectively. This case is compared with 2D SOC based on the nonchiral 2D optical Raman lattice scheme for studying the topological energy band. This paper broadens the horizon for understanding chiral physics and simulating topological quantum systems.}, archive = {J_PRA}, author = {Biao Shan and Lianghui Huang and Yuhang Zhao and Guoqi Bian and Pengjun Wang and Wei Han and Jing Zhang}, doi = {10.1103/PhysRevA.111.023323}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023323}, shortjournal = {Phys. Rev. A}, title = {Chiral raman coupling for spin-orbit coupling in ultracold atomic gases}, volume = {111}, year = {2025}, }
• (2025). Duality breaking, mobility edges, and the connection between topological aubry-andré and quantum hall insulators in atomic wires with fermions. PRA, 111(2), 023322. (www)

  @article{ , abstract = {It is well known that the Aubry-André model lacks mobility edges due to its energy-independent self-duality but may exhibit edge states. When duality is broken, we show that mobility regions arise and nontrivial topological phases emerge. By varying the degree of duality breaking, we identify mobility regions and establish a connection between Aubry-André atomic wires with fermions and quantum Hall systems for a family of Hamiltonians that depends on the relative phase of laser fields, viewed as a synthetic dimension. Depending on the filling factor and the degree of duality breaking, we find three classes of nontrivial phases: a conventional topological insulator, a conventional topological Aubry-André insulator, and an unconventional (hybrid) topological Aubry-André insulator. Finally, we discuss appropriate Chern numbers that illustrate the classification of topological phases of localized fermions in atomic wires.}, archive = {J_PRA}, author = {Bar Alluf and C. A. R. Sá de Melo}, doi = {10.1103/PhysRevA.111.023322}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023322}, shortjournal = {Phys. Rev. A}, title = {Duality breaking, mobility edges, and the connection between topological aubry-andré and quantum hall insulators in atomic wires with fermions}, volume = {111}, year = {2025}, }
• (2025). Unbalanced droplets of one-dimensional mixtures of fermions. PRA, 111(2), 023321. (www)

  @article{ , abstract = {By means of a diffusion Monte Carlo technique, we study one-dimensional unbalanced mixtures of fermionic ytterbium atoms ( and ). This means clusters in which the total number of particles is different from the sum of all the atoms belonging to the isotope. Our aim will be to check the possibility of having self-bound arrangements beyond the balanced compositions reported in previous literature rather than exploring all the situations in which that could be possible. In that vein, we focused mainly on mixtures in which the atoms belonging to one isotope are spin polarized, while the spins of the particles in the other isotope are evenly distributed in two sets. What we found was that, even though self-bound droplets are possible for different compositions, the most stable ones are clusters with a slight excess of attractively interacting particles with different spins with respect to the number of spin-polarized atoms. Clusters in which the number of repulsively interacting unequal-spin atoms are in excess with respect to the spin-polarized particles have a very narrow stability range.}, archive = {J_PRA}, author = {M. C. Gordillo}, doi = {10.1103/PhysRevA.111.023321}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023321}, shortjournal = {Phys. Rev. A}, title = {Unbalanced droplets of one-dimensional mixtures of fermions}, volume = {111}, year = {2025}, }
• (2025). Dynamics of an atomic bose-einstein condensate in an interaction-induced twisted-bilayer lattice. PRA, 111(2), 023320. (www)

  @article{ , abstract = {Creating crystal bilayers twisted with respect to each other would lead to large periodic supercell structures, which can support a wide range of novel electron correlated phenomena, where the full understanding is still under debate. Here, we propose a scheme to realize an interaction-induced twisted-bilayer lattice in an atomic Bose-Einstein condensate (BEC). The key idea here is to utilize the intrinsic atomic interaction to couple different layers and dynamically induce a supercell structure, distinct from the conventional wisdom to achieve the static twisted-bilayer lattices. To illustrate that, we study the dynamics of a two-component BEC and show that the intrinsic interaction effect arising from interacting bosonic ultracold atoms can dynamically induce both periodic (commensurable) and aperiodic (incommensurable) moiré structures. One of the interesting moiré-physics effects, i.e., the flat-band physics, is shown through investigating the dynamics of a wave packet of the BEC. Our proposal can be implemented using available state-of-the-art experimental techniques and leads to an alternative way to study twistronics in cold atom quantum simulators.}, archive = {J_PRA}, author = {Rui Tian and Yue Zhang and Tianhao Wu and Yong-Chang Zhang and Shuai Li and Bo Liu}, doi = {10.1103/PhysRevA.111.023320}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023320}, shortjournal = {Phys. Rev. A}, title = {Dynamics of an atomic bose-einstein condensate in an interaction-induced twisted-bilayer lattice}, volume = {111}, year = {2025}, }
• (2025). Macroscopic borromean and anti-borromean states of quantized vortices. PRA, 111(2), 023319. (www)

  @article{ , abstract = {Borromean states refer to a class of bound states with special topological structures, generally thought to exist only in microscopic systems. In this paper, we investigate vortex bound states in three-component Bose-Einstein condensates using coupled Gross-Pitaevskii equations. Specifically, through the competition between two-body and three-body interactions, we identify the emergence of vortex Borromean states, where only three vortices form a stable bound state while any two-vortex subsystems remain unbound. Our theoretical analysis and numerical simulations provide a comprehensive phase diagram of the vortex Borromean states. Additionally, we uncover an unconventional topological phase—a vortex anti-Borromean state—in which two vortices bind together but separate upon the addition of a third vortex. This study highlights the complex role of three-body interactions in macroscopic systems and offers different insights into the topology and phase transitions of multicomponent vortex systems.}, archive = {J_PRA}, author = {Wei-Can Yang and Makoto Tsubota and Muneto Nitta and Hua-Bi Zeng}, doi = {10.1103/PhysRevA.111.023319}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023319}, shortjournal = {Phys. Rev. A}, title = {Macroscopic borromean and anti-borromean states of quantized vortices}, volume = {111}, year = {2025}, }
• (2025). Dynamical probing of high-order spin coherence in one-dimensional mixtures. PRA, 111(2), 023318. (www)

  @article{ , abstract = {We investigate the dynamics of one-dimensional SU(2) ultracold fermions near the Tonks-Girardeau limit, confined in a box potential. The system is driven out of equilibrium by initially preparing the two spin components in a fully separated configuration, and its evolution is described by the Hamiltonian in the presence of strong repulsive interactions. Building on the results in G. Aupetit-Diallo et al. , Phys. Rev. A 107 , L061301 (2023) , we extend the analysis to out-of-equilibrium dynamics, uncovering the emergence of time-dependent oscillating high-momentum tails in the momentum distribution. These oscillations, due to the finite size of the system, are governed by a nonlocal, high-order spin coherence term, whose amplitude and phase evolve over time. We show that this term initially grows as and subsequently follows the spin-mixing dynamics of the system. Notably, when the spin components are fully mixed, the amplitude of this border-to-border spin coherence reaches its maximum value.}, archive = {J_PRA}, author = {S. Musolino and G. Aupetit-Diallo and M. Albert and P. Vignolo and A. Minguzzi}, doi = {10.1103/PhysRevA.111.023318}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023318}, shortjournal = {Phys. Rev. A}, title = {Dynamical probing of high-order spin coherence in one-dimensional mixtures}, volume = {111}, year = {2025}, }
• (2025). Effect of glancing collisions in the cold-atom vacuum standard. PRA, 111(2), 023317. (www)

  @article{ , abstract = {We theoretically investigate the effect of “glancing” collisions on the ultra-high-vacuum pressure readings of the cold-atom vacuum standard (CAVS), based on either ultracold or atoms. Here, glancing collisions are those collisions between ultracold atoms and room-temperature background atoms or molecules in the vacuum that do not impart enough kinetic energy to eject an ultracold atom from its trap. Our model is wholly probabilistic and shows that the number of the ultracold atoms remaining in the trap as a function of time is nonexponential. We update the recent results of a comparison between a traditional pressure standard—a combined flow meter and dynamic expansion system—and the CAVS [D. S. Barker et al. , AVS Quantum Sci. 5 , 035001 (2023) ] to reflect the results of our model. We find that the effect of glancing collisions shifts the theoretical predictions of the total loss rate coefficients for colliding with noble gases or by up to 0.6%. Likewise, we find that in the limit of zero trap depth, the experimentally extracted loss rate coefficients for colliding with noble gases or shift by as much as 2.2%.}, archive = {J_PRA}, author = {Stephen P. Eckel and Daniel S. Barker and James A. Fedchak and Julia Scherschligt and Jacek Kłos and Eite Tiesinga}, doi = {10.1103/PhysRevA.111.023317}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023317}, shortjournal = {Phys. Rev. A}, title = {Effect of glancing collisions in the cold-atom vacuum standard}, volume = {111}, year = {2025}, }
• (2025). Two-dimensional correlation propagation dynamics with a cluster discrete phase-space method. PRA, 111(2), 023315. (www)

  @article{ , abstract = {Nonequilibrium dynamics of highly controlled quantum systems is a challenging issue in statistical physics and quantum many-body physics, relevant to recent experimental developments of analog and digital quantum simulations. In this work, we develop a discrete phase-space approach for general ) spin systems that utilizes cluster mean-field equations, which capture nontrivial quantum correlations inside each cluster, beyond the capability of the standard discrete truncated Wigner approximation for individual classical spins. Our formalism, based on a cluster phase-point operator, enables efficient numerical samplings of cluster phase-space variables, where the total number of noise variables for a direct product state is independent of the specific way in which the entire system is divided into multiple equally sized finite clusters. We numerically demonstrate that the cluster discrete truncated Wigner approximation (C-dTWA) method can reproduce key results in a recent experiment on correlation propagation dynamics in a two-dimensional Bose-Hubbard system. We further compare the results of C-dTWA for clusters of sites with those from a two-dimensional tensor network method and discuss that both approaches agree very well in the short-time region, where the energy conservation is well maintained in the tensor network simulations. Since we formulate the C-dTWA method in a general form, it has the potential for application to various dynamical problems in isolated and open quantum systems, even in higher dimensions.}, archive = {J_PRA}, author = {Kazuma Nagao and Seiji Yunoki}, doi = {10.1103/PhysRevA.111.023315}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023315}, shortjournal = {Phys. Rev. A}, title = {Two-dimensional correlation propagation dynamics with a cluster discrete phase-space method}, volume = {111}, year = {2025}, }
• (2025). Shear-induced decaying turbulence in bose-einstein condensates. PRA, 111(2), 023314. (www)

  @article{ , abstract = {We study the creation and breakdown of a quantized vortex shear layer forming between a stationary Bose-Einstein condensate and a stirred-in persistent current. Once turbulence is established, we characterize the progressive clustering of the vortices, showing that the cluster number follows a power-law decay with time, similar to decaying turbulence in other two-dimensional systems. Numerical study of the system demonstrates good agreement of the experimental data with a point vortex model that includes damping and noise. With increasing vortex number in the computational model, we observe a convergence of the power-law exponent to a fixed value.}, archive = {J_PRA}, author = {S. Simjanovski and G. Gauthier and H. Rubinsztein-Dunlop and M. T. Reeves and T. W. Neely}, doi = {10.1103/PhysRevA.111.023314}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023314}, shortjournal = {Phys. Rev. A}, title = {Shear-induced decaying turbulence in bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Analytically solvable quasi-one-dimensional kronig-penney model. PRA, 111(2), 023313. (www)

  @article{ , abstract = {We generalize the textbook Kronig-Penney model to realistic conditions for a quantum-particle moving in the quasi-one-dimensional (quasi-1D) waveguide, where motion in the transverse direction is confined by a harmonic trapping potential. Along the waveguide, the particle scatters on an infinite array of regularized delta potentials. Our starting point is the Lippmann-Schwinger equation, which for quasi-1D geometry can be solved exactly, based on the analytical formula for the quasi-1D Green's function. We study the properties of eigenenergies as a function of particle quasimomentum, which form band structure, as in standard Kronig-Penney model. We test our model by comparing it to the numerical calculations for an atom scattering on an infinite chain of ions in quasi-1D geometry. The agreement is fairly good and can be further improved by introducing energy-dependent scattering length in the regularized delta potential. The energy spectrum exhibits the presence of multiple overlapping bands resulting from excitations in the transverse direction. At large lattice constants, our model reduces to standard Kronig-Penney result with 1D coupling constant for quasi-1D scattering, exhibiting confinement-induced resonances. In the opposite limit, when lattice constant becomes comparable to harmonic oscillator length of the transverse potential, we calculate the correction to the quasi-1D coupling constant due to the quantum interference between scatterers. Finally, we calculate the effective mass for the lowest band and show that it becomes negative for large and positive scattering lengths.}, archive = {J_PRA}, author = {Marta Sroczyńska and Tomasz Wasak and Zbigniew Idziaszek}, doi = {10.1103/PhysRevA.111.023313}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023313}, shortjournal = {Phys. Rev. A}, title = {Analytically solvable quasi-one-dimensional kronig-penney model}, volume = {111}, year = {2025}, }
• (2025). Bounds on the detection of bell correlations with entangled ultracold atoms in optical lattices under occupation defects. PRA, 111(2), 023312. (www)

  @article{ , abstract = {Bell nonlocality stems from quantum correlations effectively identified using inequalities. Spin chains, simulated with ultracold atoms in optical lattices, Rydberg atoms in tweezer arrays, trapped ions, or molecules allow single-spin control and measurement. Therefore, they are suitable for studying fundamental aspects of these correlations and nonlocality. Occupation defects, such as vacancies or multiple atoms occupying a single site due to imperfect system preparation, limit the detection of Bell correlations. We study their effects with the help of a simplified toy model parametrized by the probability of having a single occupation for a given site. Within this model, and for entangled systems obtained by one-axis twisting evolution from an initial factorized state, we derive two Bell inequalities, one based on many-site correlations and the other on two-site correlations, and identify the smallest probability that allows the Bell inequalities violation to be detected. We then consider two physical realizations using entangled ultracold atoms in optical lattices where the parameter is related to a nonunitary filling factor and nonzero temperature. We test the predictions of the toy model against exact numerical results.}, archive = {J_PRA}, author = {T. Hernández Yanes and Y. Bamaara and A. Sinatra and E. Witkowska}, doi = {10.1103/PhysRevA.111.023312}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023312}, shortjournal = {Phys. Rev. A}, title = {Bounds on the detection of bell correlations with entangled ultracold atoms in optical lattices under occupation defects}, volume = {111}, year = {2025}, }
• (2025). Excitations of a supersolid annular stripe phase in a spin-orbital-angular-momentum-coupled spin-1 bose-einstein condensate. PRA, 111(2), 023311. (www)

  @article{ , abstract = {We present a theoretical study of the collective excitations of the supersolid annular stripe phase of a spin-orbital-angular-momentum-coupled (SOAM-coupled) spin-1 Bose-Einstein condensate. The annular stripe phase simultaneously breaks two continuous symmetries, namely rotational and U ( 1 ) gauge symmetry, and is more probable in the condensates with a larger orbital angular momentum transfer imparted by a pair of Laguerre-Gaussian beams than what has been considered in the recent experiments. Accordingly, we consider a SOAM-coupled spin-1 condensate with a 4 ℏ orbital angular momentum transferred by the lasers. Depending on the values of the Raman coupling strength and quadratic Zeeman term, the condensate with realistic antiferromagnetic interactions supports three ground-state phases: the annular stripe, the vortex necklace, and the zero angular momentum phase. We numerically calculate the collective excitations of the condensate as a function of coupling and quadratic Zeeman field strengths for a fixed ratio of spin-dependent and spin-independent interaction strengths. At low Raman coupling strengths, we observe a direct transition from the zero angular momentum to the annular stripe phase, characterized by the softening of a double symmetric roton mode, which serves as a precursor to supersolidity.}, archive = {J_PRA}, author = {Paramjeet Banger and Rajat and Sandeep Gautam}, doi = {10.1103/PhysRevA.111.023311}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023311}, shortjournal = {Phys. Rev. A}, title = {Excitations of a supersolid annular stripe phase in a spin-orbital-angular-momentum-coupled spin-1 bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Breakdown of the single-mode description of ultradilute quantum droplets in binary bose mixtures: A perspective from a microscopic bosonic pairing theory. PRA, 111(2), 023309. (www)

  @article{ , abstract = {In his seminal proposal of quantum droplets in binary Bose mixtures [D. Petrov, Phys. Rev. Lett. 115 , 155302 (2015) ], Petrov suggested that the density ratio of the two bosonic components is locked to an optimal value, which is given by the square root of the ratio of the two intraspecies scattering lengths, i.e., . Due to such density locking, quantum droplets can be efficiently described by using an extended Gross-Pitaevskii equation within the single-mode approximation. Here, we find that this single-mode description necessarily breaks down in the deep quantum droplet regime, when the attractive interspecies scattering length significantly deviates away from the threshold of mean-field collapse (i.e., ). By applying a bosonic pairing theory, we show that the density ratio is allowed to fluctuate in a sizable interval. Most importantly, the optimal density ratio would be very different from , in the case of unequal intraspecies scattering lengths ( ). Our finding might provide a plausible microscopic explanation of the puzzling low critical particle number of quantum droplets, as experimentally observed. Our predicted interval of the density ratio, as a function of the interspecies scattering length, could also be experimentally examined in cold-atom laboratories in the near future.}, archive = {J_PRA}, author = {Hui Hu and Jia Wang and Han Pu and Xia-Ji Liu}, doi = {10.1103/PhysRevA.111.023309}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023309}, shortjournal = {Phys. Rev. A}, title = {Breakdown of the single-mode description of ultradilute quantum droplets in binary bose mixtures: A perspective from a microscopic bosonic pairing theory}, volume = {111}, year = {2025}, }
• (2025). Regimes of steady-state turbulence in a quantum fluid. PRA, 111(2), 023308. (www)

  @article{ , abstract = {We simulate the Gross-Pitaevskii equation to model the development of turbulence in a quantum fluid confined by a cuboid box potential and forced by shaking along one axis. We observe the development of isotropic turbulence from anisotropic forcing for a broad range of forcing amplitudes and characterize the states through their Fourier spectra, vortex distributions, and spatial correlations. For weak forcing the steady-state wave-action spectrum exhibits a k − 3.5 scaling over wave number k ; further decomposition uncovers the same power law in both compressible kinetic energy and quantum pressure, while the bulk superfluid remains phase coherent and free from extended vortices. As the forcing energy exceeds the chemical potential, extended vortices develop in the bulk, disrupting the k − 3.5 scaling. The spectrum then transitions to a k − 7 / 3 regime for compressible kinetic energy only, associated with dense vortex turbulence, and phase coherence limited to the healing length. The strong forcing regime is consistent with an inverse cascade of compressible energy driven by small-scale vortex annihilation.}, archive = {J_PRA}, author = {Tommy Z. Fischer and Ashton S. Bradley}, doi = {10.1103/PhysRevA.111.023308}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023308}, shortjournal = {Phys. Rev. A}, title = {Regimes of steady-state turbulence in a quantum fluid}, volume = {111}, year = {2025}, }
• (2025). Continuously varying critical exponents in an exactly solvable long-range cluster XY model. PRA, 111(2), 023307. (www)

  @article{ , abstract = {We investigate a generalized antiferromagnetic cluster model in a transverse magnetic field, where long-range interactions decay algebraically with distance. This model can be exactly solvable within a free fermion framework. By analyzing the gap, we explicitly derive the critical exponents and , finding that the relationship still holds. However, the values of and depend on the decaying exponent , in contrast to those for the quantum long-range antiferromagnetic Ising chain. To optimize scaling behavior, we verify these critical exponents using correlation functions and fidelity susceptibility, achieving excellent data collapse across various system sizes by adjusting fitting parameters. Finally, we compute the entanglement entropy at the critical point to determine the central charge , and find it also varies with . This study provides insights into the unique effect of long-range cluster interactions on the critical properties of quantum spin systems.}, archive = {J_PRA}, author = {Tian-Cheng Yi and Chengxiang Ding and Maoxin Liu and Liangsheng Li and Wen-Long You}, doi = {10.1103/PhysRevA.111.023307}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023307}, shortjournal = {Phys. Rev. A}, title = {Continuously varying critical exponents in an exactly solvable long-range cluster XY model}, volume = {111}, year = {2025}, }
• (2025). Energy conservation and quantum backreaction in bose-einstein condensates. PRA, 111(2), 023306. (www)

  @article{ , abstract = {Bose-Einstein condensates are suitable systems for studying fundamental aspects of quantum backreaction. Here, the backreaction problem in one-dimensional condensates is considered from the perspective of energy and momentum conservation. By assuming the validity of Bogoliubov theory, the backreaction equations are used to identify the contributions to the system energy and momentum coming from quantum fluctuations and condensate corrections. The backreaction is solved for a condensate trapped in a ring configuration such that particle interactions are gradually switched on. It is shown that the energy in the condensate cannot be addressed without taking into account how the system entered the interacting regime, and even for homogeneous condensates the power transferred to the condensate by quantum fluctuations showcases an intricate nonmonotonic pattern.}, archive = {J_PRA}, author = {Caio C. Holanda Ribeiro}, doi = {10.1103/PhysRevA.111.023306}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023306}, shortjournal = {Phys. Rev. A}, title = {Energy conservation and quantum backreaction in bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Enhanced strong-interaction effect in synthetic spin-orbit coupling with mixed spin symmetry. PRA, 111(2), 023305. (www)

  @article{ , abstract = {Synthetic spin-orbit coupling in cold atoms couples the pseudospin and spatial degrees of freedom, and therefore, the inherent spin symmetry of the system plays an important role. In systems of two pseudospin degrees, two particles contain symmetric states and antisymmetric states, but the spin symmetry can be mixed for more particles. This mixed spin symmetry has been overlooked and has not been investigated thoroughly. We study the role of mixed spin symmetry in the presence of spin-orbit coupling and consider a system of three bosons with two hyperfine states trapped in a harmonic potential. We investigate the ground state and the energy spectrum by implementing exact diagonalization. Similar to that in two-particle systems, the interplay between spin-orbit coupling and repulsive interactions between antialigned pseudospins increases the population of the unaligned spin components in the ground state. Also, the emergence of mixed-spin symmetric states compensates for the rise of the interaction energy. In contrast to two-particle systems, the pair correlation of the ground state is analogous to the Tonks-Girardeau gas even for relatively small contact interactions, and this feature is enhanced by the spin-orbit coupling.}, archive = {J_PRA}, author = {Ayaka Usui and Abel Rojo-Francàs and James Schloss and Bruno Juliá-Díaz}, doi = {10.1103/PhysRevA.111.023305}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023305}, shortjournal = {Phys. Rev. A}, title = {Enhanced strong-interaction effect in synthetic spin-orbit coupling with mixed spin symmetry}, volume = {111}, year = {2025}, }
• (2025). Vortex-lattice melting and critical temperature shift in rotating bose-einstein condensates. PRA, 111(2), 023304. (www)

  @article{ , abstract = {We investigate a shift in the critical temperature of rotating Bose-Einstein condensates mediated by the melting of the vortex lattice. Numerical simulations reveal that this temperature exhibits contrasting behavior depending on the system configuration: a negative shift occurs for fixed trap potentials due to the expansion of the condensate, while a positive shift is observed for fixed volumes, where vortex-lattice rigidity suppresses thermal fluctuations. We introduce a vortex-energy model that captures the role of vortex interactions, the positional energy of the vortex lattice, as well as the phase transition and how the vortex lattice disappears. The findings provide insights into the thermodynamic properties of rotating condensates and the dynamics of vortex-lattice melting, offering potential parallels with other quantum systems such as type-II superconductors.}, archive = {J_PRA}, author = {Julián Amette Estrada and Marc E. Brachet and Pablo D. Mininni}, doi = {10.1103/PhysRevA.111.023304}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023304}, shortjournal = {Phys. Rev. A}, title = {Vortex-lattice melting and critical temperature shift in rotating bose-einstein condensates}, volume = {111}, year = {2025}, }
• (2025). Localization transitions of correlated particles in nonreciprocal quasicrystals. PRA, 111(2), 023303. (www)

  @article{ , abstract = {The interplay among interaction, non-Hermiticity, and disorder opens a new avenue for engineering novel phase transitions. We study here the spectral and localization features of two interacting bosons in one-dimensional nonreciprocal quasicrystals. Specifically, by considering a quasiperiodic Hubbard lattice with nonreciprocal hoppings, we show that the interaction can lead to a mobility edge, which arises from the fact that the bound states display a much lower threshold for spectral and extended-localized transitions than scattering states. The localization transition of bound or scattering states is accompanied by a complex-real spectrum transition. Moreover, while the two-particle localized states are robust to the boundary conditions, the two-particle extended states turn into skin modes under open boundary conditions. We also show the correlated dynamics to characterize these localization transitions. Finally, we reveal that the bound states can form a mobility edge on their own by introducing a dimerized nonreciprocal quasicrystal. Our paper may pave the way for the study of non-Hermitian few-body physics.}, archive = {J_PRA}, author = {Lei Wang and Juan Kang and Ni Liu and Chaohua Wu and Gang Chen}, doi = {10.1103/PhysRevA.111.023303}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023303}, shortjournal = {Phys. Rev. A}, title = {Localization transitions of correlated particles in nonreciprocal quasicrystals}, volume = {111}, year = {2025}, }
• (2025). Kelvon–Bogoliubov-phonon interaction dynamics in a superfluid quantum vortex. PRA, 111(2), 023302. (www)

  @article{ , abstract = {Elementary excitation in the presence of a bosonic superfluid vortex line includes a kelvon and a Bogoliubov phonon as Nambu-Goldstone bosons, associated with spontaneous breaking of translational and U ( 1 ) symmetries, respectively. Using the Bogoliubov approximation, we construct an effective Hamiltonian to describe the interplay among kelvons and Bogoliubov phonons in a microscopic manner and apply it for the decay process of an excited kelvon with Bogoliubov-phonon emission. Such a decay process governs the late-time behavior of vortex-excitation dynamics observed in cold-atom experiments and also in follow-up numerical simulations using the time-dependent Gross-Pitaevskii equation. We show our numerical result of the decay process and compare it with these previous studies. Our formalism provides the interaction Hamiltonian in terms of wave functions and energy spectra of the elementary excitations, thus potentially being useful in the description of other low-energy phenomena caused by the kelvon–Bogoliubov-phonon interaction.}, archive = {J_PRA}, author = {Kazunari Ochi and Junichi Takahashi and Eiji Nakano}, doi = {10.1103/PhysRevA.111.023302}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023302}, shortjournal = {Phys. Rev. A}, title = {Kelvon–Bogoliubov-phonon interaction dynamics in a superfluid quantum vortex}, volume = {111}, year = {2025}, }
• (2025). Roadmap to vortex nucleation below the critical rotation frequency in a dipolar bose-einstein condensate. PRA, 111(2), 023301. (www)

  @article{ , abstract = {The formation of quantized vortices above a certain critical trap rotation frequency serves as a hallmark signature of superfluidity. Based on the beyond mean-field framework, crucial for the formation of exotic supersolid and droplet states, we investigate dynamical protocols for vortex nucleation in the superfluid and supersolid states of a dipolar Bose-Einstein condensate (BEC) at a trap rotation frequency lower than the conventional critical rotation frequency. We find that the critical rotation frequency depends not only on the dipole-dipole interaction strength, but also on the polarization direction of the external magnetic field. Interestingly, in the superfluid state, the critical rotation frequency increases with the tilt angle of the magnetic field, whereas in the supersolid state, increasing the tilt angle lowers the critical threshold. Leveraging these characteristics of dipolar BECs, along with the robustness of vortices with respect to changes in the polarization direction and -wave scattering length, we demonstrate three dynamical protocols for vortex nucleation, even when rotating below the critical rotation frequency, viz., (i) varying the -wave scattering length, (ii) changing the polarizing angle, and (iii) successive modulation of both the scattering length and polarizing angle. These dynamical vortex seeding protocols could serve as important benchmarks for future experimental studies.}, archive = {J_PRA}, author = {Soumyadeep Halder and Hari Sadhan Ghosh and Arpana Saboo and Andy M. Martin and Sonjoy Majumder}, doi = {10.1103/PhysRevA.111.023301}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023301}, shortjournal = {Phys. Rev. A}, title = {Roadmap to vortex nucleation below the critical rotation frequency in a dipolar bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Photon momentum transfer in one-photon single ionization of helium: The influence of electron correlation. PRA, 111(2), 023120. (www)

  @article{ , abstract = {The photon momentum transfer in the one-photon single ionization (1PSI) of helium is theoretically and experimentally studied. The influence of electron correlations is found to be displayed in the dimensionless photon momentum-transfer factor F , which takes a value of 8 / 5 for the 1PSI of the 1 s state of hydrogen. For the ground state of helium, we find that F first decreases and then increases with the energy of the photoelectron, which is drastically different from the monotonic behavior predicted by the mean-field approximation. When resonances due to the doubly excited states are accessible, the parameter shows dramatic fluctuations. We report experimental results for F in the energy region of the ( 2 s 2 p ) 1 P 1 and ( 2 p 2 ) 1 D 2 autoionizing states with a photon energy resolution of around 12 meV, a factor of approximately 1.7 better than the resolution reported for the pioneering data of Krässig et al. [ Phys. Rev. Lett. 88 , 203002 (2002) ]. These high-resolution data agree very well with our theoretical predictions. Our study shows that F is sensitive to effects of electron correlations.}, archive = {J_PRA}, author = {Yong-Kang Fang and Wei-Chao Jiang and Lei Geng and Iva Březinová and Laura Sommerlad and Alexander Tsertsvadze and Max Kircher and Jan Kruse and Till Jahnke and Noelle Walsh and Reinhard Dörner and Joachim Burgdörfer and Liang-You Peng}, doi = {10.1103/PhysRevA.111.023120}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023120}, shortjournal = {Phys. Rev. A}, title = {Photon momentum transfer in one-photon single ionization of helium: The influence of electron correlation}, volume = {111}, year = {2025}, }
• (2025). Suppression of heading errors in bell-bloom optically pumped free-induction-decay alkali-metal atomic magnetometers. PRA, 111(2), 023119. (www)

  @article{ , abstract = {Heading errors of atomic magnetometers refer to the dependence of measurement results on the sensor orientation with respect to the external magnetic field. There are three main sources of such errors: the light shift effect, the linear nuclear-spin Zeeman effect, and the nonlinear Zeeman effect. In this work, we suppress the first two effects by using the Bell-Bloom optical pumping method and probe the atomic signals while the pumping beam is off, and focus on the heading error induced by nonlinear Zeeman effect while the sensor operates in the geomagnetic field range. We demonstrate several schemes to suppress this remaining heading error within 1 nT using a single magnetometer or a comagnetometer. In the magnetometer system, two schemes are developed to average out the horizontal atomic polarization in space or in time, respectively. In the comagnetometer system, we combine the simultaneously measured Larmor frequencies of two different alkali atoms to either suppress the heading error or extract the orientation of the pumping beam relative to the bias field.}, archive = {J_PRA}, author = {S.-Q. Liu and X.-K. Wang and X.-D. Zhang and W. Xiao and D. Sheng}, doi = {10.1103/PhysRevA.111.023119}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023119}, shortjournal = {Phys. Rev. A}, title = {Suppression of heading errors in bell-bloom optically pumped free-induction-decay alkali-metal atomic magnetometers}, volume = {111}, year = {2025}, }
• (2025). Nonlinear dynamics in an artificial feedback spin maser. PRA, 111(2), 023118. (www)

  @article{ , abstract = {Spin masers with optical detection and artificial feedback are widely used in fundamental and practical applications. However, a full picture of the maser dynamics is still absent. By solving the feedback-driven Bloch equations, we simulated the dynamics of an ideal spin maser in a broad parameter space. Rich nonlinear dynamics including high-order-harmonic generation, nonperiodic spin oscillations, and frequency comb were revealed when the artificial feedback interaction exceeds the normal spin-field interaction. We also propose a pulse feedback spin maser protocol, which constructs an ultralow field magnetic frequency comb and could be useful in precision atomic magnetometers in searching for spin-dependent exotic interactions.}, archive = {J_PRA}, author = {Mingjun Feng and Lan Wu and Guobin Liu}, doi = {10.1103/PhysRevA.111.023118}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023118}, shortjournal = {Phys. Rev. A}, title = {Nonlinear dynamics in an artificial feedback spin maser}, volume = {111}, year = {2025}, }
• (2025). Observation of terahertz-field-induced coherent control of high-order harmonic generation in a noble gas. PRA, 111(2), 023117. (www)

  @article{ , abstract = {High-order harmonic generation in the presence of a strong co-propagating THz pulse (up to 7.5 MV/cm) is studied experimentally and compared to numerical simulations based on strong-field approximation. The time-resolved study of the high harmonic spectra together with the temporal profile of the THz electric field suggest a transient generation of even high harmonics along with odd-harmonic intensity suppression. The observed even- and odd-harmonic intensity modulation is explained by the coherent control of the subcycle interference between the adjacent attosecond bursts. A considerable cutoff extension of up to is obtained numerically under application of the THz field with the field strength up to 120 MV/cm due to the additional electron drift arising from the electron motion in the synthesized field. The obtained results represent an experimental step towards ultrafast manipulation of the high-order harmonic yield and cutoff by the optical waveform synthesis with long-wavelength fields, which may considerably extend the EUV spectrum keeping high generation efficiency inherent to near-IR drivers.}, archive = {J_PRA}, author = {B. V. Rumiantsev and E. A. Migal and A. V. Pushkin and F. V. Potemkin}, doi = {10.1103/PhysRevA.111.023117}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023117}, shortjournal = {Phys. Rev. A}, title = {Observation of terahertz-field-induced coherent control of high-order harmonic generation in a noble gas}, volume = {111}, year = {2025}, }
• (2025). Entanglement in 2p atom pairs in h2 photodissociation as studied by measuring the angular correlation function of lyman-α photon pairs on a whole sphere. PRA, 111(2), 023116. (www)

  @article{ , abstract = {An angular correlation function (ACF) of a pair of Lyman- photons produced in photodissociation of with linearly polarized incident light is measured on a whole sphere at a 33.66-eV photon energy so that we may distinctly substantiate that the atom pairs are in the state previously identified by Torizuka et al. as the atom-pair state [ Phys. Rev. A 99 , 063426 (2019) ], who measured the ACF only on a circle in the plane perpendicular to the incident light beam. The atom-pair state determined with much less uncertainty than before is investigated in terms of whether or not the state is entangled. We discover that the pair of fragment atoms is certainly entangled in terms of the electron-electron entanglement, and obtain the entanglement entropy of the atom-pair state. The similar discussion is made in terms of the electronic spatial-spin entanglement too, where the spatial motion and spin motion of electrons are considered nonidentical partial systems at variance with the former electron-electron entanglement. It turns out that the pair of fragment H( ) atoms is entangled in terms of the electronic spatial-spin entanglement as well as the electron-electron entanglement.}, archive = {J_PRA}, author = {Yutaro Torizuka and Kouichi Hosaka and Philipp Schmidt and Takeshi Odagiri and Arno Ehresmann and Masashi Kitajima and Noriyuki Kouchi}, doi = {10.1103/PhysRevA.111.023116}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023116}, shortjournal = {Phys. Rev. A}, title = {Entanglement in 2p atom pairs in h2 photodissociation as studied by measuring the angular correlation function of lyman-α photon pairs on a whole sphere}, volume = {111}, year = {2025}, }
• (2025). Direct double ionization of the he-like b3+ ion by a single photon. PRA, 111(2), 023115. (www)

  @article{ , abstract = {Within a joint experimental and theoretical research project, double photoionization of the He-like B 3 + ion by a single photon was studied in the energy range from approximately 350 to 1160 eV. With the parent-ion beam in the experiment containing both 1 s 2 1 S ground-state (90.9%) and 1 s 2 s S 3 metastable B 3 + ions (9.1%), two contributions to the apparent single- and double-ionization cross sections, σ 34 app and σ 35 app , respectively, are involved in the measurements. Ratios Y ( 5 + ) / Y ( 4 + ) of double- over single-ionization yields were experimentally determined. By multiplying the measured ratios by the known cross section σ 34 app , the apparent cross section σ 35 app for double ionization was inferred. Using the information thus obtained, the measured yield of B 5 + ions produced from hydrogenlike B 4 + could also be normalized. The results show good agreement with theoretical benchmark cross sections σ 45 for single photoionization of B 4 + . Convergent close-coupling calculations were performed to determine double-photoionization cross sections σ 35 for B 3 + ( 1 s 2 ) and B 3 + ( 1 s 2 s ) ions. The result for the ground state agrees very well with theoretical data obtained previously with an intermediate-energy R -matrix approach. Within the systematic uncertainty of the normalized experimental cross sections, calculated and measured data are in agreement with one another.}, archive = {J_PRA}, author = {A. Müller and P.-M. Hillenbrand and S.-X. Wang and S. Schippers and I. Bray and A. S. Kheifets and E. Lindroth and S. Reinwardt and M. Martins and J. Seltmann and F. Trinter}, doi = {10.1103/PhysRevA.111.023115}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023115}, shortjournal = {Phys. Rev. A}, title = {Direct double ionization of the he-like b3+ ion by a single photon}, volume = {111}, year = {2025}, }
• (2025). Near-zero-energy electron attachment to SF6 using rydberg excitation and two-color resonance-enhanced multiphoton ionization of NO. PRA, 111(2), 023114. (www)

  @article{ , abstract = {We report the formation of in a molecular beam containing coexpanded NO and by direct electron transfer from laser-excited Rydberg states of NO, and electron attachment from ultracold plasma induced by Penning ionization or photoionization of NO. At short times of up to 2 µs after laser excitation, we find that the dominant pathway for near-zero-energy electron attachment to molecules forming ions is from Rydberg electron transfer from excited Rydberg states, within a few of the Rydberg limit. ion production occurs by electron transfer from NO Rydberg states with a principal quantum number . At this principal quantum number threshold, the Rydberg reaction range is ∼15 µm. For lower-lying Rydberg states of NO, no ions are detected despite the efficiency of as an electron scavenger of weakly bound electrons. We hypothesize that anions formed in closer proximity to a cation core may undergo efficient back-electron transfer.}, archive = {J_PRA}, author = {Irina Jana and Eric J. Smoll, Jr and Jonathan H. Frank and David W. Chandler}, doi = {10.1103/PhysRevA.111.023114}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023114}, shortjournal = {Phys. Rev. A}, title = {Near-zero-energy electron attachment to SF6 using rydberg excitation and two-color resonance-enhanced multiphoton ionization of NO}, volume = {111}, year = {2025}, }
• (2025). Alternating circular dichroism in the photoelectron spectra of the ionization of polarized atoms by ultrashort pulses. PRA, 111(2), 023113. (www)

  @article{ , abstract = {Dependence of the angle-integrated probability of the ionization of a polarized atom by a few-cycle circularly polarized (CP) pulse on the rotation direction of the pulse electric field is analyzed. Numerical simulations of the ionization of excited states of the hydrogen atom reveal that the circular dichroism effect, i.e., the difference of the probability for right- and left-hand circular polarizations of the laser pulse, exhibits oscillatory behavior vanishing for some values of the photoelectron energy. This feature is most pronounced for intermediate (on the atomic scale) CP pulse intensities and very short pulse durations. We have applied the nonstationary perturbation theory (PT) in all orders to analyze the observed effects. Results of our treatment demonstrate that PT can provide an adequate qualitative description of the ionization by ultrashort pulses whose intensities are comparable to the atomic ones only upon taking into account ionization channels involving the virtual photon emission.}, archive = {J_PRA}, author = {Ph. A. Davydiak and A. V. Meremianin and N. L. Manakov}, doi = {10.1103/PhysRevA.111.023113}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023113}, shortjournal = {Phys. Rev. A}, title = {Alternating circular dichroism in the photoelectron spectra of the ionization of polarized atoms by ultrashort pulses}, volume = {111}, year = {2025}, }
• (2025). Zepto- to attosecond core-level photoemission time delays in homonuclear diatomic molecules and nondipole effects in the framework of multiple scattering theory. PRA, 111(2), 023112. (www)

  @article{ , abstract = {This study theoretically investigates the angular distribution of core-level photoem ission time delay within a molecular frame. This phenomenon can be measured with the advancement of attosecond pulsed lasers and metrology. Our focus is on homonuclear diatomic molecules. The two-center interference patterns observed in the gerade and ungerade core-level Molecular-Frame Photoelectron Angular Distributions (MFPAD) of homonuclear diatomic molecules demonstrate symmetry breaking with respect to the direction of light propagation, attributed to the nondipole (multipole) effect. This nondipole effect reflects the zeptosecond time discrepancy in the initiation of photoelectron waves at the two absorbing atoms. Our study delves into the photoemission time delay resulting from the nondipole effect through the introduction of a theoretical model. We reveal that when considering the contributions from the gerade and ungerade delocalized states in incoherent sums, the two-center interference terms cancel each other in both the MFPADs and photoemission time delays. However, a residual term persists showcasing the nondipole effect in the photoemission time delays. Furthermore, by expanding the scattering state of photoelectrons using the Multiple Scattering theory, we demonstrate the significant role played by the scattering of photoelectrons at the molecular potential in describing the photoemission time delays of homonuclear diatomic molecules. Additionally, we establish that the direct wave contribution does not exhibit angular dependence in the photoemission time delays. Next, we apply our theoretical model to a nitrogen molecule, demonstrating the energy- and angular-dependent characteristics of the MFPADs and photoemission time delays through both analytical and numerical approaches. The incoherent sums of the MFPADs in both forward and backward directions exhibit equal intensity, whereas the incoherent sums of the photoemission time delays show a slight variation of a few hundred zeptoseconds compared with numerical calculations using a multiple scattering code. Our findings demonstrate that the photoemission time delay serves as a valuable tool for investigating attosecond and zeptosecond photoionization dynamics, providing insights that may be overlooked in the MFPAD analysis. This study provides a basis for theoretical investigations into photoionization phenomena in nano systems containing numerous identical atoms, such as large polyatomic molecules and condensed matter, enabling the examination of photoemission time delays and nondipole effects.}, archive = {J_PRA}, author = {Yoshiaki Tamura and Kaoru Yamazaki and Kiyoshi Ueda and Keisuke Hatada}, doi = {10.1103/PhysRevA.111.023112}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023112}, shortjournal = {Phys. Rev. A}, title = {Zepto- to attosecond core-level photoemission time delays in homonuclear diatomic molecules and nondipole effects in the framework of multiple scattering theory}, volume = {111}, year = {2025}, }
• (2025). Dissociative rydberg-state excitation of h2 and CO molecules induced by a femtosecond laser pulse. PRA, 111(2), 023111. (www)

  @article{ , abstract = {Rydberg state excitation of atoms and molecules induced by femtosecond laser fields has attracted considerable attention due to its critical role in processes such as neutral atom acceleration and near-threshold harmonic generation. In this study, we experimentally investigate the dissociative Rydberg state excitation of and CO molecules induced by a femtosecond laser pulse centered at 400 nm. Coincidence measurements are conducted for the resulting photoelectrons, ionic, and Rydberg fragments. Electron-nuclear correlations are observed by analyzing the joint electron-nuclear energy spectrum, which shows multiple diagonal lines spaced by photon energy, indicating that the observed dissociative Rydberg state excitations are primarily accessed via multiphoton resonance excitation. The excitation pathways of and CO molecules are explored in detail. Interestingly, the dissociative Rydberg state excitations of and CO molecules exhibit distinct behavior compared to their respective dissociative double ionization channels. This notable difference is attributed to electron-nuclear correlations in photon energy sharing and is further explained through an analysis of the relevant potential energy curves. Our findings contribute to a deeper understanding of the dissociative Rydberg state excitation of molecules in femtosecond laser fields.}, archive = {J_PRA}, author = {Junyang Ma and Shuqi Li and Xueying Li and Yan Yang and Zhenrong Sun}, doi = {10.1103/PhysRevA.111.023111}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023111}, shortjournal = {Phys. Rev. A}, title = {Dissociative rydberg-state excitation of h2 and CO molecules induced by a femtosecond laser pulse}, volume = {111}, year = {2025}, }
• (2025). Asymmetric polarization gating for spectral tuning and temporal confinement of high-order harmonics. PRA, 111(2), 023110. (www)

  @article{ , abstract = {We analyze high-order harmonic generation using the asymmetric polarization gating obtained by the combination of two delayed circularly polarized counterrotating pulses with different peak amplitudes. This technique gives deeper insight into polarization gated extreme ultraviolet (XUV) generation in general, increases the control of the harmonic temporal confinement, and can be used for tuning the central frequency of the harmonic comb and optimizing the high-order harmonic generation efficiency. Experimental results clearly confirm the gate control and the XUV tunability, in agreement with a model based on the strong field approximation.}, archive = {J_PRA}, author = {C. Picot and J. Vábek and T. Němec and S. Skupin and E. Constant and F. Catoire}, doi = {10.1103/PhysRevA.111.023110}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023110}, shortjournal = {Phys. Rev. A}, title = {Asymmetric polarization gating for spectral tuning and temporal confinement of high-order harmonics}, volume = {111}, year = {2025}, }
• (2025). Breakup of positronium by compton scattering of high-energy photons. PRA, 111(2), 023109. (www)

  @article{ , abstract = {We study the breakup of positronium (Ps) by Compton scattering in the range of photon energies, where the motion of the electron and the positron remains nonrelativistic and the process is dominated by the interaction terms , where is the vector potential of the photon field. In this study we first compare the total cross section for this process with the total cross section for the positronium breakup by photoabsorption, showing that they become equal at the incident photon energy keV and that—due to strong (and opposite) dependencies of these cross sections on the photon energy—the Compton scattering rapidly becomes by far the dominant breakup channel when the photon energy exceeds . Then we explore the energy and angular spectra of electrons and positrons, which are emitted from the positronium in collisions with high-energy photons, and of the scattered photons. By analyzing the physical mechanisms, which determine the properties of the spectra, we demonstrate that in such collisions the atomic particles can be clearly subdivided into the “participator,” on which the incident photon scatters, and the “spectator,” which is not directly involved in the scattering process. The results for the positronium breakup are compared with the corresponding results for the ionization of atomic hydrogen and the similarities in these processes as well as the differences between them are discussed.}, archive = {J_PRA}, author = {B. Najjari and C. Pedain and C. Müller and A. B. Voitkiv}, doi = {10.1103/PhysRevA.111.023109}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023109}, shortjournal = {Phys. Rev. A}, title = {Breakup of positronium by compton scattering of high-energy photons}, volume = {111}, year = {2025}, }
• (2025). Modeling the laser-pulse-induced helium trimer dynamics. PRA, 111(2), 023108. (www)

  @article{ , abstract = {Motivated by ongoing pump-probe spectroscopy experiments, this work develops a theoretical framework for describing the rovibrational wave-packet dynamics that ensues when a single weakly bound van der Waals trimer is exposed to a short, subpicosecond linearly polarized pump laser pulse. The intensity of the pump laser is chosen such that excitation and ionization of the electronic degrees of freedom are negligible, while excitation of the wave packet in the nuclear degrees of freedom is non-negligible. The numerical treatment, which takes advantage of the fact that the laser pulse is very short compared to typical molecular time scales, is based on a wave-packet decomposition that utilizes hyperspherical coordinates. The framework is applied to the extremely floppy bosonic helium trimer. A convergence analysis of the partial-wave decomposition is conducted. The kinetic-energy release and orientation dynamics are presented. While the dynamics of more strongly bound van der Waals trimers such as, e.g., the argon trimer, display negligible coupling between vibrational and rotational degrees of freedom, rendering a description within a rigid-body picture appropriate, those of weakly bound trimers display non-negligible coupling between vibrational and rotational degrees of freedom, rendering a description within a rigid-body picture inappropriate. It is shown that a model that constructs the helium trimer dynamics from the dynamics of the helium dimer captures a number of key characteristics of the alignment signal, including the interference between different angular momentum wave-packet components.}, archive = {J_PRA}, author = {Q. Guan and J. Kruse and M. Kunitski and R. Dörner and D. Blume}, doi = {10.1103/PhysRevA.111.023108}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023108}, shortjournal = {Phys. Rev. A}, title = {Modeling the laser-pulse-induced helium trimer dynamics}, volume = {111}, year = {2025}, }
• (2025). Energy-conservation conditions in the saddle-point approximation for the strong-field ionization of atoms. PRA, 111(2), 023107. (www)

  @article{ , abstract = {Orbit-based methods are widespread in strong-field laser-matter interaction. They provide a framework in which photoelectron momentum distributions can be interpreted as the quantum interference between different semiclassical pathways the electron can take on its way to the detector, which brings with it great predictive power. The transition amplitude of an electron going from a bound state to a final continuum state is often written as multiple integrals, which can be computed either numerically or by employing the saddle-point method. If one computes the momentum distribution via a saddle-point method, then the obtained distribution is highly dependent on the time window from which the saddle points are selected for inclusion in the “sum over paths.” In many cases, this leads to the distributions not even satisfying the basic symmetry requirements and often containing many more oscillations and interference fringes than their numerically integrated counterparts. Using the strong-field approximation, we find that the manual enforcement of the energy-conservation condition on the momentum distribution calculated via the saddle-point method provides a unique momentum distribution which satisfies the symmetry requirements of the system and which is in a good agreement with the numerical results. We illustrate our findings using the example of the Ar atom ionized by a selection of monochromatic and bichromatic linearly polarized fields.}, archive = {J_PRA}, author = {T. Rook and D. Habibović and C. Figueira de Morisson Faria}, doi = {10.1103/PhysRevA.111.023107}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023107}, shortjournal = {Phys. Rev. A}, title = {Energy-conservation conditions in the saddle-point approximation for the strong-field ionization of atoms}, volume = {111}, year = {2025}, }
• (2025). Control of autler-townes spectra by counter-rotating circularly polarized pulses. PRA, 111(2), 023106. (www)

  @article{ , abstract = {We theoretically investigate the resonant two-photon ionization of a hydrogen atom in the counter-rotating circularly polarized double-pulse sequences, by solving the time-dependent Schrödinger equation. Due to the induced Rabi oscillations between the ground and excited states, the well-known Autler-Townes doublet is observed in the photoelectron spectra. More interestingly, our numerical results reveal an additional peak located between the Autler-Townes doublets, which originates from single-photon ionization from the excited state by the second pulse. By adjusting the laser intensity of the two pulses, the photoelectron yields of the three peaks can be sensitively modulated, under the control of completed Rabi cycles within the first pulse. In addition, our results show a potential of manipulating the photoemission anisotropy by both the laser intensity and the two-pulse time delay, through adjusting the competition of different partial waves generated by the two pulses.}, archive = {J_PRA}, author = {Yutong Deng and Yijie Liao and Xu Zhang and Miao Yu and Peixiang Lu and Yueming Zhou}, doi = {10.1103/PhysRevA.111.023106}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023106}, shortjournal = {Phys. Rev. A}, title = {Control of autler-townes spectra by counter-rotating circularly polarized pulses}, volume = {111}, year = {2025}, }
• (2025). Broadened coherent destruction of tunneling. PRA, 111(2), 023105. (www)

  @article{ , abstract = {This paper investigates the manipulation of coherent quantum tunneling by controlling second-order coupling in zigzag-shaped lattice arrays with only one site periodically driven against the others. Different from normal coherent destruction of tunneling (CDT), we propose a surprisingly large and nontrivial effect of second-order coupling on broadened CDT essentially attributed to avoided level crossings and localized Floquet states. Moreover, our results at high-frequency approximation supported by exact numerical ones demonstrate that the extent to which the normal CDT is broadened depends on the separation of quasienergy levels in the vicinity of zeros of J 0 ( A / ω ) . Remarkably, beyond the intensity of second-order coupling, the lattice size and its parity also significantly influence Floquet dynamics by either facilitating or suppressing tunneling probabilities, which in essence are also determined by noncrossing quasienergies and localized Floquet states. These findings substantially extend the theory of normal CDT, unveil the intrinsic physics behind broadened CDT, and open up an exciting possibility for quantum state control.}, archive = {J_PRA}, author = {Liping Li and Quanwei Zhao and Qing He and Jiahui Zhang and Bo Wang}, doi = {10.1103/PhysRevA.111.023105}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023105}, shortjournal = {Phys. Rev. A}, title = {Broadened coherent destruction of tunneling}, volume = {111}, year = {2025}, }
• (2025). Controlling temporal triple-slit interference by two-color circularly polarized laser fields. PRA, 111(2), 023104. (www)

  @article{ , abstract = {We investigate the photoelectron momentum distributions (PMDs) resulting from ionization of Ar atoms by bicircular two-color (800- and 1600-nm) laser fields in the laser propagation plane. Our results demonstrate that the PMDs along the laser propagation direction reveal interference structures at a certain amplitude ratio of counter-rotating two-color laser fields. We attribute the observed photoelectron interference patterns along the laser propagation direction to temporal triple-slit interference. Furthermore, we show that the temporal triple-slit interference can be controlled by tuning the amplitude ratio. These findings have significant implications for high-resolution imaging of atomic and molecular structures, as well as quantum control using temporal triple-slit interference.}, archive = {J_PRA}, author = {Xiaoxiao Long and Peizeng Li and Yankun Dou and Jing Li and Yunquan Liu}, doi = {10.1103/PhysRevA.111.023104}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023104}, shortjournal = {Phys. Rev. A}, title = {Controlling temporal triple-slit interference by two-color circularly polarized laser fields}, volume = {111}, year = {2025}, }
• (2025). Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field. PRA, 111(2), 023103. (www)

  @article{ , abstract = {Ionization of atoms by a strong laser field can be described using the improved strong-field approximation. The corresponding transition amplitude of high-order above-threshold ionization is presented in the form of a two-dimensional integral over the electron ionization time t 0 and the rescattering time t . This integral can be solved using the saddle-point (SP) method and the resulting T -matrix element is expressed as a sum (over the SP times t 0 and t ) of the partial transition amplitudes. We address the problem of finding the solutions of the system of SP equations for the times t 0 and t . For a bichromatic linearly polarized laser field with the frequencies r ω and s ω ( r and s are integers, s > r , and ω is the fundamental frequency) we found that there are 8 s 2 SP solutions per optical cycle. For one half of them the velocity of the electron emitted in the laser field polarization direction changes the sign at the rescattering time (we call such solutions backward-scattering solutions), while for the other half this velocity remains unchanged (these solutions we call forward-scattering SP solutions). For very short (or even negative) electron travel time we call these solutions backward-like and forward-like scattering SP solutions. For these solutions the imaginary parts of the times t 0 and t become large so that the concept of real electron trajectories becomes questionable. Having such a classification, we found additional SP solutions even for the simplest case of a monochromatic linearly polarized laser field. For a bichromatic linearly polarized laser field with s = 2 and equal component intensities we presented a detailed analysis of all 32 solutions per optical cycle, showing how the SP times t 0 and t and the corresponding differential ionization rates depend on the photoelectron energy. We have also analyzed the case where the intensity of the second component decreases while the sum of the component intensities remains fixed.}, archive = {J_PRA}, author = {D. Habibović and D. B. Milošević}, doi = {10.1103/PhysRevA.111.023103}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023103}, shortjournal = {Phys. Rev. A}, title = {Complete classification and additional saddle-point solutions for high-order above-threshold ionization induced by a strong laser field}, volume = {111}, year = {2025}, }
• (2025). Energy levels and transition rates of the laser-cooling candidate th−. PRA, 111(2), 023102. (www)

  @article{ , abstract = {The energy levels and transition rates of promising laser-cooling candidate thorium anion ( ) are experimentally measured in the current work. Three excited states between the lower and upper states for the bound-bound electric dipole (E1) transition of are observed: , and , and their energy levels are determined to be 1847(13), 3166.8(59), and 3666(12) , respectively. Meanwhile, the lifetime of the upper state of the E1 transition is experimentally determined to be 30(2) µs, substantially shorter than the previously calculated result, which makes the most promising candidate for laser cooling of negative ions. Furthermore, the lifetimes of two other short-lived odd-parity excited states of are also measured to be 62(5) and 53(3) µs, respectively.}, archive = {J_PRA}, author = {Rui Zhang and Yuzhu Lu and Shuaiting Yan and Chuangang Ning}, doi = {10.1103/PhysRevA.111.023102}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023102}, shortjournal = {Phys. Rev. A}, title = {Energy levels and transition rates of the laser-cooling candidate th−}, volume = {111}, year = {2025}, }
• (2025). Theory of resonant x-ray scattering with ultrafast intense pulses. PRA, 111(2), 023101. (www)

  @article{ , abstract = {We present a time-dependent Schrödinger equation approach within a nonrelativistic quantum electrodynamics framework to investigate resonant x-ray scattering driven by intense x-ray pulses. This method enables us to explore how coherent x-ray electron dynamics influence scattering signals from . We account for both resonance fluorescence and elastic scattering channels, while also considering competing photoionization and inner-shell decay processes. By computing the angular distribution and energy spectrum of scattered photons, we uncover interference effects between elastic scattering and resonance fluorescence pathways. Notably, this interference results in a small asymmetry in the energy spectrum. We discuss the experimental potential for detecting signatures of interference. Our findings demonstrate that the x-ray Rabi dynamics can be used to control scattering responses and provide insights into interference mechanisms and scattering efficiency in high-intensity x-ray regimes.}, archive = {J_PRA}, author = {Akilesh Venkatesh and Phay J. Ho}, doi = {10.1103/PhysRevA.111.023101}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {023101}, shortjournal = {Phys. Rev. A}, title = {Theory of resonant x-ray scattering with ultrafast intense pulses}, volume = {111}, year = {2025}, }
• (2025). Relativistic variational-quantum-eigensolver calculations of molecular electric dipole moments on quantum hardware. PRA, 111(2), 022817. (www)

  @article{ , abstract = {The quantum–classical hybrid variational quantum eigensolver (VQE) algorithm is among the most actively studied topics in atomic and molecular calculations on quantum computers, yet few studies address properties other than energies or account for relativistic effects. This work presents high-precision 18-qubit relativistic VQE simulations for calculating the permanent electric dipole moments (PDMs) of alkaline-earth metal monohydride molecules (BeH to RaH) on traditional computers, and 6- and 12-qubit PDM computations for SrH on IonQ quantum devices. To achieve high precision on current noisy intermediate-scale era quantum hardware, we apply various resource-reduction methods, including reinforcement learning-based and causal flow preserving ZX–calculus routines, along with error mitigation and postselection techniques. Our approach reduces the two-qubit gate count in our 12-qubit circuit by , with only a trade-off in precision for PDM when evaluated classically within a suitably chosen active space. On the current generation IonQ Forte-I hardware, the error in PDM is relative to classical calculations and only compared with the unoptimized circuit.}, archive = {J_PRA}, author = {Palak Chawla and Shweta and K. R. Swain and Tushti Patel and Renu Bala and Disha Shetty and Kenji Sugisaki and Sudhindu Bikash Mandal and Jordi Riu and Jan Nogué and V. S. Prasannaa and B. P. Das}, doi = {10.1103/PhysRevA.111.022817}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022817}, shortjournal = {Phys. Rev. A}, title = {Relativistic variational-quantum-eigensolver calculations of molecular electric dipole moments on quantum hardware}, volume = {111}, year = {2025}, }
• (2025). Self-energy correction to the e1 transition amplitudes in hydrogenlike ions. PRA, 111(2), 022816. (www)

  @article{ , abstract = {We present calculations of the self-energy correction to the transition amplitudes in hydrogenlike ions, performed to all orders in the nuclear binding strength parameter. Our results for the transition for the hydrogen isoelectronic sequence show that the perturbed-orbital part of the self-energy correction provides the dominant contribution, accounting for approximately 99% of the total correction for this transition. Detailed calculations were performed for and transitions in H-like cesium. We conclude that the perturbed-orbital part also remains dominant for other transitions, whereas for the matrix elements, this dominance no longer holds. Consequently, the self-energy corrections for the one-electron matrix elements cannot be well reproduced by means of effective QED operators constructed for energy levels.}, archive = {J_PRA}, author = {M. G. Kozlov and M. Y. Kaygorodov and Yu. A. Demidov and V. A. Yerokhin}, doi = {10.1103/PhysRevA.111.022816}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022816}, shortjournal = {Phys. Rev. A}, title = {Self-energy correction to the e1 transition amplitudes in hydrogenlike ions}, volume = {111}, year = {2025}, }
• (2025). Spontaneous torque on an inhomogeneous chiral body out of thermal equilibrium. PRA, 111(2), 022815. (www)

  @article{ , abstract = {In a previous paper we showed that an inhomogeneous body in vacuum will experience a spontaneous force if it is not in thermal equilibrium with its environment. This is due to the asymmetric asymptotic radiation pattern such an object emits. We demonstrated this self-propulsive force by considering an expansion in powers of the electric susceptibility: A torque arises in first order, but only if the material constituting the body is nonreciprocal. No force arises in first order. A force does occur for bodies made of ordinary (reciprocal) materials in second order. Here we extend these considerations to the torque. As one would expect, a spontaneous torque will also appear on an inhomogeneous chiral object if it is out of thermal equilibrium with its environment. Once a chiral body starts to rotate, it will experience a small quantum frictional torque, but much more important, unless a mechanism is provided to maintain the nonequilibrium state, is thermalization: The body will rapidly reach thermal equilibrium with the vacuum, and the angular acceleration will essentially become zero. For a small, or even a large, inhomogeneous chiral body, a terminal angular velocity will result, which seems to be in the realm of observability.}, archive = {J_PRA}, author = {Kimball A. Milton and Nima Pourtolami and Gerard Kennedy}, doi = {10.1103/PhysRevA.111.022815}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022815}, shortjournal = {Phys. Rev. A}, title = {Spontaneous torque on an inhomogeneous chiral body out of thermal equilibrium}, volume = {111}, year = {2025}, }
• (2025). Nonrelativistic expansion of the dirac-coulomb energy and the nonretarded breit-interaction correction up to order α8. PRA, 111(2), 022814. (www)

  @article{ , abstract = {The nonrelativistic expansion method of the single-electron Dirac-Coulomb equation has been extended to the study of multielectron problems. By expanding the large and small components of the Dirac wave function and the energy eigenvalues in terms of the square of the fine-structure constant , we obtain iterative equations for calculating the higher-order relativistic corrections of Coulomb systems. For a single-electron system, we prove that the operator results of the iterative equations are consistent with the existing results obtained by the Foldy-Wouthuysen transformation. Using these iterative equations, we numerically calculate the relativistic corrections up to the order of for the hydrogen atom, which rapidly converge to the analytical results of the hydrogen atom. For the two-electron Dirac-Coulomb system, we also present iterative equations for calculating high-order energy corrections, as well as numerical energy corrections of the ground state up to the order of for the helium atom. This work also presents the nonrelativistic expansion form of the nonretarded Breit interaction correction. The order correction to the Dirac-Coulomb energy and nonretarded Breit interaction precisely corresponds to the order relativistic correction. Higher-order expansion terms contribute at even powers of , which represent the contributions from all Coulomb photons and single transverse photons under the nonretarded approximation.}, archive = {J_PRA}, author = {Wanping Zhou and Sanjiang Yang and Haoxue Qiao}, doi = {10.1103/PhysRevA.111.022814}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022814}, shortjournal = {Phys. Rev. A}, title = {Nonrelativistic expansion of the dirac-coulomb energy and the nonretarded breit-interaction correction up to order α8}, volume = {111}, year = {2025}, }
• (2025). Investigating the 4D3/2|3,±2〉–4D5/2|3,±2〉 transition in nb4+ for a THz atomic clock. PRA, 111(2), 022813. (www)

  @article{ , abstract = {In this work, the transition in the ion is identified as a promising candidate for a terahertz (THz) atomic clock, with the transition frequency occurring at 56.022 4 THz. This transition is primarily driven by the magnetic dipole decay channel, which can easily be accessed by a laser. We focus on the stable isotope, which has 100% natural abundance and a nuclear spin of for experimental advantage. Our data analysis allows us to estimate potential systematic shifts in the proposed clock system, including those due to blackbody radiation, electric quadrupole, second-order Zeeman, and second-order Doppler shifts. The scheme presented in this study can help suppress the ac Stark and electric quadrupole shifts in the clock-frequency measurement. All these analyses suggest that the proposed THz atomic clock using could be valuable in both quantum thermometry and frequency metrology.}, archive = {J_PRA}, author = {Jyoti and A. Chakraborty and Zhiyang Wang and Jia Zhang and Jingbiao Chen and Bindiya Arora and B. K. Sahoo}, doi = {10.1103/PhysRevA.111.022813}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022813}, shortjournal = {Phys. Rev. A}, title = {Investigating the 4D3/2|3,±2〉–4D5/2|3,±2〉 transition in nb4+ for a THz atomic clock}, volume = {111}, year = {2025}, }
• (2025). Numerical tensor method for atomic and exotic three-particle systems. PRA, 111(2), 022812. (www)

  @article{ , abstract = {In this paper we derive a numerical tensor method to solve the many-body Schrödinger equation for three-particle systems. The Schrödinger equation is first represented in a canonical tensor format using a triple orthogonal Laguerre-based wave function in scaled perimetric coordinates. We demonstrate that the antisymmetry of the wave function can be explicitly included in the tensor method formulation by coupling the indices associated with the coordinates representing the identical fermions, e.g., electrons or muons. It is shown that energies accurate to the picohartree can be achieved in full tensor format in less than 3300 s for atomic and muonic molecular systems. Furthermore, this CPU time is reduced to less than 300 s, without compromising the accuracy of the energy or quality of the wave function, using a low-rank tensor-train decomposition.}, archive = {J_PRA}, author = {Kammegne Tcheugam Brice and Michael Melgaard and Marilia Pavlidou and Hazel Cox}, doi = {10.1103/PhysRevA.111.022812}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022812}, shortjournal = {Phys. Rev. A}, title = {Numerical tensor method for atomic and exotic three-particle systems}, volume = {111}, year = {2025}, }
• (2025). Realizing a mechanical dynamical casimir effect with a low-frequency oscillator. PRA, 111(2), 022811. (www)

  @article{ , abstract = {We propose to realize a mechanical dynamical Casimir effect (MDCE) in a hybrid optomechanical system consisting of a cavity mode, a low-frequency mechanical oscillator, and a two-level atomic system. Described by the effective Hamiltonian, the mechanical energy is directly converted to the photons through a three-wave-mixing mechanism. It is not a quantum simulation of a parametric DCE such as in superconducting circuits. Using a master-equation approach, we analyze the system dynamics in various regimes with respect to the ratio of the effective coupling strength and the loss rate of the system. The dynamics under the strong-coupling regime confirms various three-wave-mixing processes for creating photons by annihilation of mechanical and atomic excitations. Under the weak-coupling regime, a continuous production of photons can be demonstrated by driving both the mechanical oscillator and atom. By virtue of an atom of tunable frequency, our method avoids using the high-frequency mechanical oscillator, which is required for the conventional DCE in optomechanical systems under the double-photon resonance yet is out of reach of experiment. It is found that the mechanical frequency can be about two orders smaller than the cavity mode in yielding a remarkable flux of DCE photons.}, archive = {J_PRA}, author = {Tian-hao Jiang and Jun Jing}, doi = {10.1103/PhysRevA.111.022811}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022811}, shortjournal = {Phys. Rev. A}, title = {Realizing a mechanical dynamical casimir effect with a low-frequency oscillator}, volume = {111}, year = {2025}, }
• (2025). Convergent close-coupling calculations of electron scattering on LiH. PRA, 111(2), 022810. (www)

  @article{ , abstract = {Cross sections for electron scattering on the ground state of LiH are calculated using the molecular convergent close-coupling method. The fixed-nuclei approximation is utilized, and calculations are performed at the mean internuclear separation of for projectile energies ranging from 0.1 to 500 eV. A model-potential approach is utilized to treat the LiH molecule as a two-electron system, and good agreement is found with the literature for various properties of the structure model. Cross sections are presented for elastic scattering, excitation to several electronic states, and ionization. Comparison is made with existing results, and qualitative agreement is found with small close-coupling calculations at low projectile energies. Good agreement is found with first-order results at high projectile energies.}, archive = {J_PRA}, author = {Haadi Umer and Liam H. Scarlett and Adam J. C. Singor and Igor Bray and Mark C. Zammit and Dmitry V. Fursa}, doi = {10.1103/PhysRevA.111.022810}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022810}, shortjournal = {Phys. Rev. A}, title = {Convergent close-coupling calculations of electron scattering on LiH}, volume = {111}, year = {2025}, }
• (2025). Elastic and inelastic electron scattering cross sections of trichlorofluoromethane. PRA, 111(2), 022809. (www)

  @article{ , abstract = {Differential elastic electron scattering cross sections of trichlorofluoromethane ( ) were measured over a broad energy range spanning 30 to 800 eV in the angular range of 20° to 150°. The experimental results were compared with calculations using the IAM-SCAR+I model. Satisfactory agreements between both data sets were found for electron energies above 200 eV within experimental uncertainties, whereas significant deviations of up to 100% were observed at electron energies below 60 eV. In addition to the measurements of differential elastic-scattering cross sections, total inelastic-scattering cross sections of were calculated using the spherical complex optical potential model. These calculations closely match experimental total ionization cross sections available in the literature for energies below 50 eV. The sum of the experimental total elastic-scattering cross sections and the theoretical total inelastic-scattering cross sections aligns very well with the total electron scattering cross sections of measured by other groups across the entire energy range (30 to 800 eV), demonstrating the consistency among these three cross sections.}, archive = {J_PRA}, author = {M. Dinger and Y. Park and W. Y. Baek}, doi = {10.1103/PhysRevA.111.022809}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022809}, shortjournal = {Phys. Rev. A}, title = {Elastic and inelastic electron scattering cross sections of trichlorofluoromethane}, volume = {111}, year = {2025}, }
• (2025). X-ray-absorption spectrum of o2+. PRA, 111(2), 022808. (www)

  @article{ , abstract = {The x-ray absorption spectrum of the molecular cation is measured. The ions are stored in a cryogenically cooled radiofrequency ion trap and probed by tunable synchrotron radiation. The spectrum exhibits several salient features: a three-state composite resonance at the low-energy side followed by a two-component exchange split, a highly dissociative, resonance pulled down well below the ionization limit; and a complex valence-Rydberg high-energy part, including several resolved bands. Small structures are interpreted as correlation state satellites with leading internal or semi-internal configurations. Calculations using the restricted active space wave functions and quantum wave packet dynamics offer an overall excellent interpretation of the spectral features.}, archive = {J_PRA}, author = {Lucas M. Cornetta and Ludvig Kjellsson and Rafael C. Couto and Hans Ågren and Vincenzo Carravetta and Stacey L. Sörensen and Markus Kubin and Christine Bülow and Vicente Zamudio-Bayer and Bernd von Issendorff and J. Tobias Lau and Johan Söderström and Marcus Agåker and Jan-Erik Rubensson and Rebecka Lindblad}, doi = {10.1103/PhysRevA.111.022808}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022808}, shortjournal = {Phys. Rev. A}, title = {X-ray-absorption spectrum of o2+}, volume = {111}, year = {2025}, }
• (2025). Prolongation of electronic coherence for ultralong-lived charge migration anchored by a continuous-wave laser. PRA, 111(2), 022807. (www)

  @article{ , abstract = {In ideal scenarios, charge migration (CM) moves electronic charge coherently from one molecular end to the other, with periods from several hundred attoseconds to a few femtoseconds. Here we show that a well-designed continuous-wave laser can prolongate electronic coherence by more than two orders of magnitude. This enables ultralong-lived CM. The effect is demonstrated by quantum dynamics simulations for the example of prepared in a superposition of the electronic ground and first excited states. The success is due to straightforward control of the three laser parameters, i.e., the field strength, the frequency, and the carrier envelope phase, to anchor the nuclei close to the Franck-Condon point, with equal populations of the two electronic states.}, archive = {J_PRA}, author = {Dongming Jia and Chunmei Liu and Jörn Manz and Yunhui Wang and Yonggang Yang}, doi = {10.1103/PhysRevA.111.022807}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022807}, shortjournal = {Phys. Rev. A}, title = {Prolongation of electronic coherence for ultralong-lived charge migration anchored by a continuous-wave laser}, volume = {111}, year = {2025}, }
• (2025). Physical assessment of vibrationally induced magnetic-dipole transitions in polyatomic molecules. PRA, 111(2), 022806. (www)

  @article{ , abstract = {A weak magnetic-dipole absorption band has been recently identified in the Martian atmosphere. This unprecedented discovery raised a question of whether similar magnetic transitions could be found in other polyatomics as well. The present work proposes a simplified, but physically well-grounded approach, which is intended to help to evaluate the strength of magnetic-dipole transitions induced in the course of molecular vibrations. The suggested theory is developed assuming a pure vibrational magnetic moment arising within a combination band. Our estimate for the electric-dipole-forbidden band demonstrates good agreement of the transition matrix element with the value derived previously from both laboratory experiments and in-depth ab initio based consideration. The possibility is shown to observe magnetic transitions owing to a magnetic moment that is linear with respect to momentum. This prediction is discussed taking a molecule of type HCN as an example.}, archive = {J_PRA}, author = {Konstantin V. Kazakov}, doi = {10.1103/PhysRevA.111.022806}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022806}, shortjournal = {Phys. Rev. A}, title = {Physical assessment of vibrationally induced magnetic-dipole transitions in polyatomic molecules}, volume = {111}, year = {2025}, }
• (2025). Laser-assisted positronium formation in positron collisions with rydberg hydrogen. PRA, 111(2), 022805. (www)

  @article{ , abstract = {We investigate the formation of positronium (Ps) in the presence of a linearly polarized infrared laser field, via the collision of positrons with Rydberg hydrogen atoms H ( n H ) where n H is the principal quantum number. We are using the classical trajectory Monte Carlo method (CTMC) which is justified for n H ≥ 3 . The hydrogen in excited states has an effective dipole moment which in the presence of a laser field leads to a dipolar focusing [H. B. Ambalampitiya et al. , J. Phys. B: At. Mol. Opt. Phys. 57 , 10LT01 (2024) ]. Due to this effect, the Ps formation cross section is enhanced substantially as compared to the zero-field case. The degree of this enhancement is controlled by the positron velocity, laser frequency, and laser-field amplitude. The final-state distribution in Ps is much broader than in the zero-field case.}, archive = {J_PRA}, author = {M. K. Matfunjwa and H. B. Ambalampitiya and I. I. Fabrikant}, doi = {10.1103/PhysRevA.111.022805}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022805}, shortjournal = {Phys. Rev. A}, title = {Laser-assisted positronium formation in positron collisions with rydberg hydrogen}, volume = {111}, year = {2025}, }
• (2025). Accuracy estimation of the hartree-fock-slater method for calculating average atomic transition energies of ions in warm dense plasmas. PRA, 111(2), 022804. (www)

  @article{ , abstract = {The Hartree-Fock-Slater calculations of average transition energies, relevant to ionic states of warm dense plasmas, were compared to averaged transition energies of the NIST atomic lines database for oxygen, aluminum, iron, and molybdenum. A comprehensive error analysis shows the statistical nature of the theory-experiment differences almost independently of the atomic number, ionization degree, and the transitions’ atomic shells. Also, a method for the statistical analysis of the accuracy of the calculated transition energies for the plasmas’ opacity for a given density-temperature regime was suggested and demonstrated for the above-mentioned elements. This analysis show that a good accuracy of the relevant calculations is expected for temperatures larger than for these elements within the regime of , which covers a large number of laboratory-produced plasma experiments. Finally, a simple correction to the calculated transition energies is suggested for transitions which are included in the NIST database.}, archive = {J_PRA}, author = {Yair Kurzweil}, doi = {10.1103/PhysRevA.111.022804}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022804}, shortjournal = {Phys. Rev. A}, title = {Accuracy estimation of the hartree-fock-slater method for calculating average atomic transition energies of ions in warm dense plasmas}, volume = {111}, year = {2025}, }
• (2025). Precision measurement of the last bound states in h2 and determination of the H+H scattering length. PRA, 111(2), 022803. (www)

  @article{ , abstract = {The binding energies of the five bound rotational levels J = 0 – 4 in the highest vibrational level v = 14 in the X 1 Σ g + ground electronic state of H 2 were measured in a three-step ultraviolet-laser experiment. Two-photon UV photolysis of H 2 S produced population in these high-lying bound states that were subsequently interrogated at high precision via Doppler-free spectroscopy of the F 1 Σ g + − X 1 Σ g + system. A third UV laser was used for detection through auto-ionizing resonances. The experimentally determined binding energies were found to be in excellent agreement with calculations based on nonadiabatic perturbation theory, also including relativistic and quantum electrodynamical contributions. The s -wave scattering length of the H + H system is derived from the binding energy of the last bound J = 0 level via a direct semi-empirical approach, yielding a value of a s = 0.2724 ( 5 ) a 0 , in good agreement with a result from a previously followed theoretical approach. The subtle effect of the m α 4 relativity contribution to a s was found to be significant. In a similar manner a value for the p -wave scattering volume is determined via the J = 1 binding energy yielding a p = − 134.0000 ( 6 ) a 0 3 . The binding energy of the last bound state in H 2 , the ( v = 14 , J = 4 ) level, is determined at 0.023 (4) cm − 1 , in good agreement with calculation. The effect of the hyperfine substructure caused by the two hydrogen atoms at large internuclear separation, giving rise to three distinct dissociation limits, is discussed.}, archive = {J_PRA}, author = {K.-F. Lai and W. Ubachs and M. Beyer}, doi = {10.1103/PhysRevA.111.022803}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022803}, shortjournal = {Phys. Rev. A}, title = {Precision measurement of the last bound states in h2 and determination of the H+H scattering length}, volume = {111}, year = {2025}, }
• (2025). Convergent close-coupling approach to electron scattering on h3+: Scattering dynamics and dissociative processes. PRA, 111(2), 022802. (www)

  @article{ , abstract = {Cross sections for electron impact dissociative excitation and ionization in scattering on vibrationally excited levels of the ground electronic state of H 3 + , D 3 + , and T 3 + are reported in the energy range of 8–1000 eV. Calculations have been performed using a newly developed version of the molecular convergent close-coupling code. Convergence of the cross sections with the size of the projectile partial-wave and close-coupling expansions is examined. Branching ratios and cross sections for the yields of D 2 + and D + from dissociative excitation of D 3 + are presented and isotope effects are investigated. Cross sections for total dissociative ionization yielding atomic fragments such as D + are presented and the total inelastic cross section is produced. Good agreement with available experiments has been demonstrated.}, archive = {J_PRA}, author = {Reese K. Horton and Michael V. Pak and Igor Bray and Dmitry V. Fursa}, doi = {10.1103/PhysRevA.111.022802}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022802}, shortjournal = {Phys. Rev. A}, title = {Convergent close-coupling approach to electron scattering on h3+: Scattering dynamics and dissociative processes}, volume = {111}, year = {2025}, }
• (2025). Serially improved gaussian-type orbitals for molecular calculations containing third-row atoms. PRA, 111(2), 022801. (www)

  @article{ , abstract = {Serially improved Gaussian-type orbitals for molecular applications (SIGMA) basis sets have been developed for third-row elements, spanning from sodium to argon. This methodology, originally established for first- and second-row atoms, has been extended to produce both standard and augmented basis sets with sizes ranging from double-zeta to quadruple-zeta. The SIGMA basis sets yield atomic and molecular energies that are consistently lower than those obtained using Dunning basis sets with the same number of contracted functions. This advantage is observed for various computational methods, including Hartree-Fock, Møller-Plesset perturbation theory, single-double configuration interaction, and coupled-cluster approaches. Comparative analyses of SIGMA and other basis sets are presented, showing their performance in calculating atomic energies and a range of molecular properties.}, archive = {J_PRA}, author = {Ignacio Ema López and Guillermo Ramírez Moreno and Rafael López Fernández and José Manuel García de la Vega}, doi = {10.1103/PhysRevA.111.022801}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022801}, shortjournal = {Phys. Rev. A}, title = {Serially improved gaussian-type orbitals for molecular calculations containing third-row atoms}, volume = {111}, year = {2025}, }
• (2025). Quantum chernoff divergence in advantage distillation for quantum key distribution and device-independent quantum key distribution. PRA, 111(2), 022631. (www)

  @article{ , abstract = {Device-independent quantum key distribution (DIQKD) aims to mitigate adversarial exploitation of imperfections in quantum devices by providing an approach for secret key distillation with modest security assumptions. Advantage distillation, a two-way communication procedure in error correction, has proven effective in raising noise tolerances in both device-dependent and device-independent QKD. Previously, device-independent security proofs against independent and identically distributed (IID) collective attacks were developed for an advantage distillation protocol known as the repetition-code protocol, based on security conditions involving the fidelity between some states in the protocol. However, there exists a gap between the sufficient and necessary security conditions, which hinders the calculation of tight noise-tolerance bounds based on the fidelity. We close this gap by presenting an alternative proof structure that replaces the fidelity with the quantum Chernoff divergence, a distinguishability measure that arises in symmetric hypothesis testing. Working in the IID collective attacks model, we derive matching sufficient and necessary conditions for the repetition-code protocol to be secure (up to a natural conjecture regarding the latter case) in terms of the quantum Chernoff divergence, hence indicating that this serves as the relevant quantity of interest for this protocol. Furthermore, using this security condition we obtain some improvements over previous results on the noise tolerance thresholds for DIQKD. Our results provide insight into a fundamental question in quantum information theory regarding the circumstances under which DIQKD is possible.}, archive = {J_PRA}, author = {Mikka Stasiuk and Norbert Lütkenhaus and Ernest Y.-Z. Tan}, doi = {10.1103/PhysRevA.111.022631}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022631}, shortjournal = {Phys. Rev. A}, title = {Quantum chernoff divergence in advantage distillation for quantum key distribution and device-independent quantum key distribution}, volume = {111}, year = {2025}, }
• (2025). Learning to learn with an evolutionary strategy applied to variational quantum algorithms. PRA, 111(2), 022630. (www)

  @article{ , abstract = {Variational quantum algorithms (VQAs) employ parametrized quantum circuits optimized using classical methods to minimize a cost function. While VQAs have found broad applications, certain challenges persist. Notably, a significant computational burden arises during parameter optimization. The prevailing “parameter shift rule” mandates a double evaluation of the cost function for each parameter. In this paper, we introduce an optimization approach named “learning to learn with an evolutionary strategy” (LLES). LLES unifies “learning to learn” and “evolutionary strategy” methods. Learning to learn treats optimization as a learning problem, utilizing recurrent neural networks to iteratively propose VQA parameters. Conversely, evolutionary strategy employs gradient searches to estimate function gradients. Our optimization method is applied to two distinct tasks: determining the ground state of an Ising Hamiltonian and training a quantum neural network. The obtained results underscore the efficacy of this approach. Additionally, we identify a key hyperparameter that significantly influences gradient estimation using the evolutionary strategy method.}, archive = {J_PRA}, author = {Lucas Friedrich and Jonas Maziero}, doi = {10.1103/PhysRevA.111.022630}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022630}, shortjournal = {Phys. Rev. A}, title = {Learning to learn with an evolutionary strategy applied to variational quantum algorithms}, volume = {111}, year = {2025}, }
• (2025). Efficient particle-conserving symmetric quantum circuits. PRA, 111(2), 022629. (www)

  @article{ , abstract = {The variational quantum simulation technique on gate-based quantum processors can be made more efficient if symmetries of the Hamiltonian system of interest are factored into the design construction of the underlying parameterized quantum circuits (PQC) needed by the technique. In the first part of this work, we present an easy and practical approach that can be used to construct symmetric quantum circuits. The method we present can directly be adapted for any symmetry, though in the present work we focus explicitly on the examples of , and particle number conservation. We show how to construct symmetric gates that respects the aforementioned symmetries. In the second part, we focus on numerical analysis of parameterized particle-conserving gates. In variational quantum simulation, for example, the variational quantum eigensolver (VQE), the symmetric gates of the PQC are parameterized. Since there are often many possible inequivalent parametrizations, it is often not immediately obvious which gate parametrization would be most efficient in general for a wide range of Hamiltonians that respect the symmetry. We streamline our analysis to particle-conserving circuits and Hamiltonians. We numerically analyze the efficiency of different particle-conserving gate parametrizations by studying two examples, namely, a physics problem of learning the ground state of Heisenberg spin chains, and an artificial problem of learning the random arbitary states sampled within the particle number conserved subspace.}, archive = {J_PRA}, author = {Babatunde M. Ayeni}, doi = {10.1103/PhysRevA.111.022629}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022629}, shortjournal = {Phys. Rev. A}, title = {Efficient particle-conserving symmetric quantum circuits}, volume = {111}, year = {2025}, }
• (2025). Entangling distant systems via universal nonadiabatic passage. PRA, 111(2), 022628. (www)

  @article{ , abstract = {In this paper, we derive universal nonadiabatic passages in a general -dimensional discrete system, where and denote the degrees of freedom for the assistant and working subspaces, respectively, that could be separated by rotation or energy and coupled through driving. A systematic method is provided to construct parametric ancillary bases by the von Neumann equation with the time-dependent system Hamiltonian. The resulting universal passages set up connections between arbitrary initial and target states. In applications, a transitionless dynamics can be formulated to entangle distant qubits, as a crucial prerequisite for practical quantum networks. Using tunable longitudinal interaction between distant qubits and driving frequency, the superconducting qubits can be prepared from the ground state to the single-excitation Bell state with a fidelity as high as and be further converted to the double-excitation Bell state with . Moreover, our protocol is extended to generate the Greenberger-Horne-Zeilinger state for an -qubit system with steps. Our work develops a full-fledged theory for nonadiabatic state engineering, which is flexible in target selection and robust against both external noises and systematic errors in quantum information processing.}, archive = {J_PRA}, author = {Zhu-yao Jin and Jun Jing}, doi = {10.1103/PhysRevA.111.022628}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022628}, shortjournal = {Phys. Rev. A}, title = {Entangling distant systems via universal nonadiabatic passage}, volume = {111}, year = {2025}, }
• (2025). Enhancing the performance of quantum radar with zero-photon subtraction. PRA, 111(2), 022627. (www)

  @article{ , abstract = {Quantum radar, also known as quantum illumination, is a type of quantum-sensing protocol for detecting noncooperative targets hidden in noisy environments. Recently, considerable research efforts have been focused on optimizing quantum illumination via conditional photon-detection methods, such as photon subtraction and photon catalysis of the entanglement source. However, to date, almost none of these studies have considered the probability of successful detection of nonzero photons. Often, the probability of conditional nonzero photon detection is extremely low, which may negate the advantage of conditional measurements in a quantum radar. In this paper, we propose enhancing the performance of quantum radars using zero-photon subtraction (ZPS), where no physical photons are subtracted from a given optical system. We demonstrate that the probability of ZPS is one or two orders of magnitude higher than that of nonzero photon detection. Our results show that ZPS helps enhance the performance of quantum radars, even when the probability of photon detection is considered. Moreover, in this paper, we consider a more realistic quantum radar in which target detection is performed using amplitude-damped quantum entanglement, which is more commonly used in the preparation of quantum entanglement in radar transmitters. This means that ZPS is a more efficient conditional photon-detection method for quantum illumination, providing a more robust scheme for developing future quantum radars.}, archive = {J_PRA}, author = {ShengLi Zhang and Liangsheng Li and Maoxin Liu and JinChun Li and Wang Sun and QuanChun Yu}, doi = {10.1103/PhysRevA.111.022627}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022627}, shortjournal = {Phys. Rev. A}, title = {Enhancing the performance of quantum radar with zero-photon subtraction}, volume = {111}, year = {2025}, }
• (2025). Compressive quantum waveform estimation. PRA, 111(2), 022625. (www)

  @article{ , abstract = {Quantum waveform estimation, in which quantum sensors sample entire time series, promises to revolutionize the sensing of weak and stochastic signals, such as the biomagnetic impulses emitted by firing neurons. For long duration waveforms with rapid transients, regular quantum sampling becomes prohibitively resource intensive as it demands many measurements with distinct control and readout. In this paper, we demonstrate how careful choice of quantum measurements, along with the modern mathematics of compressive sensing, achieves quantum waveform estimation of sparse signals in a number of measurements far below the Nyquist requirement. We sense synthesized neural-like magnetic waveforms with radio-frequency-dressed ultracold atoms, retrieving successful waveform estimates with as few measurements as compressive theoretical bounds guarantee.}, archive = {J_PRA}, author = {Alex Tritt and Joshua Morris and Christopher C. Bounds and Hamish A. M. Taylor and James Saunderson and L. D. Turner}, doi = {10.1103/PhysRevA.111.022625}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022625}, shortjournal = {Phys. Rev. A}, title = {Compressive quantum waveform estimation}, volume = {111}, year = {2025}, }
• (2025). Simple loss-tolerant protocol for greenberger-horne-zeilinger-state distribution in a quantum network. PRA, 111(2), 022624. (www)

  @article{ , abstract = {Distributed quantum entanglement plays a crucial role in realizing networks that connect quantum devices. However, sharing entanglement between distant nodes by means of photons is a challenging process primary due to unavoidable losses in the linking channels. In this paper, we propose a simple loss-tolerant protocol for the Greenberger-Horne-Zeilinger-state distribution. We analyze the distribution rate under feasible experimental conditions and demonstrate the advantages of rate-loss scaling with respect to direct transmission. Our protocol does not use quantum repeaters and is achievable with current quantum optics technology. The result has direct application to tasks such as conference key agreement or distributed sensing. Moreover, it reduces the requirements for implementing distributed quantum error correction codes such as the surface code.}, archive = {J_PRA}, author = {Hikaru Shimizu and Wojciech Roga and David Elkouss and Masahiro Takeoka}, doi = {10.1103/PhysRevA.111.022624}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022624}, shortjournal = {Phys. Rev. A}, title = {Simple loss-tolerant protocol for greenberger-horne-zeilinger-state distribution in a quantum network}, volume = {111}, year = {2025}, }
• (2025). Deterministic single-phonon-to-photon quantum transducer for distributed quantum networks. PRA, 111(2), 022623. (www)

  @article{ , abstract = {Quantum transducers are essential for connecting hybrid quantum systems with distinct frequencies, pivotal for hybrid quantum networks. A deterministic quantum transducer protocol is proposed for the upconversion of single phonons in the microwave domain to optical photons. Utilizing a hybrid optomechanical crystal coupled to a three-level emitter, the protocol deterministically upconverts an itinerant phonon into an optical photon, when an auxiliary optical cavity mode is driven by a single photon. Furthermore, the deterministic upconversion transducer can also be achieved by driving the emitter with a classical laser pulse, rather than driving the optical cavity with a single photon. The intracavity photon numbers in both protocols are significantly less than one during the operation, thus overcoming the problem of parasitic heating within radiation-pressure coupling of hybrid optomechanical systems. These outstanding features make the protocols particularly useful for the realization of large-scale distributed hybrid quantum networks.}, archive = {J_PRA}, author = {Zhengyi Yue and Tao Li and Zhenhua Li and Keyu Xia}, doi = {10.1103/PhysRevA.111.022623}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022623}, shortjournal = {Phys. Rev. A}, title = {Deterministic single-phonon-to-photon quantum transducer for distributed quantum networks}, volume = {111}, year = {2025}, }
• (2025). Realizing two-qubit gates through mode engineering on a trapped-ion quantum computer. PRA, 111(2), 022622. (www)

  @article{ , abstract = {Two-qubit gates are a fundamental constituent of a quantum computer and typically its most challenging operation. In a trapped-ion quantum computer, this is typically implemented with laser beams which are modulated in amplitude, frequency, phase, or a combination of these. The required modulation becomes increasingly more complex as the quantum computer becomes larger, complicating the control hardware design. Here we develop a simple method to essentially remove the pulse-modulation complexity by engineering the normal modes of the ion chain. We experimentally test the feasibility of the method in a three-ion chain. This opens up the possibility to trade off complexity between the design of the trapping fields and the optical control system, which will help scale the ion-trap quantum computing platform.}, archive = {J_PRA}, author = {Ming Li and Nhung H. Nguyen and Alaina M. Green and Jason Amini and Norbert M. Linke and Yunseong Nam}, doi = {10.1103/PhysRevA.111.022622}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022622}, shortjournal = {Phys. Rev. A}, title = {Realizing two-qubit gates through mode engineering on a trapped-ion quantum computer}, volume = {111}, year = {2025}, }
• (2025). Higher-order protection of quantum gates: Hamiltonian engineering coordinated with dynamical decoupling. PRA, 111(2), 022621. (www)

  @article{ , abstract = {Dynamical decoupling represents an active approach towards the protection of quantum memories and quantum gates. Because dynamical decoupling operations can interfere with a system's own time evolution, the protection of quantum gates is more challenging than that of quantum states. In this work, we put forward a simple but general approach towards the realization of higher-order protection of quantum gates and further execute the first cloud-based demonstration of dynamical-decoupling-protected quantum gates at the first order and the second order. The central idea of our approach is to engineer (hence regain the control of) the gate Hamiltonian in coordination with higher-order dynamical decoupling sequences originally proposed for the protection of quantum memories. The physical demonstration on an IBM quantum processor indicates the effectiveness and potential of our approach on noisy intermediate scale quantum computers.}, archive = {J_PRA}, author = {P. Z. Zhao and Tianqi Chen and Sirui Liu and Jiangbin Gong}, doi = {10.1103/PhysRevA.111.022621}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022621}, shortjournal = {Phys. Rev. A}, title = {Higher-order protection of quantum gates: Hamiltonian engineering coordinated with dynamical decoupling}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic holonomic quantum gates in a decoherence-insensitive space. PRA, 111(2), 022620. (www)

  @article{ , abstract = {Nonadiabatic holonomic quantum computation (NHQC) has shown promise in mitigating control errors, but requires additional methods to further eliminate the effects of decoherence errors. Existing NHQC schemes capable of combating both types of errors often necessitate auxiliary qubits, thereby increasing qubit resource consumption. This paper proposes nonadiabatic holonomic quantum gates based on a three-level dressed state space, which have inherent insensitivity to decoherence and eliminate the need for auxiliary qubits. Through numerical simulations, the presented gates within the dressed-state framework display enhanced resistance to both control field errors and decoherence errors. Moreover, we discuss the implementation of our approach on the nitrogen-vacancy center in diamond, demonstrating its feasibility and potential for geometric quantum computation.}, archive = {J_PRA}, author = {Fangzhou Jin and Jianpei Geng and Hui Zhou}, doi = {10.1103/PhysRevA.111.022620}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022620}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic holonomic quantum gates in a decoherence-insensitive space}, volume = {111}, year = {2025}, }
• (2025). Quantum state estimation of multipartite single-photon path entanglement via local measurements. PRA, 111(2), 022619. (www)

  @article{ , abstract = {Multipartite entanglement plays a critical role in various applications of quantum internet. In these applications, the entanglement is usually shared by the distant parties. Experimentally, the distributed entanglement should be estimated by only local measurements. Furthermore, for network experiments, it is desirable to employ measurement techniques that are straightforward to implement. In this paper, we propose a method to measure arbitrary multipartite single-photon path entangled states by only local measurements. By considering practically reasonable assumptions, our method is relatively easy to implement. We experimentally demonstrate the utility of this method by reconstructing the density matrix of a 3-qubit W state.}, archive = {J_PRA}, author = {Hikaru Shimizu and Joe Yoshimoto and Kazufumi Tanji and Aruto Hosaka and Junko Ishi-Hayase and Tomoyuki Horikiri and Rikizo Ikuta and Masahiro Takeoka}, doi = {10.1103/PhysRevA.111.022619}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022619}, shortjournal = {Phys. Rev. A}, title = {Quantum state estimation of multipartite single-photon path entanglement via local measurements}, volume = {111}, year = {2025}, }
• (2025). Validity condition for high-fidelity digitized quantum annealing. PRA, 111(2), 022618. (www)

  @article{ , abstract = {Digitizing an adiabatic evolution is a strategy able to combine the good performance of gate-based quantum processors with the advantages of adiabatic algorithms, thus providing a hybrid model for efficient quantum information processing. In this work we develop validity conditions for high-fidelity digital adiabatic tasks. To this end, we assume a digitizing process based on the Suzuki-Trotter decomposition, which allows us to introduce a digitized adiabatic theorem. As a consequence of this theorem, we show that the performance of such a hybrid model is limited by the fundamental constraints on the adiabatic theorem validity, even in ideal quantum processors. We argue how our approach predicts the existence of intrinsic nonadiabatic errors reported by Barends et al. [ Nature (London) 534 , 222 (2016) ] through an empirical study of digital annealing. In addition, our approach allows us to explain the existence of a scaling of the number of Suzuki-Trotter blocks for the optimal digital circuit with respect to the optimal adiabatic total evolution time, as reported by Mbeng et al. [ Phys. Rev. B 100 , 224201 (2019) ] through robust numerical analysis of digital annealing. We illustrate our results through two examples of digitized adiabatic algorithms, namely, the two-qubit exact-cover problem and the three-qubit adiabatic factorization of the number 21.}, archive = {J_PRA}, author = {Alan C. Santos}, doi = {10.1103/PhysRevA.111.022618}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022618}, shortjournal = {Phys. Rev. A}, title = {Validity condition for high-fidelity digitized quantum annealing}, volume = {111}, year = {2025}, }
• (2025). Phenomenon of a stronger trapping behavior in Λ-type quantum systems with symmetry. PRA, 111(2), 022617. (www)

  @article{ , abstract = {Λ , V , Ξ (ladder), and other three-level quantum systems with one forbidden transition (referred to here as Λ -type systems) play an important role in quantum physics. Various applications require manipulation of such systems using as a control a shaped laser field. In this work, we study how the degeneracy of energy states or of Bohr frequencies in these systems affects the efficiency or difficulty of finding the optimal shape of the control field. For this, we adopt the notion of higher-order traps, which was introduced in Pechen and Tannor, Phys. Rev. Lett. 106 , 120402 (2011) , where second-/third-order traps were discovered for a Λ -atom with one forbidden transition and with nondegenerate energy levels. We theoretically study the control of such systems with and without degeneracy in their eigenstates and Bohr frequencies, and we investigate numerically using GRAPE and l-BFGS algorithms how this degeneracy influences the efficiency of optimizing the control laser field. We find that the degeneracy of the Bohr frequencies in the Ξ system, which makes the system energy levels symmetrically distributed, leads to the appearance of a seventh-order trap with a more significant attracting domain resulting in a more difficult optimization, while the degeneracy of energy states in generic Λ -type systems does not lead to an increase of the order of the zero control trap compared to the nondegenerate case. We also find that when not only are the Bohr frequencies degenerate in the system Ξ but also the dipole moments for the two allowed transitions coincide (in this case, the Ξ system is not controllable), then true traps arise in the quantum control landscape. In particular, the constant zero control becomes a trap.}, archive = {J_PRA}, author = {Boris Volkov and Anastasia Myachkova and Alexander Pechen}, doi = {10.1103/PhysRevA.111.022617}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022617}, shortjournal = {Phys. Rev. A}, title = {Phenomenon of a stronger trapping behavior in Λ-type quantum systems with symmetry}, volume = {111}, year = {2025}, }
• (2025). Stabilizing entanglement of boron-vacancy defects in a hexagonal boron-nitride membrane by two-phonon driving. PRA, 111(2), 022616. (www)

  @article{ , abstract = {Generating stable entanglement by mimicking a squeezed environment plays an important role in quantum metrology and quantum information. Here, we propose an efficient scheme for generating stable entanglement of two boron-vacancy (VB) defects in a suspended circular hexagonal boron nitride ( h -BN) membrane via a two-phonon drive. Compared to other reported methods, our scheme only needs a linear resource and thus is more convenient for experimental implementation. In the presence of a gradient magnetic field, the electronic spin degree of freedom of the VB defect can be coupled to the mechanical mode of h -BN membrane through spin-phonon interaction. The coupling strength is closely related to the geometry of the magnetic field and the parameters of the membrane, which allows us to realize different coupling regimes by choosing the parameter appropriately. After applying a time-dependent pump to the h -BN membrane, we can modulate its spring constant and obtain a tunable two-phonon drive to the mechanical mode. We then investigate the dissipative coupling between two VB spins in the condition of a large dissipation limit, showing that the stable entanglement can be generated under a two-phonon drive. In addition, we also take the spin dephasing into consideration to explore the robustness of our scheme. We then extend this scheme to multiparticle systems, which shows that the entanglement degree deepens with the increase of VB spin number. This work offers a fascinating platform for generating stable entanglement with VB spins in two-dimensional h -BN.}, archive = {J_PRA}, author = {Yi-Fan Qiao and Xue-Feng Pan and Xiao-Yu Yao and Xin-Lei Hei and Peng-Bo Li}, doi = {10.1103/PhysRevA.111.022616}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022616}, shortjournal = {Phys. Rev. A}, title = {Stabilizing entanglement of boron-vacancy defects in a hexagonal boron-nitride membrane by two-phonon driving}, volume = {111}, year = {2025}, }
• (2025). Efficiency of feynman's quantum computer. PRA, 111(2), 022615. (www)

  @article{ , abstract = {Feynman's circuit-to-Hamiltonian construction enables the mapping of a quantum circuit to a time-independent Hamiltonian. This model introduces a Hilbert space made from an ancillary clock register tracking the progress of the computation. In this paper, we explore the efficiency, or run time, of a quantum computer that directly implements the clock system. This relates to the model's probability of computation completion which we investigate at an established optimal time for an arbitrary number of gates . The relationship between the run time of the model and the number of gates is obtained both numerically and analytically to be . In principle, this is significantly more efficient than the well-investigated Feynman-Kitaev model of adiabatic quantum computation with a run time of . We address the challenge which stems from the small window that exists to capture the optimal stopping time, after which there are rapid oscillations of decreasing probability amplitude. We establish a relationship for the time difference between the first and second maximum which scales as O( ).}, archive = {J_PRA}, author = {R. J. Costales and A. Gunning and T. Dorlas}, doi = {10.1103/PhysRevA.111.022615}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022615}, shortjournal = {Phys. Rev. A}, title = {Efficiency of feynman's quantum computer}, volume = {111}, year = {2025}, }
• (2025). Demonstration of system-bath physics on a gate-based quantum computer. PRA, 111(2), 022614. (www)

  @article{ , abstract = {Algorithmic cooling can be used to find correlated states of many-body quantum systems. It is based on quantum circuits that perform nonunitary operations, whose implementation can be challenging on near-term quantum computers. In this work we develop a method that uses inherent qubit noise to implement nonunitary operations and algorithmic cooling. In our approach, qubit decay during quantum computation is used to simulate dissipation of auxiliary-spin bath, which cools down a simulated system towards its ground state. We test the algorithm on IBM-Q devices and demonstrate the relaxation of system spins to ferromagnetic and antiferromagnetic ordering, controlled by the definition of the system Hamiltonian. The ordering is stable as long as the algorithm is run. We are able to perform cooling and state stabilization for global systems of up to three system spins and four auxiliary spins. Our work paves the way for useful quantum simulations of many-body quantum systems on near-term quantum computers.}, archive = {J_PRA}, author = {Pascal Stadler and Matteo Lodi and Andisheh Khedri and Rolando Reiner and Kirsten Bark and Nicolas Vogt and Michael Marthaler and Juha Leppäkangas}, doi = {10.1103/PhysRevA.111.022614}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022614}, shortjournal = {Phys. Rev. A}, title = {Demonstration of system-bath physics on a gate-based quantum computer}, volume = {111}, year = {2025}, }
• (2025). Modeling error correction with lindblad dynamics and approximate channels. PRA, 111(2), 022613. (www)

  @article{ , abstract = {We analyze the performance of a quantum error-correction code subject to physically motivated noise modeled by a Lindblad master equation. We consider dissipative and coherent single-qubit terms and two-qubit crosstalk, studying how different approximations of the noise capture the success rate of a code. Focusing on the five-qubit code and adapting it to partially correct two-qubit errors in relevant parameter regimes according to the noise model, we find that a composite-channel approximation where every noise term is considered separately captures the behavior in many physical cases up to long timescales, eventually failing due to the effect of noncommuting terms. In contrast, we find that single-qubit approximations do not properly capture the error-correction dynamics with two-qubit noise, even for short times. A Pauli approximation going beyond a single-qubit channel is sensitive to the details of the noise, state, and decoder and succeeds at short timescales relative to the noise strength, beyond which it fails. Furthermore, we point out a mechanism for a Pauli model failure where it underestimates the success rate of a code even with frequent syndrome projection and correction cycles. These results shed light on the performance of error correction in the presence of realistic noise and can advance the ongoing efforts towards useful quantum error correction.}, archive = {J_PRA}, author = {Zohar Schwartzman-Nowik and Liran Shirizly and Haggai Landa}, doi = {10.1103/PhysRevA.111.022613}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022613}, shortjournal = {Phys. Rev. A}, title = {Modeling error correction with lindblad dynamics and approximate channels}, volume = {111}, year = {2025}, }
• (2025). Trotter error timescaling separation via commutant decomposition. PRA, 111(2), 022612. (www)

  @article{ , abstract = {Suppressing the Trotter error in dynamical quantum simulation typically requires running deeper circuits, posing a great challenge for noisy near-term quantum devices. Studies have shown that the empirical error is usually much smaller than the one suggested by existing bounds, implying the actual circuit cost required is much less than the ones based on those bounds. Here, we improve the estimate of the Trotter error over existing bounds, by introducing a general framework of commutant decomposition that separates disjoint error components that have fundamentally different scaling with time. In particular we identify two error components that each scale as O ( τ p t ) and O ( τ p ) for a p th -order product formula evolving to time t using a fixed step size τ , implying one would scale linearly with time t and the other would be a constant of t . We show that this formalism not only straightforwardly reproduces previous results but also provides a better error estimate for higher-order product formulas. We demonstrate the improvement both analytically and numerically. We also apply the analysis to observable error relating to the heating in Floquet dynamics and thermalization, which is of independent interest.}, archive = {J_PRA}, author = {Yi-Hsiang Chen}, doi = {10.1103/PhysRevA.111.022612}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022612}, shortjournal = {Phys. Rev. A}, title = {Trotter error timescaling separation via commutant decomposition}, volume = {111}, year = {2025}, }
• (2025). Pump-efficient josephson parametric amplifiers with high saturation power. PRA, 111(2), 022611. (www)

  @article{ , abstract = {Circuit quantum-electrodynamics-based quantum information processing relies on low noise amplification for signal readout. In the realm of microwave superconducting circuits, this amplification is often achieved via Josephson parametric amplifiers (JPAs). In the past, these amplifiers exhibited low power added efficiency (PAE), which is roughly the fraction of pump power that is converted to output signal power. This is increasingly relevant because recent attempts to build high saturation power amplifiers achieve this at the cost of very low PAE, which in turn puts a high heat load on the cryostat and limits the number of these devices that a dilution refrigerator can host. Here, we numerically investigate upper bounds on PAE. We focus on a class of parametric amplifiers that consists of a capacitor shunted by a nonlinear inductive block. We first set a benchmark for this class of amplifiers by considering nonlinear blocks described by an arbitrary polynomial current-phase relation. Next, we identify that it is important for amplifiers with inductive blocks composed of repeating elements to have monotonic current-phase relations for each element in order to avoid exciting high-frequency modes. Using this design rule, we propose two circuit implementations for repeating elements in JPA inductive blocks. Finally, we investigate polynomial amplifier chains. We find that while amplifiers with higher gain have a lower PAE, regardless of the gain there is considerable room to improve as compared with state-of-the-art devices. For example, for a degenerate amplifier with a power gain of 20 dB, the PAE is ≈ 0 . 1 % for typical JPAs, 37.9% for our simpler circuit JPAs, 42.6% for our more complex circuit JPAs, 63.3% for our arbitrary polynomial amplifiers, and at least 98% for our amplifier chains.}, archive = {J_PRA}, author = {Nicholas M. Hougland and Zhuan Li (李專 and Ryan Kaufman and Boris Mesits and Roger S. K. Mong (蒙紹璣 and Michael Hatridge and David Pekker}, doi = {10.1103/PhysRevA.111.022611}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022611}, shortjournal = {Phys. Rev. A}, title = {Pump-efficient josephson parametric amplifiers with high saturation power}, volume = {111}, year = {2025}, }
• (2025). Improved finite-size key rates for discrete-modulated continuous-variable quantum key distribution under coherent attacks. PRA, 111(2), 022610. (www)

  @article{ , abstract = {Continuous-variable quantum key distribution (CVQKD) with discrete modulation combines advantages of CVQKD, such as implementability using readily available technologies, with advantages of discrete variable quantum key distribution, such as easier error correction procedures. We consider a prepare-and-measure CVQKD protocol, where Alice chooses from a set of four coherent states and Bob performs a heterodyne measurement, the result of which is discretized in both key and test rounds. We provide a security proof against coherent attacks in the finite-size regime based on the generalized entropy accumulation theorem. We compute the corresponding asymptotic key rate imposing a photon-number cutoff and recent advances in conic optimization. Our method yields significant improvements on key rates: at metropolitan distances, it provides positive key rates for block sizes of the order of rounds, orders of magnitude smaller compared to previous works.}, archive = {J_PRA}, author = {Carlos Pascual-García and Stefan Bäuml and Mateus Araújo and Rotem Liss and Antonio Acín}, doi = {10.1103/PhysRevA.111.022610}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022610}, shortjournal = {Phys. Rev. A}, title = {Improved finite-size key rates for discrete-modulated continuous-variable quantum key distribution under coherent attacks}, volume = {111}, year = {2025}, }
• (2025). Quantum next-generation reservoir computing and its quantum optical implementation. PRA, 111(2), 022609. (www)

  @article{ , abstract = {Quantum reservoir computing (QRC) exploits the information-processing capabilities of quantum systems to tackle time-series forecasting tasks, which is expected to be superior to their classical counterparts. By far, many QRC schemes have been theoretically proposed. However, most of these schemes involve long-time evolution of quantum systems or networks with quantum gates. This poses a challenge for practical implementation of these schemes, as precise manipulation of quantum systems is crucial, and this level of control is currently hard to achieve with the existing state of quantum technology. Here we propose a different QRC scheme, which is friendly to experimental realization. It implements the quantum version of nonlinear vector autoregression, extracting linear and nonlinear features of quantum data by measurements. Thus, the evolution of complex networks of quantum gates can be avoided. Compared to other QRC schemes, our proposal also achieves an advance by effectively reducing the necessary training data for reliable predictions in time-series forecasting tasks. Furthermore, we experimentally verify our proposal by performing the forecasting tasks, and the observation matches well with the theoretical ones. Our work opens up a different way for complex tasks to be solved by using QRC, which can herald the next generation of QRC.}, archive = {J_PRA}, author = {Longhan Wang and Peijie Sun and Ling-Jun Kong and Yifan Sun and Xiangdong Zhang}, doi = {10.1103/PhysRevA.111.022609}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022609}, shortjournal = {Phys. Rev. A}, title = {Quantum next-generation reservoir computing and its quantum optical implementation}, volume = {111}, year = {2025}, }
• (2025). Enhanced detection of time-dependent dielectric structure: Rayleigh limit and quantum vacuum. PRA, 111(2), 022608. (www)

  @article{ , abstract = {Detection of scattered light can determine the susceptibility of dielectrics. Such imaging normally holds Rayleigh's limit: details finer than the wavelength of the incident light cannot be determined from the far-field zone. We show that time -modulation of an inhomogeneous dielectric can be used to determine its susceptibility. To this end, we focus on the inverse quantum optics problem for spatially and temporally modulated metamaterial, whose dielectric susceptibility is similar to moving dielectrics. We show that the vacuum contribution to the photodetection signal is nonzero due to the negative frequencies even in the far-field zone. Hence, certain dielectric features can be determined without radiating any incident field on the dielectric. When the incident light is scattered (or reradiated), the determination of dielectric susceptibility is enhanced and overcomes Rayleigh's limit in the far-field zone. We study similar effects for an inhomogeneous dielectric moving with a constant speed, a problem we consider within relativistic optics. Now the vacuum contribution to the photodetection signal reflects dielectric features, can be long-range in space but is not a far-field effect.}, archive = {J_PRA}, author = {V. E. Mkrtchian and H. S. Avetisyan and A. E. Allahverdyan}, doi = {10.1103/PhysRevA.111.022608}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022608}, shortjournal = {Phys. Rev. A}, title = {Enhanced detection of time-dependent dielectric structure: Rayleigh limit and quantum vacuum}, volume = {111}, year = {2025}, }
• (2025). Two-photon hong-ou-mandel-based sensor with N-fold maximal precision. PRA, 111(2), 022607. (www)

  @article{ , abstract = {The two-photon Hong-Ou-Mandel (HOM) interferometry sensor has attracted much attention in recent decades due to its numerous advantages, such as robustness against background noise, group velocity dispersion, and phase perturbations. However, the maximum measurement precision of a single measurement is limited by the Heisenberg uncertainty at the two-photon level, which constrains the development of a HOM-based sensor. In this paper, we combine the multipass approach of a sequential scheme for quantum metrology with the traditional HOM-based sensor, and provide a general theoretical scheme of a multipass HOM-based sensor. For N passes of the probe through the sample, our proposed scheme offers an N -fold improvement in the precision of parameter estimation compared to a traditional HOM-based sensor under the same number of measurement repetitions. Furthermore, we present the simulation results of decoherence models for the multipass HOM-based sensor by introducing phase diffusion and photon loss, which are significantly enhanced due to the multipass approach. Last, we present the predictions of achievable precision for the multipass HOM-based sensor, considering measurement repetitions of the order of 10 4 in a sample with a thickness of 100 µ m .}, archive = {J_PRA}, author = {Qian Li and Yifan Sun and Xiangdong Zhang}, doi = {10.1103/PhysRevA.111.022607}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022607}, shortjournal = {Phys. Rev. A}, title = {Two-photon hong-ou-mandel-based sensor with N-fold maximal precision}, volume = {111}, year = {2025}, }
• (2025). Ambiguous resonances in multipulse quantum sensing with nitrogen-vacancy centers. PRA, 111(2), 022606. (www)

  @article{ , abstract = {Dynamical decoupling multipulse sequences can be applied to solid-state spins for sensing weak oscillating fields from nearby single nuclear spins. By periodically reversing the probing system's evolution, other noises are counteracted and filtered out over the total evolution. However, the technique is subject to intricate interactions resulting in additional resonant responses, which can be misinterpreted with the actual signal intended to be measured. We experimentally characterize three of these effects present in single nitrogen-vacancy centers in diamond, where we also develop a numerical simulation model without rotating-wave approximation, showing robust correlation to the experimental data. Regarding centers with the nitrogen isotope, we observe that a small misalignment in the bias magnetic field causes the precession of the nitrogen nuclear spin to be sensed by the electronic spin of the center. Another studied case of ambiguous resonances comes from the coupling with lattice nuclei, where we use the echo modulation frequencies to obtain the interaction Hamiltonian and then utilize the latter to simulate multipulse sequences. Finally, we also measure and simulate the effects from the free evolution of the quantum system during finite pulse durations. Due to the large data volume and the strong dependence of these ambiguous resonances with specific experimental parameters, we provide a simulations data set with a user-friendly graphical interface, where users can compare simulations with their own experimental data for spectral disambiguation. Although focused on nitrogen-vacancy centers and dynamical decoupling sequences, these results and the developed model can potentially be applied to other solid-state spins and quantum sensing techniques.}, archive = {J_PRA}, author = {Lucas Tsunaki and Anmol Singh and Kseniia Volkova and Sergei Trofimov and Tommaso Pregnolato and Tim Schröder and Boris Naydenov}, doi = {10.1103/PhysRevA.111.022606}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022606}, shortjournal = {Phys. Rev. A}, title = {Ambiguous resonances in multipulse quantum sensing with nitrogen-vacancy centers}, volume = {111}, year = {2025}, }
• (2025). Molecular nanomagnet Cu2+Ni2+Cu2+ as a resource for bipartite and tripartite quantum entanglement and coherence. PRA, 111(2), 022605. (www)

  @article{ , abstract = {We investigate key quantum characteristics of the mixed spin-(1/2,1,1/2) Heisenberg trimer under the influence of an external magnetic field. Specifically, we analyze the distributions of bipartite and tripartite entanglement quantified through the respective negativities and the -norm of coherence with the help of rigorous analytical and numerical methods. Our findings suggest that the heterotrinuclear molecular nanomagnet , which represents an experimental realization of the mixed spin-(1/2,1,1/2) Heisenberg trimer, exhibits a significant bipartite entanglement between and magnetic ions along with robust tripartite entanglement among all three constituent magnetic ions. The significant bipartite and tripartite entanglement persists even at relatively high temperatures up to and magnetic fields up to , whereby the coherence is maintained even at elevated temperatures. It is evidenced that the aforementioned molecular complex with the magnetic core provides an intriguing quantum resource, which exhibits a star-shaped state within the singlet eigenstate at low magnetic fields and W-like state within the triplet eigenstate at moderate magnetic fields.}, archive = {J_PRA}, author = {Azadeh Ghannadan and Hamid Arian Zad and Saeed Haddadi and Jozef Strečka and Zhirayr Adamyan and Vadim Ohanyan}, doi = {10.1103/PhysRevA.111.022605}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022605}, shortjournal = {Phys. Rev. A}, title = {Molecular nanomagnet Cu2+Ni2+Cu2+ as a resource for bipartite and tripartite quantum entanglement and coherence}, volume = {111}, year = {2025}, }
• (2025). Simulation of the dissipative dynamics of strongly interacting nitrogen-vacancy centers with tensor networks. PRA, 111(2), 022604. (www)

  @article{ , abstract = {Nitrogen-vacancy (NV) centers in diamond are a promising platform for highly sensitive quantum sensors for magnetic fields and other physical quantities. The quest for high sensitivity combined with high spatial resolution naturally leads to dense ensembles of NV centers and hence to strong, long-range interactions between them. Hence, simulating strongly interacting NVs becomes essential. However, obtaining the exact dynamics for a many-spin system is a challenging task due to the exponential scaling of the Hilbert space dimension, a problem that is exacerbated when the system is modeled as an open quantum system. In this work, we employ the matrix product density operator (MPDO) method to represent the many-body mixed state and to simulate the dynamics of an ensemble of NVs in the presence of strong long-range couplings due to dipole-dipole forces. We benchmark different time-evolution algorithms in terms of numerical accuracy and stability against time evolution based on exact numerical diagonalization. Subsequently, we simulate the dynamics in the strong-interaction regime and study the impact of decoherence on the accuracy of the MPDO method. Last, we investigate the dynamics of quantum Fisher information and show that for small distances below about 5 nm the resulting strong dipole-dipole interaction can improve the sensitivity for magnetic field sensing when the ensemble is driven by pulses of constant amplitude.}, archive = {J_PRA}, author = {Jirawat Saiphet and Daniel Braun}, doi = {10.1103/PhysRevA.111.022604}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022604}, shortjournal = {Phys. Rev. A}, title = {Simulation of the dissipative dynamics of strongly interacting nitrogen-vacancy centers with tensor networks}, volume = {111}, year = {2025}, }
• (2025). Scalable and verifiable quantum secret sharing with photonic efficiency via quasicausal cones in the multiscale entanglement renormalization ansatz framework. PRA, 111(2), 022603. (www)

  @article{ , abstract = {Quantum secret sharing (QSS) is set to revolutionize secure communication. However, achieving practical implementations that balance efficiency, security, and flexibility remains a significant challenge. To address this issue, we propose an innovative QSS scheme that integrates a verification mechanism for the distribution process by leveraging quasicausal cones within the multiscale entanglement renormalization ansatz framework. This approach ensures the secure dissemination of entangled photons across a multiuser network while enhancing the integrity of the quantum state against disturbances. A key feature of our scheme is the application of quasicausal cones, which improve the system's fault tolerance and recovery precision, preserving quantum state coherence and stability even in the presence of errors or losses. The recursive and hierarchical design of our framework enables it to dynamically adapt to fluctuations in network size and the number of participants, making it well suited for large-scale quantum networks. Furthermore, our method reduces the costs associated with photon transmission and storage, enhancing resource allocation within expansive quantum networks. The strategic incorporation of quasicausal cones represents a major advancement, streamlining the flow of quantum information and minimizing the overall resource footprint. By flexibly accommodating varying network sizes and configurations, our scheme marks a significant step towards efficient large-scale QSS, underscoring the critical role of quasicausal cones in advancing quantum communication technologies.}, archive = {J_PRA}, author = {Hong Lai and Zhongrui Huang and Li Ren and Josef Pieprzyk and Qibin Zhao and Leongchuan Kwek}, doi = {10.1103/PhysRevA.111.022603}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022603}, shortjournal = {Phys. Rev. A}, title = {Scalable and verifiable quantum secret sharing with photonic efficiency via quasicausal cones in the multiscale entanglement renormalization ansatz framework}, volume = {111}, year = {2025}, }
• (2025). Error mitigation of BQP computations using measurement-based verification. PRA, 111(2), 022602. (www)

  @article{ , abstract = {We present a modular error mitigation protocol for running bounded-error quantum polynomial time (BQP) computations on a quantum computer with time-dependent noise. Utilizing existing tools from quantum verification and measurement-based quantum computation, our protocol interleaves standard computation rounds alongside test rounds for noise sampling and inherits an exponential bound (in the number of circuit runs) on the probability that a returned classical output is correct. We introduce a postselection technique called basketing to address time-dependent noise and reduce overhead. The result is an error mitigation protocol which requires minimal noise assumptions, making it straightforwardly implementable on existing, noisy intermediate-scale quantum devices. We perform a demonstration of the protocol using classical noisy simulation, presenting a universal measurement pattern which directly maps to (and can be tiled on) the heavy-hex layout of current IBM hardware.}, archive = {J_PRA}, author = {Joseph Harris and Elham Kashefi}, doi = {10.1103/PhysRevA.111.022602}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022602}, shortjournal = {Phys. Rev. A}, title = {Error mitigation of BQP computations using measurement-based verification}, volume = {111}, year = {2025}, }
• (2025). Reconstruction of quantum states by applying an analytical optimization model. PRA, 111(2), 022601. (www)

  @article{ , abstract = {When working with quantum states, analysis of the final quantum state generated through probabilistic measurements is essential. This analysis is typically conducted by constructing the density matrix from either partial or full tomography measurements of the quantum state. While full tomography measurement offers the most accurate reconstruction of the density matrix, limited measurements pose challenges for reconstruction algorithms, often resulting in nonphysical density matrices with negative eigenvalues. This is often remedied using maximum likelihood estimators, which have a high computing time or by other estimation methods that decrease the reconstructed fidelity. In this paper, we show that when restricting the measurement sample size, improvement over existing algorithms can be achieved. Our findings underline the multiplicity of solutions in the reconstruction problem, depending upon the generated state and measurement model utilized, thus motivating further research towards identifying optimal algorithms tailored to specific experimental contexts.}, archive = {J_PRA}, author = {Rohit Prasad and Pratyay Ghosh and Ronny Thomale and Tobias Huber-Loyola}, doi = {10.1103/PhysRevA.111.022601}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022601}, shortjournal = {Phys. Rev. A}, title = {Reconstruction of quantum states by applying an analytical optimization model}, volume = {111}, year = {2025}, }
• (2025). One-shot manipulation of coherence in dynamic quantum resource theory. PRA, 111(2), 022447. (www)

  @article{ , abstract = {A fundamental problem in quantum information is to understand the operational significance of quantum resources. Quantum resource theories (QRTs) provide a powerful theoretical framework that aids in the analysis and comprehension of the operational meaning of these resources. Early resource theories primarily focused on analyzing static quantum resources. Recently, interest in the study of dynamic quantum resources has been growing. In this paper, we utilize superchannel theory to describe the dynamic resource theory of quantum coherence. In this dynamic resource theory, we treat classical channels as free channels and consider two classes of free superchannels that preserve channel incoherence [maximally incoherent superchannels (MISCs) and dephasing-covariant incoherent superchannels (DISCs)] as free resources. We regard the quantum Fourier transform as the golden unit of dynamic coherence resources. We first establish the one-shot theory of dynamic coherence cost and dynamic coherence distillation, which involves converting the quantum Fourier transform into an arbitrary quantum channel using MISCs and DISCs. Next, we introduce a class of free superchannels known as -MISCs, which asymptotically generate negligible dynamic coherence. Finally, we provide upper and lower bounds for the one-shot catalytic dynamic coherence cost of quantum channels under the action of these -MISC superchannels.}, archive = {J_PRA}, author = {Yu Luo}, doi = {10.1103/PhysRevA.111.022447}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022447}, shortjournal = {Phys. Rev. A}, title = {One-shot manipulation of coherence in dynamic quantum resource theory}, volume = {111}, year = {2025}, }
• (2025). Quantum advantage in a unified scenario and secure detection of resources. PRA, 111(2), 022446. (www)

  @article{ , abstract = {Quantum resources may provide an advantage over their classical counterparts in communication tasks. We refer to this as quantum advantage . Here, we consider a single communication task to study different approaches of observing quantum advantage. We call this setting a unified scenario . Our task is described as the following. There are three parties—the Manager, Alice, and Bob. The Manager sends a value of a random variable to Alice, and at the same time Bob receives some partial information regarding that value. Initially, neither Alice nor Bob knows the input of the other, which is received from the Manager. The goal of the task is achieved if and only if the value of the random variable, sent to Alice by the Manager, is identified by Bob with a success probability greater than half all the time. Here, nonzero error probability is allowed. However, to help Bob, Alice sends a limited amount of classical or quantum information to him (cbit or qubit). We show that the goal of the task can be achieved when Alice sends a qubit. On the other hand, a cbit communication is not sufficient for achieving the goal. Thus, it establishes quantum advantage. We further show that the optimal success probability in the overall process for a qubit communication can be higher than the optimal success probability for a cbit communication. In fact, this success probability is higher for qubit communication even if along with cbit communication Alice and Bob share randomness which allows mixing of classical strategies. Clearly, it not only establishes quantum advantage, it also demonstrates a more prominent nonclassical feature. Actually, we obtain higher success probability compared to other tasks. This also suggests the experiment-friendly nature of our task. For applications, we connect our task with semi-device-independence and show how our task can be useful to detect quantumness of a communication in a secure way. Moreover, within the same setting, we provide a way to detect universal coherence present in an ensemble. For a high-dimensional random variable, to achieve the goal, it may require a high-dimensional classical communication, while it can be achieved with only a qubit communication. This establishes a large separation between the quantum and the classical communication.}, archive = {J_PRA}, author = {Saronath Halder and Alexander Streltsov}, doi = {10.1103/PhysRevA.111.022446}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022446}, shortjournal = {Phys. Rev. A}, title = {Quantum advantage in a unified scenario and secure detection of resources}, volume = {111}, year = {2025}, }
• (2025). Quantum speed limit on the production of quantumness of observables. PRA, 111(2), 022445. (www)

  @article{ , abstract = {Nonclassical features of quantum systems can degrade when subjected to environment and noise. Here, we ask a fundamental question: What is the minimum amount of time it takes for a quantum system to exhibit nonclassical features in the presence of noise? Here, we prove distinct speed limits on the quantumness of observable as the norm of the commutator of two given observables. The speed limit on such quantumness measures sets the fundamental upper bound on the rate of change of quantumness, which provides the lower bound on the time required to change the quantumness of a system by a given amount. Additionally, we prove the speed limit for the nonclassical features such as quantum coherence that captures the amount of superposition in the quantum systems. We demonstrate the attainability of the upper bounds for processes of physical interest and verify their tightness through illustrated cases.}, archive = {J_PRA}, author = {Divyansh Shrimali and Swapnil Bhowmick and Arun Kumar Pati}, doi = {10.1103/PhysRevA.111.022445}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022445}, shortjournal = {Phys. Rev. A}, title = {Quantum speed limit on the production of quantumness of observables}, volume = {111}, year = {2025}, }
• (2025). Genuine tripartite entanglement in graviton-matter interactions. PRA, 111(2), 022444. (www)

  @article{ , abstract = {We demonstrate the existence of genuine tripartite non-Gaussian entanglement in a quantum gravitational system formed by a quantum harmonic oscillator coupled to a single frequency of a quantized gravitational wave. For this purpose, we introduce an entanglement witness, well suited for the graviton-matter interaction Hamiltonian analyzed here. We show that the witness is nonzero for the three-mode states generated by the Hamiltonian when the system starts in the ground state, thus proving the generation of genuine multipartite quantum entanglement at the most fundamental level of theoretical graviton-matter interactions.}, archive = {J_PRA}, author = {Pablo Guillermo Carmona Rufo and Anupam Mazumdar and Carlos Sabín}, doi = {10.1103/PhysRevA.111.022444}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022444}, shortjournal = {Phys. Rev. A}, title = {Genuine tripartite entanglement in graviton-matter interactions}, volume = {111}, year = {2025}, }
• (2025). Quantum information flow in impurity qubits interacting with bose-bose mixtures. PRA, 111(2), 022443. (www)

  @article{ , abstract = {We investigate the dynamics of quantum information flow in one and two impurity qubits trapped in a double-well potential and interacting with a one-dimensional ultracold Bose-Bose mixture reservoir. For a single qubit immersed in a binary Bose mixture, we show that the system maintains coherence over finite timescales and exhibits non-Markovian dynamics, particularly in the upper branch of the environment. We explore the transition from Markovian to non-Markovian dephasing through the Ohmicity of the spectral density functions, which are significantly influenced by interspecies interactions. In the case of two spatially separated qubits coupled to the Bose-Bose mixture reservoir, we demonstrate that collective decoherence affects the system dynamics, leading to prolonged coherence survival in both branches of the mixture. The intricate evolution of the decoherence factors is reflected in the density spectral functions and their Ohmicity characteristics. We find that the decoherence functions and spectra oscillate with increasing distance between the qubits, modifying the information flow dynamics. Additionally, we conduct a thorough investigation of the entanglement dynamics between the two qubits induced by the binary Bose mixture reservoir in both branches, underscoring the critical role of interspecies interactions.}, archive = {J_PRA}, author = {Abdelâali Boudjemâa and Lan Xu and Qing-Shou Tan}, doi = {10.1103/PhysRevA.111.022443}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022443}, shortjournal = {Phys. Rev. A}, title = {Quantum information flow in impurity qubits interacting with bose-bose mixtures}, volume = {111}, year = {2025}, }
• (2025). Progress towards neutron-scattering simulation on an analog quantum processor. PRA, 111(2), 022442. (www)

  @article{ , abstract = {Neutron-scattering characterization of materials allows for the study of entanglement and microscopic structure but is inefficient to simulate classically for comparison to theoretical models and predictions. However, quantum processors, notably analog quantum simulators, have the potential to offer an unprecedented, efficient method of Hamiltonian simulation by evolving a state in real time to compute phase transitions, dynamical properties, and entanglement witnesses. To elucidate the response of materials to neutron scattering, we present a method for simulating the spin dynamics in the transverse field Ising chain on QuEra's Aquila processor by calculating the dynamic structure factor (DSF) and propose a method for error mitigation. We provide numerical simulations and experimental results for the performance of the procedure on the hardware, up to a chain of length . Additionally, the DSF result is used to compute the quantum Fisher information (QFI) density, where we confirm bipartite entanglement in the system experimentally.}, archive = {J_PRA}, author = {Nora Bauer and Victor Ale and Pontus Laurell and Serena Huang and Seth Watabe and David Alan Tennant and George Siopsis}, doi = {10.1103/PhysRevA.111.022442}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022442}, shortjournal = {Phys. Rev. A}, title = {Progress towards neutron-scattering simulation on an analog quantum processor}, volume = {111}, year = {2025}, }
• (2025). Deviations from geodesic evolutions and energy waste on the bloch sphere. PRA, 111(2), 022441. (www)

  @article{ , abstract = {In optimal quantum-mechanical evolutions, motion can occur along nonpredetermined paths of shortest length in an optimal time. Alternatively, optimal evolutions can happen along predefined paths with no waste of energy resources and 1 0 0 % speed efficiency. Unfortunately, realistic physical scenarios typically result in less-than-ideal evolutions. In this paper we study different families of suboptimal qubit Hamiltonians, both stationary and time varying, for which the so-called geodesic efficiency and the speed efficiency of the corresponding quantum evolutions are less than one. Furthermore, after proposing an alternative hybrid efficiency measure constructed out of the two previously mentioned efficiency quantifiers, we provide illustrative examples where the average departures from time optimality and 1 0 0 % speed efficiency are globally captured over a limited time period. In particular, due to this hybrid measure, quantum evolutions are partitioned in four categories: geodesic unwasteful, nongeodesic unwasteful, geodesic wasteful, and nongeodesic wasteful. Finally, we discuss Hamiltonians specified by magnetic-field configurations, both stationary and nonstationary, yielding optimal hybrid efficiency, that it, both time optimality and 1 0 0 % speed efficiency, over a finite time interval.}, archive = {J_PRA}, author = {Leonardo Rossetti and Carlo Cafaro and Paul M. Alsing}, doi = {10.1103/PhysRevA.111.022441}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022441}, shortjournal = {Phys. Rev. A}, title = {Deviations from geodesic evolutions and energy waste on the bloch sphere}, volume = {111}, year = {2025}, }
• (2025). Finite-size catalysis in quantum resource theories. PRA, 111(2), 022440. (www)

  @article{ , abstract = {Quantum catalysis, the ability to enable previously impossible transformations by using auxiliary systems without degrading them, has emerged as a powerful tool in various resource theories. Although catalytically enabled state transformations have been formally characterized by the monotonic behavior of entropic quantifiers (e.g., the von Neumann entropy or nonequilibrium free energy), such characterizations often rely on unphysical assumptions, namely, the ability of using catalysts of infinitely large dimension. This approach offers very limited insights into the practical significance of using catalysis for quantum information processing. Here, we address this problem across a broad class of quantum resource theories. Leveraging quantum information tools beyond the asymptotic regime, we establish sufficient conditions for the existence of catalytic transformations with finite-size catalysts. We further unveil connections between finite-size catalysis and multicopy transformations. Notably, we discover a phenomenon of catalytic resonance : by carefully tailoring the catalysts's state, one can drastically reduce the required dimension of the catalyst, thus enabling efficient catalytic transformations with minimal resources. Finally, we illustrate our findings with examples from the resource theories of entanglement and thermodynamics, as well in the context of catalytic unitary transformations.}, archive = {J_PRA}, author = {Patryk Lipka-Bartosik and Kamil Korzekwa}, doi = {10.1103/PhysRevA.111.022440}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022440}, shortjournal = {Phys. Rev. A}, title = {Finite-size catalysis in quantum resource theories}, volume = {111}, year = {2025}, }
• (2025). Characterizing the set of quantum correlations in prepare-and-measure quantum multichain-shaped networks. PRA, 111(2), 022439. (www)

  @article{ , abstract = {We introduce a hierarchy of tests satisfied by any probability distribution that represents the quantum correlations generated in prepare-and-measure (P&M) quantum multichain-shaped networks, assuming only the inner-product information of prepared states. The P&M quantum multichain-shaped networks involve multiple measurement parties, with each measurement party potentially having multiple sequential receivers. We adapt the original Navascués, Pironio, and Acín (NPA) hierarchy by incorporating a finite number of linear and positive semi-definite constraints to characterize the quantum correlations in P&M quantum multichain-shaped networks. These constraints in each hierarchy are derived from sequential measurements and the inner-product matrix of prepared states. The adapted NPA hierarchy is further applied to tackle some quantum information tasks, including sequential quantum random access codes (QRACs) and semi-device-independent randomness certification. First, we derive the optimal trade-off between the two sequential receivers in the sequential QRACs, and investigate randomness certification in its double violation region. Second, considering the presence of an eavesdropper in actual communication, we show how much local and global randomness can be certified using the optimal trade-off of sequential QRACs. We also quantify the amount of local and global randomness that can be certified from the complete set of probabilities generated by the two sequential receivers. Our conclusion is that utilizing the full set of probabilities certifies more randomness than relying solely on the optimal trade-off relationship.}, archive = {J_PRA}, author = {Yanning Jia and Fenzhuo Guo and Yukun Wang and Haifeng Dong and Fei Gao}, doi = {10.1103/PhysRevA.111.022439}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022439}, shortjournal = {Phys. Rev. A}, title = {Characterizing the set of quantum correlations in prepare-and-measure quantum multichain-shaped networks}, volume = {111}, year = {2025}, }
• (2025). Attainability of quantum state discrimination bounds with collective measurements on finite copies. PRA, 111(2), 022438. (www)

  @article{ , abstract = {One of the fundamental tenets of quantum mechanics is that nonorthogonal states cannot be distinguished perfectly. When distinguishing multiple copies of a mixed quantum state, a collective measurement, which generates entanglement between the different copies of the unknown state, can achieve a lower error probability than nonentangling measurements. The error probability that can be attained using a collective measurement on a finite number of copies of the unknown state is given by the Helstrom bound. In the limit where we can perform a collective measurement on asymptotically many copies of the quantum state, the quantum Chernoff bound gives the attainable error probability. It is natural to ask, then, what strategies can be employed to reach these two bounds—is entanglement across all available modes always necessary or can other, experimentally more simple measurements saturate these bounds? In this work we address this question. We find analytic expressions for the Helstrom bound for arbitrarily many copies of the unknown state in simple qubit examples. Using these analytic expressions, we investigate whether the quantum Chernoff bound can be saturated by repeatedly implementing the -copy Helstrom measurement. We also investigate the necessary conditions to saturate the -copy Helstrom bound. It is known that a collective measurement on all copies of the unknown state is always sufficient to saturate the -copy Helstrom bound. However, general conditions for when such a measurement is necessary to saturate the Helstrom bound remain unknown. We investigate specific measurement strategies which involve entangling operations on fewer than all copies of the unknown state. For many regimes we find that a collective measurement on all copies of the unknown state is necessary to saturate the -copy Helstrom bound.}, archive = {J_PRA}, author = {Lorcán O. Conlon and Jin Ming Koh and Biveen Shajilal and Jasminder Sidhu and Ping Koy Lam and Syed M. Assad}, doi = {10.1103/PhysRevA.111.022438}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022438}, shortjournal = {Phys. Rev. A}, title = {Attainability of quantum state discrimination bounds with collective measurements on finite copies}, volume = {111}, year = {2025}, }
• (2025). Detecting quasidegenerate ground states in topological models via the variational quantum eigensolver. PRA, 111(2), 022437. (www)

  @article{ , abstract = {We study the exact ground states of the Su-Schrieffer-Heeger open chain and of the Kitaev open chain, using the variational quantum eigensolver (VQE) algorithm. These models host symmetry-protected topological phases, characterized by edge modes with vanishing single-particle energy in the thermodynamic limit. The same fact prevents the standard VQE algorithm from converging to the correct ground state for finite chains, since it is quasidegenerate in energy with other many-body states. Notably, this quasidegeneracy cannot be removed by small perturbations, as in typical spin systems. We address this issue by imposing appropriate constraints on the VQE evolution and constructing appropriate variational circuits, to restrict the probed portion of the Hilbert space along the same evolution. These constraints stem from general properties both of the topological phases and of the studied Hamiltonians. In this way, the improved VQE algorithm achieves an accurate convergence to the exact ground states in each phase. The present approach promises large applicability, also to realistic systems with different topologies and/or not easily removable degeneracies, thanks to the very high fidelity achievable also on systems with a relatively high number of qubits.}, archive = {J_PRA}, author = {Carola Ciaramelletti and Martin Beseda and Mirko Consiglio and Luca Lepori and Tony J. G. Apollaro and Simone Paganelli}, doi = {10.1103/PhysRevA.111.022437}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022437}, shortjournal = {Phys. Rev. A}, title = {Detecting quasidegenerate ground states in topological models via the variational quantum eigensolver}, volume = {111}, year = {2025}, }
• (2025). Optimal local measurements in single-parameter quantum metrology. PRA, 111(2), 022436. (www)

  @article{ , abstract = {Quantum measurement plays a crucial role in quantum metrology. Due to the limitations of experimental capabilities, collectively measuring multiple copies of probing systems can present significant challenges. Therefore, the concept of locality in quantum measurements must be considered. In this work, we investigate the possibility of achieving the quantum Cramér-Rao bound (QCRB) through local measurements (LMs). We first demonstrate that if there exists a LM to saturate the QCRB for qubit systems, then we can construct another rank-1 local projective measurement to saturate the QCRB. In this sense, rank-1 local projective measurements are sufficient to analyze the problem of saturating the QCRB. For pure qubits, we propose two necessary and sufficient methods to determine whether and how a given parameter estimation model can achieve the QCRB through LMs. The first method, dubbed the iterative matrix partition method and based on unitary transformations that render the diagonal entries of a traceless matrix vanish, elucidates the underlying mathematical structure of LMs as well as the local measurements with classical communications (LMCC), generalizing the result by Zhou et al . [ Quantum Sci. Technol. 5 , 025005 (2020) ], which only holds for the later case. We clarify that the saturation of the QCRB through LMs for the Greenberger–Horne–Zeilinger-encoded states is actually due to the self-similar structure in this approach. The second method, dubbed the hierarchy of orthogonality conditions and based on the parametrization of rank-1 measurements for qubit systems, allows us to construct several examples of saturating QCRBs, including the three-qubit states and the -qubit states ( ). Our findings offer insights into achieving optimal performance in quantum metrology when measurement resources are limited.}, archive = {J_PRA}, author = {Jia-Xuan Liu and Jing Yang and Hai-Long Shi and Sixia Yu}, doi = {10.1103/PhysRevA.111.022436}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022436}, shortjournal = {Phys. Rev. A}, title = {Optimal local measurements in single-parameter quantum metrology}, volume = {111}, year = {2025}, }
• (2025). Quantum metrology of rotations with mixed spin states. PRA, 111(2), 022435. (www)

  @article{ , abstract = {The efficiency of a quantum metrology protocol can be significantly diminished by the interaction of the system with its environment, leading to a loss of purity and, as a result, a mixed state for the probing system. An example is the measurement of a magnetic field through the rotation of a spin that is subject to decoherence due to its coupling to a surrounding spin or bosonic bath. In this work we define mixed optimal quantum rotosensors (OQRs) as mixed spin- states that achieve maximum sensitivity to estimate infinitesimal rotations, when the rotation axis is unknown. We study two scenarios, where the probe states saturate the averaged fidelity or the averaged quantum Cramér-Rao bound, the latter giving the ultimate sensitivity. We find that mixed OQRs can achieve sensitivity equal to that of pure states and are obtained by mixing states from linear subspaces of anticoherent states. We present several examples of mixed OQRs and their associated anticoherent subspaces. We also show that OQRs maximize entanglement in a specific sense, preserving the known relation between entanglement and optimal rotation sensitivity for pure states, even in the context of mixed states. Our results highlight the interconnection between quantum metrology of rotations, anticoherence, and entanglement in mixed spin states.}, archive = {J_PRA}, author = {Eduardo Serrano-Ensástiga and Chryssomalis Chryssomalakos and John Martin}, doi = {10.1103/PhysRevA.111.022435}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022435}, shortjournal = {Phys. Rev. A}, title = {Quantum metrology of rotations with mixed spin states}, volume = {111}, year = {2025}, }
• (2025). Genuine multipartite entanglement in quantum optimization. PRA, 111(2), 022434. (www)

  @article{ , abstract = {The ability to generate bipartite entanglement in quantum computing technologies is widely regarded as pivotal. However, the role of genuinely multipartite entanglement is much less understood than bipartite entanglement, particularly in the context of solving complicated optimization problems using quantum devices. It is thus crucial from both the algorithmic and hardware standpoints to understand whether multipartite entanglement contributes to achieving a good solution. Here we tackle this challenge by analyzing genuine multipartite entanglement—quantified by the generalized geometric measure—generated in Trotterized quantum annealing and the quantum approximate optimization algorithm. Using numerical benchmarks, we analyze its occurrence in the annealing schedule in detail. We observe a multipartite-entanglement barrier, and we explore how it correlates to the algorithm's success. We also prove how multipartite entanglement provides an upper bound to the overlap of the instantaneous state with an exact solution. Vice versa, the overlaps to the initial and final product states, which can be easily measured experimentally, offer upper bounds for the multipartite entanglement during the entire schedule. Our results help to shed light on how complex quantum correlations come to bear as a resource in quantum optimization.}, archive = {J_PRA}, author = {Gopal Chandra Santra and Sudipto Singha Roy and Daniel J. Egger and Philipp Hauke}, doi = {10.1103/PhysRevA.111.022434}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022434}, shortjournal = {Phys. Rev. A}, title = {Genuine multipartite entanglement in quantum optimization}, volume = {111}, year = {2025}, }
• (2025). Architecture for fast implementation of quantum low-density parity-check codes with optimized rydberg gates. PRA, 111(2), 022433. (www)

  @article{ , abstract = {We propose an implementation of bivariate bicycle codes [S. Bravyi et al. , Nature (London) 627 , 778 (2024) ] based on long-range Rydberg gates between stationary neutral atom qubits. An optimized layout of data and ancilla qubits reduces the maximum Euclidean communication distance needed for nonlocal parity-check operators. An optimized Rydberg gate pulse design enables entangling operations with fidelity at a distance greater than . The combination of optimized layout and gate design leads to a quantum error correction cycle time of for a [[144,12,12]] code, which is nearly a factor-of-two improvement over previous designs.}, archive = {J_PRA}, author = {C. Poole and T. M. Graham and M. A. Perlin and M. Otten and M. Saffman}, doi = {10.1103/PhysRevA.111.022433}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022433}, shortjournal = {Phys. Rev. A}, title = {Architecture for fast implementation of quantum low-density parity-check codes with optimized rydberg gates}, volume = {111}, year = {2025}, }
• (2025). Bosonic quantum error correction with neutral atoms in optical dipole traps. PRA, 111(2), 022432. (www)

  @article{ , abstract = {Bosonic quantum error correction codes encode logical qubits in the Hilbert space of one or multiple harmonic oscillators. A prominent class of bosonic codes is that of Gottesman-Kitaev-Preskill (GKP) codes of which implementations have been demonstrated with trapped ions and microwave cavities. In this paper, we investigate theoretically the preparation and error correction of a GKP qubit in a vibrational mode of a neutral atom stored in an optical dipole trap. This platform has recently shown remarkable progress in simultaneously controlling the motional and electronic degrees of freedom of trapped atoms. The protocols we develop make use of motional states and, additionally, internal electronic states of the trapped atom to serve as an ancilla qubit. We compare optical tweezer arrays and optical lattices and find that the latter provide more flexible control over the confinement in the out-of-plane direction, which can be utilized to optimize the conditions for the implementation of GKP codes. Concretely, the different frequency scales that the harmonic oscillators in the axial and radial lattice directions exhibit and a small oscillator anharmonicity prove to be beneficial for robust encodings of GKP states. Finally, we underpin the experimental feasibility of the proposed protocols by numerically simulating the preparation of GKP qubits in an optical lattice with realistic parameters.}, archive = {J_PRA}, author = {Leon H. Bohnmann and David F. Locher and Johannes Zeiher and Markus Müller}, doi = {10.1103/PhysRevA.111.022432}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022432}, shortjournal = {Phys. Rev. A}, title = {Bosonic quantum error correction with neutral atoms in optical dipole traps}, volume = {111}, year = {2025}, }
• (2025). Effective quantum feature maps in quantum extreme reservoir computation from the XY model. PRA, 111(2), 022431. (www)

  @article{ , abstract = {It is well known in quantum machine learning that the form of the feature map has a significant effect on the operation and performance of those tasks being undertaken. It is essential to investigate how to generate an effective feature map within the limitations of the number of qubits and quantum gates to apply in noisy intermediate-scale quantum devices. In this paper, we explore how the qubit connectivity impacts the performance of quantum extreme reservoir computation (QERC) for image classification using the XY Hamiltonian. We find that networks of qubits with simple connectivity generate an effective feature map, whereas a network with high connectivity does not since the XY Hamiltonian on it yields a unitary map with a periodic property. The existence of the periodicity can be fully determined by the underlying connectivity and the overall symmetry of the Hamiltonian. However, the symmetries in the XY Hamiltonians can contribute to a better generalization for QERC. We further find that it is possible to design QERC to give this high generalization property while maintaining high accuracy. Our work suggests that Hamiltonian dynamics with simple connectivity or symmetry can be exploited as a computational resource in quantum machine learning.}, archive = {J_PRA}, author = {Aoi Hayashi and Akitada Sakurai and William J. Munro and Kae Nemoto}, doi = {10.1103/PhysRevA.111.022431}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022431}, shortjournal = {Phys. Rev. A}, title = {Effective quantum feature maps in quantum extreme reservoir computation from the XY model}, volume = {111}, year = {2025}, }
• (2025). Adiabatic modulation of driving protocols in periodically driven quantum systems. PRA, 111(2), 022430. (www)

  @article{ , abstract = {We consider a periodically driven system where the high-frequency driving protocol consists of a sequence of potentials switched on and off at different instants within a period. We explore the possibility of introducing an adiabatic modulation of the driving protocol by considering a slow evolution of the instants when the sequence of potentials is switched on and off. We examine how this influences the long-term dynamics of periodically driven quantum systems. By assuming that the slow and fast timescales in the problem can be decoupled, we derive the stroboscopic (effective) Hamiltonian for a four-step driving sequence up to the first order in perturbation theory. We then apply this approach to a spin- system, where the adiabatic modulation of the driving protocol is chosen to produce an evolving emergent magnetic field that interacts with the spin. We study the emergence of diabolical points and diabolical loci in the parameter space of the effective Hamiltonian. Further, we study the topological properties of the maps of the adiabatic paths in the parameter space to the eigenspace of the effective Hamiltonian. In effect, we obtain a technique for tuning the topological properties of the eigenstates by selecting different adiabatic evolutions of the driving protocol, characterized by distinct paths in parameter space. This technique can be applied to any periodic driving protocol to achieve desirable topological effects.}, archive = {J_PRA}, author = {Ashwin Murali and Tapomoy Guha Sarkar and Jayendra N. Bandyopadhyay}, doi = {10.1103/PhysRevA.111.022430}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022430}, shortjournal = {Phys. Rev. A}, title = {Adiabatic modulation of driving protocols in periodically driven quantum systems}, volume = {111}, year = {2025}, }
• (2025). Expressivity of deterministic quantum computation with one qubit. PRA, 111(2), 022429. (www)

  @article{ , abstract = {Deterministic quantum computation with one qubit (DQC1) is of significant theoretical and practical interest due to its computational advantages in certain problems, despite its subuniversality with limited quantum resources. In this work, we introduce parametrized DQC1 as a quantum machine learning model. We demonstrate that the gradient of the measurement outcome of a DQC1 circuit with respect to its gate parameters can be computed directly using the DQC1 protocol. This allows for gradient-based optimization of DQC1 circuits, positioning DQC1 as a quantum protocol for both training and inference. We then analyze the expressivity of the parametrized DQC1 circuits characterizing the set of learnable functions, and show that DQC1-based machine learning (ML) is as powerful as quantum neural networks based on universal computation. Our findings highlight the potential of DQC1 as a practical and versatile platform for ML, capable of rivaling more complex quantum computing models while utilizing simpler quantum resources.}, archive = {J_PRA}, author = {Yujin Kim and Daniel K. Park}, doi = {10.1103/PhysRevA.111.022429}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022429}, shortjournal = {Phys. Rev. A}, title = {Expressivity of deterministic quantum computation with one qubit}, volume = {111}, year = {2025}, }
• (2025). Practicality of a quantum adiabatic algorithm for chemistry applications. PRA, 111(2), 022428. (www)

  @article{ , abstract = {Despite its simplicity and strong theoretical guarantees, adiabatic state preparation has received considerably less interest than variational approaches for the preparation of low-energy electronic structure states. Two major reasons for this are the large number of gates required for Trotterizing time-dependent electronic structure Hamiltonians, as well as discretization errors heating the state. We show that a recently proposed randomized algorithm [E. Granet and H. Dreyer, npj Quantum Inf. 10 , 82 (2024) ], which implements exact adiabatic evolution without heating and with far fewer gates than Trotterization, can overcome this problem. We develop three methods for measuring the energy of the prepared state in an efficient and noise-resilient manner, yielding chemically accurate results on a four-qubit molecule in the presence of realistic gate noise, without the need for error mitigation. These findings suggest that adiabatic approaches to state preparation could play a key role in quantum chemistry simulations both in the era of noisy as well as error-corrected quantum computers.}, archive = {J_PRA}, author = {Etienne Granet and Khaldoon Ghanem and Henrik Dreyer}, doi = {10.1103/PhysRevA.111.022428}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022428}, shortjournal = {Phys. Rev. A}, title = {Practicality of a quantum adiabatic algorithm for chemistry applications}, volume = {111}, year = {2025}, }
• (2025). Entanglement and operator correlation signatures of many-body quantum zeno phases in inefficiently monitored noisy systems. PRA, 111(2), 022427. (www)

  @article{ , abstract = {The interplay between information-scrambling Hamiltonians and local continuous measurements hosts platforms for exotic measurement-induced phase transition in out-of-equilibrium steady states. Here, we consider such transitions under the addition of local random white noise and measurement inefficiency in an XX spin chain. We identify a nonmonotonic dependence on the local noise strength in both the averaged entanglement and operator correlations, specifically the subsystem parity variance. While the nonmonotonicity persists at any finite efficiency for the operator correlations, it disappears at finite inefficiency for the entanglement. The analysis of scaling with the system size in a finite-length chain indicates that, at finite efficiency, this effect leads to distinct measurement-induced phase transitions for operator correlations and entanglement. Our result hints at a difference between area-law entanglement scaling and Zeno-localized phases for inefficient monitoring.}, archive = {J_PRA}, author = {Chun Y. Leung and Alessandro Romito}, doi = {10.1103/PhysRevA.111.022427}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022427}, shortjournal = {Phys. Rev. A}, title = {Entanglement and operator correlation signatures of many-body quantum zeno phases in inefficiently monitored noisy systems}, volume = {111}, year = {2025}, }
• (2025). Avoiding barren plateaus with entanglement. PRA, 111(2), 022426. (www)

  @article{ , abstract = {In the search for quantum advantage with near-term quantum devices, navigating the optimization landscape is significantly hampered by the barren plateaus phenomenon. This study presents a strategy to overcome this obstacle without changing the quantum circuit architecture. We propose incorporating auxiliary control qubits to shift the circuit from a unitary 2-design to a unitary 1-design, mitigating the prevalence of barren plateaus. We then remove these auxiliary qubits to return to the original circuit structure while preserving the unitary 1-design properties. Our numerical simulation suggests that the proposed structure effectively mitigates the barren plateaus phenomenon. A significant finding is that the gradient of θ 1 , 1 , the first parameter in the quantum circuit, displays a broader distribution as the number of qubits and layers increases. This suggests a higher probability of obtaining effective gradients. This stability is critical for the efficient training of quantum circuits, especially for larger and more complex systems. The results of this study represent a significant advance in the optimization of quantum circuits and offer a promising avenue for the scalable and practical implementation of quantum computing technologies. This approach opens up new opportunities in quantum learning and other applications that require robust quantum computing power.}, archive = {J_PRA}, author = {Yuhan Yao and Yoshihiko Hasegawa}, doi = {10.1103/PhysRevA.111.022426}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022426}, shortjournal = {Phys. Rev. A}, title = {Avoiding barren plateaus with entanglement}, volume = {111}, year = {2025}, }
• (2025). Fractals and spontaneous symmetry breaking with type-B goldstone modes: A perspective from entanglement. PRA, 111(2), 022425. (www)

  @article{ , abstract = {The one-dimensional spin- 𝑠 ⁢ S U ⁡ ( 2 ) ferromagnetic Heisenberg model, as a paradigmatic example for spontaneous symmetry breaking (SSB) with type-B Goldstone modes (GMs), is expected to exhibit an abstract fractal underlying the ground-state subspace. This intrinsic abstract fractal is here revealed from a systematic investigation into the entanglement entropy for a linear combination of factorized (unentangled) ground states on a fractal decomposable into a set of the Cantor sets. The entanglement entropy scales logarithmically with the block size, with the prefactor being half the fractal dimension of a fractal, as first noted by Castro-Alvaredo and Doyon for the spin- 1 / 2 ferromagnetic Heisenberg model [ Phys. Rev. Lett. 108 (2012) 120401], as long as the norm for the linear combination scales as the square root of the number of the self-similar building blocks kept at each step 𝑘 for a fractal, under an assumption that the maximum absolute value of the coefficients in the linear combination is chosen to be around one, and the coefficients in the linear combination are almost constants within the building blocks. Actually, the set of the fractal dimensions for all the Cantor sets forms a dense subset in the interval [0,1]. As a consequence, the ground-state subspace is separated into a disjoint union of countably infinitely many regions, each of which is labeled by a decomposable fractal. Hence, the interpretation of the prefactor as half the fractal dimension is valid for any support beyond a fractal, which in turn leads to the identification of the fractal dimension with the number of type-B GMs for the orthonormal basis states. Our argument may be extended to any quantum many-body systems undergoing SSB with type-B GMs.}, archive = {J_PRA}, author = {Huan-Qiang Zhou and Qian-Qian Shi and John O. Fjærestad and Ian P. McCulloch}, doi = {10.1103/PhysRevA.111.022425}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022425}, shortjournal = {Phys. Rev. A}, title = {Fractals and spontaneous symmetry breaking with type-B goldstone modes: A perspective from entanglement}, volume = {111}, year = {2025}, }
• (2025). Retrieving maximum information of symmetric states from their corrupted copies. PRA, 111(2), 022424. (www)

  @article{ , abstract = {Using quantum measurements to extract information from states is a matter of routine in quantum science and technologies. A recent work [ Phys. Rev. Lett. 133 , 040202 (2024) ] reported the finding that the symmetric structures of a state can be harnessed to dramatically reduce the sample complexity in extracting information from the state. However, due to the presence of noise, the actual state at hand is often corrupted, making its symmetric structures distorted before the execution of quantum measurements. Here, using the methodology of quantum metrology, we identify the optimal measurement that can retrieve maximum information of a symmetric state from its corrupted copies. We show that this measurement can be found by solving a semidefinite program in generic cases and can be explicitly determined for a large class of noise models covariant under the symmetry group in question. The results of this study nicely complement the recent work by providing a method to optimally utilize the distorted symmetric structures of corrupted states for information retrieval.}, archive = {J_PRA}, author = {Zhao-Yi Zhou and Da-Jian Zhang}, doi = {10.1103/PhysRevA.111.022424}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022424}, shortjournal = {Phys. Rev. A}, title = {Retrieving maximum information of symmetric states from their corrupted copies}, volume = {111}, year = {2025}, }
• (2025). High-dimensional subspace expansion using classical shadows. PRA, 111(2), 022423. (www)

  @article{ , abstract = {We introduce a postprocessing technique for classical shadow measurement data that enhances the precision of ground state estimation through high-dimensional subspace expansion; the dimensionality is only limited by the amount of classical postprocessing resources rather than by quantum resources. Crucial steps of our approach are the efficient identification of useful observables from shadow data, followed by our regularized subspace expansion that is designed to be numerically stable even when using noisy data. We analytically investigate noise propagation within our method, and upper bound the statistical fluctuations due to the limited number of snapshots in classical shadows. In numerical simulations, our method can achieve a reduction in the energy estimation errors in many cases, sometimes by more than an order of magnitude. We also demonstrate that our performance improvements are robust against both coherent errors (bad initial state) and gate noise in the state-preparation circuits. Furthermore, performance is guaranteed to be at least as good—and in many cases better—than direct energy estimation without using additional quantum resources, and the approach is thus a very natural alternative for estimating ground state energies directly from classical shadow data.}, archive = {J_PRA}, author = {Gregory Boyd and Bálint Koczor and Zhenyu Cai}, doi = {10.1103/PhysRevA.111.022423}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022423}, shortjournal = {Phys. Rev. A}, title = {High-dimensional subspace expansion using classical shadows}, volume = {111}, year = {2025}, }
• (2025). Dynamical resource theory of incompatibility preservability. PRA, 111(2), 022422. (www)

  @article{ , abstract = {The uncertainty principle is one of quantum theory's most foundational features. It underpins a quantum phenomenon called measurement incompatibility—two physical observables of a single quantum system may not always be measured simultaneously. Apart from being fundamentally important, measurement incompatibility is also a powerful resource in the broad quantum science and technologies, with wide applications to cryptography, communication, random number generation, and device-independent tasks. Since every physical system is unavoidably subject to noise, an important, yet still open, question is how to characterize the ability of noisy quantum dynamics to preserve measurement incompatibility. This work fills this gap by providing a resource theory of this ability, termed incompatibility preservability. We quantify incompatibility preservability by a robustness measure. Then, we introduce an operational task, entanglement-assisted filter game, to completely characterize both the robustness measure and the conversion of incompatibility preservability. Our results provide a general framework to describe how noisy dynamics affect the uncertainty principle's signature.}, archive = {J_PRA}, author = {Chung-Yun Hsieh and Benjamin Stratton and Chao-Hsien Wu and Huan-Yu Ku}, doi = {10.1103/PhysRevA.111.022422}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022422}, shortjournal = {Phys. Rev. A}, title = {Dynamical resource theory of incompatibility preservability}, volume = {111}, year = {2025}, }
• (2025). Noise-resilient and resource-efficient hybrid algorithm for robust quantum gap estimation. PRA, 111(2), 022421. (www)

  @article{ , abstract = {We present a hybrid quantum algorithm for estimating gaps in many-body energy spectra, supported by an analytic proof of its inherent resilience to state preparation and measurement errors, as well as midcircuit multiqubit depolarizing noise. Our analysis extends to a broader class of Markovian noise, employing error mitigation strategies that optimize the utilization of quantum resources. By integrating trial-state optimization and classical signal processing into the algorithm, we amplify the signal peak corresponding to the exact target gap beyond the error threshold, thereby significantly reducing gap estimate errors. The algorithm's robustness is demonstrated through noisy simulations on the Qiskit Aer simulator and demonstrations on IBM Quantum processors. These results underscore the potential to enable accurate quantum simulations on near-term noisy quantum devices without resource-intensive error correction.}, archive = {J_PRA}, author = {Woo-Ram Lee and Nathan M. Myers and V. W. Scarola}, doi = {10.1103/PhysRevA.111.022421}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022421}, shortjournal = {Phys. Rev. A}, title = {Noise-resilient and resource-efficient hybrid algorithm for robust quantum gap estimation}, volume = {111}, year = {2025}, }
• (2025). Parity-controlled gate in a two-dimensional neutral-atom array. PRA, 111(2), 022420. (www)

  @article{ , abstract = {We propose a parity-controlled gate within a two-dimensional Rydberg atom array, enabling efficient discrimination between even and odd parities of virtually excited control atoms by monitoring the dynamic evolution of an auxiliary atom. This is achieved through the use of spin-exchange dipolar interactions between Rydberg states and coupling between ground states and Rydberg states. For practical applications, we explore its implementation in three-qubit repetition codes and rotated surface codes featuring stabilizers, enabling single-shot readout of stabilizer measurements. Comprehensive numerical simulations are conducted to assess the feasibility of the proposed approach, taking into account potential experimental imperfections such as unwanted interactions between Rydberg states, atomic position fluctuations, laser phase noise, and Rabi amplitude noise. Our study highlights the inherent advantages of the physical mechanisms underlying parity measurement, demonstrating its reliability and practicality. These findings establish our protocol as a highly promising solution for quantum error detection and computation within Rydberg atom systems, with significant potential for future experimental realizations.}, archive = {J_PRA}, author = {F. Q. Guo and Shi-Lei Su and Weibin Li and X. Q. Shao}, doi = {10.1103/PhysRevA.111.022420}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022420}, shortjournal = {Phys. Rev. A}, title = {Parity-controlled gate in a two-dimensional neutral-atom array}, volume = {111}, year = {2025}, }
• (2025). Strategies for simulating the time evolution of hamiltonian lattice field theories. PRA, 111(2), 022419. (www)

  @article{ , abstract = {Simulating the time evolution of quantum field theories given some Hamiltonian requires developing algorithms for implementing the unitary operator . A variety of techniques exist that accomplish this task, with the most common technique used so far being Trotterization, which is a special case of the application of a product formula. However, other techniques exist that promise better asymptotic scaling in certain parameters of the theory being simulated, the most efficient of which are based on the concept of block encoding. In this work we study the performance of such algorithms in simulating lattice field theories. We derive and compare the asymptotic gate complexities of several commonly used simulation techniques in application to Hamiltonian lattice field theories. Using the scalar theory as a test, we also perform numerical studies and compare the gate costs required by product formulas and signal-processing-based techniques to simulate time evolution. For the latter, we use the linear combination of unitaries (LCU) construction augmented with the quantum Fourier transform circuit to switch between the field and momentum eigenbases, which leads to immediate order-of-magnitude improvement in the cost of preparing the block encoding. This paper also includes a pedagogical review of the techniques used, in particular product formulas, LCU, qubitization, quantum signal processing, as well as the technique for simulating geometrically-local Hamiltonians developed by Haah, Hastings, Kothari, and Low.}, archive = {J_PRA}, author = {Siddharth Hariprakash and Neel S. Modi and Michael Kreshchuk and Christopher F. Kane and Christian W. Bauer}, doi = {10.1103/PhysRevA.111.022419}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022419}, shortjournal = {Phys. Rev. A}, title = {Strategies for simulating the time evolution of hamiltonian lattice field theories}, volume = {111}, year = {2025}, }
• (2025). Symmetry-informed transferability of optimal parameters in the quantum approximate optimization algorithm. PRA, 111(2), 022418. (www)

  @article{ , abstract = {One of the main limitations of variational quantum algorithms is the classical optimization of the highly dimensional nonconvex variational parameter landscape. To simplify this optimization, we can reduce the search space using problem symmetries and typical optimal parameters as initial points if they concentrate. In this article, we consider typical values of optimal parameters of the quantum approximate optimization algorithm for the MAXCUT problem with -regular tree subgraphs and reuse them in different graph instances. We prove symmetries in the optimization landscape of several kinds of weighted and unweighted graphs, which explains the existence of multiple sets of optimal parameters. However, we observe that not all optimal sets can be successfully transferred between problem instances. We find specific transferable domains in the search space and show how to translate an arbitrary set of optimal parameters into the adequate domain using the studied symmetries. Finally, we extend these results to general classical optimization problems described by Ising Hamiltonians, the Hamiltonian variational ansatz for relevant physical models, and the recursive and multiangle quantum approximate optimization algorithms.}, archive = {J_PRA}, author = {Isak Lyngfelt and Laura García-Álvarez}, doi = {10.1103/PhysRevA.111.022418}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022418}, shortjournal = {Phys. Rev. A}, title = {Symmetry-informed transferability of optimal parameters in the quantum approximate optimization algorithm}, volume = {111}, year = {2025}, }
• (2025). Lower bounds for the trotter error. PRA, 111(2), 022417. (www)

  @article{ , abstract = {In analog and digital simulations of practically relevant quantum systems, the target dynamics can only be implemented approximately. The Trotter product formula is the most common approximation scheme as it is a generic method which allows tuning accuracy. The Trotter simulation precision will always be inexact for noncommuting operators, but it is currently unknown what the minimum possible error is. This is an important quantity because upper bounds for the Trotter error are known to often be vast overestimates. Here we present explicit lower bounds on the error, in norm and on states, allowing to derive minimum resource requirements. Numerical comparison with the true error shows that our bounds offer accurate and tight estimates.}, archive = {J_PRA}, author = {Alexander Hahn and Paul Hartung and Daniel Burgarth and Paolo Facchi and Kazuya Yuasa}, doi = {10.1103/PhysRevA.111.022417}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022417}, shortjournal = {Phys. Rev. A}, title = {Lower bounds for the trotter error}, volume = {111}, year = {2025}, }
• (2025). Minimal nonlocality in multipartite quantum systems. PRA, 111(2), 022416. (www)

  @article{ , abstract = {Quantum nonlocality, rooted in the quantum state discrimination task, contributes to the development of the theory of local distinguishability of quantum states. Recently, Zhu et al. [ Phys. A (Amsterdam, Neth.) 624 , 128956 (2023) ] found that a nonlocal set of orthogonal product states (OPSs) can be perfectly identified by local operations and classical communication after removing a specific quantum state in a bipartite quantum system. They called this phenomenon minimal nonlocality. It is obvious that minimal nonlocality effectively reflects the lower boundary of the elements contained in a nonlocal set of OPSs. In this paper, we generalize the methods of constructing nonlocal sets with minimal nonlocality from bipartite systems to multipartite systems and from orthogonal product states to entangled states. First, we give a method to construct a set of OPSs with minimal nonlocality in the quantum system, and then we extend it to the quantum system for and . In addition, we give a method to construct a nonlocal set of orthogonal states with entanglement relations in the quantum system, and we prove that this set has minimal nonlocality, which can also be extended to the quantum system.}, archive = {J_PRA}, author = {Guang-Bao Xu and Yong-Qi Zhang and Dong-Huan Jiang}, doi = {10.1103/PhysRevA.111.022416}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022416}, shortjournal = {Phys. Rev. A}, title = {Minimal nonlocality in multipartite quantum systems}, volume = {111}, year = {2025}, }
• (2025). Class of codes correcting absorptions and emissions. PRA, 111(2), 022415. (www)

  @article{ , abstract = {We construct a general family of quantum codes that protect against all emission, absorption, dephasing, and raising or lowering errors up to an arbitrary fixed order. Such codes are known in the literature as absorption-emission (AE) codes. We derive simplified error correction conditions for a general AE code and show that any permutation-invariant code that corrects or fewer errors can be mapped to an AE code that corrects up to order- transitions. Carefully tuning the parameters of permutationally invariant codes, we construct several examples of efficient AE codes, hosted in systems with low total angular momentum. Our results also imply that spin codes can be mapped to AE codes, enabling us to characterize logical operators for certain subclasses of such codes.}, archive = {J_PRA}, author = {Arda Aydin and Alexander Barg}, doi = {10.1103/PhysRevA.111.022415}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022415}, shortjournal = {Phys. Rev. A}, title = {Class of codes correcting absorptions and emissions}, volume = {111}, year = {2025}, }
• (2025). Bounded light cone and robust topological order out of equilibrium. PRA, 111(2), 022414. (www)

  @article{ , abstract = {The ground-state degeneracy of topologically ordered gapped Hamiltonians is the bedrock for self-correcting quantum memories, which are unfortunately not stable away from equilibrium even at zero temperature. This plague precludes practical robust self-correction since stability at zero temperature is a prerequisite for finite-temperature robustness. In this work, we show that the emergence of a bounded light cone renders the unitary time evolution a quasiadiabatic continuation that preserves topological order, with the initial ground space retaining its macroscopic distance at all times as a quantum code. We also show how bounded light cones can emerge through suitable perturbations in Kitaev's toric code and honeycomb model. Our results suggest that topological orders and self-correcting quantum memories can be dynamically robust at zero temperature.}, archive = {J_PRA}, author = {Yu Zeng and Alioscia Hamma and Yu-Ran Zhang and Jun-Peng Cao and Heng Fan and Wu-Ming Liu}, doi = {10.1103/PhysRevA.111.022414}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022414}, shortjournal = {Phys. Rev. A}, title = {Bounded light cone and robust topological order out of equilibrium}, volume = {111}, year = {2025}, }
• (2025). Noisy certification of continuous-variable graph states. PRA, 111(2), 022413. (www)

  @article{ , abstract = {Continuous variables (CV) offer a promising platform for the development of various applications, such as quantum communication, computing, and sensing, and CV graph states represent a family of powerful entangled resource states for all these areas. In many of these protocols, a crucial aspect is the certification of the quantum state subsequently used. While numerous protocols exist, most rely on assumptions unrealistic for physical continuous-variable states, such as infinite precision in quadrature measurement or the use of states requiring infinite squeezing. In this work, we adapt existing protocols to deal with these unavoidable considerations and use them to certify their application for different quantum information tasks. More specifically, we show how CV graph states can be efficiently verified and certified even in a noisy and imperfect setting. We then discuss how our findings impact the usability of states obtained after the protocol for different applications, including quantum teleportation, computing, and sensing.}, archive = {J_PRA}, author = {Éloi Descamps and Damian Markham}, doi = {10.1103/PhysRevA.111.022413}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022413}, shortjournal = {Phys. Rev. A}, title = {Noisy certification of continuous-variable graph states}, volume = {111}, year = {2025}, }
• (2025). Entanglement estimation of werner states with a quantum extreme learning machine. PRA, 111(2), 022412. (www)

  @article{ , abstract = {Quantum extreme learning machines (QELMs) have emerged as a potent tool for various quantum information processing tasks. We present a QELM protocol for estimating the amount of entanglement in Werner states. The protocol requires the generation of a sequence of random Werner states, which are then combined with a reservoir state and evolved using an Ising Hamiltonian. A set of observables based on the Bloch basis is constructed and employed to train the system to recognize unseen features. To assess the protocol's robustness, noise is introduced into the input states, and the system's performance under these noisy conditions is analyzed. Additionally, the influence of the magnetic-field parameter within the Ising Hamiltonian on the estimation accuracy is investigated.}, archive = {J_PRA}, author = {Hajar Assil and Abderrahim El Allati and Gian Luca Giorgi}, doi = {10.1103/PhysRevA.111.022412}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022412}, shortjournal = {Phys. Rev. A}, title = {Entanglement estimation of werner states with a quantum extreme learning machine}, volume = {111}, year = {2025}, }
• (2025). Benchmarking adiabatic transformation by alternating unitaries. PRA, 111(2), 022411. (www)

  @article{ , abstract = {Adiabatic transformation can be approximated as alternating unitary operators of a Hamiltonian and its parameter derivative as proposed in a gate-based approach to counterdiabatic driving [D. van Vreumingen, Phys. Rev. A 110 , 052419 (2024) ]. In this paper, we conduct numerical benchmarking of this alternating unitary method in a finite parameter range against adiabatic driving in a nonadiabatic timescale. We find that the alternating unitary method results in a broader distribution on energy eigenstates than that obtained by adiabatic driving, but it has the ability to sample low-energy eigenstates when an energy gap of a given Hamiltonian is small. It indicates that the alternating unitary method may be able to find good approximate solutions in quantum annealing applied to hard instances.}, archive = {J_PRA}, author = {Takuya Hatomura}, doi = {10.1103/PhysRevA.111.022411}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022411}, shortjournal = {Phys. Rev. A}, title = {Benchmarking adiabatic transformation by alternating unitaries}, volume = {111}, year = {2025}, }
• (2025). Shortcuts to adiabatic state transfer in time-modulated two-level non-hermitian systems. PRA, 111(2), 022410. (www)

  @article{ , abstract = {Nontrivial spectral properties of non-Hermitian systems can give rise to intriguing effects that lack counterparts in Hermitian systems. For instance, when dynamically varying system parameters along a path enclosing an exceptional point (EP), chiral mode conversion occurs. A recent study [ Phys. Rev. Lett. 133 , 113802 (2024) ] demonstrates the achievability of pure adiabatic state transfer by specifically selecting a trajectory in the system parameter space where the corresponding evolution operator exhibits a real spectrum while winding around an EP. However, the intended adiabatic state transfer becomes fragile when taking into account the effect of the nonadiabatic transition. In this work, we propose a scheme for achieving robust and rapid adiabatic state transfer in time-modulated two-level non-Hermitian systems by appropriately modulating the system Hamiltonian and time-evolution trajectory. Numerical simulations confirm that a complete adiabatic transfer can always be achieved even under nonadiabatic conditions after one period for different initialized adiabatic states, and the scheme remains insensitive to moderate fluctuations in control parameters. Therefore, this scheme offers alternative approaches for quantum-state engineering in non-Hermitian systems.}, archive = {J_PRA}, author = {Qi-Cheng Wu and Jun-Long Zhao and Yan-Hui Zhou and Biao-Liang Ye and Yu-Liang Fang and Zheng-Wei Zhou and Chui-Ping Yang}, doi = {10.1103/PhysRevA.111.022410}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022410}, shortjournal = {Phys. Rev. A}, title = {Shortcuts to adiabatic state transfer in time-modulated two-level non-hermitian systems}, volume = {111}, year = {2025}, }
• (2025). Bargmann invariants for quantum imaginarity. PRA, 111(2), 022409. (www)

  @article{ , abstract = {The imaginary in quantum theory plays a crucial role in describing quantum coherence and is widely applied in quantum information tasks such as state discrimination, pseudorandomness generation, and quantum metrology. A recent paper by Fernandes et al. [ Phys. Rev. Lett. 133 , 190201 (2024) ] showed how to use the Bargmann invariant to witness the imaginarity of a set of quantum states. In this work, we delve into the structure of Bargmann invariants and their quantum realization in qubit systems. First, we present a characterization of special sets of Bargmann invariants (also studied by Fernandes et al. for a set of four states) for a general set of n quantum states. Then, we study the properties of the relevant Bargmann invariant set B n and its quantum realization in qubit systems. Our results provide new insights into the structure of Bargmann invariants, contributing to the advancement of quantum information techniques, particularly within qubit systems.}, archive = {J_PRA}, author = {Mao-Sheng Li and Yi-Xi Tan}, doi = {10.1103/PhysRevA.111.022409}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022409}, shortjournal = {Phys. Rev. A}, title = {Bargmann invariants for quantum imaginarity}, volume = {111}, year = {2025}, }
• (2025). Optimal conversion of kochen-specker sets into bipartite perfect quantum strategies. PRA, 111(2), 022408. (www)

  @article{ , abstract = {Bipartite perfect quantum strategies (BPQSs) allow two players isolated from each other to win every trial of a nonlocal game. BPQSs have crucial roles in recent developments in quantum information and quantum computation. However, only few BPQSs with a small number of inputs are known and only one of them has been experimentally tested. It has recently been shown that every BPQS has an associated Kochen-Specker (KS) set. Here, we first prove that any BPQS of minimum input cardinality that can be obtained from a generalized KS set can also be obtained from a KS set of pure states. We address the problem of finding BPQSs of small input cardinality starting from KS sets. We introduce an algorithm that identifies the BPQS with the minimum number of settings for any given KS set. We apply it to many well-known KS sets of small cardinality in dimensions 3, 4, 5, 6, 7, and 8. In each dimension, the algorithm either recovers the best BPQS known or finds one with fewer inputs.}, archive = {J_PRA}, author = {Stefan Trandafir and Adán Cabello}, doi = {10.1103/PhysRevA.111.022408}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022408}, shortjournal = {Phys. Rev. A}, title = {Optimal conversion of kochen-specker sets into bipartite perfect quantum strategies}, volume = {111}, year = {2025}, }
• (2025). Multipartite entangling power by von neumann entropy. PRA, 111(2), 022407. (www)

  @article{ , abstract = {Quantifying the entanglement generation of a multipartite unitary operation is a key problem in quantum information processing. We introduce the definition of multipartite entangling, assisted entangling, and disentangling power, which is a natural generalization of the bipartite ones. We show that they are assumed at a specified quantum state. We analytically derive the entangling power of Schmidt-rank-two multiqubit unitary operations by the minimal convex sum of modulo-one complex numbers. Besides we show the necessary and sufficient condition that the assisted entangling power of Schmidt-rank-two unitary operations reaches the maximum. We investigate the widely used multiqubit gates, for example, the entangling power of CCZS gate, the entangling and assisted entangling power of the n -qubit Toffoli gate. The entangling power of the three-qubit Fredkin gate is two ebits, and that of the four-qubit Fredkin gate is in two to log 2 5 ebits. Further we investigate the entangling power during the noisy implementation of operations.}, archive = {J_PRA}, author = {Xinyu Qiu and Zhiwei Song and Lin Chen}, doi = {10.1103/PhysRevA.111.022407}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022407}, shortjournal = {Phys. Rev. A}, title = {Multipartite entangling power by von neumann entropy}, volume = {111}, year = {2025}, }
• (2025). Channel-based framework for phase estimation of multiple eigenvalues. PRA, 111(2), 022406. (www)

  @article{ , abstract = {Quantum phase estimation (QPE) is a crucial subroutine in many quantum algorithms. It is used to estimate the eigenvalues of a unitary operator acting on a target quantum system. Conventional QPE is often expensive to implement because it requires a large number of ancilla qubits and the ability to perform quantum Fourier transform. Recent developments in iterative QPE reduce the implementation cost by repetitive uses of a single ancilla and classical postprocessing. However, both conventional and iterative schemes often require preparation of the target system in an eigenstate of the unitary operator, while it remains ambiguous to achieve QPE of multiple eigenvalues with no need of initial-state preparation. Here we clarify this issue by developing a theoretical framework based on sequential quantum channels for iterative QPE. We find that QPE of multiple eigenvalues can be efficiently realized for arbitrary initial target system state by actively utilizing the measurement backaction of iterative QPE on the target system with a long coherence time. Specifically, we investigate two iterative QPE schemes based on sequential Ramsey interferometry measurements (RIMs) of an ancilla qubit: (a) the repetitive scheme, which conducts repetitive RIMs to achieve the standard quantum limit in estimating the eigenvalues; (b) the adaptive scheme, which adjusts the parameters of each RIM based on prior measurement outcomes to attain the Heisenberg limit. In both schemes, sequential ancilla measurements generate sequential quantum channels on the target system, gradually steering it to the eigenstates of the estimated unitary operator, while the measurement statistics of the ancilla can reveal the embedded information about its eigenvalues with proper postprocessing. We demonstrate the analysis by simulating a central spin model and evaluate the performance and noise resilience of both schemes.}, archive = {J_PRA}, author = {Yuan-De Jin and Shi-Yu Zhang and Wen-Long Ma}, doi = {10.1103/PhysRevA.111.022406}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022406}, shortjournal = {Phys. Rev. A}, title = {Channel-based framework for phase estimation of multiple eigenvalues}, volume = {111}, year = {2025}, }
• (2025). Quantifying imaginarity in terms of pure-state imaginarity. PRA, 111(2), 022405. (www)

  @article{ , abstract = {Complex numbers are widely used in quantum physics and are indispensable components for describing quantum systems and their dynamical behavior. The resource theory of imaginarity has been built recently, enabling a systematic research of complex numbers in quantum information theory. In this work, we develop two theoretical methods for quantifying imaginarity, motivated by recent progress within resource theories of entanglement and coherence. We provide quantifiers of imaginarity by the convex roof construction and quantifiers of the imaginarity by the least imaginarity of the input pure states under real operations. We also apply these tools to study the state conversion problem in the resource theory of imaginarity.}, archive = {J_PRA}, author = {Shuanping Du and Zhaofang Bai}, doi = {10.1103/PhysRevA.111.022405}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022405}, shortjournal = {Phys. Rev. A}, title = {Quantifying imaginarity in terms of pure-state imaginarity}, volume = {111}, year = {2025}, }
• (2025). Quantum state discrimination via generalized bounds on löwner partial order sets. PRA, 111(2), 022404. (www)

  @article{ , abstract = {This paper introduces a novel class of upper and lower bounds for a set of Hermitian operators with elements. These bounds, derived from the Löwner partial ordering, represent the maximal lower and minimal upper bounds for a pair of Hermitian operators. Additionally, the paper redefines the minimum Bayes cost and minimum error quantum state discrimination problems by identifying the maximal lower and minimal upper bounds for quantum density operators. These proposed bounds are then utilized to establish a tight bound for the error probability of quantum state discrimination problem. Furthermore, the paper provides a geometric interpretation of these bounds, offering valuable insights into the quantum state discrimination problem and aiding in the understanding of the optimal measurement strategy, especially for qubits.}, archive = {J_PRA}, author = {Amir Mohammad Yaghoobianzadeh and Jawad A. Salehi}, doi = {10.1103/PhysRevA.111.022404}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022404}, shortjournal = {Phys. Rev. A}, title = {Quantum state discrimination via generalized bounds on löwner partial order sets}, volume = {111}, year = {2025}, }
• (2025). Topological quantum state transfer via resonant adiabatic passage. PRA, 111(2), 022403. (www)

  @article{ , abstract = {We present a fast and robust protocol for realizing topological quantum state transfer in a dimeric Su-Schrieffer-Heeger spin chain. By giving a more general condition sufficient for the resonant adiabatic evolution, we develop a method of constructing time-driving functions for topological quantum state transfer, which makes it possible to shorten the needed operation time via resonant adiabatic passage between topologically protected edge states. Compared with previous protocols, our protocol can shorten the operation time appreciably while maintaining robustness against disorder in the spin chain, thereby avoiding decoherence resulting from long-running evolution and increasing transmission efficiency. Numerical simulations demonstrate that our protocol possesses excellent robustness and scalability. Our results provide a promising route for the realization of fast and robust quantum state transfer in spin chain systems.}, archive = {J_PRA}, author = {K. Z. Li and J. Z. Tian and L. T. Xiao}, doi = {10.1103/PhysRevA.111.022403}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022403}, shortjournal = {Phys. Rev. A}, title = {Topological quantum state transfer via resonant adiabatic passage}, volume = {111}, year = {2025}, }
• (2025). Continuous-variable quantum teleportation using a photon-subtracted and photon-added two-mode squeezed coherent state. PRA, 111(2), 022402. (www)

  @article{ , abstract = {We consider non-Gaussian states generated by photon subtraction (PS) and photon addition (PA) on two-mode squeezed coherent (TMSC) states as resource states for continuous variable quantum teleportation. To this end, we derive the Wigner characteristic function for the family of photon-subtracted and photon-added TMSC states, which is then utilized to calculate the fidelity of teleporting a single-mode coherent state and a squeezed vacuum state. The analysis shows that, while symmetric PS enhances the fidelity of teleportation in an extensive range of squeezing, asymmetric PS enhances the performance marginally and only in the low squeezing regime. The addition operations, however, are less useful, symmetric three-PA leads to a marginal improvement while the other addition operations are useless. We consider the actual experimental setup for PS and PA operations and compute their success probabilities, which should be kept in mind while advocating the use of these operations. We could compute the fidelity of teleportation for a broad range of states because we analytically derive the Wigner characteristic function for these family of states, which we think will be useful for various other applications of these families of states.}, archive = {J_PRA}, author = {Shikhar Arora and Chandan Kumar and Arvind}, doi = {10.1103/PhysRevA.111.022402}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022402}, shortjournal = {Phys. Rev. A}, title = {Continuous-variable quantum teleportation using a photon-subtracted and photon-added two-mode squeezed coherent state}, volume = {111}, year = {2025}, }
• (2025). Cancellation of phonon hopping in trapped ions by modulation of the trap potential. PRA, 111(2), 022401. (www)

  @article{ , abstract = {The local modes of trapped ions can be used to construct an analog quantum simulator and a digital quantum computer. However, the control of the phonon hopping remains difficult because it proceeds among all the local modes through the Coulomb coupling. We propose a method to cancel the phonon hopping among a given set of local modes by applying a sequence of phase shift gates implemented through the modulation of the trap potential. We analyze the error scaling in the algorithm to treat three or more modes and show that the error can be suppressed by repeating the pulse sequence. The duration of the phase shift gate in the present method can be as short as a few microseconds, which is an order of magnitude faster than the laser-based method. This short duration of the phase shift gate facilitates the suppression of the gate error. We finally show how the present method can be applied to the implementation of the beam splitter. The present method can also be applied to the simulation of bosonic systems as well as to the continuous variable encoding of quantum computing using trapped ions.}, archive = {J_PRA}, author = {Takanori Nishi and Kaoru Yamanouchi and Ryoichi Saito and Takashi Mukaiyama}, doi = {10.1103/PhysRevA.111.022401}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022401}, shortjournal = {Phys. Rev. A}, title = {Cancellation of phonon hopping in trapped ions by modulation of the trap potential}, volume = {111}, year = {2025}, }
• (2025). Measuring the local efficiency of symmetric informationally complete positive operator-valued measures in two-level systems with the density of quantum states. PRA, 111(2), 022224. (www)

  @article{ , abstract = {We study the local efficiency of symmetric informationally complete positive operator-valued measures (SIC-POVMs) from an information geometrical perspective. The local efficiency of a SIC-POVM is defined as the relative magnitude of the density of distinguishable states acquired via the measurement over the intrinsic density of quantum states. The two densities measure the local distinguishability of quantum states and its corresponding quantum resources, respectively. Strikingly, the efficiency is intrinsic in the sense of invariance under reparametrization. Specific to two-level systems, the efficiency is highly anisotropic and has a tetrahedral symmetry. Especially for a shell of the Bloch sphere, states in directions parallel (antiparallel) to the measurement basis have minimal (maximal) efficiency. Furthermore, the optimality of SIC-POVM versus other equal-length measurements is shown.}, archive = {J_PRA}, author = {Hai-Jun Xing}, doi = {10.1103/PhysRevA.111.022224}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022224}, shortjournal = {Phys. Rev. A}, title = {Measuring the local efficiency of symmetric informationally complete positive operator-valued measures in two-level systems with the density of quantum states}, volume = {111}, year = {2025}, }
• (2025). Quantum many-body theory for q-deformed fermions and bosons. PRA, 111(2), 022223. (www)

  @article{ , abstract = {We present a comprehensive quantum many-body theory for -deformed fermions and bosons, offering a novel framework that relates particle statistics directly to effective interaction strength. Deformed by the parameters and , these particles exhibit statistical behaviors that interpolate between conventional bosonic and fermionic systems, enabling us to model complex interactions via statistical modifications. We develop a generalized Wick theorem and extended Feynman diagrammatics tailored to particles, allowing us to calculate two types of Green's functions. Explicit expressions for these Green's functions are derived in both direct and momentum spaces, providing key insights into the collective properties of -fermionic and bosonic systems. Using a random-phase approximation, we estimate the dielectric function for -fermion gas ( ) and analyze the Friedel oscillations, the plasmon excitations, and the energy-loss function. Our results demonstrate that the effective interaction is tuned by the value of so that a noninteracting limit is obtained as , where the Friedel and the plasma oscillations disappear. An optimal value of , namely, the plasma frequency, and the energy-loss function show an absolute maximum and the effective interaction changes behavior.}, archive = {J_PRA}, author = {Habib Esmaili and Hosein Mohammadzadeh and Mehdi Biderang and Morteza NattaghNajafi}, doi = {10.1103/PhysRevA.111.022223}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022223}, shortjournal = {Phys. Rev. A}, title = {Quantum many-body theory for q-deformed fermions and bosons}, volume = {111}, year = {2025}, }
• (2025). Single-atom dissipation and dephasing in dicke and tavis-cummings quantum batteries. PRA, 111(2), 022222. (www)

  @article{ , abstract = {We study the influence of single-atom dissipation and dephasing noise on the performance of Dicke and Tavis-Cummings quantum batteries, where the electromagnetic field of the cavity hosting the system acts as a charger. For these models a genuine charging process can only occur in the transient regime. Indeed, unless the interaction with the environment is cut off, the asymptotic energy of the battery is solely determined by the environment and does not depend on the initial energy of the electromagnetic field. We numerically estimate the fundamental figures of merit for the model, including the time at which the battery reaches its maximum ergotropy, the average energy, and the energy that needs to be used to switch the battery-charger interaction on and off. Depending on the scaling of the coupling between the battery and the charger, we show that the model can still exhibit a subextensive charging time. However, for the Dicke battery, this effect comes with a higher cost when switching the battery-charger interaction on and off. We also show that as the number of battery constituents increases, both the Dicke and Tavis-Cummings models become asymptotically free, meaning the amount of energy that is not unitarily extractable becomes negligible. We obtain this result numerically and demonstrate analytically that it is a consequence of the symmetry under permutations of the model. Finally, we perform simulations for different values of the detuning, showing that the optimal regime for the Dicke battery is off-resonance, in contrast with what is observed in the Tavis-Cummings case.}, archive = {J_PRA}, author = {Andrea Canzio and Vasco Cavina and Marco Polini and Vittorio Giovannetti}, doi = {10.1103/PhysRevA.111.022222}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022222}, shortjournal = {Phys. Rev. A}, title = {Single-atom dissipation and dephasing in dicke and tavis-cummings quantum batteries}, volume = {111}, year = {2025}, }
• (2025). Single-shot distinguishability and antidistinguishability of quantum measurements. PRA, 111(2), 022221. (www)

  @article{ , abstract = {Among the surprising features of quantum measurements, the problem of distinguishing and antidistinguishing general quantum measurements is fundamentally appealing. Unlike classical systems, quantum theory offers entangled states and peculiar state update rule of the postmeasurement state, which gives rise to four distinct scenarios for distinguishing (and antidistinguishing) quantum measurements: (i) probing single systems and without access to the postmeasurement states, (ii) probing entangled systems and without access to the postmeasurement states, (iii) probing single systems with access to the postmeasurement states, and (iv) probing entangled systems with access to the postmeasurement states. In these scenarios, we consider the probability of distinguishing (and antidistinguishing) quantum measurements sampled from a given set in the single-shot regime. For some scenarios, we provide the analytical expressions of distinguishability (and antidistinguishability) for qubit projective measurements. We show that the distinguishability of any pair of qubit projective measurements in scenario (iii) is always greater than its values in scenario (ii). Interestingly, we find certain pairs of qubit nonprojective measurements for which the optimal distinguishability in scenario (ii) is achieved using a nonmaximally entangled state. It turns out that, for any set of measurements, distinguishability (and antidistinguishability) in scenario (i) is always less than or equal to in any other scenario, while it reaches its highest possible value in scenario (iv). We establish that the relations form a strict hierarchy, and there is no hierarchical relation between scenarios (ii) and (iii). In particular, we introduce different variants of the well-known “trine” qubit measurement to construct pairs (and triples) of qubit quantum measurements such that they are perfectly distinguishable (and antidistinguishable) in scenario (ii) but not in scenario (iii) and vice versa. Additionally, we present qubit measurements that are perfectly distinguishable (and antidistinguishable) in scenario (iv) but not in any other scenario.}, archive = {J_PRA}, author = {Satyaki Manna and Sneha Suresh and Manan Singh Kachhawaha and Debashis Saha}, doi = {10.1103/PhysRevA.111.022221}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022221}, shortjournal = {Phys. Rev. A}, title = {Single-shot distinguishability and antidistinguishability of quantum measurements}, volume = {111}, year = {2025}, }
• (2025). Precision measurement for open systems by the non-hermitian linear response. PRA, 111(2), 022220. (www)

  @article{ , abstract = {The lower bound of estimated precision for a coherent parameter unitarily encoded in closed systems has been obtained, and such a lower bound is inversely proportional to the fluctuation of the encoding operator. In this paper, we first derive some general results regarding the lower bound of estimated precision for a dissipative parameter, which is nonunitarily encoded in open systems, by combining the law of error propagation and the non-Hermitian linear response theory. This lower bound is related to the correlation of the encoding dissipative operator and the evolution time. We next demonstrate the utility of our general results by considering three different kinds of nonunitary encoding processes, including particle loss, relaxation, and dephasing. We finally compare the lower bound with the quantum Fisher information obtained by tomography and find they are consistent in the regime where the non-Hermitian linear response applies. This lower bound can guide us to find the optimal initial states and detecting operators to significantly simplify the measurement process.}, archive = {J_PRA}, author = {Peng Xu and Gang Chen}, doi = {10.1103/PhysRevA.111.022220}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022220}, shortjournal = {Phys. Rev. A}, title = {Precision measurement for open systems by the non-hermitian linear response}, volume = {111}, year = {2025}, }
• (2025). Localized states in monitored quantum walks. PRA, 111(2), 022219. (www)

  @article{ , abstract = {In this paper we study localized states in a monitored evolution on a finite graph and how they are distinguished from the delocalized states in terms of the transition probabilities and the mean transition times. Monitoring is performed by repeated projective measurements with respect to a single quantum state. Our constructive approach is based on a mapping from a set of energy levels and an eigenvector basis onto the monitored evolution matrix. The eigenvalues of the latter are distributed over the complex unit disk and the corresponding transition probabilities decay quickly in the quantum Zeno regime at frequent measurements. A localized basis favors the return to the initial state, while a delocalized basis favors transitions between different states. This provides a practical criterion to identify localized states by measuring the mean transition time.}, archive = {J_PRA}, author = {K. Ziegler}, doi = {10.1103/PhysRevA.111.022219}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022219}, shortjournal = {Phys. Rev. A}, title = {Localized states in monitored quantum walks}, volume = {111}, year = {2025}, }
• (2025). Quantum equilibration under extended experimentally realistic conditions. PRA, 111(2), 022218. (www)

  @article{ , abstract = {Understanding how macroscopic systems exhibit irreversible thermal behavior has been a longstanding challenge, first brought to prominence by Boltzmann. Recent advances have established rigorous conditions for isolated quantum systems to equilibrate to a maximum entropy state, contingent upon weak assumptions. These theorems, while powerful, applied for a sudden quench. However, natural processes involve finite-time perturbations or quenches, which raises a crucial question: Can these systems still equilibrate under more realistic, finite-time dynamics? In this work, we extend the established results to account for finite-time quenches, demonstrating that, even under finite-time perturbations, the system will equilibrate provided it populates many significant energy levels. While the mathematical proof is more intricate than in the instantaneous case, the physical conclusion remains the same: sufficient perturbation leads to equilibration. Our results provide a broader and more physically realistic framework for understanding thermalization in isolated quantum systems.}, archive = {J_PRA}, author = {M. R. Passos and Thiago R. de Oliveira}, doi = {10.1103/PhysRevA.111.022218}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022218}, shortjournal = {Phys. Rev. A}, title = {Quantum equilibration under extended experimentally realistic conditions}, volume = {111}, year = {2025}, }
• (2025). Robustness of contextuality under different types of noise as quantifiers for parity-oblivious multiplexing tasks. PRA, 111(2), 022217. (www)

  @article{ , abstract = {Generalized contextuality is the notion of nonclassicality powering up a myriad of quantum tasks, among which is the celebrated case of a two-party information processing task where classical information is compressed in a quantum channel, the parity-oblivious multiplexing (POM) task. The success rate is the standard quantifier of resourcefulness for this task, while robustness-based quantifiers are as operationally motivated and have known general properties. In this work we leverage analytical and numerical tools to estimate robustness of contextuality in POM scenarios under different types of noise. We conclude that for the 3-to-1 case, robustness of contextuality to depolarization as well as a minimization of robustness of contextuality to dephasing over all bases are good quantifiers for the nonclassical advantage of this scenario. Moreover, we obtain a general relation between robustness of contextuality to depolarization and the success rate in any -to-1 POM scenario and show how it can be used to bound the number of bits encoded in this task.}, archive = {J_PRA}, author = {Amanda M. Fonseca and Vinicius P. Rossi and Roberto D. Baldijão and John H. Selby and Ana Belén Sainz}, doi = {10.1103/PhysRevA.111.022217}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022217}, shortjournal = {Phys. Rev. A}, title = {Robustness of contextuality under different types of noise as quantifiers for parity-oblivious multiplexing tasks}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal quantum heat engine in a spinning optomechanical system. PRA, 111(2), 022216. (www)

  @article{ , abstract = {We propose a nonreciprocal quantum heat engine based on a spinning optomechanical system, in which the properties of the polariton branches are modified by tuning the detuning to realize the Otto cycle, enabling the conversion of thermal energy into mechanical energy. The Sagnac effect resulting from the rotation of the resonator leads to a pronounced disparity in work output and efficiency when the resonator is driven from opposing directions, establishing a distinct nonreciprocal behavior. Additionally, the performance of the engine can be precisely modulated by controlling the frequency shift, allowing for flexible and efficient optimization of the quantum heat engine's operation while markedly reducing its reliance on cavity field frequencies. These results provide critical insights and a solid theoretical foundation for the advancement of quantum heat engines.}, archive = {J_PRA}, author = {Jing-Yu Zhang and Ke-Yu Shi and Zuan Meng and Rui Hou and Xue Han and Hong-Fu Wang and Shou Zhang}, doi = {10.1103/PhysRevA.111.022216}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022216}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal quantum heat engine in a spinning optomechanical system}, volume = {111}, year = {2025}, }
• (2025). Quantum mpemba effect of localization in the dissipative mosaic model. PRA, 111(2), 022215. (www)

  @article{ , abstract = {The quantum Mpemba effect in open quantum systems has been extensively studied, but a comprehensive understanding of this phenomenon remains elusive. In this paper, we conduct an analytical investigation of the dissipative dynamics of single excitations in the mosaic model. Surprisingly, we discover that the presence of an asymptotic mobility edge, denoted as , can lead to unique dissipation behavior, serving as a hallmark of the quantum Mpemba effect. Especially, it is found that the energy level exhibits a global periodicity in the real configuration, which acts to inhibit dissipation in the system. Conversely, when the system deviates from , the quasidisorder sets in, leading to increased dissipative effects due to the broken of periodicity. Furthermore, we find that the rate of dissipation is closely linked to the localization of the initial state. As a result, the quantum Mpemba effect can be observed clearly by a measure of localization.}, archive = {J_PRA}, author = {J. W. Dong and H. F. Mu and M. Qin and H. T. Cui}, doi = {10.1103/PhysRevA.111.022215}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022215}, shortjournal = {Phys. Rev. A}, title = {Quantum mpemba effect of localization in the dissipative mosaic model}, volume = {111}, year = {2025}, }
• (2025). Emergent topological re-entrant phase transition in a generalized quasiperiodic modulated su-schrieffer-heeger model. PRA, 111(2), 022214. (www)

  @article{ , abstract = {We study the topological properties of the one-dimensional generalized quasiperiodic modulated Su-Schrieffer-Heeger model. The results reveal that the topological re-entrant phase transition emerges. Through the analysis of a real-space winding number, we divide the emergent topological re-entrant phase transitions into two types. The first is the re-entrant phase transition from the traditional topological insulator phase into the topological Anderson insulator phase, and the second is the re-entrant phenomenon from one topological Anderson insulator phase into another topological Anderson insulator phase. These two types of re-entrant phase transitions correspond to bounded and unbounded cases of quasiperiodic modulation, respectively. Furthermore, we verify the above topological re-entrant phase transitions by analyzing the Lyapunov exponent and bulk gap. Since Su-Schrieffer-Heeger models have been realized in various artificial systems (such as cold atoms, optical waveguide arrays, ion traps, Rydberg atom arrays, etc.), the two types of topological re-entrant phase transitions predicted in this paper are expected to be realized in the near future.}, archive = {J_PRA}, author = {Xiao-Ming Wang and Shan-Zhong Li and Zhi Li}, doi = {10.1103/PhysRevA.111.022214}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022214}, shortjournal = {Phys. Rev. A}, title = {Emergent topological re-entrant phase transition in a generalized quasiperiodic modulated su-schrieffer-heeger model}, volume = {111}, year = {2025}, }
• (2025). Multitype entanglement dynamics induced by exceptional points. PRA, 111(2), 022213. (www)

  @article{ , abstract = {As a most important feature of non-Hermitian systems, exceptional points (EPs) lead to a variety of unconventional phenomena and applications. Here, we study a generic model composed of two coupled non-Hermitian qubits; the EPs can be easily obtained in this system by adjusting the driving amplitude applied to the qubits. The diverse entanglement dynamics on the two sides of the original fourth-order EP ( ) and second-order EP (EP2) can be observed simultaneously in the weak coupling regime. With the increase of the coupling strength, the is replaced by an additional EP2, leading to the disappearance of the entanglement dynamics change induced by in the strong coupling regime. Considering the case of Ising-type interaction, we also realize EP-induced entanglement dynamics changing without the driving field. Our study paves the way for the investigation of EP-induced quantum effects and applications of EP-related quantum technologies.}, archive = {J_PRA}, author = {Zigeng Li and Xinyao Huang and Hongyan Zhu and Guofeng Zhang and Fan Wang and Xiaolan Zhong}, doi = {10.1103/PhysRevA.111.022213}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022213}, shortjournal = {Phys. Rev. A}, title = {Multitype entanglement dynamics induced by exceptional points}, volume = {111}, year = {2025}, }
• (2025). Non-markovian to markovian decay in structured environments with correlated disorder. PRA, 111(2), 022212. (www)

  @article{ , abstract = {Manipulating the dynamics of open quantum systems is a crucial requirement for large-scale quantum computers. Finding ways to overcome or extend decoherence times is a challenging task. Already at the level of a single two-level atom, its reduced dynamics with respect to a larger environment can be very complex. Structured environments, for instance, can lead to various regimes other than memoryless Markovian spontaneous emission. Here, we consider an atom coupled to an array of coupled cavities in the presence of on-site correlated disorder. The correlation is long-ranged and associated with the trace of a fractional Brownian motion following a power-law spectrum. With the cavity modes playing the role of the environment, we study the dynamics of the spontaneous emission. We observe a change from non-Markovian to Markovian decay in the presence of disorder by tuning the correlation parameter. This is associated with a localization-delocalization transition involving the field modes. Two dissipative models that effectively reproduce the behavior of the non-Markovianity are discussed. The dissipation dynamics of the atom can thus be used to extract information about the phase of the environment. Our results provide a direction in the engineering of disordered quantum systems to function as controllable reservoirs.}, archive = {J_PRA}, author = {Mariana O. Monteiro and Nadja K. Bernardes and Eugene M. Broni and Francisco A. B. F. de Moura and Guilherme M. A. Almeida}, doi = {10.1103/PhysRevA.111.022212}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022212}, shortjournal = {Phys. Rev. A}, title = {Non-markovian to markovian decay in structured environments with correlated disorder}, volume = {111}, year = {2025}, }
• (2025). Non-hermitian generalization of rayleigh-schrödinger perturbation theory. PRA, 111(2), 022211. (www)

  @article{ , abstract = {While perturbation theories constitute a significant foundation of modern quantum system analysis, extending them from the Hermitian to the non-Hermitian regime remains a nontrivial task. In this work, we generalize the Rayleigh-Schrödinger perturbation theory to the non-Hermitian regime by employing a geometric formalism. This framework allows us to compute perturbative corrections to eigenstates and eigenvalues of Hamiltonians iteratively to any order. Furthermore, we observe that the recursion equation for the eigenstates resembles the form of the Girard-Newton formulas, which helps us uncover the general solution to the recursion equation. Moreover, we demonstrate that the perturbation method proposed in this paper reduces to the standard Rayleigh-Schrödinger perturbation theory in the Hermitian regime.}, archive = {J_PRA}, author = {Wei-Ming Chen and Yen-Ting Lin and Chia-Yi Ju}, doi = {10.1103/PhysRevA.111.022211}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022211}, shortjournal = {Phys. Rev. A}, title = {Non-hermitian generalization of rayleigh-schrödinger perturbation theory}, volume = {111}, year = {2025}, }
• (2025). Quantum and classical effects in system-bath correlations and optical line shapes. PRA, 111(2), 022210. (www)

  @article{ , abstract = {System-bath correlations play a pivotal role in the study of open quantum systems and have emerged as an important feature in distinguishing between quantum and classical behavior in energy transfer and spectroscopy. A variety of classical models have been constructed to test the limits of purely classical mechanics to capture such effects and, thus, by elimination to identify features that are unique to quantum systems. Yet numerical modeling in such classical frameworks has been largely limited to perturbative approximations, leaving some doubt regarding the extent to which these models are capable of capturing system-bath correlation effects. To overcome this gap, we here apply the numerically exact hierarchical equations of motion (HEOM) framework to examine dynamics under a “classical density matrix” framework that follows strictly Newtonian dynamics. Under the assumption of a Drude-Lorenz spectral density, we show that the resulting HEOM framework becomes identical to the stochastic Liouville equation. By comparing numerically exact dynamical simulations under this model with various “flavors” of the quantum HEOM formalism and with experimental absorption and fluorescence data, we examine the various roles that system-bath interactions play in thermalization and spectroscopic line-shape functions. Although the numerically exact classical simulations do reveal transient system-bath correlations, these are generally weaker than their quantum counterparts and vanish as the system approaches thermal equilibrium to produce a factorized equipartition state. For experimentally relevant parameters, we find that the classical treatment provides a fairly accurate treatment of absorption spectroscopy but that loss of the quantum detailed balance condition leads to a (sometimes dramatic) failure in describing fluorescence spectra.}, archive = {J_PRA}, author = {Rajesh Dutta and Mike Reppert}, doi = {10.1103/PhysRevA.111.022210}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022210}, shortjournal = {Phys. Rev. A}, title = {Quantum and classical effects in system-bath correlations and optical line shapes}, volume = {111}, year = {2025}, }
• (2025). Strong symmetries in collision models and physical dilations of covariant quantum maps. PRA, 111(2), 022209. (www)

  @article{ , abstract = {Quantum maps are fundamental to quantum information theory and open quantum systems. Covariant or weakly symmetric quantum maps, in particular, play a key role in defining quantum evolutions that respect thermodynamics, establish free operations in resource theories, and are consistent with transformations of quantum reference frames. To implement quantum maps in the laboratory, one typically engineers a physical dilation, which corresponds to a unitary evolution entangling the system with an environment . This work systematically explores how weak symmetries of quantum maps manifest in their dilations. We demonstrate that for various classes of physical dilations, including Hamiltonian-driven dilations and short-time collision models that simulate Markovian open quantum dynamics, weak symmetries always lead to strong symmetries in the dilated evolution, resulting in conserved quantities in the system-environment space. We also characterize the subspace where these symmetries arise using Krylov subspaces. Moreover, we show that some different types of physical dilations have no constraints on the dilated evolution, requiring no strong symmetry. Finally, we complement our findings with a variety of illustrative and pedagogical examples. Our results provide essential guidelines for constructing physical dilations of quantum maps, offering a comprehensive understanding of how symmetries shape their implementations in a laboratory or on a quantum computer.}, archive = {J_PRA}, author = {Marco Cattaneo}, doi = {10.1103/PhysRevA.111.022209}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022209}, shortjournal = {Phys. Rev. A}, title = {Strong symmetries in collision models and physical dilations of covariant quantum maps}, volume = {111}, year = {2025}, }
• (2025). Currents in nonequilibrium steady states of open inhomogeneous XX spin chains. PRA, 111(2), 022208. (www)

  @article{ , abstract = {We investigate spin and heat currents in the nonequilibrium steady state of inhomogeneous X X -spin chains, which act as interfaces between two bosonic heat baths. Using special functions that diagonalize the single-particle Hamiltonian, we derive closed-form expressions for these currents. For small temperature differences between the baths, we show that inhomogeneities breaking the mirror symmetry of the chain significantly reduce both heat and spin conductivities. Connections with perfect state transfer are discussed.}, archive = {J_PRA}, author = {Pierre-Antoine Bernard and Ismaël Bussière and Roberto Floreanini and Luc Vinet}, doi = {10.1103/PhysRevA.111.022208}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022208}, shortjournal = {Phys. Rev. A}, title = {Currents in nonequilibrium steady states of open inhomogeneous XX spin chains}, volume = {111}, year = {2025}, }
• (2025). Dynamical landauer principle: Thermodynamic criteria of transmitting classical information. PRA, 111(2), 022207. (www)

  @article{ , abstract = {Transmitting energy and information are two essential aspects of nature. Recent findings suggest they are closely related, while a quantitative equivalence between them is still unknown. This thus motivates us to ask the following: Can information transmission tasks equal certain energy transmission tasks? We answer this question positively by bounding various one-shot classical capacities via different energy transmission tasks. Such bounds provide the physical implication that in the one-shot regime, transmitting 𝑛 bits of classical information is equivalent to 𝑛 × 𝑘 𝐵 ⁢ 𝑇 ⁢ l n ⁡ 2 transmitted energy. Unexpectedly, these bounds further uncover a dynamical version of Landauer's principle, showing the strong link between transmitting (rather than erasing ) information and energy. Finally, in the asymptotic regime, our findings further provide thermodynamic meanings for the Holevo-Schumacher-Westmoreland Theorem and a series of strong converse properties as well as no-go theorems.}, archive = {J_PRA}, author = {Chung-Yun Hsieh}, doi = {10.1103/PhysRevA.111.022207}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022207}, shortjournal = {Phys. Rev. A}, title = {Dynamical landauer principle: Thermodynamic criteria of transmitting classical information}, volume = {111}, year = {2025}, }
• (2025). Efficient and operational quantifier of nondivisibility in terms of channel discrimination. PRA, 111(2), 022206. (www)

  @article{ , abstract = {The understanding of open quantum systems is crucial for the development of quantum technologies. Of particular relevance is the characterization of divisible quantum dynamics, seen as a generalization of Markovian processes to the quantum setting. Here, we propose a way to detect divisibility and quantify how nondivisible a quantum channel is through the concept of channel discrimination. We ask how well we can distinguish generic dynamics from divisible dynamics. We show that this question can be answered efficiently through semidefinite programming, which provides us with an operational and efficient way to quantify nondivisibility.}, archive = {J_PRA}, author = {Ranieri Nery and Nadja K. Bernardes and Daniel Cavalcanti and Rafael Chaves and Cristhiano Duarte}, doi = {10.1103/PhysRevA.111.022206}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022206}, shortjournal = {Phys. Rev. A}, title = {Efficient and operational quantifier of nondivisibility in terms of channel discrimination}, volume = {111}, year = {2025}, }
• (2025). Unraveling-induced entanglement phase transition in diffusive trajectories of continuously monitored noninteracting fermionic systems. PRA, 111(2), 022205. (www)

  @article{ , abstract = {The competition between unitary quantum dynamics and dissipative stochastic effects, as emerging from continuous-monitoring processes, can culminate in measurement-induced phase transitions. Here, a many-body system abruptly passes, when exceeding a critical measurement rate, from a highly entangled phase to a low-entanglement one. We consider a different perspective on entanglement phase transitions and explore whether these can emerge when the measurement process itself is modified, while keeping the measurement rate fixed. To illustrate this idea, we consider a noninteracting fermionic system and focus on diffusive detection processes. Through extensive numerical simulations, we show that, upon varying a suitable unraveling parameter —interpolating between measurements of different quadrature operators—the system displays a transition from a phase with area-law entanglement to one where entanglement scales logarithmically with the system size. Our findings may be relevant for tailoring quantum correlations in noisy quantum devices and for conceiving optimal classical simulation strategies.}, archive = {J_PRA}, author = {Moritz Eissler and Igor Lesanovsky and Federico Carollo}, doi = {10.1103/PhysRevA.111.022205}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022205}, shortjournal = {Phys. Rev. A}, title = {Unraveling-induced entanglement phase transition in diffusive trajectories of continuously monitored noninteracting fermionic systems}, volume = {111}, year = {2025}, }
• (2025). Consequences of the single-pair measurement of the bell parameter. PRA, 111(2), 022204. (www)

  @article{ , abstract = {Bell inequalities represent a milestone for contemporary physics, both for quantum foundation investigations and technological applications (e.g., quantum communication and entanglement certification). Although loophole-free tests have been recently performed, a strong debate is still ongoing on the actual meaning of Bell inequality tests, for example, on the possible additional hypotheses and eventual loopholes to be included in Bell's theorem, as well as on the implications for certain interpretations of quantum mechanics. A recent work [S. Virzì et al. , Quantum Sci. Technol. 9 , 045027 (2024) ] challenges some of the statements appeared in this debate, achieving an experimental estimation of the entire Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) parameter from a single entangled pair owing to a weak-interaction-based measurement approach. Here, we analyze the implications of this result for quantum mechanics foundations investigation, illustrating how it can tackle some of the aforementioned interpretations of Bell inequality tests and, more in general, of quantum mechanics itself.}, archive = {J_PRA}, author = {Marco Genovese and Fabrizio Piacentini}, doi = {10.1103/PhysRevA.111.022204}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022204}, shortjournal = {Phys. Rev. A}, title = {Consequences of the single-pair measurement of the bell parameter}, volume = {111}, year = {2025}, }
• (2025). Characterizing entangled state update in different reference frames with weak measurements. PRA, 111(2), 022203. (www)

  @article{ , abstract = {As per the projection postulate, the evolution of the quantum state of a system upon measurement results in state update. In this work we investigate the characterization of updated states of multipartite entangled qubit states with nondestructive weak measurements, involving weakly coupling a pointer to each qubit while considering a relativistic setup involving different reference frames. As is well known, the updated state at intermediate times is frame dependent and outcome randomness, intrinsic to projective measurements, prevents any information from being acquired on the updated state. Here we will see that when weak measurements are implemented there is instead an interplay between randomness and interference, depending on the number of qubits, so as to maintain consistency between descriptions in arbitrary reference frames. Analytical results are given for a small or infinite number of qubits, while for a finite number of qubits we resort to Monte Carlo sampling in order to simulate numerically the results of weak measurements. As a by-product, we show how a single-shot measurement of the pointers' positions allows us to make quantitative predictions on the outcomes that can be obtained for any observable measured on a distant qubit of the multipartite state.}, archive = {J_PRA}, author = {J. Allam and A. Matzkin}, doi = {10.1103/PhysRevA.111.022203}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022203}, shortjournal = {Phys. Rev. A}, title = {Characterizing entangled state update in different reference frames with weak measurements}, volume = {111}, year = {2025}, }
• (2025). Dirac brackets and the lindblad equation: A correspondence. PRA, 111(2), 022202. (www)

  @article{ , abstract = {The time evolution of an open quantum system is governed by the Gorini-Kossakowski-Sudarshan-Lindblad equation for the reduced density operator of the system. This operator is obtained from the full density operator of the composite system involving the system itself, the bath, and the correlations between them, by performing a partial trace over the bath degrees of freedom. The entanglement between the system and the bath leads to a generalized Liouville evolution that involves, among other things, dissipation and decoherence of the system. In a similar fashion, the time evolution of a physical observable in a classically constrained dynamical system is governed by a generalization of the Liouville equation, in which the usual Poisson bracket is replaced by the so-called Dirac bracket. The generalization takes into account the reduction in the phase space of the system because of constraints that arise either because they are introduced by hand or because of singular Lagrangians. We derive an intriguing but precise classical-quantum correspondence between the aforementioned situations which connects the Lindblad operators to the constraints. The correspondence is illustrated in the ubiquitous example of coupled simple harmonic oscillators studied earlier in various contexts such as quantum optics, dissipative quantum systems, Brownian motion, and the area law for the entropy of black holes.}, archive = {J_PRA}, author = {Aleek Maity and V. V. Sreedhar}, doi = {10.1103/PhysRevA.111.022202}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022202}, shortjournal = {Phys. Rev. A}, title = {Dirac brackets and the lindblad equation: A correspondence}, volume = {111}, year = {2025}, }
• (2025). Network nonlocality sharing in the star-shaped scenario using only projective measurements. PRA, 111(2), 022201. (www)

  @article{ , abstract = {Sequential measurements present a novel framework for constructing large-scale quantum networks, particularly in quantum correlation sharing. In this paper, we design projective measurements and combination strategies to achieve nonlocality sharing in star-shaped networks by leveraging shared classical randomness. This network consists of 𝑛 branches, each containing one or two sequential observers. By investigating two-sided nonlocality sharing within a 2-local network, we identify the optimal projective measurement combination strategy based on the double violation of the 2-locality inequality. Utilizing this optimal strategy, we demonstrate that four inequalities can be violated simultaneously in the 2-local scenario. Furthermore, in an 𝑛 -local scenario involving 𝑚 ( 1 ≤ 𝑚 ≤ 𝑛 ) branches with two sequential observers, our optimal strategy shows that non- 𝑛 -locality sharing among all observers can be achieved through the simultaneous violation of 2 𝑚 𝑛 -locality inequality. Our findings provide a distinctive perspective on quantum correlation sharing in networks.}, archive = {J_PRA}, author = {Hao Sun and Fenzhuo Guo and Haifeng Dong and Fei Gao and Sujuan Qin}, doi = {10.1103/PhysRevA.111.022201}, journal = {Physical Review a}, month = {2}, number = {2}, pages = {022201}, shortjournal = {Phys. Rev. A}, title = {Network nonlocality sharing in the star-shaped scenario using only projective measurements}, volume = {111}, year = {2025}, }
• (2025). Optimal cavity design for minimizing errors in cavity-QED-based atom-photon entangling gates with finite temporal duration. PRA, 111(1), L011701. (www)

  @article{ , abstract = {We investigate atom-photon entangling gates based on cavity quantum electrodynamics (QED) for a finite photon-pulse duration, where not only the photon loss but also the temporal mode-mismatch of the photon pulse becomes a severe source of error. We analytically derive relations between cavity parameters, including transmittance, length, and effective cross-sectional area of the cavity, that minimize both the photon loss probability and the error rate due to temporal mode-mismatch by taking it into account as state-dependent pulse delay. We also investigate the effects of pulse distortion using numerical simulations for the case of short pulse duration. We believe that these analyses are the first to suggest that a cavity has an optimal length for the atom-photon gate, providing a fundamental guideline for implementing quantum information processing.}, archive = {J_PRA}, author = {Takeru Utsugi and Rui Asaoka and Yuuki Tokunaga and Takao Aoki}, doi = {10.1103/PhysRevA.111.L011701}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011701}, shortjournal = {Phys. Rev. A}, title = {Optimal cavity design for minimizing errors in cavity-QED-based atom-photon entangling gates with finite temporal duration}, volume = {111}, year = {2025}, }
• (2025). Quantum correlations, mixed states, and bistability at the onset of lasing. PRA, 111(1), L011501. (www)

  @article{ , abstract = {We derive a model for a single-mode laser that includes all two-particle quantum correlations between photons and electrons. In contrast to the predictions of semiclassical models, we find that lasing takes place in the presence of quantum bistability between a nonlasing and a nonclassical coherent state. The coherent state is characterized by a central frequency and a finite linewidth and emerges with finite amplitude from a saddle-node bifurcation together with an unstable coherent state. Hence coherent emission in nanolasers originates through a mixing of lasing and nonlasing states. In the limit of a macrolaser with a large number of emitters and nonresonant modes, the laser threshold approaches the prediction of the semiclassical theory, but with the important difference that lasing can be achieved only in the presence of finite-size perturbations.}, archive = {J_PRA}, author = {Francesco Papoff and Mark Anthony Carroll and Gian Luca Lippi and Gian-Luca Oppo and Giampaolo D'Alessandro}, doi = {10.1103/PhysRevA.111.L011501}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011501}, shortjournal = {Phys. Rev. A}, title = {Quantum correlations, mixed states, and bistability at the onset of lasing}, volume = {111}, year = {2025}, }
• (2025). Supersolidity in rydberg tweezer arrays. PRA, 111(1), L011305. (www)

  @article{ , abstract = {Rydberg tweezer arrays provide a versatile platform to explore quantum magnets with dipolar XY or van der Waals Ising ZZ interactions. Here, we propose a scheme combining dipolar and van der Waals interactions between two Rydberg states, where the amplitude of the latter can be greater than that of the former, realizing an extended Hubbard model with long-range tunnelings in optical tweezer arrays. On the triangular lattice with repulsive interactions, we predict the existence of a robust supersolid phase with a critical entropy per particle S / N ≈ 0.19 accessible in current Rydberg tweezer experiments supported by large-scale quantum Monte Carlo simulations. We further demonstrate the experimental feasibility by identifying pairs of Rydberg states in Rb 87 realizing the required interactions. Such a lattice supersolid is long lived, found over a wide parameter range in an isotropic and flat two-dimensional geometry, and can be realized for hundreds of particles allowing one to directly probe the defect-induced picture of supersolids. Its thermodynamical and dynamical properties can hence be studied at a far larger scale than hitherto possible.}, archive = {J_PRA}, author = {Lukas Homeier and Simon Hollerith and Sebastian Geier and Neng-Chun Chiu and Antoine Browaeys and Lode Pollet}, doi = {10.1103/PhysRevA.111.L011305}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011305}, shortjournal = {Phys. Rev. A}, title = {Supersolidity in rydberg tweezer arrays}, volume = {111}, year = {2025}, }
• (2025). Realization of a period-3 coplanar state in one-dimensional spin-orbit-coupled optical lattices. PRA, 111(1), L011304. (www)

  @article{ , abstract = {In ultracold atoms, achieving a period-3 structure poses a significant challenge. In this work, we propose a three-sublattice spin-flop transition mechanism, differing from the two-sublattice counterpart used to explain the emergence of ferrimagnetic orders in higher dimensions. Guided by this mechanism, we design a setup of alkaline-earth-metal atoms to create a spin-orbit-coupled optical lattice, where we identify a triplefold degenerate state with a period-3 coplanar spin ordering within the deep Mott-insulating phase region of the ground-state phase diagram. The state is protected by a finite gap, and its characteristic angle can be finely tuned by specific setup parameters. Moreover, we use the Rabi spectroscopy technique to detect the state. Our work not only shows the feasibility of achieving a period-3 structure via the new mechanism but also suggests its potential applications for exploring other periodic structures in optical lattices.}, archive = {J_PRA}, author = {Yida Chu and Shijie Hu and Tao Wang}, doi = {10.1103/PhysRevA.111.L011304}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011304}, shortjournal = {Phys. Rev. A}, title = {Realization of a period-3 coplanar state in one-dimensional spin-orbit-coupled optical lattices}, volume = {111}, year = {2025}, }
• (2025). Floquet geometric squeezing in fast-rotating condensates. PRA, 111(1), L011303. (www)

  @article{ , abstract = {Constructing and manipulating quantum states in fast-rotating Bose-Einstein condensates (BECs) has long stood as a significant challenge as the rotating speed approached a critical velocity. Although a recent experiment [R. J. Fletcher et al. , Science 372 , 1318 (2021) ] has realized the geometrically squeezed state of the guiding-center mode, the remaining degree of freedom, the cyclotron mode, remains unsqueezed due to the large energy gap of the Landau levels. To overcome this limitation, in this Letter, we propose a Floquet-based state-preparation protocol by periodically driving an anisotropic potential. This protocol not only facilitates single-cyclotron-mode squeezing, but also enables two-mode squeezing. Such two-mode squeezing offers a richer set of dynamics compared to single-mode squeezing and can achieve a wave-packet width well below the lowest-Landau-level limit. Our work provides a highly controllable knob for realizing diverse geometrically squeezed states in ultracold quantum gases within the quantum Hall regime.}, archive = {J_PRA}, author = {Li Chen and Fei Zhu and Yunbo Zhang and Han Pu}, doi = {10.1103/PhysRevA.111.L011303}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011303}, shortjournal = {Phys. Rev. A}, title = {Floquet geometric squeezing in fast-rotating condensates}, volume = {111}, year = {2025}, }
• (2025). Superfluid fraction of interacting bosonic gases. PRA, 111(1), L011302. (www)

  @article{ , abstract = {The superfluid fraction f of a quantum fluid is defined in terms of the response of the system to a weak and constant drag. Notably, Leggett long ago derived two simple expressions providing a rigorous upper bound and a heuristic lower bound for f . Here we study the superfluid fraction of bosonic gases in various two-dimensional potentials, such as regular optical lattices and disordered speckles, by solving the Gross-Pitaevskii equation and performing diffusion Monte Carlo simulations. We show that under conditions relevant for most ultracold experiments the bounds proposed by Leggett provide a surprisingly narrow bracketing of the exact value of the superfluid fraction.}, archive = {J_PRA}, author = {Daniel Pérez-Cruz and Grigori E. Astrakharchik and Pietro Massignan}, doi = {10.1103/PhysRevA.111.L011302}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011302}, shortjournal = {Phys. Rev. A}, title = {Superfluid fraction of interacting bosonic gases}, volume = {111}, year = {2025}, }
• (2025). Supersolidity of dipolar bose-einstein condensates induced by coupling to fermions. PRA, 111(1), L011301. (www)

  @article{ , abstract = {We study a mixture of a repulsive dipolar condensate and a degenerate Fermi gas in a quasi-one-dimensional geometry. We demonstrate that the presence of fermions, which attract bosons, drastically changes the behavior of the dipolar condensate. For a strong enough boson-fermion attraction, a dipolar Bose-Fermi droplet appears in the mixture, and as the attraction becomes stronger, a roton excitation develops in the Bogoliubov spectrum, leading to the formation of a supersolid, and eventually a crystal of isolated droplets. We describe the system by coupled extended Gross-Pitaevskii (bosons) and Hartree-Fock (fermions) equations. We study the excitation spectrum of the system and identify a number of Goldstone and Higgs modes in the supersolid regime.}, archive = {J_PRA}, author = {Maciej Lewkowicz and Tomasz Karpiuk and Mariusz Gajda and Mirosław Brewczyk}, doi = {10.1103/PhysRevA.111.L011301}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011301}, shortjournal = {Phys. Rev. A}, title = {Supersolidity of dipolar bose-einstein condensates induced by coupling to fermions}, volume = {111}, year = {2025}, }
• (2025). Strong-field ionization with few-cycle, midinfrared laser pulses inducing a localized ionization followed by long-lasting charge migration in halogenated organic molecules. PRA, 111(1), L011101. (www)

  @article{ , abstract = {We show that applying a few-femtosecond midinfrared laser pulse parallel to the backbone of a halogenated, conjugated organic molecule induces localized ionization followed by long-lasting field-free charge migration (CM). Through time-dependent density-functional theory calculations, we find that this CM is robust with respect to the parameters of the applied laser pulse. We document the spatial and temporal origin of the localized hole, which is initiated via strong-field tunnel ionization in the halogen end of the molecule and near the peak of the laser electric field. In bromobutadiyne, we find a range of wavelengths around 1500 nm that consistently leads to the initiation of high-contrast CM. In addition, we show that the inclusion of Ehrenfest nuclear dynamics does not disrupt the creation of the localized hole, nor the subsequent CM motion, in bromobutadiyne or para bromoaniline.}, archive = {J_PRA}, author = {Kyle A. Hamer and François Mauger and Kenneth Lopata and Kenneth J. Schafer and Mette B. Gaarde}, doi = {10.1103/PhysRevA.111.L011101}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L011101}, shortjournal = {Phys. Rev. A}, title = {Strong-field ionization with few-cycle, midinfrared laser pulses inducing a localized ionization followed by long-lasting charge migration in halogenated organic molecules}, volume = {111}, year = {2025}, }
• (2025). Theory for the rydberg states of helium: Comparison with experiment for the 1s24pP11 state (n=24). PRA, 111(1), L010803. (www)

  @article{ , abstract = {Recent measurements of the ionization energies of the Rydberg P 1 states of helium for principal quantum number n = 24 and higher present a new challenge to theoretical atomic physics. A long-standing obstacle to high-precision atomic theory for three-body systems is a rapid loss of accuracy for variational calculations with increasing principal quantum number n . We show that this problem can be overcome with the use of a “triple” basis set in Hylleraas coordinates. Nonrelativistic energies accurate to 23 significant figures are obtained with basis sets of relatively modest size (6744 terms). Relativistic and quantum electrodynamic effects are calculated, including an estimate of terms of order m α 6 from a 1 / n 3 extrapolation, resulting in an estimated accuracy of ± 1 kHz. The calculated ionization energy of 5 704 980.348(1) MHz is in excellent agreement with the experimental value 5 704 980.312(95) MHz. These results establish the ionization energy of the 1 s 24 p P 1 1 state as an absolute point of reference for transitions to lower-lying states, and they confirm an 11 σ disagreement between theory and experiment in the triplet spectrum of helium. Results are also given for the 1 s 24 p P J 3 states, in agreement with a recent experiment on the triplet Rydberg series, thereby confirming the discrepancy. Results are also given for the 1 s 24 p 3 P J states which are in agreement with a recent experiment on the triplet- P Rydberg series, thereby confirming a discrepancy of 0.468 ± 0.055 MHz for the ionization energy of the 1 s 2 s 3 S 1 state.}, archive = {J_PRA}, author = {Aaron T. Bondy and G. W. F. Drake and Cody McLeod and Evan M. R. Petrimoulx and Xiao-Qiu Qi and Zhen-Xiang Zhong}, doi = {10.1103/PhysRevA.111.L010803}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010803}, shortjournal = {Phys. Rev. A}, title = {Theory for the rydberg states of helium: Comparison with experiment for the 1s24pP11 state (n=24)}, volume = {111}, year = {2025}, }
• (2025). One-body dynamical correlation function of the lieb-liniger model at finite temperature. PRA, 111(1), L010802. (www)

  @article{ , abstract = {The dynamical correlated properties of one-dimensional (1D) Bose gases provide profound understanding of novel physics emergent from collective excitations, for instance, the breakdown of off-diagonal long-range order, and the establishment of Tomonaga-Luttinger liquid theory. However, due to the nonperturbative nature of 1D many-body systems, the exact evaluation of correlation functions is notoriously difficult. Here, by means of a form factor approach based on an algebraic Bethe ansatz and numerics, we present a thorough study on the one-body dynamical correlation function (1BDCF) of the Lieb-Liniger model at finite temperature. The influence of thermal fluctuation and interaction on the behavior of 1BDCF has been demonstrated and analyzed from various perspectives, including the spectral distribution, the line shape at fixed momentum, and the corresponding static correlations.}, archive = {J_PRA}, author = {Song Cheng and Yang-Yang Chen and Xi-Wen Guan and Wen-Li Yang and Hai-Qing Lin}, doi = {10.1103/PhysRevA.111.L010802}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010802}, shortjournal = {Phys. Rev. A}, title = {One-body dynamical correlation function of the lieb-liniger model at finite temperature}, volume = {111}, year = {2025}, }
• (2025). On-the-fly ab initio hagedorn wave-packet dynamics: Single vibronic level fluorescence spectra of difluorocarbene. PRA, 111(1), L010801. (www)

  @article{ , abstract = {Hagedorn wave packets have been used to compute single vibronic level (SVL) spectra efficiently in model harmonic potentials. To make the Hagedorn approach practical for realistic polyatomic molecules with anharmonicity, here we combine local harmonic Hagedorn wave-packet dynamics with on-the-fly ab initio dynamics. We then test this method by computing the SVL fluorescence spectra of difluorocarbene, a small, floppy molecule with a very anharmonic potential energy surface. Our time-dependent approach obtains the emission spectra of all initial vibrational levels from a single anharmonic semiclassical wave-packet trajectory without the need to fit individual anharmonic vibrational wave functions and to calculate the Franck-Condon factors for all vibronic transitions. We show that, whereas global harmonic models are inadequate for , the spectra computed with the on-the-fly local harmonic Hagedorn wave-packet dynamics agree well with experimental data, especially for low initial excitations.}, archive = {J_PRA}, author = {Zhan Tong Zhang and Máté Visegrádi and Jiří J. L. Vaníček}, doi = {10.1103/PhysRevA.111.L010801}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010801}, shortjournal = {Phys. Rev. A}, title = {On-the-fly ab initio hagedorn wave-packet dynamics: Single vibronic level fluorescence spectra of difluorocarbene}, volume = {111}, year = {2025}, }
• (2025). Entanglement transitions induced by quantum-data collection. PRA, 111(1), L010402. (www)

  @article{ , abstract = {We present an entanglement transition in an array of qubits, induced by the transfer of quantum information from a system to a quantum computer. This quantum-data collection is an essential protocol in quantum machine learning algorithms that promise exponential advantage over their classical counterparts. In this and an accompanying work [ Phys. Rev. A 111 , 012425 (2025) ], we identify sufficient conditions for an entanglement transition to occur in the late-time state of the system and quantum computer. In this Letter, we present an example entanglement transition occurring in a system comprised of a one-dimensional (1D) chain of qubits evolving under a random brickwork circuit. After each layer, a fraction p of sites undergo noisy quantum transduction in which quantum information is transferred to a quantum computer but at the cost of introducing noise from an environment. For an entanglement transition to occur, we argue that the environment must obtain the same amount of information as gained by the computer. Under this condition, the circuit shows a transition from volume law to area law entanglement as the rate p is increased above a critical threshold. Our work delineates the prerequisites for quantum-data collection to induce entanglement transitions, thereby establishing a foundational framework for emergent entanglement phenomena in protocols relevant to quantum machine learning.}, archive = {J_PRA}, author = {Shane P. Kelly and Jamir Marino}, doi = {10.1103/PhysRevA.111.L010402}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010402}, shortjournal = {Phys. Rev. A}, title = {Entanglement transitions induced by quantum-data collection}, volume = {111}, year = {2025}, }
• (2025). Ancilla-entangling floquet kicks for accelerating quantum algorithms. PRA, 111(1), L010401. (www)

  @article{ , abstract = {Quantum simulation with adiabatic annealing can provide insight into difficult problems that are impossible to study with classical computers. However, it deteriorates when the systems scale up due to the shrinkage of the excitation gap and thus places an annealing rate bottleneck for high success probability. Here, we accelerate quantum simulation using digital multiqubit gates that entangle primary system qubits with ancillary qubits. The practical benefits originate from tuning the ancillary gauge degrees of freedom to enhance the quantum algorithm's original functionality in the system registry. For simple but nontrivial short-ranged, infinite long-ranged transverse-field Ising models, and the hydrogen molecule model after qubit encoding, we show improvement in the time to solution by one hundred percent but with higher accuracy through exact state-vector numerical simulation in a digital-analog setting. The findings are further supported by time-averaged Hamiltonian theory.}, archive = {J_PRA}, author = {C.-C. Joseph Wang and Phillip C. Lotshaw and Titus Morris and Vicente Leyton-Ortega and Daniel Claudino and Travis S. Humble}, doi = {10.1103/PhysRevA.111.L010401}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010401}, shortjournal = {Phys. Rev. A}, title = {Ancilla-entangling floquet kicks for accelerating quantum algorithms}, volume = {111}, year = {2025}, }
• (2025). Experimental demonstration of single-spin stirling engine cycles with enhanced efficiency. PRA, 111(1), L010203. (www)

  @article{ , abstract = {Quantum heat engines (QHEs) employing Otto, Carnot, and Szilard cycles have already been demonstrated. Experimental demonstration of the quantum Stirling engine has been hindered due to the challenges in realizing a quantum isothermal process with qubits. Here, we experimentally execute a single-ion Stirling QHE and demonstrate that its efficiency is enhanced when dephasing is involved during the heat release strokes, which is contrary to the conventional viewpoint that dephasing deteriorates quantum features, resulting in reduced performance in QHEs. We also observe periodic oscillations in the heat absorption and the efficiency of the Stirling QHE, indicating the involvement of quantum coherence in the engine cycles. Our experiment is the first execution of Stirling QHE in a spin system, which may help better understand quantum thermodynamics and open new possibilities toward harnessing decoherence as a resource to improve the performance of QHEs.}, archive = {J_PRA}, author = {P.-D. Li and G.-Y. Ding and J.-Q. Zhang and Q. Yuan and S.-Q. Dai and T.-H. Cui and F. Zhou and L. Chen and Q. Zhong and H. Jing and Ş. K. Özdemir and M. Feng}, doi = {10.1103/PhysRevA.111.L010203}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010203}, shortjournal = {Phys. Rev. A}, title = {Experimental demonstration of single-spin stirling engine cycles with enhanced efficiency}, volume = {111}, year = {2025}, }
• (2025). Quasiperiodic floquet-gibbs states in rydberg atomic systems. PRA, 111(1), L010202. (www)

  @article{ , abstract = {Open systems that are weakly coupled to a thermal environment and driven by fast, periodically oscillating fields are commonly assumed to approach an equilibriumlike steady state with respect to a truncated Floquet-Magnus Hamiltonian. Using a general argument based on Fermi's golden rule, we show that such Floquet-Gibbs states emerge naturally in periodically modulated Rydberg atomic systems, whose laboratory-frame Hamiltonian is a quasiperiodic function of time. Our approach applies as long as the inherent Bohr frequencies of the system, the modulation frequency, and the frequency of the driving laser, which is necessary to uphold high-lying Rydberg excitations, are well separated. To corroborate our analytical results, we analyze a realistic model of up to five interacting Rydberg atoms with periodically changing detuning. We demonstrate numerically that the second-order Floquet-Gibbs state of this system is essentially indistinguishable from the steady state of the corresponding Redfield equation if the modulation and driving frequencies are sufficiently large.}, archive = {J_PRA}, author = {Wilson S. Martins and Federico Carollo and Kay Brandner and Igor Lesanovsky}, doi = {10.1103/PhysRevA.111.L010202}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010202}, shortjournal = {Phys. Rev. A}, title = {Quasiperiodic floquet-gibbs states in rydberg atomic systems}, volume = {111}, year = {2025}, }
• (2025). Certification of unbounded randomness with arbitrary noise. PRA, 111(1), L010201. (www)

  @article{ , abstract = {Random number generators play an essential role in cryptography and key distribution. It is thus important to verify whether the random numbers generated from these devices are genuine and unpredictable by any adversary. Recently, quantum nonlocality has been identified as a resource that can be utilized to certify randomness. Although these schemes are device independent and thus highly secure, the observation of quantum nonlocality is extremely difficult from a practical perspective. In this work, we provide a scheme to certify unbounded randomness in a semi-device-independent way based on the maximal violation of Leggett-Garg inequalities. Interestingly, the scheme is independent of the choice of the quantum state and consequently even classical noise like a thermal state or even microwave background radiation could be utilized to self-test quantum measurements and generate unbounded randomness, making the scheme highly efficient for practical purposes.}, archive = {J_PRA}, author = {Shubhayan Sarkar}, doi = {10.1103/PhysRevA.111.L010201}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {L010201}, shortjournal = {Phys. Rev. A}, title = {Certification of unbounded randomness with arbitrary noise}, volume = {111}, year = {2025}, }
• (2025). Erratum: Quantum advantage in batteries for sachdev-ye-kitaev interactions [Phys. rev. a 110, 062209 (2024)]. PRA, 111(1), 019901. (www)

  @article{ , abstract = {Phys. Rev. A 111, 019901 (2025)}, archive = {J_PRA}, author = {Gianluca Francica}, doi = {10.1103/PhysRevA.111.019901}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {019901}, shortjournal = {Phys. Rev. A}, title = {Erratum: Quantum advantage in batteries for sachdev-ye-kitaev interactions [Phys. rev. a 110, 062209 (2024)]}, volume = {111}, year = {2025}, }
• (2025). Reply to “Comment on ‘Revisiting the divergent multipole expansion of atom-surface interactions: Hydrogen and positronium, α-quartz, and physisorption' ”. PRA, 111(1), 016802. (www)

  @article{ , abstract = {It is shown that the criticism formulated in the preceding Comment fails to appreciate recently obtained results for the upper limit of the short-range expansion of atom-surface interactions, and that the application of our results to physisorption is based on a valid extension of Lifshitz theory to the physisorption range, which can be accomplished by refining the concept of the atom-surface distance with the help of a reference-plane that takes the response function of the solid into account. Some details on the calculation of the reference-plane are recalled from the literature.}, archive = {J_PRA}, author = {Ulrich D. Jentschura}, doi = {10.1103/PhysRevA.111.016802}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {016802}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Revisiting the divergent multipole expansion of atom-surface interactions: Hydrogen and positronium, α-quartz, and physisorption' ”}, volume = {111}, year = {2025}, }
• (2025). Comment on “Revisiting the divergent multipole expansion of atom-surface interactions: Hydrogen and positronium, α-quartz, and physisorption”. PRA, 111(1), 016801. (www)

  @article{ , abstract = {Recently, Jentschura [ Phys. Rev. A 109 , 012802 (2024) ] rederived the multipole corrections to the dipole part of the atom-wall interaction described by the Lifshitz theory using the concept of volume dielectric permittivity. These corrections were computed for the hydrogen and positronium atoms in close proximity to the α -quartz wall and claimed to be numerically significant within the short-range regime. Here, it is shown that the application areas of the obtained expressions in both the short- and long-range asymptotic regimes are indicated incorrectly, in contradiction with those dictated by the Lifshitz theory. As a result, within the valid application areas, all multipole corrections to the Casimir-Polder dipole part of the atom-wall interaction turned out to be negligibly small.}, archive = {J_PRA}, author = {G. L. Klimchitskaya}, doi = {10.1103/PhysRevA.111.016801}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {016801}, shortjournal = {Phys. Rev. A}, title = {Comment on “Revisiting the divergent multipole expansion of atom-surface interactions: Hydrogen and positronium, α-quartz, and physisorption”}, volume = {111}, year = {2025}, }
• (2025). Reply to “Comment on ‘Experimentally adjudicating between different causal accounts of bell-inequality violations via statistical model selection' ”. PRA, 111(1), 016201. (www)

  @article{ , abstract = {Our article described an experiment that adjudicates between different causal accounts of Bell inequality violations by a comparison of their predictive power, finding that certain types of models that are structurally radical but parametrically conservative—of which a class of superdeterministic models are an example—overfit the data relative to models that are structurally conservative but parametrically radical in the sense of endorsing an intrinsically quantum generalization of the framework of causal modeling. In their comment [ Phys. Rev. A 109 , 026201 (2024) ], Hance and Hossenfelder argue that we have misrepresented the purpose of superdeterministic models. We here dispute this claim by recalling the different classes of superdeterministic models we defined in our article and our conclusions regarding which of these are disfavored by our experimental results. Their confusion on this point seems to have arisen in part from the fact that we characterized superdeterministic models within a causal modeling framework and from the fact that we referred to this framework as “classical” in order to contrast it with an intrinsically quantum alternative. In this Reply, therefore, we take the opportunity to clarify these points. They also claim that if one is adjudicating between a pair of models, where one model can account for strictly more operational statistics than the other, the first model will tend to overfit the data relative to the second. Because this model inclusion relation can arise for pairs of models in a reductionist hierarchy, they conclude that overfitting should not be taken as evidence against the first model. We point out here that, contrary to this claim, one does not expect overfitting to arise generically in cases of model inclusion, so that it is indeed sometimes appropriate to consider overfitting as a criterion for adjudicating between such models.}, archive = {J_PRA}, author = {Patrick J. Daley and Kevin J. Resch and Robert W. Spekkens}, doi = {10.1103/PhysRevA.111.016201}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {016201}, shortjournal = {Phys. Rev. A}, title = {Reply to “Comment on ‘Experimentally adjudicating between different causal accounts of bell-inequality violations via statistical model selection' ”}, volume = {111}, year = {2025}, }
• (2025). Extended superradiance in two mechanically coupled dicke models. PRA, 111(1), 013717. (www)

  @article{ , abstract = {In this work, we explore the superradiant behavior of two Dicke models mechanically coupled through a shared vibrating membrane. Using a variational mean-field approach, we analyze the system's critical behavior and derive analytical expressions that reveal a threshold for the mechanical coupling. Below this threshold, the system allows for higher atomic-radiation couplings before resonant damping occurs, thereby extending the superradiant region compared to a single-cavity optomechanical Dicke model. Additionally, we examine the behavior of relevant observables across all regions of the phase diagram. Our findings suggest that these observables provide a more accurate characterization of the system's critical behavior than the traditionally used coupling parameters.}, archive = {J_PRA}, author = {L. F. Quezada and Guo-Qing Zhang and Shi-Hai Dong}, doi = {10.1103/PhysRevA.111.013717}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013717}, shortjournal = {Phys. Rev. A}, title = {Extended superradiance in two mechanically coupled dicke models}, volume = {111}, year = {2025}, }
• (2025). Coherent competition and control between three-wave mixing and four-wave mixing in superconducting circuits. PRA, 111(1), 013716. (www)

  @article{ , abstract = {Exploring intermixing and interplay between different frequency-mixing processes has always been one of the interesting subjects at the interface of nonlinear optics with quantum optics. Here we investigate coherent competition and control between three-wave mixing (TWM) and four-wave mixing (FWM) in a cyclic Δ -type three-level superconducting quantum system. In the weak control-field regime, strong competition leads to an alternating oscillation between TWM and FWM signals and this oscillation is a signature of strong energy exchange between these two nonlinear processes. In particular, such oscillation is absent from conventional multiwave mixing in atomic systems. Surprisingly, synchronous TWM and FWM processes are demonstrated in the strong control-field regime and, at the same time, their efficiencies can be as high as 42 and 47%, respectively. Our paper shows that these competitive behaviors between TWM and FWM can be manipulated by tuning the control-field intensity.}, archive = {J_PRA}, author = {Miao-Xiang Liang and Yu-Xiang Qiu and Hai-Chao Li and Wei Xiong}, doi = {10.1103/PhysRevA.111.013716}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013716}, shortjournal = {Phys. Rev. A}, title = {Coherent competition and control between three-wave mixing and four-wave mixing in superconducting circuits}, volume = {111}, year = {2025}, }
• (2025). Intracavity squeezing for a kerr quantum nondemolition measurement scheme. PRA, 111(1), 013715. (www)

  @article{ , abstract = {In the work by Balybin et al. [ Phys. Rev. A 108 , 053708 (2023) ], the scheme of quantum nondemolition measurement of optical quanta that uses a resonantly enhanced Kerr nonlinearity in the optical microresonator, presqueezing of the probe beam, and its parametric amplification before the detection was analyzed theoretically. It was shown that the main factor that limits the sensitivity of the considered scheme is the interplay of optical losses and the nonlinear self-phase modulation (SPM) effect. Here we show that using the intracavity squeezing of the probe beam in this scheme, it is possible to cancel out the SPM effect. In this case, the sensitivity will be limited only by the available power in the pump beam and by the input/output losses in the signal beam. Our estimates show that using the best optical microresonators currently available, the sensitivity for the intracavity photon number approaching the single-photon one can be achieved. Therefore, this scheme could be of interest for optical quantum information processing tasks.}, archive = {J_PRA}, author = {Dariya Salykina and Stepan Balybin and Farid Ya. Khalili}, doi = {10.1103/PhysRevA.111.013715}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013715}, shortjournal = {Phys. Rev. A}, title = {Intracavity squeezing for a kerr quantum nondemolition measurement scheme}, volume = {111}, year = {2025}, }
• (2025). Superconducting quantum circuit to simulate the dynamical casimir effect in a double cavity. PRA, 111(1), 013714. (www)

  @article{ , abstract = {In this work we study simulations of photon generation due to the dynamical Casimir effect (DCE) in a one-dimensional ( ) double superconducting cavity. To achieve this, we propose the use of a superconducting quantum circuit so as to be able to experimentally perform quantum simulations of the DCE. The simulated cavity consists of two perfectly conducting mirrors and a dielectric membrane of infinitesimal depth that effectively couples two cavities. The total length of the double cavity , the difference in length between the two cavities , and the electric susceptibility and conductivity of the dielectric membrane are tunable parameters. All four parameters are treated as independent and are allowed to be tuned at the same time, even with different frequencies. We analyze the cavity's energy spectra under different conditions, finding a transition between two distinct regimes that is accurately described by . In particular, a lowest-energy mode is forbidden in one of the regimes while it is allowed in the other. We compare analytical approximations obtained through the multiple-scale analysis method with exact numerical solutions, obtaining the typical results when is not being tuned. However, when the susceptibility is tuned, different behaviors (such as oscillations in the number of photons of a cavity prepared in a vacuum state) can arise if the frequencies and amplitudes of all parameters are adequate. These oscillations might be considered as adiabatic shortcuts where all generated photons are eventually destroyed.}, archive = {J_PRA}, author = {Jean Paul Louys Sansó and Nicolás F. Del Grosso and Fernando C. Lombardo and Paula I. Villar}, doi = {10.1103/PhysRevA.111.013714}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013714}, shortjournal = {Phys. Rev. A}, title = {Superconducting quantum circuit to simulate the dynamical casimir effect in a double cavity}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal entanglement in cavity magnomechanics via the barnett effect. PRA, 111(1), 013713. (www)

  @article{ , abstract = {We theoretically propose a scheme for achieving nonreciprocal bipartite and tripartite entanglement among magnons, photons, and phonons utilizing the Barnett effect in a cavity magnomechanical (CMM) system where a rotating yttrium iron garnet sphere is placed in a microwave cavity. The Barnett effect induces a Barnett frequency shift that can be effectively controlled to be either positive or negative by adjusting the direction of the magnetic field. As a result, nonreciprocal bipartite and tripartite entanglement can be achieved, exhibiting robustness against the bath temperature. Our work provides a very accessible way to manipulate photon-magnon-phonon quantum resources based on CMM devices with the Barnett effect.}, archive = {J_PRA}, author = {Tian-Xiang Lu and Zi-Shan Li and Liu-Sha Chen and Yan Wang and Xing Xiao and Hui Jing}, doi = {10.1103/PhysRevA.111.013713}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013713}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal entanglement in cavity magnomechanics via the barnett effect}, volume = {111}, year = {2025}, }
• (2025). Controllable on-chip generation and detection of path-entangled microwave photons. PRA, 111(1), 013712. (www)

  @article{ , abstract = {Path-entangled optical photons have played an important role in the multinode quantum network and quantum sensing, although most of them were usually generated probabilistically with linear optical platforms. Here, by using the spontaneous radiations of a pair of entangled solid-state qubits coupled to a common one-dimensional waveguide, we alternatively propose an on-chip approach to deterministically generate the path-entangled microwave single-photon state. With the trapped electrons on liquid helium, we specifically demonstrate its feasibility. In addition to the calculation of the von Neumann entropy for the entanglement witness, we show that the generated path-entanglement photons can be experimentally tested by simply measuring the distinguishability of the spontaneously emitted spectra of the photons being detected by the left and right single-photon detectors. The generalization of the proposal to the other solid-state experimental platforms is also discussed.}, archive = {J_PRA}, author = {Y. F. Li and D. He and S. R. He and L. F. Wei}, doi = {10.1103/PhysRevA.111.013712}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013712}, shortjournal = {Phys. Rev. A}, title = {Controllable on-chip generation and detection of path-entangled microwave photons}, volume = {111}, year = {2025}, }
• (2025). Spatial averaging for light reflection and transmission through cold-atom arrays. PRA, 111(1), 013711. (www)

  @article{ , abstract = {We theoretically and computationally investigate the role that the spatial spread of atoms plays in the transmission and reflection of weak light from atom arrays. In particular, we investigate whether coherent wave functions for the atoms' positions leads to different results from a thermal distribution with the same spatial spread. We find that the coherence is not relevant when the light is weak and the electronic states evolve on timescales shorter than the oscillation period of the atoms in their traps. Full numerical calculations and derivations using the sudden approximation show that reflection and transmission agree with the simple averaging over atom positions for these conditions. For parameters outside these restrictions, the simple spatial averaging may lead to inaccurate results.}, archive = {J_PRA}, author = {F. Robicheaux}, doi = {10.1103/PhysRevA.111.013711}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013711}, shortjournal = {Phys. Rev. A}, title = {Spatial averaging for light reflection and transmission through cold-atom arrays}, volume = {111}, year = {2025}, }
• (2025). Tripartite multiphoton jaynes-cummings model: Analytical solution and wigner nonclassicalities. PRA, 111(1), 013710. (www)

  @article{ , abstract = {We investigate a generic tripartite quantum system featuring a single qubit interacting concurrently with two quantized harmonic oscillators via nonlinear multiphoton Jaynes-Cummings (MPJC) interactions. Assuming the qubit is initially prepared in a superposition state and the two oscillators are in arbitrary Fock states, we analytically trace the temporal evolution of this tripartite pure initial state. We identify four broad cases, each further divided into two subcases, and derive exact analytical solutions for most cases. Notably, we obtain perfect transfer of excitations between the oscillators by carefully selecting system parameters. In addition, we extensively examine the manner in which the nonclassicalities of various initial oscillator Fock states, quantified by the volume of negative regions in the associated Wigner functions, evolve under the MPJC Hamiltonian, considering diverse system parameters including environmental effects. Besides producing substantial enhancements in the initial value for higher-photon-number states, our analysis reveals that driven solely by the initial qubit energy, with both oscillators initialized in the vacuum state, the nonlinear MPJC interaction yields a significant amount of nontrivial Wigner negativity in the oscillators. The additional nonlinearity introduced by the multiphoton process plays a pivotal role in surpassing the initial nonclassicalities of the photon-number states.}, archive = {J_PRA}, author = {Pradip Laha and P. A. Ameen Yasir and Peter van Loock}, doi = {10.1103/PhysRevA.111.013710}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013710}, shortjournal = {Phys. Rev. A}, title = {Tripartite multiphoton jaynes-cummings model: Analytical solution and wigner nonclassicalities}, volume = {111}, year = {2025}, }
• (2025). Enhancing tripartite photon-phonon-magnon entanglement by synergizing parametric amplifications. PRA, 111(1), 013709. (www)

  @article{ , abstract = {Tripartite entanglement as a remarkable resource in quantum information science has been extensively investigated in hybrid quantum systems, whereas it is generally weak and prone to be suppressed by noise, restricting its practical application in quantum technologies. Here, we propose how to enhance the tripartite entanglement among magnons, photons, and phonons in a hybrid cavity-magnon optomechanical system by exploiting a synergistic effect of the optical parametric amplification (OPA) and mechanical parametric amplification (MPA). We find that in the case of individually applying the OPA or MPA, the tripartite entanglement can be enhanced by several folds. Remarkably, upon suitably tuning the phase matching of the two parametric fields presented simultaneously, the strengths of the entanglement can be further enhanced due to the constructive interference between the OPA and MPA. We also show that our method can improve the robustness of the entanglement against thermal noise. Our work provides a promising method for manipulating the entanglement with easy tunability and may serve as a useful tool for the enhancement and protection of fragile quantum resources.}, archive = {J_PRA}, author = {Yan Wang and Jin-Lei Wu and Ya-Feng Jiao and Tian-Xiang Lu and Hui-Lai Zhang and Li-Ying Jiang and Le-Man Kuang and Hui Jing}, doi = {10.1103/PhysRevA.111.013709}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013709}, shortjournal = {Phys. Rev. A}, title = {Enhancing tripartite photon-phonon-magnon entanglement by synergizing parametric amplifications}, volume = {111}, year = {2025}, }
• (2025). Kerr-magnon-assisted asymptotic stationary photon-phonon squeezing. PRA, 111(1), 013708. (www)

  @article{ , abstract = {Bosonic two-mode squeezed states are paradigmatic entangled states in continuous variable systems, which have broad applications in quantum information processing. In this work, we propose a photon-phonon squeezing protocol assisted by a Kerr magnon within a hybrid cavity magnomechanical system. We construct an effective Hamiltonian that accounts for photon-phonon squeezing through strong photon-magnon interaction and modulation over the driving on the photon mode. The effective Hamiltonian can be confirmed by the diagonalization of the system's Liouvillian superoperator. With the effective Hamiltonian and quantum Langevin equation, we provide a rigorous theoretical solution for the dynamical process of squeezing generation. Our finding indicates that the asymptotic stationary squeezing can be obtained by optimizing the squeezing quadrature operator, even when the covariance matrix of the system still varies with time. This squeezing level can exceed the maximum value under stable conditions. Moreover, our analysis reveals that a proper Kerr nonlinearity of the magnon can further promote the squeezing generation. Our work provides an extendable framework for generating squeezed states of two Gaussian modes with indirect coupling.}, archive = {J_PRA}, author = {Shi-fan Qi and Jun Jing}, doi = {10.1103/PhysRevA.111.013708}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013708}, shortjournal = {Phys. Rev. A}, title = {Kerr-magnon-assisted asymptotic stationary photon-phonon squeezing}, volume = {111}, year = {2025}, }
• (2025). Coherent control of spontaneous emission for a giant driven Λ-type three-level atom. PRA, 111(1), 013707. (www)

  @article{ , abstract = {Quantum optics with giant atoms provides a new approach for implementing optical memory devices at the atomic scale. Here, we theoretically investigate the relaxation dynamics of a single driven three-level atom interacting with a one-dimensional waveguide via two coupling points. Under certain conditions, after long-time dynamics, we find that the population of the giant atom can either remain stable or exhibit regular periodic oscillations, while photons are trapped within the region of the giant atom. This phenomenon cannot be realized using a two-level atom configured with two coupling points. It is noteworthy that the atomic excitation probability of a stable bound state is a constant value, which is determined by the size of the atom. Importantly, the size of the atom, defined as the distance between the two coupling points, is significantly larger than the wavelength of the light field, which is a necessary condition for the existence of oscillating bound states.}, archive = {J_PRA}, author = {Ya Yang (杨亚 and Ge Sun (孙葛 and Jing Li (李静 and Jing Lu (卢竞 and Lan Zhou (周兰}, doi = {10.1103/PhysRevA.111.013707}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013707}, shortjournal = {Phys. Rev. A}, title = {Coherent control of spontaneous emission for a giant driven Λ-type three-level atom}, volume = {111}, year = {2025}, }
• (2025). Tunable ultrahigh broadband reflection via collective atom-atom interaction in a waveguide-QED system. PRA, 111(1), 013706. (www)

  @article{ , abstract = {We present a scheme for achieving broadband complete reflection by constructing photonic band gap via collective atom-atom interaction in a one-dimensional (1D) waveguide quantum electrodynamics (QED) system. Moreover, we propose several strategies to further expand the ultrahigh-reflection windows, including increasing the number of atoms with separations near the Bragg distance and inducing gradient frequency modulation among the atoms. The center frequency and bandwidth of the ultrahigh-reflection window are dynamically adjustable by applying external electromagnetic field. The results here can enrich the many-body physics of the waveguide-QED system and offer a pathway for achieving broadened ultrahigh reflection in a controllable way, which can find important applications in the realms of chip-integrated band filter, quantum storage, optical switching, and wavelength-selective devices.}, archive = {J_PRA}, author = {Xin Wang and Junjun He and Zeyang Liao and M. Suhail Zubairy}, doi = {10.1103/PhysRevA.111.013706}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013706}, shortjournal = {Phys. Rev. A}, title = {Tunable ultrahigh broadband reflection via collective atom-atom interaction in a waveguide-QED system}, volume = {111}, year = {2025}, }
• (2025). Self-ordering, cooling, and lasing in an ensemble of clock atoms. PRA, 111(1), 013705. (www)

  @article{ , abstract = {Active atomic clocks are predicted to provide far better short-term stability and robustness against thermal fluctuations than typical feedback-based optical atomic clocks. However, continuous laser operation using an ensemble of clock atoms still remains an experimentally challenging task. We study spatial self-organization in a transversely driven ensemble of clock atoms inside an optical resonator and coherent light emission from the cavity. We focus on the spectral properties of the emitted light in the narrow atomic linewidth regime, where the phase coherence providing frequency stability is stored in the atomic dipoles rather than the cavity field. The atoms are off-resonantly driven by a standing-wave coherent laser transversely to the cavity axis, allowing for atomic motion along the cavity axis as well as along the pump. In order to treat larger atom numbers we employ a second-order cumulant expansion which allows us to calculate the spectrum of the cavity light field. We identify the self-organization threshold where the atoms align themselves in a checkerboard pattern, thus maximizing light scattering into the cavity, which simultaneously induces cooling. For a larger driving intensity, more atoms are transferred to the excited state, reducing cooling but increasing light emission from the excited atoms. This can be enhanced via a second cavity mode at the atomic frequency spatially shifted by a quarter wavelength. For large enough atom numbers we observe laser-like emission close to the bare atomic transition frequency.}, archive = {J_PRA}, author = {Anna Bychek and Laurin Ostermann and Helmut Ritsch}, doi = {10.1103/PhysRevA.111.013705}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013705}, shortjournal = {Phys. Rev. A}, title = {Self-ordering, cooling, and lasing in an ensemble of clock atoms}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal steering between optical and microwave waves by bogoliubov cooling in a cavity optomagnonic system. PRA, 111(1), 013704. (www)

  @article{ , abstract = {Optical-microwave quantum correlations are pivotal for hybrid quantum network construction. Here, we propose a scheme to achieve nonreciprocal optical-microwave steering via Bogoliubov cooling in a cavity optomagnonic system, where optical and microwave modes couple to magnons in a YIG sphere through optomagnonic and magnetic dipole interactions, respectively. By selectively applying bias magnetic fields to the YIG sphere in different directions, Kerr nonlinearity induces nonreciprocal Bogoliubov cooling effects, thereby engendering highly nonreciprocal steering. Our study presents a novel avenue for achieving nonreciprocal steering between optical and microwave fields, with potential applications in chiral quantum networking.}, archive = {J_PRA}, author = {Deyi Kong and Fei Wang}, doi = {10.1103/PhysRevA.111.013704}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013704}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal steering between optical and microwave waves by bogoliubov cooling in a cavity optomagnonic system}, volume = {111}, year = {2025}, }
• (2025). Quantum and classical correlations in four-wave mixing from cold ensembles of two-level atoms. PRA, 111(1), 013703. (www)

  @article{ , abstract = {Quantum correlations in four-wave-mixing from ensembles of cold two-level atoms may prevail without filtering over background light with well-known classical interpretations, such as Rayleigh scattering, as recently experimentally demonstrated in Phys. Rev. Lett. 128 , 083601 (2022) . Here we provide an extended investigation of this effect, in which we detail the experimental procedure and the variation of the quantum correlation with various parameters of the system. Particularly, we show that the decay rate of the quantum correlations changes with the number of atoms in the sample, providing another indication of its superradiance-like nature. The nonclassical aspects of the signal occur for short timescales, but the long timescales carry as well a lot of information on the classical correlations of the system. This slow classical regime presents also two clearly distinct timescales, which we explain by two different pathways for the creation of biphotons. From the global analysis of the data in all its timescales, we are able to derive an empirical expression to fit the data, resulting in information on, among other parameters, the sample's temperature and superradiant-like acceleration. In general, the reported quantum correlations present a dependence on critical parameters of the system, such as optical depth and excitation power, that is quite different from other systems used for biphoton generation, and are more robust to changes in these parameters. This opens the possibility of exploring this process for efficient generation of narrow-band biphotons or of other quantum-correlated photonic states of higher order.}, archive = {J_PRA}, author = {Lucas S. Marinho and Michelle O. Araújo and Daniel Felinto}, doi = {10.1103/PhysRevA.111.013703}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013703}, shortjournal = {Phys. Rev. A}, title = {Quantum and classical correlations in four-wave mixing from cold ensembles of two-level atoms}, volume = {111}, year = {2025}, }
• (2025). Quantum-noise-induced nonreciprocity for single-photon transport in parity-time-symmetric systems. PRA, 111(1), 013702. (www)

  @article{ , abstract = {We show nonreciprocal light propagation for single-photon inputs due to quantum noise in coupled optical systems with gain and loss. We consider two parity-time -symmetric linear optical systems consisting of either two directly coupled resonators or two finite-length waveguides evanescently coupled in parallel. One resonator or waveguide is filled with an active gain medium and the other with a passive loss medium. The light propagation is reciprocal in such -symmetric linear systems without quantum noise. We show here that light transmission becomes nonreciprocal when we include quantum noises in our modeling, which is essential for a proper physical description. The quantum nonreciprocity is especially pronounced in the broken phase. Transmitted light intensity in the waveguide of incidence is asymmetric for two waveguides, even without noise. Quantum noise significantly enhances such asymmetry in the broken phase.}, archive = {J_PRA}, author = {Dibyendu Roy and G. S. Agarwal}, doi = {10.1103/PhysRevA.111.013702}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013702}, shortjournal = {Phys. Rev. A}, title = {Quantum-noise-induced nonreciprocity for single-photon transport in parity-time-symmetric systems}, volume = {111}, year = {2025}, }
• (2025). Single-photon microwave switch with a recoverable control photon. PRA, 111(1), 013701. (www)

  @article{ , abstract = {Scalable quantum technologies may be applied in prospective architectures employing traditional information processing elements, such as transistors, rectifiers, or switches modulated by low-power inputs. In this respect, recently developed quantum processors based, e.g., on superconducting circuits may alternatively be employed as the basic platform for ultra-low-power consumption classical processors, in addition to obvious applications in quantum information processing and quantum computing. Here we propose a single-photon microwave switch based on a circuit quantum electrodynamics setup, in which a single control photon in a transmission line is able to switch on or off the propagation of another single photon in a separate line. The performances of this single-photon switch are quantified in terms of the photon flux through the output channel, providing a direct comparison of our results with available data. Furthermore, we show how the design of this microwave switch enables the recovery of the single control photon after the switching process. This proposal may be readily realized in state-of-art superconducting circuit technology.}, archive = {J_PRA}, author = {Davide Rinaldi and Davide Nigro and Dario Gerace}, doi = {10.1103/PhysRevA.111.013701}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013701}, shortjournal = {Phys. Rev. A}, title = {Single-photon microwave switch with a recoverable control photon}, volume = {111}, year = {2025}, }
• (2025). Phase-tunable inverse hong-ou-mandel interference: Principles and demonstration in a photon pair source. PRA, 111(1), 013531. (www)

  @article{ , abstract = {A method is presented for the separation of polarization-entangled, frequency-degenerate photon pairs based on inverse Hong-Ou-Mandel interference. Adjusting the phase between photon states is achieved by exploiting the wavelength dispersion of optical glass, for which process a complete mathematical description is given. To experimentally demonstrate the phenomenon, a custom photon pair source has been built using spontaneous parametric downconversion of type-0 phase matching and a Sagnac interferometer. The effect of phase tuning was characterized by the modulation of coincidence probability. The visibility of quantum interference was found to be 0.820 and 0.720 for photons being in purely horizontal or vertical polarization state. In case of polarization entanglement, the measured state fidelity with respect to the Bell state was 0.914.}, archive = {J_PRA}, author = {Csaba Tamás Holló and Tamás Sarkadi and Attila Barócsi and Pál Koppa and Gábor Erdei}, doi = {10.1103/PhysRevA.111.013531}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013531}, shortjournal = {Phys. Rev. A}, title = {Phase-tunable inverse hong-ou-mandel interference: Principles and demonstration in a photon pair source}, volume = {111}, year = {2025}, }
• (2025). Laser filamentation: Insights from inverse-scattering analysis. PRA, 111(1), 013530. (www)

  @article{ , abstract = {The inverse-scattering analysis of the nonlinear Schrödinger equation (NSE) is shown to provide powerful insights into a beam breakup and filamentation dynamics of high-power laser pulses. In the highly nonlinear regime, in which a laser beam tends to break up into multiple filaments as a part of its nonlinear dynamics, the scattering-space waves representing real-space NSE fields are shown to obey the scalar wave equation for the field in a fictitious waveguide with an index profile as dictated by the Kerr lens induced by the laser beam. Despite the drastic differences in the ways the inverse-scattering framework and the Bespalov-Talanov theory of beam filamentation treat nonlinear beam dynamics, the angular spectrum of beam instabilities and the transverse size of filaments in both frameworks can be understood on strikingly similar grounds—in terms of wave-vector matching, reflecting the wave-by-wave scattering nature of the emerging filamentary beam structure.}, archive = {J_PRA}, author = {A. M. Zheltikov}, doi = {10.1103/PhysRevA.111.013530}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013530}, shortjournal = {Phys. Rev. A}, title = {Laser filamentation: Insights from inverse-scattering analysis}, volume = {111}, year = {2025}, }
• (2025). Bound states in the continuum in a double whispering-gallery resonator. PRA, 111(1), 013529. (www)

  @article{ , abstract = {In this work we investigate the single-photon transport through two whispering-gallery resonators (WGRs) coupled to a one-dimensional waveguide. Using the Green's-function formalism, we compute the transmission spectra and the photonic density of states for the stationary states. We also obtain the formation of two types of bound states in the continuum (BICs). The first kind is localized in the WGR and is symmetry-protected BICs. In contrast, the second depends on the distance between resonators through the waveguide and is of the Fabry-Pérot kind. These BICs are represented as Dirac functions in the local density of states. Additionally, we show that quasi-BICs manifest as sharp resonances in photonic transmission due to small symmetry-breaking perturbations. Furthermore, we investigate the dynamics of a single-photon wave packet interacting with the WGRs and analyze the mechanism for storing the wave packet in the structure formed by the WGRs and the finite waveguide between them.}, archive = {J_PRA}, author = {Alexis R. Legón and M. Ahumada and J. P. Ramos-Andrade and Rafael A. Molina and P. A. Orellana}, doi = {10.1103/PhysRevA.111.013529}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013529}, shortjournal = {Phys. Rev. A}, title = {Bound states in the continuum in a double whispering-gallery resonator}, volume = {111}, year = {2025}, }
• (2025). Classical dipole radiation revisited. PRA, 111(1), 013528. (www)

  @article{ , abstract = {The fields produced by a classical point electric dipole are investigated. The dipole is turned on smoothly at t = 0 and the classical dipole moment is assumed to correspond to either a linearly polarized damped oscillator, a static dipole, or a rotating dipole. It is shown that Poynting's theorem can be violated if it is assumed the dipole is turned on suddenly and derivatives of the step function associated with the sudden turn on are not properly accounted for. For the rotating dipole, it is shown that the angular momentum in the field need not be equal to the sum of its spin and orbital components. Moreover, the total angular momentum that is radiated by the rotating dipole is not equal to the original mechanical angular momentum of the dipole.}, archive = {J_PRA}, author = {P. R. Berman and A. Kuzmich and P. W. Milonni}, doi = {10.1103/PhysRevA.111.013528}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013528}, shortjournal = {Phys. Rev. A}, title = {Classical dipole radiation revisited}, volume = {111}, year = {2025}, }
• (2025). Relationship between total reflection and fabry-perot bound states in the continuum. PRA, 111(1), 013527. (www)

  @article{ , abstract = {Bound states in the continuum (BICs) have interesting properties and important applications in photonics. A particular class of BICs are found in Fabry-Perot (FP) cavities formed by two parallel periodic dielectric layers separated by a distance . A periodic dielectric layer can totally reflect a plane incident wave with a particular frequency and a particular wave number. Existing FP-BICs are found when is close to the values deduced from a phase-matching condition related to the reflection coefficient, but they are obtained in FP cavities where the periodic layers have a reflection symmetry in the periodic direction. In this paper, we further clarify the connection between total reflections and FP-BICs. Our numerical results indicate that if the wave number is zero or the periodic layers have a reflection symmetry in the periodic direction, FP-BICs can indeed be found near the parameters of total reflections. However, if the wave number is nonzero and the periodic layer is asymmetric (in the periodic direction), we are unable to find a FP-BIC (with a frequency and a wave number near those of a total reflection) by tuning or other structural parameters. Consequently, a total reflection does not always lead to a FP-BIC even when the parameters of the FP cavity are tuned.}, archive = {J_PRA}, author = {Zitao Mai and Ya Yan Lu}, doi = {10.1103/PhysRevA.111.013527}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013527}, shortjournal = {Phys. Rev. A}, title = {Relationship between total reflection and fabry-perot bound states in the continuum}, volume = {111}, year = {2025}, }
• (2025). Long-range dipole-dipole interactions enabled with the guided plasmons of matched nanoparticle-on-mirror antenna pairs. PRA, 111(1), 013526. (www)

  @article{ , abstract = {Ruling a wide range of phenomena, dipole-dipole interactions (DDI) are typically constrained to the short range due to their rapid decay with increasing dipole separations, limiting performance in long-range applications. By judiciously designing the photonic structures that control the two-point Green's functions of the electromagnetic environment, the spontaneous emission of quantum emitters (luminescence) and their interactions (e.g., Förster energy transfer) can be conveniently tuned. In this paper, we design a matched nanoparticle-on-mirror antenna pair with enhanced DDI guided by surface plasmon polaritons confined to the metal substrate, which ensures concentrated and enhanced interaction over long ranges of tens of wavelengths. The long-range ( ) DDI between donor-acceptor emitters is enhanced by times respective to bare gold film, and times respective to a vacuum. Our result provides a promising testbed for investigating long-range DDI phenomena on the nanoscale.}, archive = {J_PRA}, author = {Bowen Kang and Huatian Hu and Huan Chen and Zhenglong Zhang}, doi = {10.1103/PhysRevA.111.013526}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013526}, shortjournal = {Phys. Rev. A}, title = {Long-range dipole-dipole interactions enabled with the guided plasmons of matched nanoparticle-on-mirror antenna pairs}, volume = {111}, year = {2025}, }
• (2025). Two-membrane etalon. PRA, 111(1), 013525. (www)

  @article{ , abstract = {Optomechanics with semi-transparent membrane multioscillators in a high-finesse cavity is an established solution for designing the dispersive interaction, and reaching many achievements, such as the study of nonlinear dynamics, heat transfer, and so on. The multioscillators are dielectric slabs, usually with low reflectivity, constituting an etalon. Here we propose the theoretical and experimental investigation of a low-finesse optical cavity formed by two (nominally identical) parallel semi-transparent membranes. The experiment consists in laser-driving the cavity, detecting interferometrically the field reflected by the etalon, and measuring the intensity of the transmitted field, for different distances within the two membranes. A complete characterization of the membrane sandwich is provided. Moreover, we develop an analytical model to describe the fields, which reproduces all the experimental results, under specific approximations. As expected, the model reproduces the known results when high-reflectivity, and/or fixed mirrors conditions are restored. This work paves the way for a complete and analytical model to describe multi-oscillators “membrane-in-the-middle” optomechanics.}, archive = {J_PRA}, author = {F. Marzioni and R. Natali and N. Malossi and D. Vitali and G. Di Giuseppe and P. Piergentili}, doi = {10.1103/PhysRevA.111.013525}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013525}, shortjournal = {Phys. Rev. A}, title = {Two-membrane etalon}, volume = {111}, year = {2025}, }
• (2025). Effects of quadratic optomechanical coupling on bipartite entanglements, mechanical ground-state cooling, and mechanical quadrature squeezing in an electro-optomechanical system. PRA, 111(1), 013524. (www)

  @article{ , abstract = {We theoretically investigate the steady-state bipartite entanglements, mechanical ground-state cooling, and mechanical quadrature squeezing in a hybrid electro-optomechanical system where a moving membrane is linearly coupled to the microwave field mode of an LC circuit, while it simultaneously interacts both linearly and quadratically with the radiation pressure of a single-mode optical cavity. We show that by choosing a suitable sign and amplitude for the quadratic optomechanical coupling (QOC), one can achieve enhanced and thermally robust stationary bipartite entanglement between the subsystems, improved mechanical ground-state cooling, and -quadrature squeezing of the mechanical mode beyond the 3-dB limit of squeezing. In particular, we find that in the presence of QOC with negative sign and in the resolved sideband regime the bipartite optical-mechanical entanglement can be increased by about 2 orders of magnitude around the temperature of 1 mK, and it can be preserved against thermal noise up to the ambient temperature of 0.1 K. Furthermore, the QOC with positive sign can give rise to the enhancement of the mechanical ground-state cooling by about 1 order of magnitude in the optical and microwave red-detuned regime. We also find that for the positive sign of QOC and near the microwave resonance frequency the squeezing degree of the quadrature of the mechanical mode can be amplified up to 15 dB. Such a hybrid electro-optomechanical system can serve as a promising platform to engineer an improved entangled source for quantum sensing as well as quantum information processing.}, archive = {J_PRA}, author = {N. Ghorbani and Ali Motazedifard and M. H. Naderi}, doi = {10.1103/PhysRevA.111.013524}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013524}, shortjournal = {Phys. Rev. A}, title = {Effects of quadratic optomechanical coupling on bipartite entanglements, mechanical ground-state cooling, and mechanical quadrature squeezing in an electro-optomechanical system}, volume = {111}, year = {2025}, }
• (2025). Self-cleaning of nondiffracting speckle fields in second-harmonic generation. PRA, 111(1), 013523. (www)

  @article{ , abstract = {We present results on the second-harmonic generation using nondiffracting speckle fields in the fundamental frequency to pump a nonlinear medium to obtain the sum-frequency generation. Our findings reveal a significant enhancement in the spatial coherence within the central region of the far-field diffraction pattern of the second-harmonic field when using nondiffracting speckles, compared to a diffracting speckle field of the same coherence length before the nonlinear medium. Our findings may contribute to the design of systems for free-space optical communication or the implementation of imaging and sensing systems using nondiffracting speckles fields.}, archive = {J_PRA}, author = {José G. M. N. Neto and Eduardo J. S. Fonseca and Alcenísio J. Jesus-Silva}, doi = {10.1103/PhysRevA.111.013523}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013523}, shortjournal = {Phys. Rev. A}, title = {Self-cleaning of nondiffracting speckle fields in second-harmonic generation}, volume = {111}, year = {2025}, }
• (2025). Half-cycle dissipative solitons in a multilevel resonant medium. PRA, 111(1), 013522. (www)

  @article{ , abstract = {We theoretically investigate the possibility of the formation of subcycle dissipative solitons propagating in a multilevel resonant medium. We examine the case when the duration of light pulses is significantly smaller than the periods of resonant transitions in the medium. Within such an approximation, a nonlinear integro-differential equation describing the spatiotemporal evolution of the electric field was derived. We demonstrate that in the case of a preexcited medium, this equation has solutions in the form of stable half-cycle unipolar dissipative solitons with the parameters determined by the medium properties. The obtained results can provide an important step towards the efficient transmission of subcycle pulses through optical media.}, archive = {J_PRA}, author = {Anton Pakhomov}, doi = {10.1103/PhysRevA.111.013522}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013522}, shortjournal = {Phys. Rev. A}, title = {Half-cycle dissipative solitons in a multilevel resonant medium}, volume = {111}, year = {2025}, }
• (2025). Motional entanglement of remote optically levitated nanoparticles. PRA, 111(1), 013521. (www)

  @article{ , abstract = {We show how to entangle the motion of optically levitated nanoparticles in distant optical tweezers. The scheme consists in coupling the inelastically scattered light of each particle into transmission lines and directing it towards the other particle. The interference between this light and the background field introduces an effective coupling between the two particles while simultaneously reducing the effect of recoil heating. We analyze the system dynamics, showing that both transient and conditional entanglement between remote particles can be achieved under realistic experimental conditions.}, archive = {J_PRA}, author = {N. Carlon Zambon and M. Rossi and M. Frimmer and L. Novotny and C. Gonzalez-Ballestero and O. Romero-Isart and A. Militaru}, doi = {10.1103/PhysRevA.111.013521}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013521}, shortjournal = {Phys. Rev. A}, title = {Motional entanglement of remote optically levitated nanoparticles}, volume = {111}, year = {2025}, }
• (2025). Optical forces on atoms subject to higher-order poincaré vortex modes. PRA, 111(1), 013520. (www)

  @article{ , abstract = {The interaction of atoms with higher-order Poincaré optical vortex modes of order is explored for light close to resonance with atomic dipole transitions. It is well known that atoms subject to optical vortex modes experience both translational and rotational forces acting on the atomic center of mass, leading to atom dynamics and atom trapping. Here we consider the optical forces on atoms immersed in general paraxial higher-order Poincaré optical vector modes. The coupling to atoms gives rise to wide-ranging scenarios involving such modes in which any specific polarization is within a spectrum of wave polarization and all the interactions are treatable within a single formulation. We show that this gives rise to a variety of physical situations, governed by the mode order , the polarization represented by the angular coordinates of the mode on the surface of the unit Poincaré sphere, the atomic transitions involved, and their selection rules. We present the analytical steps leading to the optical forces on sodium atoms and display their variations in various situations.}, archive = {J_PRA}, author = {Smail Bougouffa and Mohamed Babiker}, doi = {10.1103/PhysRevA.111.013520}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013520}, shortjournal = {Phys. Rev. A}, title = {Optical forces on atoms subject to higher-order poincaré vortex modes}, volume = {111}, year = {2025}, }
• (2025). Mode competition of a phonon laser induced by ultrastrong cavity-magnon coupling. PRA, 111(1), 013519. (www)

  @article{ , abstract = {In cavity magnomechanics, we find that the unique ultrastrong magnon-microwave photon interaction can induce mode competition in multimode phonon lasers, even though each mechanical mode is coupled to its respective driven magnon mode, which plays the similar role of the gain medium in the optical laser. Such a separate model corresponds to a richer phase diagram compared to that in which all modes are immersed in a common gain medium, in particular containing a second-order phase transition: the excited oscillator changes its behavior from suppression to absorption of the other oscillator's energy, leading to an obvious cooling by heating phenomenon. The mode competition phase transition also has a good correspondence with the synchronization phenomenon between the self-sustaining dynamics of the phonon modes. Finally, we discuss that the mode competition will be weakened as more modes are present in the system. Our work provides a foundation for related studies such as the self-sustaining dynamics of multibodies with complex structures.}, archive = {J_PRA}, author = {Wenlin Li and Jiong Cheng and Jie Li}, doi = {10.1103/PhysRevA.111.013519}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013519}, shortjournal = {Phys. Rev. A}, title = {Mode competition of a phonon laser induced by ultrastrong cavity-magnon coupling}, volume = {111}, year = {2025}, }
• (2025). Dynamical phases of a bose-einstein condensate in a bad optical cavity at optomechanical resonance. PRA, 111(1), 013518. (www)

  @article{ , abstract = {We study the emergence of dynamical phases of a Bose-Einstein condensate that is optomechanically coupled to a dissipative cavity mode and transversally driven by a laser. We focus on the regime close to the optomechanical resonance, where the atoms' refractive index shifts the cavity into resonance, assuming fast cavity relaxation. We derive an effective model for the atomic motion, where the cavity degrees of freedom are eliminated using perturbation theory in the atom-cavity coupling and benchmark its predictions using numerical simulations based on the full model. Away from the optomechanical resonance, perturbation theory in the lowest order (adiabatic elimination) reliably describes the dynamics and predicts chaotic phases with unstable oscillations. Interestingly, the dynamics close to the optomechanical resonance are qualitatively captured only by including the corrections to next order (nonadiabatic corrections). In this regime we find limit-cycle phases that describe stable oscillations of the density with a well-defined frequency. We further show that such limit-cycle solutions are metastable configurations of the adiabatic model. Our work sheds light on the mechanisms that are required to observe dynamical phases and predict their existence in atom-cavity systems where a substantial timescale separation is present.}, archive = {J_PRA}, author = {Gage W. Harmon and Giovanna Morigi and Simon B. Jäger}, doi = {10.1103/PhysRevA.111.013518}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013518}, shortjournal = {Phys. Rev. A}, title = {Dynamical phases of a bose-einstein condensate in a bad optical cavity at optomechanical resonance}, volume = {111}, year = {2025}, }
• (2025). Nonreciprocal photonic transistor with a spinning polaritonic microcavity. PRA, 111(1), 013517. (www)

  @article{ , abstract = {We propose a theoretical scheme to achieve a nonreciprocal polaritonic photonic transistor by using a spinning microresonator coupled to a tapered fiber. In such a nonreciprocal device, owing to the combination of Sagnac effects and Stokes or anti-Stokes scattering, the transmission of probe light in clockwise and counterclockwise directions exhibits clockwise (counterclockwise) unidirectional amplification, bidirectional amplification, and bidirectional attenuation, simultaneously accompanied by unidirectional slow-fast light, bidirectional fast light, and bidirectional slow light, which can be effectively modulated by pump fields and couplings among excitons, photons, and phonons. In particular, we also discover perfect unidirectional transmission, i.e., the transmission in the opposite direction is completely blocked, and fast-slow light switching by appropriately regulating pump fields, which is optimal for signal isolation and controllable group advance-delay switching. Therefore, our proposed nonreciprocal photonic transistor is an excellent multifunctional device with various amplification-attenuation transmission and fast-slow light nonreciprocities. Our results provide an opportunity to engineer multifunctional nonreciprocal photonic devices, which may be useful for building integrated photonic circuits, chiral quantum technologies, and quantum communication networks.}, archive = {J_PRA}, author = {Zi-Fa Yu and Peng-Fei Yan and Ji-Ming Gao and Fang-Qi Hu and Zhengmei Zhang and Ai-Xia Zhang and Ju-Kui Xue}, doi = {10.1103/PhysRevA.111.013517}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013517}, shortjournal = {Phys. Rev. A}, title = {Nonreciprocal photonic transistor with a spinning polaritonic microcavity}, volume = {111}, year = {2025}, }
• (2025). Physical origin of the repelling gradient force on a dielectric sphere in an evanescent wave. PRA, 111(1), 013516. (www)

  @article{ , abstract = {Generally, a gradient force draws a dielectric sphere towards the region of high light intensity. However, this force may repel the sphere when a Rayleigh particle's effective polarizability has a negative real part, or when a dielectric sphere's whispering gallery modes (WGMs) are excited. For a dielectric sphere larger than a Rayleigh particle but not large enough to excite WGMs, the possibility of experiencing this “anomalous” gradient force remains uncertain. Our study employs multipole expansion theory to investigate gradient forces on a dielectric sphere in an evanescent wave. We find that the sphere may be pushed away from the high-intensity region regardless of WGM excitation, due to multipole-incident field coupling. However, the underlying mechanisms differ. For an -polarized incident evanescent wave, WGM excitation limits the contribution to the gradient force from a specific order of multipole. The gradient force is notably stronger for transverse magnetic mode excitation compared to transverse electric mode, due to differences in the electromagnetic energy density gradient's contribution. Without WGMs, multiple multipoles—interestingly, only magnetic ones—contribute to this gradient force. We provide an intuitive explanation for the dielectric sphere experiencing gradient forces in opposite directions by analyzing internal field distributions and the optical force density within the sphere. Additionally, we explore how evanescent wave decay rates and polarizations influence gradient forces by analyzing recoil forces and imaginary Poynting momentum density contributions. These in-depth studies deepen our understanding of near-field optical manipulation mechanisms and provide a theoretical foundation for designing innovative optical devices and systems.}, archive = {J_PRA}, author = {Yaxin Li and Xinning Yu and Tiantao Qu and Lei Zhang and Jun Chen}, doi = {10.1103/PhysRevA.111.013516}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013516}, shortjournal = {Phys. Rev. A}, title = {Physical origin of the repelling gradient force on a dielectric sphere in an evanescent wave}, volume = {111}, year = {2025}, }
• (2025). LiNbO3 and AlGaAs on-insulator platforms for second-harmonic generation: Comparison and perspectives. PRA, 111(1), 013515. (www)

  @article{ , abstract = {The rise of aluminum gallium arsenide on-insulator (AlGaAsOI) and lithium niobate on-insulator (LNOI) platforms presents new opportunities for advancing on-chip and ultracompact nonlinear photonic devices. In this study, we investigate theoretically and via numerical simulations second-harmonic generation (SHG) in AlGaAsOI and LNOI waveguides across a wide range of pulse widths, from the subpicosecond to the continuous-wave regime, and peak power levels spanning from milliwatts to hundreds of watts. Our research aims to identify optimal time and power regimes for achieving high SHG conversion efficiency, exploring the detrimental impact of linear and nonlinear losses as well as dispersion effects. Additionally, we assess the performance of SHG against manufacturing errors and surface roughness, comparing our findings with state-of-the-art solutions. These results offer insights into the robustness and potential applications of SHG in these advanced photonic platforms.}, archive = {J_PRA}, author = {Jack Haines and Pooja Uday Naik and Massimiliano Guasoni and Marco Gandolfi}, doi = {10.1103/PhysRevA.111.013515}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013515}, shortjournal = {Phys. Rev. A}, title = {LiNbO3 and AlGaAs on-insulator platforms for second-harmonic generation: Comparison and perspectives}, volume = {111}, year = {2025}, }
• (2025). Nonlinear multistable potential traps. PRA, 111(1), 013514. (www)

  @article{ , abstract = {This paper presents a comprehensive theoretical framework for nonlinear optical trapping, verified by numerical simulations. The roles of thermal nonlinearity, two-photon absorption (TPA), and Kerr nonlinearity are thoroughly examined in the formation of split traps. We demonstrate the formation of an attractive scattering force generated by TPA, which is distinct from previously reported attractive scattering forces J. Chen et al. [ Nat. Photon. 5 , 531 (2011) ; O. Brzobohatỳ et al. , Nat. Photon. 7 , 123 (2013) ]. We also introduce efficient methods for accurately calculating trap stiffness by modeling nonlinear trap potentials as nonlinear harmonic oscillators. Furthermore, we offer an alternative perspective on nonlinear traps by considering them as hybrid traps. This work enhances the understanding of the nonlinear optical trapping mechanism and provides a robust framework for future experimental studies in quantum mechanics and high-precision optical manipulation.}, archive = {J_PRA}, author = {S. Mirzaei-Ghormish and D. Smalley and R. Camacho}, doi = {10.1103/PhysRevA.111.013514}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013514}, shortjournal = {Phys. Rev. A}, title = {Nonlinear multistable potential traps}, volume = {111}, year = {2025}, }
• (2025). Period-4 modulation instability in ring fiber cavities. PRA, 111(1), 013513. (www)

  @article{ , abstract = {We predict the existence of a period-4 temporal dynamics in the nonlinear stage of modulation instability of light inside a passive ring fiber Kerr cavity. We investigate analytically and numerically the stability of period-doubled continuous-wave solutions of the Ikeda map describing waves oscillating between two well-defined power levels at consecutive round trips. We prove that conditions exist for which spectral sidebands can be amplified leading to the formation of a temporal modulation pattern which repeats itself identically every four cavity round trips. We show that this dynamics exists for realistic parameters of a driven fiber cavity, which makes it potentially accessible to experimental observation.}, archive = {J_PRA}, author = {Minji Shi and Matteo Conforti and Arnaud Mussot and Auro M. Perego}, doi = {10.1103/PhysRevA.111.013513}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013513}, shortjournal = {Phys. Rev. A}, title = {Period-4 modulation instability in ring fiber cavities}, volume = {111}, year = {2025}, }
• (2025). Polarization transformation of high-order harmonic radiation in an optically modulated plasma-based x-ray laser: Account of the nonlinearity and finite width of the harmonic spectral lines. PRA, 111(1), 013512. (www)

  @article{ , abstract = {The method proposed by Khairulin et al. [ JETP Lett. 117 , 652 (2023) ] for converting the linearly polarized radiation of high-order harmonics of an optical field into the circularly polarized in an optically modulated active medium of a plasma-based x-ray laser has been developed. This method is extended to the case of finite width of spectral lines (finite pulse duration) of high-harmonic radiation and nonlinear interaction of radiation with matter. The transformation of the polarization of the harmonic field is achieved by introducing a phase shift of π/2 between its polarization components, parallel and orthogonal to the polarization of the modulating field, through resonant dispersion on the spectral wings of the induced gain lines of the active medium and is accompanied by an increase in the power of high harmonics. It is shown that for harmonics with a finite bandwidth, the polarization of the output radiation is nonuniform in time. The reasons for such nonuniformity are analyzed and the conditions for its minimization are found. The influence of nonlinearity and amplified spontaneous emission of the active medium on the high-harmonic polarization is investigated. The possibilities for the experimental implementation of this effect in a neonlike active medium of a plasma x-ray laser based on ions with an unperturbed wavelength of the inverted transition at 32.6 nm are analyzed.}, archive = {J_PRA}, author = {V. A. Antonov and I. R. Khairulin and M. Yu. Ryabikin}, doi = {10.1103/PhysRevA.111.013512}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013512}, shortjournal = {Phys. Rev. A}, title = {Polarization transformation of high-order harmonic radiation in an optically modulated plasma-based x-ray laser: Account of the nonlinearity and finite width of the harmonic spectral lines}, volume = {111}, year = {2025}, }
• (2025). Interpreting purcell enhancement of non-hermitian metasurfaces with spectral parameters. PRA, 111(1), 013511. (www)

  @article{ , abstract = {The Purcell effect describes the enhancement of the spontaneous emission rate of an emitter near a resonant structure. However, evaluating the Purcell factor quantitatively and empirically is difficult due to the difficulties in measuring the electromagnetic near field of an optical resonance for calculation of the exact effective modal volume, especially with non-Hermitian resonators. Therefore, we propose an analytical approach to circumvent the need to measure the near field and predict the Purcell enhancement with spectral parameters, which can be directly measured in the far field or fitted from such spectral measurements. Our proposed model predicts the averaged Purcell enhancement by metasurfaces on a photoluminescent medium, and is verified with experimental measurements and numerical simulations of nanoparticle arrays coupled to a fluorescent thin film. The model directly analyzes the photoluminescence enhancement and extraction efficiency of the metasurface, and can be generalized to work with an arbitrarily shaped photoluminescent medium that is coupled to a resonator. This discovery provides a practical and accessible way to understand the underlying mechanisms of photoluminescence enhancement and will facilitate optimization of metasurfaces for efficient extraction of the enhanced luminescence.}, archive = {J_PRA}, author = {Joshua T. Y. Tse and Shunsuke Murai and Katsuhisa Tanaka}, doi = {10.1103/PhysRevA.111.013511}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013511}, shortjournal = {Phys. Rev. A}, title = {Interpreting purcell enhancement of non-hermitian metasurfaces with spectral parameters}, volume = {111}, year = {2025}, }
• (2025). Interactions of dark solitons in one-dimensional self-defocusing media with fourth-order diffraction. PRA, 111(1), 013510. (www)

  @article{ , abstract = {We investigate dark solitons and their interactions in one-dimensional self-defocusing media with fourth-order diffraction (FOD). Anomalous FOD supports bifurcated dark solitons when the coefficient of FOD exceeds a threshold. Dark solitons are stable (unstable) against perturbations when FOD is normal (anomalous). FOD also controls flexibly interactions of well-separated parallel dark solitons, leading to the formation of bound states of parallel solitons pairs which are always repulsive in conventional local nonlinear media with standard (quadratic) diffraction.}, archive = {J_PRA}, author = {Miaomiao Li and Ming Shen}, doi = {10.1103/PhysRevA.111.013510}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013510}, shortjournal = {Phys. Rev. A}, title = {Interactions of dark solitons in one-dimensional self-defocusing media with fourth-order diffraction}, volume = {111}, year = {2025}, }
• (2025). Overcoming the standard quantum limit with an electro-optomechanical hybrid system for enhanced force sensing. PRA, 111(1), 013509. (www)

  @article{ , abstract = {We investigate the reduction of measurement-added noise in force sensing by analyzing its power spectral density (PSD) within a hybrid optomechanical system. The setup is comprised of an optomechanical cavity equipped with a movable mirror which acts as the mechanical oscillator, a stationary semi-transparent mirror, a superconducting qubit, and an optical parametric amplifier (OPA). By utilizing the concept of coherent quantum noise cancellation (CQNC), we derive the conditions necessary for complete cancellation of back-action force, thereby enhancing force sensitivity. Furthermore, with the gradual increase in the OPA pump gains, we suppress the sensitivity beyond the standard quantum limit (SQL) at a lower value of laser power. The removal of back-action noise, along with the reduction of shot noise, improves force detection capabilities, thereby surpassing the standard quantum limit associated with weak force detection.}, archive = {J_PRA}, author = {Alolika Roy and Amarendra K. Sarma}, doi = {10.1103/PhysRevA.111.013509}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013509}, shortjournal = {Phys. Rev. A}, title = {Overcoming the standard quantum limit with an electro-optomechanical hybrid system for enhanced force sensing}, volume = {111}, year = {2025}, }
• (2025). Quantum correlations via vector soliton interactions. PRA, 111(1), 013508. (www)

  @article{ , abstract = {Quantum correlations play a prominent role in numerous applications, from quantum communications and networking to enhanced sensing. I propose using optical soliton splitting and inelastic soliton collision to generate pulse pairs with highly correlated photon number fluctuations. The fluctuations are studied using the linearized quantum fluctuation theory of vector solitons. I show that the interpulse correlations arise in the process of inelastic soliton interactions initiated by the polarization mode dispersion and modulation of the fiber dispersion. The inelastic soliton interactions produce pulses with highly correlated quantum fluctuations in the orthogonal polarization components of the field. In the time domain, the pulses have a four-lobe correlation pattern. In the frequency domain, the correlation functions acquire a “checkerboard” structure with alternating positive and negative regions. Correlations between the separated pulses arise only with appropriate pulse width, group velocity dispersion, and polarization mode dispersion. The generation of pulses with high intrapulse correlations offers the possibility of producing entangled sources for continuous-variable quantum communication and computation.}, archive = {J_PRA}, author = {Andrey Konyukhov}, doi = {10.1103/PhysRevA.111.013508}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013508}, shortjournal = {Phys. Rev. A}, title = {Quantum correlations via vector soliton interactions}, volume = {111}, year = {2025}, }
• (2025). Enhancement of the photon pair generation rate by spontaneous four-wave mixing in bent waveguides. PRA, 111(1), 013507. (www)

  @article{ , abstract = {Enhancing nonlinear optical effects is critical to improving the performance of many functional devices for nonlinear and quantum optical applications. Here, we study the possibility of bending a waveguide to enhance the photon pair generation rate in a spontaneous four-wave mixing process. Whereas intuition might suggest that bending makes the process less efficient because the waveguides are more lossy when bent, we show that the increase in the effective nonlinearity outperforms the loss disadvantage for moderate bending radii. That can be explained by a better localization of the guided eigenmodes, leading to a reduced mode area. By studying selected waveguide devices with a fixed length, we demonstrate an improvement in the photon pair generation rate between 5% and 210% for an optimal bending radius. These findings have implications for the future design of integrated photonic devices for quantum optical applications, especially in cases where the chip estate tends to be a limiting factor.}, archive = {J_PRA}, author = {Maria Paszkiewicz and Carsten Rockstuhl}, doi = {10.1103/PhysRevA.111.013507}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013507}, shortjournal = {Phys. Rev. A}, title = {Enhancement of the photon pair generation rate by spontaneous four-wave mixing in bent waveguides}, volume = {111}, year = {2025}, }
• (2025). Coherent feedback control for cavity optomechanical systems with a frequency-dependent mirror. PRA, 111(1), 013506. (www)

  @article{ , abstract = {Ground-state cooling of mechanical resonators is a prerequisite for the observation of various quantum effects in optomechanical systems and thus has always been a crucial task in quantum optomechanics. In this paper, we study how to realize ground-state cooling of the mechanical mode in a Fano-mirror optomechanical setup, which allows for enhanced effective optomechanical interaction but typically works in the (deeply) unresolved-sideband regime. We reveal that for such a two-sided cavity geometry with very different decay rates at the two cavity mirrors, it is possible to cool the mechanical mode down to its ground state within a broad range of parameters by using an appropriate single-sided coherent feedback. This is possible even if the total optical loss is more than seven orders of magnitude larger than the mechanical frequency and the feedback efficiency is relatively low. Importantly, we show that a more standard double-sided feedback scheme is not appropriate to cooperate with a Fano-mirror system.}, archive = {J_PRA}, author = {Lei Du and Juliette Monsel and Witlef Wieczorek and Janine Splettstoesser}, doi = {10.1103/PhysRevA.111.013506}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013506}, shortjournal = {Phys. Rev. A}, title = {Coherent feedback control for cavity optomechanical systems with a frequency-dependent mirror}, volume = {111}, year = {2025}, }
• (2025). Nonlinear spectral phase retardance induced in cylindrical vector-polarized, optical parametric chirped-pulse amplification. PRA, 111(1), 013505. (www)

  @article{ , abstract = {Cylindrical vector (CV) beams have garnered widespread research interest owing to their polarization symmetry and unique properties. The advent of high-intensity ultrafast CV laser sources is poised to advance ultrafast science and attosecond physics. The type-II phase-matched, wavelength-degenerate optical parametric amplification (OPA) configuration can realize polarization-independent parametric amplification for the signal. When combined with chirped-pulse amplification (CPA) technology, this method shows promise for producing ultrafast vector beams with customizable polarization profiles at ultrahigh intensities. However, in addition to the linear spectral phase retardance introduced by the birefringent OPA crystal, known as the wave-plate effect, the optical parametric phase (OPP) inherently induced in optical parametric CPA (OPCPA) may cause another type of spectral phase retardation between the ordinary and extraordinary polarized components of the signal. This nonlinear spectral phase retardance depends significantly on the parametric process. This paper presents the results of a comprehensive theoretical investigation of nonlinear spectral phase retardance and correlates it with its linear counterpart. The dynamic behavior of nonlinear spectral phase retardance and its impact on the temporal compensation of compressed signal pulses are comprehensively discussed. These findings are expected to guide the design of CV-polarized OPCPA systems and their future applications.}, archive = {J_PRA}, author = {Xinhao Ren and Xingjie Ren and Yifan Zhong and Junfeng Ye and Changwen Xu and Ying Li and Dianyuan Fan and Haizhe Zhong}, doi = {10.1103/PhysRevA.111.013505}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013505}, shortjournal = {Phys. Rev. A}, title = {Nonlinear spectral phase retardance induced in cylindrical vector-polarized, optical parametric chirped-pulse amplification}, volume = {111}, year = {2025}, }
• (2025). Shaping space-time wave packets beyond the paraxial limit using a dispersion magnifier. PRA, 111(1), 013504. (www)

  @article{ , abstract = {Space-time wave packets (STWPs) have received significant attention since they can propagate in free space at arbitrary group velocity without dispersion and diffraction. However, at present, the generation of STWPs has been limited to the paraxial regime. Here we show that conventional optical elements can be used to extend STWPs beyond the paraxial regime. A dispersion magnifier, consisting of two lenses and a beam expander, applies spatiotemporal shaping to paraxial STWPs to create nonparaxial STWPs. The control of the magnification ratio results in versatile engineering capabilities on group velocity, beam diameter, and propagation distance. As an example, we numerically demonstrate long-distance propagation or slow group velocity of the output wave packet with subwavelength cross sections.}, archive = {J_PRA}, author = {Dongha Kim and Cheng Guo and Peter B. Catrysse and Shanhui Fan}, doi = {10.1103/PhysRevA.111.013504}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013504}, shortjournal = {Phys. Rev. A}, title = {Shaping space-time wave packets beyond the paraxial limit using a dispersion magnifier}, volume = {111}, year = {2025}, }
• (2025). Backaction suppression for levitated dipolar scatterers. PRA, 111(1), 013503. (www)

  @article{ , abstract = {Levitated dipolar scatterers exhibit exceptional performance as optomechanical systems for observing quantum mechanics at the mesoscopic and atomic scales. These systems scatter photons in almost every direction, and, with generally limited light collection efficiency, only partial information about the state of the system can be extracted. In this article, we present a setup to enhance information extraction of optomechanical measurements by constraining light scattering to a specific spatial direction. The setup consists of a hollow hemispherical mirror that controls the light scattered by a dipolar scatterer at high scattering angles outside the hole's region. Control of light scattering at high angles can be used to suppress the corresponding optomechanical backaction, which results in focusing of the measurement information at low angles. This mirror is compatible with existing setups commonly employed in levitated optomechanics, including confocal lenses and optical resonators.}, archive = {J_PRA}, author = {Y. Weiser and T. Faorlin and L. Panzl and T. Lafenthaler and L. Dania and D. S. Bykov and T. Monz and R. Blatt and G. Cerchiari}, doi = {10.1103/PhysRevA.111.013503}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013503}, shortjournal = {Phys. Rev. A}, title = {Backaction suppression for levitated dipolar scatterers}, volume = {111}, year = {2025}, }
• (2025). Subcycle optical solitons in a medium with several resonances. PRA, 111(1), 013502. (www)

  @article{ , abstract = {We theoretically demonstrate the existence of subcycle solitons in a medium with several optical resonances, with the soliton duration smaller than the periods of all resonant transitions in the medium. We show that the evolution of the electric field in this case is governed by the generalized sine-Gordon equation. We find the solitary-wave solutions of this equation both in the case of a conservative and dissipative optical medium. It is shown that stable subcycle solitons in general can only exist in an initially preexcited medium with nonresonant losses. In this case, half-cycle dissipative solitons can be formed and steadily propagate in the resonant medium. In contrast, the stable conservative solitary waves are obtained to only exist at integer ratios of the transition dipole moments of all resonances that are involved.}, archive = {J_PRA}, author = {Anton Pakhomov}, doi = {10.1103/PhysRevA.111.013502}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013502}, shortjournal = {Phys. Rev. A}, title = {Subcycle optical solitons in a medium with several resonances}, volume = {111}, year = {2025}, }
• (2025). Modulation of harmonics from solids by laser pulses with a small chirp. PRA, 111(1), 013501. (www)

  @article{ , abstract = {Solid's harmonic spectra can be controlled and optimized by the driving laser pulse; especially the laser's chirp apparently affects the harmonic waveform. In this work, we investigate the harmonic spectrum structure and frequency modulation of ZnO crystal under the influence of the laser pulses with a small chirp. It is found that by fine-tuning the laser chirp, not only the monochromaticity of the harmonic spectrum can be improved, eliminating the subpeak structures in the ZnO harmonic spectrum, but also the double-peak or triple-peak structure of the harmonics can be generated in the ZnO crystals with the electronic population almost unchanged. Through the analysis of the harmonic intensity and phase contributed by the rising and falling parts of the laser pulse, we elucidate the reasons behind the harmonic modulation of the ZnO crystal under the laser pulses with a small chirp. Leveraging the chirped pulse-induced frequency shifts in harmonic emission from the rising and falling parts of the laser, we further manipulate the harmonic spectrum structure of the ZnO crystal. This study provides insights into solid harmonic regulation, facilitating the optimization of solid spectral structures.}, archive = {J_PRA}, author = {Yue Qiao and Susu Zhang and Wenli Jiang and Fuming Guo and Jun Wang and Jigen Chen and Yujun Yang}, doi = {10.1103/PhysRevA.111.013501}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013501}, shortjournal = {Phys. Rev. A}, title = {Modulation of harmonics from solids by laser pulses with a small chirp}, volume = {111}, year = {2025}, }
• (2025). Density-dependent gauge field with raman lattices. PRA, 111(1), 013319. (www)

  @article{ , abstract = {The study of the gauge field is an everlasting topic in modern physics. Spin-orbit coupling is a powerful tool in ultracold atomic systems, resulting in an artificial gauge field that can be easily manipulated and observed in a tabletop environment. Combining optical Raman lattices and atom-atom interactions, the artificial gauge field can be made density dependent. In this work we propose a straightforward way to engineer a one-dimensional density-dependent gauge field in a Bose-Hubbard model in spin-orbit-coupled Raman lattices. We study the model from two perspectives: few-body quantum-walk dynamics and the many-body ground state. From the first perspective, we show that large spin-flipped tunneling can lead to a deep two-body bound state. From the second perspective, mean-field and density-matrix renormalization-group calculations consistently reveal three different phases, i.e., the Mott insulator phase, the superfluid phase, and the magnetic superfluid phase. Finally, we discuss the experimental protocol with Raman lattices based on existing experimental platforms.}, archive = {J_PRA}, author = {Xiang-Can Cheng and Zong-Yao Wang and Jinyi Zhang and Shuai Chen and Xiaotian Nie}, doi = {10.1103/PhysRevA.111.013319}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013319}, shortjournal = {Phys. Rev. A}, title = {Density-dependent gauge field with raman lattices}, volume = {111}, year = {2025}, }
• (2025). Two-component droplet phases and their spectral stability in one dimension. PRA, 111(1), 013318. (www)

  @article{ , abstract = {We unravel the existence and stability properties of one-dimensional droplets arising in genuine two-component particle-imbalanced bosonic mixtures under the influence of a weak harmonic confinement. A plethora of miscible droplet phases is found with the majority component atoms in the vicinity of the minority ones assembling in a droplet configuration, while the remaining excess atoms are in the gas state. Our computations identify a transition from a bound to a trapped gas many-body state for increasing total atom number and fixed interactions, with the bound character being prolonged for stronger intercomponent attractions. The spectral stability of these two-component droplets is revealed by examining their underlying Bogoliubov–de Gennes excitation spectrum. Furthermore, the collective dynamics associated with the fundamental dipole and breathing modes of the system is monitored by suddenly shifting the trap's center or quenching the trap's frequency, respectively. There, a backaction of the significantly localized minority component is imprinted in the majority cloud. The present findings can be simulated in recent cold-atom experiments, thus setting the stage for probing the complex nonequilibrium dynamics of two-component droplets.}, archive = {J_PRA}, author = {E. G. Charalampidis and S. I. Mistakidis}, doi = {10.1103/PhysRevA.111.013318}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013318}, shortjournal = {Phys. Rev. A}, title = {Two-component droplet phases and their spectral stability in one dimension}, volume = {111}, year = {2025}, }
• (2025). Modeled vortex dynamics in a bose-einstein condensate in a rotating lattice. PRA, 111(1), 013317. (www)

  @article{ , abstract = {We study the dynamics of vortices in a Bose-Einstein condensate within a rotating four-site lattice, which can be effectively described by a multimode model. Such a vortex dynamics develops along the low-density paths that separate the sites, and it is ruled by the phase differences between them. Hence, by appropriately selecting the initial conditions for on-site populations and phase differences, one can access distinct types of evolutions. We show that, by choosing equal populations in alternate sites, one can construct two-mode model Hamiltonians, which allows us to model a large variety of associated vortex orbits. In particular, one can select the type of trajectory of the vortex and predict the creation and annihilation of vortex-antivortex pairs near the trap center. Estimates for the periods of closed vortex orbits and for the times that the vortices spend inside the lattice when dealing with open orbits, are obtained in terms of the two-mode models parameters and the rotation frequency only. We believe that the present study establishes a suitable platform to engineer different vortex dynamics.}, archive = {J_PRA}, author = {P. Capuzzi and D. M. Jezek}, doi = {10.1103/PhysRevA.111.013317}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013317}, shortjournal = {Phys. Rev. A}, title = {Modeled vortex dynamics in a bose-einstein condensate in a rotating lattice}, volume = {111}, year = {2025}, }
• (2025). Global phase diagram of the cluster-XY spin chain with dissipation. PRA, 111(1), 013316. (www)

  @article{ , abstract = {We study the ground-state phase diagram of a non-Hermitian cluster- spin chain in the language of free fermions. By calculating the second derivative of ground-state energy density and various types of order parameters, we establish the global ground-state phase diagram of the model, exhibiting rich quantum phases and corresponding phase transitions. Specifically, the results reveal that the non-Hermitian cluster- model contains five different phases and two critical regions, i.e., ferromagnetic (FM), antiferromagnetic (AFM), symmetry-protected topological (SPT), paramagnetic (PM), Luttinger liquid-like phase, as well as critical regions I and II. The order parameters and critical behaviors are investigated and the correctness of the theory is confirmed.}, archive = {J_PRA}, author = {Wei-Lin Li and Ying-Ao Chen and Zheng-Xin Guo and Xue-Jia Yu and Zhi Li}, doi = {10.1103/PhysRevA.111.013316}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013316}, shortjournal = {Phys. Rev. A}, title = {Global phase diagram of the cluster-XY spin chain with dissipation}, volume = {111}, year = {2025}, }
• (2025). One-dimensional quench dynamics in an optical lattice: Sine-gordon and bose-hubbard descriptions. PRA, 111(1), 013315. (www)

  @article{ , abstract = {We investigate the dynamics of one-dimensional interacting bosons in an optical lattice after a sudden quench in the weakly interacting (Bose-Hubbard) and strongly interacting (sine-Gordon) regimes. While in a higher dimension, the Mott-superfluid phase transition is observed for weakly interacting bosons in deep lattices, in one dimension an instability is generated also for shallow lattices with a commensurate periodic potential pinning the atoms to the Mott state through a transition described by the sine-Gordon model. The present work aims at identifying the quench dynamics in both the Bose-Hubbard and sine-Gordon interaction regimes. We numerically exactly solve the time-dependent Schrödinger equation for a small number of atoms and obtain dynamical measures of several key quantities. We investigate the correlation dynamics of first and second order; both exhibit rich many-body features in the dynamics. We conclude that in both cases, dynamics exhibits collapse-revival phenomena, though with different timescales. We argue that the dynamical fragmentation is a convenient quantity to distinguish the dynamics especially near the pinning zone. To understand the relaxation process we measure the many-body information entropy. Bose-Hubbard dynamics clearly establishes the possible relaxation to the maximum entropy state. In contrast, the sine-Gordon dynamics is so fast that it does not exhibit any signature of relaxation in the present timescale of computation.}, archive = {J_PRA}, author = {Subhrajyoti Roy and Rhombik Roy and Andrea Trombettoni and Barnali Chakrabarti and Arnaldo Gammal}, doi = {10.1103/PhysRevA.111.013315}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013315}, shortjournal = {Phys. Rev. A}, title = {One-dimensional quench dynamics in an optical lattice: Sine-gordon and bose-hubbard descriptions}, volume = {111}, year = {2025}, }
• (2025). Measurement of p-wave contacts in an ultracold fermi gas of li6 atoms. PRA, 111(1), 013314. (www)

  @article{ , abstract = {Using radio-frequency (rf) spectroscopy, we measure the -wave contacts in a Fermi gas of atoms near the -wave Feshbach resonance. The rf spectrum exhibits clear asymptotic behavior, characterized by and dependencies. The magnetic-field dependence of the -wave contacts agrees reasonably well with the virial expansion theory in a detuned magnetic-field range, validating the theory near half of the Fermi temperature. The -wave contacts measured in this article constitute a second data set, complementing the data obtained from the system and contributing valuable insights into -wave interactions in ultracold Fermi gases.}, archive = {J_PRA}, author = {Kenta Nagase and Soki Oshima and Hikaru Takahashi and Takashi Mukaiyama}, doi = {10.1103/PhysRevA.111.013314}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013314}, shortjournal = {Phys. Rev. A}, title = {Measurement of p-wave contacts in an ultracold fermi gas of li6 atoms}, volume = {111}, year = {2025}, }
• (2025). Quantum protocols in demixed dipolar bose-einstein-condensate mixtures in one dimension. PRA, 111(1), 013313. (www)

  @article{ , abstract = {Long-range dipolar effects in one-dimensional (1D) systems, either in free or inhomogeneous space, are the basis of the state preparation protocol here proposed. Under the presence of an external time-dependent magnetic field, dipole-dipole interactions in the binary ultracold Er 166 - Dy 164 system were tuned from repulsive to attractive to access either the droplet regime or the cloud one filling the full space, where individual species can be found in mixed or demixed phases. A thorough exploration of weak contact and dipole-dipole effective interaction parameters leads us to determine the phase diagrams of the 1D Bose clouds affected by three different external fields: free homogeneous, harmonic, and optical lattice confining potentials. These results were used to propose long-life states composed of alternate assemblies of individual species confined in optical lattices that mimics magnetic domains, whose size can be adjusted. Our analysis, based on numerical experiments within a mean-field scheme, considered large enough systems as those commonly used in experimental platforms.}, archive = {J_PRA}, author = {C. Madroñero and R. Paredes}, doi = {10.1103/PhysRevA.111.013313}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013313}, shortjournal = {Phys. Rev. A}, title = {Quantum protocols in demixed dipolar bose-einstein-condensate mixtures in one dimension}, volume = {111}, year = {2025}, }
• (2025). Lieb excitations and topological flat mode of the spectral function of a tonks-girardeau gas in a kronig-penney potential. PRA, 111(1), 013312. (www)

  @article{ , abstract = {Lieb excitations are fundamental to the understanding of the low-energy behavior of many-body quantum gases. Here we study the spectral function of a Tonks-Girardeau gas in a finite-sized Kronig-Penney potential and show that the Lieb-I and Lieb-II excitations can become gapped as a function of the barrier height. Moreover, we reveal the existence of a topological flat mode near the Fermi energy and at zero momentum and show that this is robust to perturbations in the system. Through a scaling analysis, we determine the divergent behavior of the spectral function. Our results provide a significant reference for the observation and understanding of the gapped Lieb excitations and the topological flat mode of quantum gases in experimentally realistic subwavelength optical lattice potentials.}, archive = {J_PRA}, author = {Wen-Bin He and Giedrius Žlabys and Hoshu Hiyane and Sarika Sasidharan Nair and Thomas Busch}, doi = {10.1103/PhysRevA.111.013312}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013312}, shortjournal = {Phys. Rev. A}, title = {Lieb excitations and topological flat mode of the spectral function of a tonks-girardeau gas in a kronig-penney potential}, volume = {111}, year = {2025}, }
• (2025). Exploring thouless pumping in the generalized creutz model: A graphical method and modulation schemes. PRA, 111(1), 013311. (www)

  @article{ , abstract = {Thouless pumping with nontrivial topological phases provides a powerful means for the manipulation of matter waves in one-dimensional lattice systems. The band topology is revealed by the quantization of pumped charge. In the context of Thouless pumping, we present a graphical representation for the topological phases characterized by the Chern number of an effective two-dimensional band. We illustrate how two topological phases with a distinct Zak phase are connected in the pumping process. Such a visual depiction exhibits typical patterns that is directly related to a linking number and to the Chern number, allowing for the construction of Thouless pumping schemes in a practical way. As a demonstration, we present a generalized Creutz model with a tunable Peierls phase, interleg imbalance, and diagonal hopping. Various modulation schemes for Thouless pumping are studied, focusing on their graphical representations in Bloch space, as well as the quantized pumping phenomenon in real space.}, archive = {J_PRA}, author = {Yan-Jue Lv and Yang Peng and Yong-Kai Liu and Yi Zheng}, doi = {10.1103/PhysRevA.111.013311}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013311}, shortjournal = {Phys. Rev. A}, title = {Exploring thouless pumping in the generalized creutz model: A graphical method and modulation schemes}, volume = {111}, year = {2025}, }
• (2025). Photonic bands and normal mode splitting in optical lattices interacting with cavities. PRA, 111(1), 013310. (www)

  @article{ , abstract = {The strong collective interaction of atoms with an optical cavity causes normal mode splitting of the cavity's resonances, whose width is given by the collective coupling strength. At low optical density of the atomic cloud, the intensity distribution of light in the cavity is ruled by the cavity's mode function, which is determined solely by its geometry. In this regime the dynamics of the coupled atom-cavity system is conveniently described by the open Dicke model, which we apply to calculating normal mode splitting generated by periodically ordered clouds in linear and ring cavities. We also show how to use normal mode splitting as a witness for Wannier-Bloch oscillations in the tight-binding limit. At high optical density the atomic distribution contributes to shaping the mode function. This regime escapes the open Dicke model, but can be treated by a transfer matrix model provided the saturation parameter is low. Applying this latter model to an atomic cloud periodically ordered into a one-dimensional lattice, we observe the formation of photonic bands gaps competing with the normal mode splitting. We discuss the limitations of both models and point out possible pathways to generalized theories.}, archive = {J_PRA}, author = {Ph. W. Courteille and D. Rivero and G. H. de França and C. A. Pessoa, Jr and A. Cipris and M. Núñez Portela and R. C. Teixeira and S. Slama}, doi = {10.1103/PhysRevA.111.013310}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013310}, shortjournal = {Phys. Rev. A}, title = {Photonic bands and normal mode splitting in optical lattices interacting with cavities}, volume = {111}, year = {2025}, }
• (2025). Universal corrections to the superfluid gap in a cold fermi gas. PRA, 111(1), 013309. (www)

  @article{ , abstract = {A framework for computing the superfluid gap in an effective field theory (EFT) of fermions interacting via momentum-independent contact forces is developed. The leading universal corrections in the EFT are one-loop in-medium effects at the Fermi surface, and reproduce the well-known Gor'kov-Melik-Barkhudarov result. The complete subleading universal corrections are presented here, and include one-loop effects away from the Fermi surface, two-loop in-medium effects, as well as modifications to the fermion propagator. Together, these effects are found to reduce the gap at low densities. Applications to neutron superfluidity in neutron stars are also discussed.}, archive = {J_PRA}, author = {Silas R. Beane and Zeno Capatti and Roland C. Farrell}, doi = {10.1103/PhysRevA.111.013309}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013309}, shortjournal = {Phys. Rev. A}, title = {Universal corrections to the superfluid gap in a cold fermi gas}, volume = {111}, year = {2025}, }
• (2025). Spin hierarchy in van der waals molecule formation via ultracold three-body recombination. PRA, 111(1), 013308. (www)

  @article{ , abstract = {We theoretically investigate the product-state distribution of weakly bound diatomic van der Waals molecules via ultracold three-body recombination of bosonic alkali-metal atoms. We find a two-level hierarchy of spin propensity rules at zero magnetic field. The primary propensity rule states that nearly all molecular products conserve the total hyperfine spin of a reactant atomic pair, while molecular products not conserving the total spin are highly suppressed. For the dominant molecular products, there is a secondary propensity to conserve certain spin components of the reactant pair such as the atomic hyperfine spins, or the total electronic or nuclear spins. The second propensity varies across species and depends fundamentally on the interplay between effective electronic spin exchange and hyperfine interactions. The spin sensitivity of product-state distribution can potentially open up new avenues for controlling state-to-state reaction rates in ultracold three-body recombination.}, archive = {J_PRA}, author = {Jing-Lun Li and Paul S. Julienne and Johannes Hecker Denschlag and José P. D'Incao}, doi = {10.1103/PhysRevA.111.013308}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013308}, shortjournal = {Phys. Rev. A}, title = {Spin hierarchy in van der waals molecule formation via ultracold three-body recombination}, volume = {111}, year = {2025}, }
• (2025). Deceleration of heavy atoms with a continuous stimulated force. PRA, 111(1), 013307. (www)

  @article{ , abstract = {Heavy atoms play a critical role in scientific research and applications by providing a better understanding of fundamental physical phenomena. The use of a slowed atomic beam to extend the interaction time is expected to enhance measurement sensitivity, resolution, and precision. Here, we theoretically demonstrate a rapid and short-distance deceleration of heavy atoms by using a continuous stimulated force with optical phase compensation and frequency chirping. The scheme effectively overcomes the spatial inhomogeneity of the stimulated force on atoms during deceleration. Our approach employs the numerical solutions of the optical Bloch equations for two-level atoms driven by time-dependent fields, and simulates atom trajectories using a three-dimensional Monte Carlo method. Concerning a buffer-gas-cooled radium atom beam with an initial velocity of 130 m/s, from our simulations it can be decelerated to 5 m/s within 5 cm distance using 40 mW laser power, achieving a deceleration force approximately 35 times stronger than the radiation force and covering an effective velocity range over eight times that of the radiation force. In addition, the deceleration of other heavy atoms, such as francium and thallium, also are applicable. This approach offers an efficient tool for rapidly slowing and cooling complex atoms and molecules, facilitating future precision measurements.}, archive = {J_PRA}, author = {Jin Wei and Di Wu and Taojing Dong and Chenyu Zu and Yong Xia and Jianping Yin}, doi = {10.1103/PhysRevA.111.013307}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013307}, shortjournal = {Phys. Rev. A}, title = {Deceleration of heavy atoms with a continuous stimulated force}, volume = {111}, year = {2025}, }
• (2025). Effective approaches to the dynamical properties of two distinguishable bose polarons. PRA, 111(1), 013306. (www)

  @article{ , abstract = {We explore effective approaches for describing the dynamics of induced interactions among two noninteracting distinguishable impurities (Bose polarons) when their couplings to the host species are switched on. First, we evaluate the time-dependent characteristics of each polaron through reduced single-particle models. Their validity is ultimately judged by comparing them to observables obtained within a many-body variational approach. We argue that utilizing a time-dependent optimization process with the effective mass and frequency being fitting parameters leads to an accurate matching on the level of one-body observables with the prediction of the many-body method. Next, we construct two-body effective models, which, in addition to the effective parameters of the single polaron, include a contact interaction potential modeling the induced interactions. It is shown that the instantaneous coupling strength obtained with a time-dependent optimization process allows for an accurate description of the impurities two-body correlation dynamics when compared to the many-body calculations. In this sense, it is possible to describe the dynamical crossover from correlated to anticorrelated impurity patterns related to the transition from attractive to repulsive induced interactions. Our results should facilitate the description of strongly particle-imbalanced mixtures via reduced models and hence their experimental understanding.}, archive = {J_PRA}, author = {F. Theel and S. I. Mistakidis and P. Schmelcher}, doi = {10.1103/PhysRevA.111.013306}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013306}, shortjournal = {Phys. Rev. A}, title = {Effective approaches to the dynamical properties of two distinguishable bose polarons}, volume = {111}, year = {2025}, }
• (2025). Yrast states of quantum droplets confined in a ring potential. PRA, 111(1), 013305. (www)

  @article{ , abstract = {We consider a quantum droplet which is confined in a ring potential. We investigate the so-called yrast state, i.e., the lowest-energy state of the droplet assuming that it has some fixed expectation value of the angular momentum. Two of the most interesting aspects of this problem are the nonlinear term—which is partly attractive and partly repulsive—and the periodic boundary conditions. For some range of the parameters, the attractive or the repulsive part of the nonlinear term dominates and one gets the expected behavior. In some intermediate regime, the two nonlinear terms are of comparable size. In this case, both the solution and the corresponding dispersion relation show an interesting behavior. Finally, we make contact with the problem of solitary-wave excitation since the derived solutions are traveling-wave, i.e., solitary-wave, solutions.}, archive = {J_PRA}, author = {M. Ögren and G. M. Kavoulakis}, doi = {10.1103/PhysRevA.111.013305}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013305}, shortjournal = {Phys. Rev. A}, title = {Yrast states of quantum droplets confined in a ring potential}, volume = {111}, year = {2025}, }
• (2025). Instability and particle-current control of a parametrically driven bose-einstein condensate in a ring-shaped lattice. PRA, 111(1), 013304. (www)

  @article{ , abstract = {We investigate the dynamics of a Bose-Einstein condensate in a one-dimensional ring-shaped lattice with the Peierls phase and site-dependent modulations, where the condensate is confined in a single deep trap and the interparticle interaction strength is modulated by a time-periodic driving field. The system has a finite spectrum, which limits the excitation regimes, and the Peierls phase typically induces imbalanced complex hopping amplitudes in each direction, leading to nonzero net particle currents along the lattice chain, which can hold nearly persistent even when the driving field is turned off after half of the period. The configuration provides a specific way for the coherent control of particle currents in many-body quantum systems with the help of an external driving field and promotes the possible applications in future closed-loop atom circuits.}, archive = {J_PRA}, author = {L. Q. Lai}, doi = {10.1103/PhysRevA.111.013304}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013304}, shortjournal = {Phys. Rev. A}, title = {Instability and particle-current control of a parametrically driven bose-einstein condensate in a ring-shaped lattice}, volume = {111}, year = {2025}, }
• (2025). Comparison of renormalized interactions using one-dimensional few-body systems as a testbed. PRA, 111(1), 013303. (www)

  @article{ , abstract = {Even though the one-dimensional contact interaction requires no regularization, renormalization methods have been shown to improve the convergence of numerical calculations considerably. In this work, we compare and contrast these methods: “the running coupling constant” where the two-body ground-state energy is used as a renormalization condition, and two effective interaction approaches that include information about the ground as well as excited states. In particular, we calculate the energies and densities of few-fermion systems in a harmonic oscillator with the configuration-interaction method and compare the results based upon renormalized and bare interactions. We find that the use of the running coupling constant instead of the bare interaction improves convergence significantly. A comparison with an effective interaction, which is designed to reproduce the relative part of the energy spectrum of two particles, showed a similar improvement. The effective interaction provides an additional improvement if the center-of-mass excitations are included in the construction. Finally, we discuss the transformation of observables alongside the renormalization of the potential, and demonstrate that this might be an essential ingredient for accurate numerical calculations.}, archive = {J_PRA}, author = {Fabian Brauneis and Hans-Werner Hammer and Stephanie M. Reimann and Artem G. Volosniev}, doi = {10.1103/PhysRevA.111.013303}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013303}, shortjournal = {Phys. Rev. A}, title = {Comparison of renormalized interactions using one-dimensional few-body systems as a testbed}, volume = {111}, year = {2025}, }
• (2025). Analyzing the sensitivity of an atom interferometer with a phase-modulation readout scheme. PRA, 111(1), 013302. (www)

  @article{ , abstract = {The sensitivity of an interferometer depends on its readout scheme. However, little attention has been paid to the readout schemes of atom interferometers from the viewpoint of their sensitivity. The difference in sensitivity between readout schemes or their optimization has not been considered in the literature. Herein we analytically calculate the sensitivities of an atom interferometer with typical readout schemes by applying the two-photon formalism, which was developed for optical interferometers to deal with quantum noise. Our calculations reveal that by using sinusoidal phase modulation, the sensitivity can surpass that obtained by the conventional phase sweeping scheme. The superiority of this phase modulation scheme for both cold and thermal atomic beams is demonstrated. In addition, we show that the phase modulation scheme is advantageous for atom-flux fluctuation and resists atom-flux drift. This study performs a general analysis of the sensitivity of atom interferometers and identifies an advantageous readout scheme.}, archive = {J_PRA}, author = {Takuya Kawasaki and Sotatsu Otabe and Tomoya Sato and Martin Miranda and Nobuyuki Takei and Mikio Kozuma}, doi = {10.1103/PhysRevA.111.013302}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013302}, shortjournal = {Phys. Rev. A}, title = {Analyzing the sensitivity of an atom interferometer with a phase-modulation readout scheme}, volume = {111}, year = {2025}, }
• (2025). Spontaneous creation of skyrmions in a two-component bose-einstein condensate. PRA, 111(1), 013301. (www)

  @article{ , abstract = {We investigate the stability of a vortex ring in a miscible two-component Bose-Einstein condensate confined in a harmonic potential, where the vortex cores in the two components are initially overlapped. Solving the Gross-Pitaevskii equation numerically, we find that the overlapped vortex rings in the two components are dynamically unstable against separation and that they can form linked vortex rings, resulting in a three-dimensional skyrmion. The parameter range for spontaneous skyrmion generation is determined by the Bogoliubov analysis.}, archive = {J_PRA}, author = {Rabeea Kiran and Hiroki Saito}, doi = {10.1103/PhysRevA.111.013301}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013301}, shortjournal = {Phys. Rev. A}, title = {Spontaneous creation of skyrmions in a two-component bose-einstein condensate}, volume = {111}, year = {2025}, }
• (2025). Coherent postionization dynamics of molecules based on adiabatic strong-field approximation. PRA, 111(1), 013124. (www)

  @article{ , abstract = {Taking N 2 and O 2 as examples, we theoretically study the postionization dynamics of molecules in strong laser fields using a density matrix method for open systems, focusing on the effect of ionization-produced coherence on the dynamics of residual ions. We apply the adiabatic strong-field approximation (ASFA) method to predict the coherences between ionic states resulting from multiorbital strong-field ionizations. Compared with the standard strong-field approximation, the ASFA method can be applied across a wide range of laser intensities due to the consideration of orbital distortion effects. Based on the ASFA, it is found that there are obvious coherences between ionic states in residual molecular ions. These coherences significantly influence the transitions between ionic states, which finally change the postionization dynamics of molecular ions. Our findings reveal the importance of the ionization-produced coherences in modulating postionization molecular dynamics.}, archive = {J_PRA}, author = {Shan Xue and Wenli Yang and Ping Li and Yuxuan Zhang and Pengji Ding and Song-Feng Zhao and Hongchuan Du and Anh-Thu Le}, doi = {10.1103/PhysRevA.111.013124}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013124}, shortjournal = {Phys. Rev. A}, title = {Coherent postionization dynamics of molecules based on adiabatic strong-field approximation}, volume = {111}, year = {2025}, }
• (2025). Formation of singly ionized oxygen atoms from o2 driven by XUV pulses: A toolkit for the breakup of free-electron-laser-driven diatomics. PRA, 111(1), 013123. (www)

  @article{ , abstract = {We formulate a general hybrid quantum-classical technique to describe the interaction of diatomic molecules with XUV pulses. We demonstrate the accuracy of our model in the context of the interaction of the molecule with an XUV pulse with photon energy ranging from 20–42 eV. We account for the electronic structure and electron ionization quantum mechanically employing accurate molecular continuum wave functions. We account for the motion of the nuclei using classical equations of motion. However, the force of the nuclei is computed by obtaining accurate potential-energy curves of up to , relevant to the 20–42 eV photon-energy range, using advanced quantum-chemistry techniques. We find the dissociation limits of these states and the resulting atomic fragments and employ the velocity-Verlet algorithm to compute the velocities of these fragments. We incorporate both electron ionization and nuclear motion in a stochastic Monte Carlo simulation and identify the ionization and dissociation pathways when interacts with an XUV pulse. Focusing on the dissociation pathway, we obtain the kinetic-energy release (KER) distributions of the atomic fragments and find very good agreement with experimental results. Also, we explain the main features of the KER in terms of ionization sequences consisting of two sequential single-photon absorptions resulting in different and electronic state configurations involved in the two transitions.}, archive = {J_PRA}, author = {M. Mountney and Z. Wang and S. Meister and F. Trost and H. Lindenblatt and A. Magunia and R. Moshammer and T. Pfeifer and A. Emmanouilidou}, doi = {10.1103/PhysRevA.111.013123}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013123}, shortjournal = {Phys. Rev. A}, title = {Formation of singly ionized oxygen atoms from o2 driven by XUV pulses: A toolkit for the breakup of free-electron-laser-driven diatomics}, volume = {111}, year = {2025}, }
• (2025). Spin-orbit splitting on photodissociation in open-shell diatomics by intense UV pulses. PRA, 111(1), 013122. (www)

  @article{ , abstract = {Spin-orbit (SO) splitting in open-shell diatomic molecules gives rise to unique doublet electronic states and a wide range of rotational spectra. In spite of high importance of SO effect its manifestation at interaction with ultrashort and intense ultraviolet (UV) laser pulses is weakly studied. Our simulations confirm clearly manifestations of nonlinear phenomena in SO-splitting fragment spectra as the UV pulse intensity increases. These nonlinear effects in kinetic energy release and photofragment angular distribution spectra clearly reflect the SO splitting of the state and the coupling ( is the nuclear rotational angular momentum and is the projection of total angular momentum on the molecule axis). We show that in case of nonresolved rotational excitation the coupling on doublet-state transitions can be effectively approximated as the coupling, as for a singlet state, yet including actual SO splitting on the potential energy curve of the doublet state. The present investigation not only reveals the nonlinear SO-splitting effects on photodissociation dynamics induced by intense UV pulses, but also provides practical approaches for efficient modeling of the photoinduced ultrafast nuclear dynamics incorporating the SO-splitting phenomena.}, archive = {J_PRA}, author = {Yan Rong Liu and Victor Kimberg and Maomao Gong and Yongjun Cheng and Yong Wu and Jian Guo Wang and Song Bin Zhang}, doi = {10.1103/PhysRevA.111.013122}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013122}, shortjournal = {Phys. Rev. A}, title = {Spin-orbit splitting on photodissociation in open-shell diatomics by intense UV pulses}, volume = {111}, year = {2025}, }
• (2025). On-shot, high-intensity laser aberration measurements via ponderomotive electron ejection. PRA, 111(1), 013121. (www)

  @article{ , abstract = {We present a technique to assess the spatial aberration content of a focused multiterawatt laser when fired at full power. This method leverages the direct detection of electrons ponderomotively accelerated from the focal volume formed in a low-pressure gaseous backfill. Our results show that the spatial distribution of emitted electrons exhibits distinct features correlated to the laser aberration type and magnitude. This work represents progress toward the complete and accurate in situ spatiotemporal characterization of focused high-intensity lasers.}, archive = {J_PRA}, author = {A. E. Raymond and S. Ravichandran and S.-W. Bahk and A. Longman and L. Roso and R. Fedosejevs and C. Mileham and I. A. Begishev and S. Qin and N. Dauphin and J. Shamlian and W. T. Hill, III and H. G. Rinderknecht}, doi = {10.1103/PhysRevA.111.013121}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013121}, shortjournal = {Phys. Rev. A}, title = {On-shot, high-intensity laser aberration measurements via ponderomotive electron ejection}, volume = {111}, year = {2025}, }
• (2025). Ion-kinetic-energy sampling in a 22-pole trap using ring-electrode evaporation. PRA, 111(1), 013120. (www)

  @article{ , abstract = {We present an experimental method for the characterization of the kinetic energies of ions confined in a 22-pole radio frequency trap by inducing a small potential barrier using the surrounding ring electrodes, allowing the selective extraction of ions. Energy sampling experiments have been performed on buffer-gas thermalized ions at trap temperatures between 10 and 180 K, resulting in distinct extraction curves as a function of the potential barrier, and a differentiated behavior depending on the escape time from the trap. The experiments are complemented by Monte Carlo simulations of the ion trajectories inside the calculated trap potential and allow us to investigate the properties of the sampling method, the role of ion motion coupling, and the impact of residual buffer-gas collisions on the observed results. The technique has also been successfully applied to identify energetic ions produced in an exothermic reaction inside the trap. Upon calibration, this method can provide relative kinetic energy distributions or be used to filter the maximum desired kinetic energy of the ions inside the trap.}, archive = {J_PRA}, author = {Miguel Jiménez-Redondo and Dieter Gerlich and Paola Caselli and Pavol Jusko}, doi = {10.1103/PhysRevA.111.013120}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013120}, shortjournal = {Phys. Rev. A}, title = {Ion-kinetic-energy sampling in a 22-pole trap using ring-electrode evaporation}, volume = {111}, year = {2025}, }
• (2025). Photoelectron–residual-ion interaction in angle-resolved streaked shake-up ionization of helium. PRA, 111(1), 013119. (www)

  @article{ , abstract = {Streaked photoelectron emission spectra access the correlated dynamics of photoelectrons and residual target electrons with attosecond temporal resolution. We calculated ab initio single-ionization spectra for photoemission from helium atoms by colinearly polarized ultrashort XUV and assisting few-femtosecond IR pulses. Distinguishing direct and shake-up ionization resulting in ground-state and excited ( ) ions, respectively, we examined the effects of the correlated photoemission dynamics on the photoelectron phase accumulation as a function of the observable photoelectron detection direction and kinetic energy and XUV–IR pulse delay. We tracked the dynamical evolution of the residual ion in relative streaked photo- emission delays and found dominant contributions for shake-up emission from the residual-ion–photoelectron interaction. These are in very good and fair agreement, respectively, for and shake-up photoemission along the pulse-polarization directions, with previous experimental and theoretical investigations [Ossiander et al. , Nat. Phys. 13 , 280 (2017) ] and reveal a strong photoemission-direction dependence for shake-up ionization due to the coupling between the photoelectron and evolving residual-ion charge distribution in the IR-laser field.}, archive = {J_PRA}, author = {Hongyu Shi and Uwe Thumm}, doi = {10.1103/PhysRevA.111.013119}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013119}, shortjournal = {Phys. Rev. A}, title = {Photoelectron–residual-ion interaction in angle-resolved streaked shake-up ionization of helium}, volume = {111}, year = {2025}, }
• (2025). Photodissociation dynamics of SiH+: Rovibrationally resolved feshbach resonances mediated by coupled excited states in the ultraviolet region. PRA, 111(1), 013118. (www)

  @article{ , abstract = {Photodissociation cross sections of have been explored within the uncoupled theoretical framework, notably in the work of Stancil et al. [ Astrophys. J. 486 , 574 (1997) ]. However, in the system, there are significant nonadiabatic interactions between the and states, which substantially affect the photodissociation process, particularly in the region between the Lyman line and the Lyman limit. These nonadiabatic couplings give rise to numerous Feshbach resonances, significantly altering the final photodissociation cross sections. The present study highlights the critical importance of incorporating nonadiabatic electronic couplings to achieve accurate cross-section calculations. The results substantially enrich the data set on small molecular structures and spectra in interstellar clouds, providing essential theoretical support for future experimental investigations and for the modeling and analysis of stellar spectra. Additionally, this work offers key insights into the underlying physical mechanisms by which Feshbach resonances modulate line shapes in coupled photodissociation scattering cross sections.}, archive = {J_PRA}, author = {Yu Kun Yang and Xing Guang Su and Kun Wang and Yongjun Cheng and Quan Wei Nan and Zeqing Wang and Danny L. Yeager and Yong Wu and Jian Guo Wang and Ke Dong Wang and Yu Wang and Song Bin Zhang}, doi = {10.1103/PhysRevA.111.013118}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013118}, shortjournal = {Phys. Rev. A}, title = {Photodissociation dynamics of SiH+: Rovibrationally resolved feshbach resonances mediated by coupled excited states in the ultraviolet region}, volume = {111}, year = {2025}, }
• (2025). All-electron molecular tunnel ionization based on the weak-field asymptotic theory in the integral representation. PRA, 111(1), 013117. (www)

  @article{ , abstract = {Tunnel ionization (TI) underlies many important ultrafast processes, such as high-harmonic generation and strong-field ionization. Among the existing theories for TI, many-electron weak-field asymptotic theory (ME-WFAT) is by design capable of accurately treating many-electron effects in TI. An earlier version of ME-WFAT relied on an accurate representation of the asymptotic tail of the orbitals, which hindered its implementation in Gaussian-basis-set-based quantum chemistry programs. In this work, we reformulate ME-WFAT in the integral representation, which makes the quality of the asymptotic tail much less critical, hence greatly facilitating its implementation in standard quantum chemistry packages. The integral reformulation introduced here is therefore much more robust when applied to molecules with arbitrary geometry. We present several case studies, among which is the CO molecule where some earlier theories disagree with experiments. Here we find that ME-WFAT produces the largest ionization probability when the field points from C to O, as experiments suggest. An attractive feature of ME-WFAT is that it can be used with various types of multielectron methods whether of density functional [I. S.Wahyutama et al., Phys. Rev. A 106 , 052211 (2022) ] or multiconfiguration types, this in turn facilitates tunnel ionization calculation in systems exhibiting a strong multireference character.}, archive = {J_PRA}, author = {Imam S. Wahyutama and Denawakage D. Jayasinghe and François Mauger and Kenneth Lopata and Kenneth J. Schafer}, doi = {10.1103/PhysRevA.111.013117}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013117}, shortjournal = {Phys. Rev. A}, title = {All-electron molecular tunnel ionization based on the weak-field asymptotic theory in the integral representation}, volume = {111}, year = {2025}, }
• (2025). Observation and origin of multi-THz quantum beats in superfluorescent emission from argon. PRA, 111(1), 013116. (www)

  @article{ , abstract = {We report observation of multi-THz quantum beats in the amplitude of superfluorescence in pure argon gas, using a time delayed 780-nm probe beam that interrogates the relevant population densities. The superfluorescence is induced by three-photon absorption of an ultrashort 260.5-nm laser pulse that creates coherent and coupled populations in multiple closely spaced and Ar levels. Argon pressure and pump laser focusing parameters are seen to modify the frequency of the quantum beats, which is attributed to the absorption of the self-generated, nonresonant third harmonic of the pump from Ar near the zero of the real part of the overlapping linear susceptibilities of the closely spaced and excited states. The self-absorption of the phase-matched THG photons creates a coherent population of atoms which acts like an atomic excited state ( -induced state). We have also observed a new two-step superfluorescent cascade that results from the population redistribution enabled by the 780-nm probe pulse between the and the -induced state and gives rise to a previously unknown transition that emits on 1587 nm.}, archive = {J_PRA}, author = {Noa Nambu and Zan Nie and Ken Marsh and C. Kumar N. Patel and Olga Smirnova and Misha Ivanov and Chan Joshi}, doi = {10.1103/PhysRevA.111.013116}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013116}, shortjournal = {Phys. Rev. A}, title = {Observation and origin of multi-THz quantum beats in superfluorescent emission from argon}, volume = {111}, year = {2025}, }
• (2025). Magic running- and standing-wave optical traps for rydberg atoms. PRA, 111(1), 013115. (www)

  @article{ , abstract = {Magic trapping of ground and Rydberg states, which equalizes the AC Stark shifts of these two levels, enables increased ground-to-Rydberg state coherence times. We measure via photon storage and retrieval how the ground-to-Rydberg state coherence depends on trap wavelength for two different traps and find different optimal wavelengths for a one-dimensional optical lattice trap and a running wave optical dipole trap. Comparison to theory reveals that this is caused by the Rydberg electron sampling different potential landscapes. The observed difference increases for higher principal quantum numbers, where the extent of the Rydberg electron wave function becomes larger than the optical lattice period. Our analysis shows that optimal magic trapping conditions depend on the trap geometry, in particular for optical lattices and tweezers.}, archive = {J_PRA}, author = {Lukas Ahlheit and Chris Nill and Daniil Svirskiy and Jan de Haan and Simon Schroers and Wolfgang Alt and Nina Stiesdal and Igor Lesanovsky and Sebastian Hofferberth}, doi = {10.1103/PhysRevA.111.013115}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013115}, shortjournal = {Phys. Rev. A}, title = {Magic running- and standing-wave optical traps for rydberg atoms}, volume = {111}, year = {2025}, }
• (2025). Controlling nondipole effects with bicircular laser fields. PRA, 111(1), 013114. (www)

  @article{ , abstract = {We experimentally and theoretically investigate the nondipole shift of the electron momentum distribution in the light-propagation direction in strong-field ionization of Ar atoms using counterrotating circularly polarized two-color laser fields. We observe that the electron mean momentum in the laser propagation direction in bicircular fields is strongly dependent on both the emission angle and the radial momentum of the electron. In low-energy electrons, the mean momentum follows the relation ( is the velocity of light and is the ionization potential), while for high-energy electrons it is significantly suppressed and deviates from the predicted values. Using nondipole-corrected classical trajectory Monte Carlo simulations, we identify that the nondipole shift is significantly influenced by the electron scattering process. The dominance of scattered electrons in the high-energy region leads to the reduction of the mean momentum shift. By extracting the angle- and momentum-resolved mean momentum spectrum, we show that the scattered and nonscattered electrons are emitted at different angles in counterrotating circularly polarized fields due to the nondipole shift. The sensitivity of the nondipole effect to the scattering process serves as a promising tool for probing strong-field-driven electron dynamics.}, archive = {J_PRA}, author = {Yankun Dou and Xiaoxiao Long and Peizeng Li and Peipei Ge and Yongkai Deng and Qihuang Gong and Yunquan Liu}, doi = {10.1103/PhysRevA.111.013114}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013114}, shortjournal = {Phys. Rev. A}, title = {Controlling nondipole effects with bicircular laser fields}, volume = {111}, year = {2025}, }
• (2025). Hierarchy of approximations for describing quantum light from high-harmonic generation: A fermi-hubbard-model study. PRA, 111(1), 013113. (www)

  @article{ , abstract = {The quantum optical description of high-order harmonic generation where both the electrons of the generating medium and the driving and generated light fields are described quantum mechanically has been of significant interest in the past years. The quantum optical formulation leads to equations of motion for the generated light field in which the quantum optical field couples to the time-dependent current of the electronic medium irrespectively of the specifics of the electronic system being an atom, molecule, or solid. These equations of motion are not solvable for any realistic system and accurate and verified approximations are hence needed. In this paper, we present a hierarchy of approximations for the equations of motion for the photonic state. At each level in this hierarchy, we compare it to the previous level justifying the validity using the Fermi-Hubbard model as an example of an electronic system with correlations. This model allows us to perform an accurate simulation of the electron motion of all the required states. We find that for the typical experimental situation of weak quantized-light-matter-coupling constant and at intensities well below the damage threshold, an explicit expression for the generated quantum light, referred to as the Markov-state approximation, captures the high-harmonic spectrum quantitatively and describes the single-mode quantum properties of the generated light as characterized by the Mandel- parameter and the degree of squeezing qualitatively.}, archive = {J_PRA}, author = {Christian Saugbjerg Lange and Lars Bojer Madsen}, doi = {10.1103/PhysRevA.111.013113}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013113}, shortjournal = {Phys. Rev. A}, title = {Hierarchy of approximations for describing quantum light from high-harmonic generation: A fermi-hubbard-model study}, volume = {111}, year = {2025}, }
• (2025). Electronic-decay-process spectra including nuclear degrees of freedom. PRA, 111(1), 013112. (www)

  @article{ , abstract = {In the field of chemistry, where nuclear motion has traditionally been a focal point, we now explore the ultrarapid electronic motion spanning attoseconds to femtoseconds, demonstrating that it is equally integral and relevant to the discipline. The advent of ultrashort attosecond pulse technology has revolutionized our ability to directly observe electronic rearrangements in atoms and molecules, offering a time-resolved insight into these swift processes. Prominent examples include Auger-Meitner decay and interparticle Coulombic decay. However, the real challenge lies in interpreting these observations, where theoretical models are indispensable. Building upon the analytical framework introduced by Fasshauer and Madsen [ Phys. Rev. A 101 , 043414 (2020) ], which analyzed the spectra of electrons emitted during electronic decay processes from a purely electronic perspective, we extend this theoretical base to include nuclear dynamics, utilizing the Born-Oppenheimer approximation to deepen our understanding of the intricate interaction between electronic and nuclear motion in these processes. We illustrate the impact of incorporating nuclear degrees of freedom in several theoretical cases characterized by different numbers of vibrational bound states in both the electronic resonance and the electronic final state. This approach not only clarifies complex spectral features and unusual peak shapes but also demonstrates a method for extracting the energy differences between multiple vibrational resonance states through their distinctive interference patterns.}, archive = {J_PRA}, author = {Alexander V. Riegel and Elke Fasshauer}, doi = {10.1103/PhysRevA.111.013112}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013112}, shortjournal = {Phys. Rev. A}, title = {Electronic-decay-process spectra including nuclear degrees of freedom}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic strong-field ionization of aligned n2 molecules. PRA, 111(1), 013111. (www)

  @article{ , abstract = {We experimentally and theoretically study the nonadiabatic strong-field ionization of prealigned nitrogen molecules in an elliptically polarized laser pulse with an attoclock configuration. We observe an obvious oscillation of the most probable radial electron momentum with respect to the molecular alignment angle. Using a semiclassical model, we identify the influence of the molecular orbital and the long-range Coulombic potential on the alignment-dependent final radial momentum. We show that the oscillation of the radial electron momentum results from the effect of the alignment-dependent nonadiabatic initial transverse momenta at the tunnel exit that is induced by a spatial offset along the tunneling direction when the electron starts to tunnel, which depends on the molecular orientation. Our work deepens the understanding of how the molecular orbital affects the nonadiabatic tunneling process of the electron in strong laser pulses.}, archive = {J_PRA}, author = {Zichen Li and Peipei Ge and Jiaqing Yan and Wenhai Xie and Yang Liu and Yupeng Liu and Weibin Liu and Kunlong Liu and Yueming Zhou and Min Li and Peixiang Lu}, doi = {10.1103/PhysRevA.111.013111}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013111}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic strong-field ionization of aligned n2 molecules}, volume = {111}, year = {2025}, }
• (2025). Angular momentum dependence in multiphoton ionization and attosecond time delays. PRA, 111(1), 013110. (www)

  @article{ , abstract = {Multiphoton interference measurements in attosecond physics, e.g., the reconstruction of attosecond beating by interference of two-photon transitions (RABITT), are the typical methods of choice to experimentally access the photoionization delay in atoms and molecules. The exact relation between the measurable multiphoton delays and the theoretical single-photon delays is typically modeled by correction terms, continuum-continuum delays, obtained from a high-energy limit of the theory. However, these are unreliable at photoelectron kinetic energies smaller than about 10 eV, and do not have photoemission angular dependence. In this work we develop an accurate analytic alternative that gives accurate correction terms even at very low energies. Our method is computationally very straightforward, predicts correct multiphoton photoelectron angular distributions as well as the expected angular dependence of the continuum-continuum delay. We validate the approach theoretically against state-of-the-art ab initio calculations as well as experimentally with a two-harmonic RABITT setup, which properly separates different higher-order multiphoton pathways and offers a promising way of analyzing congested molecular photoionization spectra.}, archive = {J_PRA}, author = {Jakub Benda and Zdeněk Mašín and Sreelakshmi Palakkal and Franck Lépine and Saikat Nandi and Vincent Loriot}, doi = {10.1103/PhysRevA.111.013110}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013110}, shortjournal = {Phys. Rev. A}, title = {Angular momentum dependence in multiphoton ionization and attosecond time delays}, volume = {111}, year = {2025}, }
• (2025). Fragmentation in coulomb explosion of hydrocarbon molecules. PRA, 111(1), 013109. (www)

  @article{ , abstract = {Fragmentation dynamics in the Coulomb explosion of hydrocarbons, specifically methane, ethane, propane, and butane, are investigated using time-dependent density functional theory (TDDFT) simulations. The goal of this work is to elucidate the distribution of fragments generated under laser-driven Coulomb explosion conditions. Detailed analysis reveals the types of fragments formed, their respective charge states, and the optimal laser intensities required for achieving various fragmentations. Our results indicate distinct fragmentation patterns for each hydrocarbon, correlating with the molecular structure and ionization potential. Additionally, we identify the laser parameters that maximize fragmentation efficiency, providing valuable insights for experimental setups. This research advances our understanding of Coulomb explosion mechanisms and offers a foundation for further studies in controlled molecular fragmentation.}, archive = {J_PRA}, author = {Samuel S. Taylor and Kálmán Varga and Károly Mogyorósi and Viktor Chikán and Cody Covington}, doi = {10.1103/PhysRevA.111.013109}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013109}, shortjournal = {Phys. Rev. A}, title = {Fragmentation in coulomb explosion of hydrocarbon molecules}, volume = {111}, year = {2025}, }
• (2025). Resonant enhancement of high-order harmonic generation by ba and cs atoms. PRA, 111(1), 013107. (www)

  @article{ , abstract = {High-order harmonic generation (HHG) driven by infrared laser pulses in Ba and Cs atoms is studied numerically and analytically by solving the time-dependent Kohn-Sham equations. We show that the energy transfer from the returning electron, ejected from the outer subshell, to the electrons in the fourth shell results in a giant broadband HHG enhancement at frequencies in Ba and Cs similar to that in Xe, where the returning electron is ejected from the outer subshell. The high degree of delocalization of the outer subshell in Ba and Cs slows down the spreading of the laser-driven electron wave packet outside the atom, which ensures high amplitudes of all generated harmonics. We demonstrate that the giant enhancement region can be reached in both Ba and Cs subjected to a low-intensity mid-IR laser pulse. Also, for Ba at high intensity , singly ionized atoms contribute to HHG; thus, the giant enhancement region in Ba can be reached using intense near-IR laser pulses. For this case, the HHG yield in Ba is more than an order of magnitude higher than that in Xe. In addition to the giant enhancement, the rescattering photoelectron excites in Ba and Cs autoionizing states with vacancy on the subshell, which results in the narrowband HHG enhancement at frequencies .}, archive = {J_PRA}, author = {A. A. Romanov and A. A. Silaev and N. V. Vvedenskii}, doi = {10.1103/PhysRevA.111.013107}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013107}, shortjournal = {Phys. Rev. A}, title = {Resonant enhancement of high-order harmonic generation by ba and cs atoms}, volume = {111}, year = {2025}, }
• (2025). Chirp effects on photoelectron vortices in multiphoton ionization by chirped circularly polarized attosecond pulses. PRA, 111(1), 013106. (www)

  @article{ , abstract = {We theoretically investigate the multiphoton ionization of the xenon atom by pairs of linearly chirped, time-delayed circularly polarized pulses. The numerical results are obtained by solving the two-dimensional time-dependent Schrödinger equation and analyzed by using perturbation theory. By comparing observables such as the ionization probabilities and the energy, momentum, and angular distributions for laser pulses with different chirp rates, we find that the ionization processes have a clear dependence on the pulse chirp. Specifically, the dependence of the energy separation between adjacent interference fringes in the photoelectron energy distributions on the chirp rate is studied in corotating pulses. In counter-rotating pulses, the analysis of the photoelectron angular distributions reveals that the photoelectron ejection angle is sensitive to the chirp rate due to chirp-induced phase difference. Moreover, the critical chirp rates for different multiphoton ionization processes are determined from the multistart spiral structures in photoelectron momentum distributions and applied for control of the photoelectron vortices. The chirp dependence of the emitted electron observables discussed here may provide an ideal diagnostic tool for characterizing the chirped laser pulses.}, archive = {J_PRA}, author = {Run Wang and Qingbin Zhang and Yixian Qian}, doi = {10.1103/PhysRevA.111.013106}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013106}, shortjournal = {Phys. Rev. A}, title = {Chirp effects on photoelectron vortices in multiphoton ionization by chirped circularly polarized attosecond pulses}, volume = {111}, year = {2025}, }
• (2025). Photoionization of the CH molecule. PRA, 111(1), 013105. (www)

  @article{ , abstract = {The photoionization (PI) spectrum of the CH molecule is evaluated theoretically and compared with available experimental data for photon energies from the photoionization threshold up to 12 eV. The vibrational motion and the vibronic coupling between the lowest vibrational and electronic states of CH and are accounted for in the present study. The multichannel quantum-defect theory with the vibrational frame transformation is employed in modeling the PI cross section of CH. The PI cross section is calculated for several initial vibrational levels of CH. A good agreement with the experiment by Gans et al. [ J. Chem. Phys. 144 , 204307 (2016) ] for positions of observed resonances and a qualitative agreement for the intensities of the resonances are found.}, archive = {J_PRA}, author = {Conner Penson and Joshua Forer and Mehdi Ayouz and Nicolas Douguet and Samantha Fonseca dos Santos and Mikhail Guchkov and Jean-Christophe Loison and Bérenger Gans and Viatcheslav Kokoouline}, doi = {10.1103/PhysRevA.111.013105}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013105}, shortjournal = {Phys. Rev. A}, title = {Photoionization of the CH molecule}, volume = {111}, year = {2025}, }
• (2025). Simulating feedback cooling of incoherent quantum mixtures. PRA, 111(1), 013104. (www)

  @article{ , abstract = {We develop an approach for efficient and scalable simulations of measurement and control of quantum systems built upon existing phase-space methods, namely, the truncated Wigner approximation.. We benchmark against existing particle-filter methods by simulating measurement-based feedback cooling in a two-mode system, whose low-dimensional nature permits a computation of an exact solution. The advantage of our method is multimode scalability, which we demonstrate through the successful simulation of measurement-based feedback cooling of an incoherent quasi-one-dimensional thermal ensemble to quantum degeneracy. As the underlying principle of our approach exploits a general correspondence between measurement and coherent feedback, we anticipate it is also applicable across a broad range of other quantum control scenarios.}, archive = {J_PRA}, author = {Kaiwen K. Zhu (朱凯文 and Zain Mehdi and Joseph J. Hope and Simon A. Haine}, doi = {10.1103/PhysRevA.111.013104}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013104}, shortjournal = {Phys. Rev. A}, title = {Simulating feedback cooling of incoherent quantum mixtures}, volume = {111}, year = {2025}, }
• (2025). Magnetic-resonance linewidth of alkali-metal vapor in the unresolved zeeman-resonance regime. PRA, 111(1), 013103. (www)

  @article{ , abstract = {The study of magnetic-resonance linewidth is crucial in magnetic-resonance physics and its applications. Previous studies focused on the linewidth of alkali metal atoms within the spin-exchange relaxation-free regime near zero magnetic field and in strong magnetic fields where Zeeman resonances are well resolved due to the quadratic Zeeman effect. However, the linewidth in the unresolved-Zeeman-resonance regime, which is prevalent in various magnetometer and comagnetometer applications, is not well understood. To address this, we developed a theoretical framework based on the master equation for alkali metal atoms and solved it under the rotating-wave approximation and weak-driving conditions. Our numerical calculations and analytical expressions reveal that the light-narrowing effect occurs only when the ratio of the spin-exchange rate to the spin destruction rate exceeds a critical value. Additionally, we show that the linewidth in the unresolved Zeeman-resonance regime is significantly influenced by the mutual coupling of quantum coherence between different Zeeman sublevels. These findings provide a theoretical tool for understanding spin relaxation in alkali-metal atoms and optimizing the performance of atomic magnetometers and comagnetometers operating in this regime.}, archive = {J_PRA}, author = {Feng Tang and Nan Zhao}, doi = {10.1103/PhysRevA.111.013103}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013103}, shortjournal = {Phys. Rev. A}, title = {Magnetic-resonance linewidth of alkali-metal vapor in the unresolved zeeman-resonance regime}, volume = {111}, year = {2025}, }
• (2025). Observation of collective nonradiative coherence in potassium atoms with two-dimensional coherent spectroscopy. PRA, 111(1), 013102. (www)

  @article{ , abstract = {Quantum coherence of collective states plays a pivotal role in understanding many-body cooperative behaviors. Collective coherences between the ground state and excited states in potassium atoms were previously revealed; however, the coherence between collectively excited states has hitherto been overlooked, and its observation has remained challenging. Here we present a joint experimental and theoretical investigation of coherence effects in K atomic vapor using two-dimensional coherent spectroscopy. By collecting zero-quantum, double-quantum, and double-quantum–zero-quantum two-dimensional spectra, distinct coherence signatures are spectroscopically accessible. The experimental spectra are well reproduced by numerically solving the time dependence of the Lindblad equation, and further analyses unveil nonradiative coherence as the origin of the observations. Our work provides comprehensive insight into the collective coherence effect in multiatom systems.}, archive = {J_PRA}, author = {YiFeng Geng and ShaoGang Yu and YanZuo Chen and SongPo Xu and YanLan Wang and LinQiang Hua and XuanYang Lai and XiaoJun Liu}, doi = {10.1103/PhysRevA.111.013102}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013102}, shortjournal = {Phys. Rev. A}, title = {Observation of collective nonradiative coherence in potassium atoms with two-dimensional coherent spectroscopy}, volume = {111}, year = {2025}, }
• (2025). Coherent nonlinear thomson scattering of laguerre-gauss beams on an electron sheet. PRA, 111(1), 013101. (www)

  @article{ , abstract = {We present a study of the scattering of a monochromatic helical laser beam, described by a Laguerre-Gauss solution of the Maxwell equations, on an electron sheet, initially at rest in the focal plane of the laser; the interaction is described in the framework of a local plane-wave approximation. We calculate the scattered electromagnetic field observed in an arbitrary point at a large distance from the laser focal spot, by adding coherently the contributions of each point in the electron sheet. Due to the interference effects, the radiation is emitted only into the forward direction, within a narrow cone, and it has a spatial structure that we analyze theoretically and numerically. For circularly polarized incident fields, the structure is also helical, with a helical index which depends on the helical index of the incident radiation and the harmonic order. These structures can be observed experimentally, as each harmonic order is emitted with a different frequency, and within cones of different opening angles. Our findings are in agreement with experimental results in the literature which demonstrate the generation of orbital angular momentum carrying photons by radiation scattering on electrons.}, archive = {J_PRA}, author = {Petru-Vlad Toma and Andrei Cristian Opinca and Virgil Baran and Madalina Boca}, doi = {10.1103/PhysRevA.111.013101}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {013101}, shortjournal = {Phys. Rev. A}, title = {Coherent nonlinear thomson scattering of laguerre-gauss beams on an electron sheet}, volume = {111}, year = {2025}, }
• (2025). Metrology in a two-electron atom: The ionization energy of metastable triplet helium 2S13. PRA, 111(1), 012817. (www)

  @article{ , abstract = {Helium (He) is the ideal atom to perform tests of ab initio calculations in two-electron systems that consider all known effects, including quantum-electrodynamics and nuclear-size contributions. Recent state-of-the-art calculations and measurements of energy intervals involving the He metastable state reveal discrepancies at the level of that require clarification both from the experimental and theoretical sides. We report on a new determination of the ionization energy of the metastable state of He. The measurements rely on an approach combining interferometric laser-alignment control, SI-traceable frequency calibration, and imaging-assisted Doppler-free spectroscopy. With this approach we record spectra of the Rydberg series in a highly collimated cold supersonic beam of metastable He generated by a cryogenic valve and an electric discharge. Extrapolation of the Rydberg series yields a new value of the ionization energy [ ] that deviates by from the most precise theoretical result [ ], reported by Patkóš et al. [ Phys. Rev. A 103 , 042809 (2021) ], confirming earlier discrepancies between experiment and theory in this fundamental system.}, archive = {J_PRA}, author = {Gloria Clausen and Kai Gamlin and Josef A. Agner and Hansjürg Schmutz and Frédéric Merkt}, doi = {10.1103/PhysRevA.111.012817}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012817}, shortjournal = {Phys. Rev. A}, title = {Metrology in a two-electron atom: The ionization energy of metastable triplet helium 2S13}, volume = {111}, year = {2025}, }
• (2025). Casimir repulsion turned into attraction by the nonlocal response of salted water. PRA, 111(1), 012816. (www)

  @article{ , abstract = {The Dzyaloshinskii-Lifshitz-Pitaevskii (DLP) theory of Casimir forces predicts a repulsion between two material surfaces separated by a third medium with an intermediate dielectric function. This DLP repulsion paradigm constitutes an important example with many applications. We show here that it is broken when the surfaces interact across salted water due to the nonlocal response of the ions in solution. We consider the interaction between silica and gold and show that the zero-frequency contribution, which is the only one affected by the nonlocal response, is dominant for distances in the range near 100 nm and beyond. As a result, the total Casimir force between gold and silica surfaces in salted water is always attractive in spite of the DLP repulsion paradigm.}, archive = {J_PRA}, author = {Larissa Inácio and Felipe S. S. Rosa and Serge Reynaud and Paulo A. Maia Neto}, doi = {10.1103/PhysRevA.111.012816}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012816}, shortjournal = {Phys. Rev. A}, title = {Casimir repulsion turned into attraction by the nonlocal response of salted water}, volume = {111}, year = {2025}, }
• (2025). Quantitative analysis of aligned-molecule photoelectron angular distributions. PRA, 111(1), 012815. (www)

  @article{ , abstract = {Molecular frame photoelectron angular distributions (MFPADs) provide the full available detail of the photoionization process. Careful analysis of the evolving photoelectron angular distribution during the coherent rotation of a nonadiabatically aligned sample of molecules allows the detail which is smoothed out by orientational averaging in the laboratory frame to be resolved. Here we exploit a high flux monochromated HHG lightsource to provide single-photon photoelectron angular distributions of field-free aligned molecules. Our measurements are sensitive to alignment frame variations in even 𝛽 𝑛 parameters up to 𝑛 = 6 in the PADs of the first four ionization channels of OCS, allowing for rigorous benchmarking of the cutting edge theoretical methods used for simulation of MFPADs. We demonstrate that experimentally derived molecular alignment distributions may be combined with theoretical MFPADs to generate theoretical alignment-frame PADs which provide a quantitative comparison to the experimental 𝛽 𝑛 parameters. The experimental data and ePSproc simulated PADs show quantitative agreement and sensitivity to picometer-scale changes in the molecular geometry. This combined methodology therefore provides a versatile way of studying geometry-sensitive continuum structural features for nondissociative ionization processes which may not be studied in the recoil frame. These measurements therefore provide a strict test of the theoretical descriptions and will stand as benchmark measurements for future comparisons to higher-level theory.}, archive = {J_PRA}, author = {Joanne L. Woodhouse and James O. F. Thompson and Jakub Benda and Richard T. Chapman and Paul Hockett and Varun Makhija and Zdeněk Mašín and Katharine L. Reid and Emma Springate and Adam S. Wyatt and Yu Zhang and Russell S. Minns}, doi = {10.1103/PhysRevA.111.012815}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012815}, shortjournal = {Phys. Rev. A}, title = {Quantitative analysis of aligned-molecule photoelectron angular distributions}, volume = {111}, year = {2025}, }
• (2025). Determination of the landé gJ factor and zeeman coefficients in ground-state 171Yb+ and their applications to quantum frequency standards. PRA, 111(1), 012814. (www)

  @article{ , abstract = {We report the determination of the Landé factor and Zeeman coefficients for the ground-state of , relevant to microwave quantum frequency standards (QFSs). The factor is obtained by using two independent methods, the multiconfiguration Dirac-Hartree-Fock and multireference configuration-interaction methods, yielding a consistent value of . The first- and second-order Zeeman coefficients are determined as and , respectively, based on the calculated factor. These coefficients enable reduced magnetic-field-induced uncertainties, improving the accuracy of the microwave QFSs. The results reported in this work also offer potential for improved constraints on variations in fundamental constants through frequency comparisons and advancing trapped-ion quantum computers based on the ground-state hyperfine splitting of .}, archive = {J_PRA}, author = {Jize Han and Benquan Lu and Yanmei Yu and Jiguang Li and Zhiguo Huang and Jingwei Wen and Ling Qian and Lijun Wang}, doi = {10.1103/PhysRevA.111.012814}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012814}, shortjournal = {Phys. Rev. A}, title = {Determination of the landé gJ factor and zeeman coefficients in ground-state 171Yb+ and their applications to quantum frequency standards}, volume = {111}, year = {2025}, }
• (2025). Polarization tensor in spacetime of three dimensions and a quantum field-theoretical description of the nonequilibrium casimir force in graphene systems. PRA, 111(1), 012812. (www)

  @article{ , abstract = {The polarization tensor of graphene derived in the framework of the Dirac model using the methods of thermal quantum field theory in ( ) dimensions is recast in a mathematically equivalent but more compact and convenient in computations form along the real frequency axis. The obtained unified expressions for the components of the polarization tensor are equally applicable in the regions of the on- and off-the-mass-shell electromagnetic waves. The advantages of the presented formalism are demonstrated on the example of nonequilibrium Casimir force in the configuration of two parallel graphene-coated dielectric plates, one of which is either hotter or colder than the environment. This force is investigated as a function of temperature, the energy gap, and chemical potential of graphene coatings with the account of the effects of spatial dispersion. In addition to the thermodynamically nonequilibrium Casimir and Casimir-Polder forces, the obtained form of the polarization tensor can be useful for investigation of many diverse physical phenomena in graphene systems, such as surface plasmons, reflectances, electrical conductivity, radiation heat transfer, and so on.}, archive = {J_PRA}, author = {G. L. Klimchitskaya and C. C. Korikov and V. M. Mostepanenko}, doi = {10.1103/PhysRevA.111.012812}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012812}, shortjournal = {Phys. Rev. A}, title = {Polarization tensor in spacetime of three dimensions and a quantum field-theoretical description of the nonequilibrium casimir force in graphene systems}, volume = {111}, year = {2025}, }
• (2025). Radiative decay of muonic molecules in resonance states. PRA, 111(1), 012811. (www)

  @article{ , abstract = {In this study, we theoretically investigated x-ray spectra from the radiative decay of muonic deuterium molecules in resonance states , which plays an important role in a new kinetic model of muon catalyzed fusion ( ). The resonance states are Feshbach resonances located below the ) d threshold energy and radiatively decay into the continuum or bound states. The x-ray spectra having characteristic shapes according to the radial distribution of the two nuclei are obtained using precise three-body wave functions. We carefully examined the convergence of the x-ray spectra and achieved agreements between the length- and velocity-gauge calculations. We revealed a nonadiabatic kinetic energy distribution of the decay fragments, indicating that the radiative decay becomes a heating source of muonic atoms. We also investigated the decay branch that directly results in bound-state muonic molecules. Some resonance states and are found to have high branching ratios to the bound state where intramolecular nuclear fusion occurs. The formation of the muonic molecules in the bound states from metastable muonic atoms can be a fast track in the cycle, which skips a slow path to form the bound state from the ground-state muonic atoms and increases the cycle rate. Although the spectra from the radiative decays are located in the energy range of 1.5–1.997 keV, which is close to the x-ray of 1.997 keV from muonic deuterium atoms, state-of-the-art microcalorimeters can distinguish them.}, archive = {J_PRA}, author = {Takuma Yamashita and Kazuhiro Yasuda and Yasushi Kino}, doi = {10.1103/PhysRevA.111.012811}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012811}, shortjournal = {Phys. Rev. A}, title = {Radiative decay of muonic molecules in resonance states}, volume = {111}, year = {2025}, }
• (2025). Measurement of the 13S1→23S1 interval in positronium using field ionization of rydberg states. PRA, 111(1), 012810. (www)

  @article{ , abstract = {We report a 40 parts per measurement of the positronium interval using pulsed two-photon optical spectroscopy. The transition is detected via field ionization of atoms excited from the to the Rydberg state. Precise Monte Carlo line-shape simulations allow for the accounting of effects such as Doppler and ac Stark shifts, while an optical heterodyne measurement of the excitation laser pulse is used to correct for laser frequency chirp. A value of is obtained. This scheme allows for the measurement of the velocity distribution of positronium atoms to correct for the second-order Doppler effect. This is a major source of systematic uncertainty expected for future measurements of this transition with a cw laser; thus, our technique paves the way toward a new generation of a high-precision determination of this interval in positronium.}, archive = {J_PRA}, author = {Michael W. Heiss and Lucas de Sousa Borges and Artem Golovizin and Paolo Crivelli}, doi = {10.1103/PhysRevA.111.012810}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012810}, shortjournal = {Phys. Rev. A}, title = {Measurement of the 13S1→23S1 interval in positronium using field ionization of rydberg states}, volume = {111}, year = {2025}, }
• (2025). Unveiling MgC2 reaction dynamics using a permutation-invariant-polynomial neural-network potential energy surface constructed via the trust region framework. PRA, 111(1), 012809. (www)

  @article{ , abstract = {Recognized as an astrophysical molecule, has garnered significant attention. In this study, we employed the DW-SA-CASSCF/icMRCI+Q/AV(Q+d)Z (Dynamic-weighting-state-averaged-complete active space self-consistent field/Internally contracted multi reference configuration interaction with Davidson correction based on augmented valence quadruple zeta with added diffuse and polarization functions) method to compute high-precision ab initio energy points. A neural-network approach was subsequently utilized to fit the global potential energy surface of the molecule in its state. In contrast to previous methods, the optimization of neural-network parameters in this study was carried out using the trust region framework (TRF). The TRF algorithm exhibits superior performance in parameter optimization and demonstrates reduced dependency on neuron parameters compared to the Levenberg-Marquardt algorithm. Utilizing the obtained potential energy surface, three reaction pathways for were identified, confirming that this reaction proceeds as a barrierless exothermic process. To further verify the accuracy of the fitted potential energy surface, the reaction cross section was calculated under the initial condition for this reaction. By integrating the cross section with the relative translational energy, rate coefficients were determined under various initial conditions. Under the initial condition , the rate coefficient is at its maximum, and the trend of the rate coefficient with temperature first decreases and then increases. At a temperature of 100 K, the rate coefficient reaches its minimum value. At low temperatures, the rate coefficient is very high, which is consistent with the characteristics of a barrierless exothermic reaction.}, archive = {J_PRA}, author = {Guosen Wang and Xia Huang and Changmin Guo and Chuanyu Zhang and Xinlu Cheng}, doi = {10.1103/PhysRevA.111.012809}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012809}, shortjournal = {Phys. Rev. A}, title = {Unveiling MgC2 reaction dynamics using a permutation-invariant-polynomial neural-network potential energy surface constructed via the trust region framework}, volume = {111}, year = {2025}, }
• (2025). Transmission spectroscopy of CF4 molecules in intense x-ray fields. PRA, 111(1), 012808. (www)

  @article{ , abstract = {The nonlinear interaction of x rays with matter is at the heart of understanding and controlling ultrafast molecular dynamics from an atom-specific viewpoint, providing new scientific and analytical opportunities to explore the structure and dynamics of small quantum systems. At increasingly high x-ray intensity, the sensitivity of ultrashort x-ray pulses to specific electronic states and emerging short-lived transient intermediates is of particular relevance for our understanding of fundamental multiphoton absorption processes. In this work, intense x-ray free-electron laser (XFEL) pulses at the European XFEL are combined with a gas cell and grating spectrometer for a high-intensity transmission spectroscopy study of multiphoton-induced ultrafast molecular fragmentation dynamics in . This approach unlocks the direct intrapulse observation of transient fragments, including neutral atoms, by their characteristic absorption lines in the transmitted broadband x-ray spectrum. The dynamics with and without initially producing fluorine -shell holes are studied by tuning the central photon energy. The absorption spectra are measured at different FEL intensities to observe nonlinear effects. Transient isolated fluorine atoms and ions are spectroscopically recorded within the ultrashort pulse duration of a few tens of femtoseconds. An isosbestic point that signifies the correlated transition between intact neutral molecules and charged atomic fragments is observed near the fluorine edge. The dissociation dynamics and the multiphoton absorption-induced dynamics encoded in the spectra are theoretically interpreted. Overall, this study demonstrates the potential of high-intensity x-ray transmission spectroscopy to study ultrafast molecular dynamics with sensitivity to specific intermediate species and their electronic structure.}, archive = {J_PRA}, author = {Rui Jin and Adam Fouda and Alexander Magunia and Yeonsig Nam and Marc Rebholz and Alberto De Fanis and Kai Li and Gilles Doumy and Thomas M. Baumann and Michael Straub and Sergey Usenko and Yevheniy Ovcharenko and Tommaso Mazza and Jacobo Montaño and Marcus Agåker and Maria Novella Piancastelli and Marc Simon and Jan-Erik Rubensson and Michael Meyer and Linda Young and Christian Ott and Thomas Pfeifer}, doi = {10.1103/PhysRevA.111.012808}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012808}, shortjournal = {Phys. Rev. A}, title = {Transmission spectroscopy of CF4 molecules in intense x-ray fields}, volume = {111}, year = {2025}, }
• (2025). Quasianalytical line shape for the 1S−2S laser spectroscopy of antihydrogen and hydrogen. PRA, 111(1), 012807. (www)

  @article{ , abstract = {The accuracy of high precision and fundamental measurements of atomic transition frequencies via laser spectroscopy depends upon fitting the spectral data with a line shape. With atomic hydrogen and antihydrogen two-photon spectroscopy, computer-intensive Monte Carlo simulations have been used to compute the optical Bloch equations in order to match and interpret the experimental spectra. For the highest resolutions, one tries to minimize saturation effects going to regimes of low excitation probability, where perturbation theory can provide reliable results. Here we describe an analytical approach to the line shape based on perturbation theory accounting for the AC-Stark shift and ionization. The expressions can be used for beam experiments or integrated over the magnetic field profile for a trapped sample. Theses line shapes, providing fast results, allow for studies of many systematic effects that influence the accuracy of the determination of the central frequency. This development has relevance to hydrogen beam experiments and to trapped hydrogen and antihydrogen, as developed by the ALPHA collaboration at CERN, for tests of the charge-parity-time symmetry and the highest-accuracy measurement on antimatter.}, archive = {J_PRA}, author = {Levi O. A. Azevedo and Claudio Lenz Cesar}, doi = {10.1103/PhysRevA.111.012807}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012807}, shortjournal = {Phys. Rev. A}, title = {Quasianalytical line shape for the 1S−2S laser spectroscopy of antihydrogen and hydrogen}, volume = {111}, year = {2025}, }
• (2025). Neural networks for the prediction of electronic excitation dynamics. PRA, 111(1), 012806. (www)

  @article{ , abstract = {We demonstrate a machine-learning-based approach that can learn the time-dependent electronic excitation dynamics of small molecules subjected to ion irradiation. Ensembles of neural networks are trained on data generated by time-dependent density-functional theory to relate atomic positions to occupations of molecular orbitals. New data are incrementally and efficiently added to the training data using an active learning process, thereby improving model accuracy. Predicted changes in orbital occupations made by the neural network ensemble are found to have errors and one-standard-deviation uncertainties which are two orders of magnitude smaller than the typical values of the orbital occupation numbers. The trained neural network ensembles demonstrate a limited ability to generalize to molecules not used to train the models. In such cases, the models are able to identify key qualitative features, but struggle to match the quantitative values. The machine-learning procedure developed here is potentially broadly applicable and has the potential to enable study of broad ranges of both materials and dynamical processes by drastically lowering the computational cost and providing surrogate model for multiscale simulations.}, archive = {J_PRA}, author = {Ethan P. Shapera and Cheng-Wei Lee}, doi = {10.1103/PhysRevA.111.012806}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012806}, shortjournal = {Phys. Rev. A}, title = {Neural networks for the prediction of electronic excitation dynamics}, volume = {111}, year = {2025}, }
• (2025). Competing ionization and dissociation: Extension of the energy-dependent frame transformation to the gerade symmetry of h2. PRA, 111(1), 012805. (www)

  @article{ , abstract = {This article solves two major tasks that frequently arise in the theory of electron collisions with a target molecular cation. First, it extends the energy-dependent frame transformation (EDFT) treatment, which is needed to map fixed-nuclei electron-molecule scattering matrices into an energy-dependent laboratory-frame scattering matrix with vibrational channel indices. The EDFT mapping can now be carried out even when the target molecule possesses multiple low-energy potential curves, significantly transcending previous applications. Second, it implements a method to extract the rest of the full laboratory-frame scattering matrix, i.e., the columns and rows describing input and/or output dissociation channels. The treatment is benchmarked in this article against the essentially exact solution of a refined two-dimensional model of the singlet gerade symmetry of . Our tests demonstrate that the theory accurately maps fixed-nuclei scattering information, of the type provided by existing electron-molecule computer codes, into a laboratory-frame scattering matrix that includes both ionization and dissociation. This treatment can provide a general framework applicable to a broad class of electron collision processes involving diatomic target ions, suitable for an accurate description of challenging processes such as dissociative recombination.}, archive = {J_PRA}, author = {Dávid Hvizdoš and Roman Čurík and Chris H. Greene}, doi = {10.1103/PhysRevA.111.012805}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012805}, shortjournal = {Phys. Rev. A}, title = {Competing ionization and dissociation: Extension of the energy-dependent frame transformation to the gerade symmetry of h2}, volume = {111}, year = {2025}, }
• (2025). Observing young-type double-slit interference in slow- and intermediate-velocity ion-molecule collisions. PRA, 111(1), 012804. (www)

  @article{ , abstract = {We study the fragmentation dynamics of CO molecules in slow- (0.16 a.u. ) and intermediate- (1.41 a.u. ) velocity electron capture collisions. The kinetic energy release distributions of the fragmentation channel show the variation of energy depositions during the collisions for the associated capture paths. We have also observed molecular-axis orientation-dependent variations in the angle-differential cross sections for the double-electron capture and transfer ionization processes. A simple mathematical model based on Young's optical double-slit experiment has been invoked. The variations are attributed to the molecular double-slit-type interference phenomena arising from the interference between the two outgoing de Broglie waves formed by electron capture. The asymmetry in the interference pattern due to the scattering phase gives insight into the role of the quantum phenomena in characterizing such collision dynamics. Our study thus provides general evidence of the wave-particle duality in low to highly perturbative ion-molecule collisions.}, archive = {J_PRA}, author = {Md Abul Kalam Azad Siddiki and Deepankar Misra}, doi = {10.1103/PhysRevA.111.012804}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012804}, shortjournal = {Phys. Rev. A}, title = {Observing young-type double-slit interference in slow- and intermediate-velocity ion-molecule collisions}, volume = {111}, year = {2025}, }
• (2025). Changing the paradigm in f-containing cold molecules: The impact of spin-orbit coupling and f−d transitions. PRA, 111(1), 012803. (www)

  @article{ , abstract = {Present-day state-of-the-art ab initio many-body calculations on -block-containing cold molecules rely heavily on perturbative approaches for spin-orbit coupling and exclude a substantial part of the atomic transitions in the and shells. Here, we demonstrate the importance of proper relativistic treatment of the and shells in Yb-containing diatomics and the inclusion of the transition to obtain accurate spectra of . We focus on state-of-the-art relativistic many-body calculations for the Yb atom's ground and excited states and the potential energy surface. For that purpose, we exploit various quantum many-body methods, namely, a spin-free and four-component implementation of the coupled-cluster singles and doubles (CCSD) model and its equation-of-motion (EOM) extensions, spin-free complete-active-space self-consistent field, and internally contracted multireference (MR) configuration interaction approaches. We oppose scalar relativistic calculations to four-component variants to support the reliability of our EOM-CCSD study and shed new light on the interplay between these systems' spin-orbit coupling and the proper treatment of relativistic effects. Finally, we provide new reference potential-energy curves for ground and excited states. Additionally, we compute spectroscopic constants and analyze the Einstein coefficients.}, archive = {J_PRA}, author = {Marta Gałyńska and Matheus M. F. de Moraes and Paweł Tecmer and Katharina Boguslawski}, doi = {10.1103/PhysRevA.111.012803}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012803}, shortjournal = {Phys. Rev. A}, title = {Changing the paradigm in f-containing cold molecules: The impact of spin-orbit coupling and f−d transitions}, volume = {111}, year = {2025}, }
• (2025). One-loop electron self-energy with accelerated partial-wave expansion in the coulomb gauge. PRA, 111(1), 012802. (www)

  @article{ , abstract = {Numerical calculations of the electron self-energy without any expansion in the binding nuclear field are required in order to match the rapidly advancing precision of experimental spectroscopy. For the lightest elements, particularly hydrogen, these computations are complicated by large numerical cancelations and the slow convergence of the partial-wave expansion. Methods with accelerated convergence of the partial-wave expansion have been recently put forward [V. A. Yerokhin, K. Pachucki, and V. M. Shabaev, Phys. Rev. A 72 , 042502 (2005) ; J. Sapirstein and K. T. Cheng, Phys. Rev. A 108 , 042804 (2023) ]. In our work we extend the accelerated-convergence methods to the previously hardly accessible region of nuclear charges and higher excited states.}, archive = {J_PRA}, author = {V. A. Yerokhin and Z. Harman and C. H. Keitel}, doi = {10.1103/PhysRevA.111.012802}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012802}, shortjournal = {Phys. Rev. A}, title = {One-loop electron self-energy with accelerated partial-wave expansion in the coulomb gauge}, volume = {111}, year = {2025}, }
• (2025). Polarizability of molecular hydrogen and gas metrology. PRA, 111(1), 012801. (www)

  @article{ , abstract = {The polarizability of the hydrogen molecule can be precisely calculated based on the quantum electrodynamics (QED) theory and a few fundamental physical constants. Therefore, experimental measurements with comparable accuracy can test the theory and establish gas metrology with hydrogen as the working gas. An optical refractometer was built and its performance was tested by measuring the electric dipole polarizabilities of argon, neon, and nitrogen. The polarizability of the molecule was determined to be 2.031 027(71) . The result agrees with the current calculated value, indicating the potential of a primary standard for pressure or temperature through measuring the polarizability of .}, archive = {J_PRA}, author = {Zhong-Liang Nie (聂中梁 and Jin Wang (王进 and Chang-Le Hu (胡常乐 and Yu R. Sun (孙羽 and Cun-Feng Cheng (程存峰 and Yan Tan (谈艳 and Shui-Ming Hu (胡水明}, doi = {10.1103/PhysRevA.111.012801}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012801}, shortjournal = {Phys. Rev. A}, title = {Polarizability of molecular hydrogen and gas metrology}, volume = {111}, year = {2025}, }
• (2025). Image classification by combining quantum kernel learning and tensor networks. PRA, 111(1), 012630. (www)

  @article{ , abstract = {Several variational quantum circuits for machine learning have been proposed in recent years, with one promising class of variational algorithms involving tensor networks operating on states resulting from local feature maps. In contrast, a random feature approach known as quantum kitchen sinks (C. M. Wilson et al. , Quantum kitchen sinks: An algorithm for machine learning on near-term quantum computers, arXiv:1806.08321 ) provides comparable performance, but leverages nonlocal feature maps. Here we combine these two approaches by proposing a circuit Ansatz where a tree tensor network coherently processes the nonlocal feature maps of quantum kitchen sinks and we run numerical experiments to evaluate the performance of the Ansatz on image classification. From the perspective of classification performance, we find that simply combining quantum kitchen sinks with tensor networks yields no qualitative improvements. However, the addition of feature optimization greatly boosts performance, leading to state-of-the-art quantum circuits for image classification, requiring only shallow circuits and a small number of qubits, both well within reach of near-term quantum devices.}, archive = {J_PRA}, author = {Nathan X. Kodama and Alex Bocharov and Marcus P. da Silva}, doi = {10.1103/PhysRevA.111.012630}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012630}, shortjournal = {Phys. Rev. A}, title = {Image classification by combining quantum kernel learning and tensor networks}, volume = {111}, year = {2025}, }
• (2025). Simulating a quasiparticle on a quantum device. PRA, 111(1), 012629. (www)

  @article{ , abstract = {We propose a variational approach to explore quasiparticle excitations in interacting quantum many-body systems, motivated by the potential in leveraging near-term noisy intermediate scale quantum devices for quantum-state preparation. By exploiting translation invariance and potentially other Abelian symmetries of the many-body Hamiltonian, we extend the variational quantum eigensolver (VQE) approach to construct spatially localized quasiparticle states that encode information on the whole excited band, allowing us to achieve quantum parallelism. We benchmark the proposed algorithm via numerical simulations performed on the one-dimension transverse field Ising chain. Our numerical results demonstrate that VQE can capture both the magnon quasiparticles of the paramagnetic phase, and the topologically nontrivial domain wall excitations in the ferromagnetic regime. We argue that the localized quasiparticle states constructed with VQE contain accessible information on the full band of quasiparticles, and provide valuable insight into the way interactions renormalize the bare spin flip or domain wall excitations of the simple, trivially solvable limits of the model. These results serve as important theoretical input towards utilizing quantum simulators to directly access the quasiparticles of strongly interacting quantum systems, as well as to gain insight into crucial experimentally measured properties directly determined by the nature of these quasiparticles.}, archive = {J_PRA}, author = {Rimika Jaiswal and Izabella Lovas and Leon Balents}, doi = {10.1103/PhysRevA.111.012629}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012629}, shortjournal = {Phys. Rev. A}, title = {Simulating a quasiparticle on a quantum device}, volume = {111}, year = {2025}, }
• (2025). Surface-enhanced stimulated raman spectroscopy with squeezed photonic states. PRA, 111(1), 012628. (www)

  @article{ , abstract = {Recent advances in generating light in specific quantum states facilitate new sensing applications and enhance or revitalize established measurement and sensing techniques. Stimulated Raman spectroscopy (SRS), a measurement modality based on Raman scattering, could benefit from tuning the quantum properties of the pump and the Stokes lights or the properties of quantum states of the stimulating and excitation fields. Additionally, this modality could also benefit from field enhancement accompanied by plasmon excitation in the surface regions of metal nanoparticles. We present a theoretical investigation of stimulated Raman scattering involving squeezed states of light. The concept of surface- and quantum-enhanced stimulated Raman scattering is introduced. Furthermore, expressions for the respective SRS transition rates are derived, and their dependence on the quantum states of the optical field is discussed, with particular emphasis on the squeezing parameters characterizing these states. For cases involving surface enhancements, we also employ classical computational electrodynamics to guide our exploration of atomically large systems that support plasmon excitation.}, archive = {J_PRA}, author = {Frank Hagelberg and Ali Passian}, doi = {10.1103/PhysRevA.111.012628}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012628}, shortjournal = {Phys. Rev. A}, title = {Surface-enhanced stimulated raman spectroscopy with squeezed photonic states}, volume = {111}, year = {2025}, }
• (2025). Optimal scheduling of graph states via path decompositions. PRA, 111(1), 012627. (www)

  @article{ , abstract = {We study the optimal scheduling of graph states in measurement-based quantum computation, establishing an equivalence between measurement schedules and path decompositions of graphs. We define the spatial cost of a measurement schedule based on the number of simultaneously active qubits and prove that an optimal measurement schedule corresponds to a path decomposition of minimal width. Our analysis shows that approximating the spatial cost of a graph is NP-hard, while for graphs with bounded spatial cost, we establish an efficient algorithm for computing an optimal measurement schedule.}, archive = {J_PRA}, author = {Samuel J. Elman and Jason Gavriel and Ryan L. Mann}, doi = {10.1103/PhysRevA.111.012627}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012627}, shortjournal = {Phys. Rev. A}, title = {Optimal scheduling of graph states via path decompositions}, volume = {111}, year = {2025}, }
• (2025). Probing the limits of variational quantum algorithms for nonlinear ground states on real quantum hardware: The effects of noise. PRA, 111(1), 012626. (www)

  @article{ , abstract = {A recently proposed variational quantum algorithm has expanded the horizon of variational quantum computing to nonlinear physics and fluid dynamics. In this work, we probe the ability of such approach to capture the ground state of the nonlinear Schrödinger equation for a range of parameters on real superconducting quantum processors. Specifically, we study the expressivity of real-amplitude, hardware-efficient Ansatz to capture the ground state of this nonlinear system across various interaction regimes and implement different noise scenarios in both simulators and cloud processors. Our investigation reveals that although quantum hardware noise impairs the evaluation of the energy cost function, certain small instances of the problem consistently converge to the ground state. We test and demonstrate a variety of cases on IBM Q superconducting devices and analyze the discrepancies in the energy cost function evaluation due to quantum hardware noise. These discrepancies are absent in the state fidelity estimation because of the shallow state preparation circuit. Our comprehensive analysis offers valuable insights into the practical implementation and advancement of the variational algorithms for nonlinear problems.}, archive = {J_PRA}, author = {Muhammad Umer and Eleftherios Mastorakis and Sofia Evangelou and Dimitris G. Angelakis}, doi = {10.1103/PhysRevA.111.012626}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012626}, shortjournal = {Phys. Rev. A}, title = {Probing the limits of variational quantum algorithms for nonlinear ground states on real quantum hardware: The effects of noise}, volume = {111}, year = {2025}, }
• (2025). Generic and scalable differential-equation solver for quantum scientific computing. PRA, 111(1), 012625. (www)

  @article{ , abstract = {One of the most important topics in quantum scientific computing is solving differential equations. In this paper, a generalized quantum functional expansion (QFE) framework is proposed. In the QFE framework, a functional expansion of the solution is encoded into a quantum state and the time evolution of the quantum state is solved with variational quantum simulation (VQS). The quantum functional encoding supports different numerical schemes of functional expansions. If the solution space is infinite-order differentiable, the lower bound of the required number of qubits under the quantum function encoding scheme is the double logarithm of the inverse error bound. Furthermore, a parallel Pauli operation strategy is proposed to significantly improve the scalability of VQS. The number of circuits in VQS is exponentially reduced to only the quadratic order of the number of ansatz parameters. Four example differential equations are solved to demonstrate the generic QFE framework.}, archive = {J_PRA}, author = {Jinhwan Sul and Yan Wang}, doi = {10.1103/PhysRevA.111.012625}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012625}, shortjournal = {Phys. Rev. A}, title = {Generic and scalable differential-equation solver for quantum scientific computing}, volume = {111}, year = {2025}, }
• (2025). Detecting quantum steering in networks. PRA, 111(1), 012624. (www)

  @article{ , abstract = {Quantum networks promise an unprecedented leap in semi-device-independent communication and security by capitalizing on quantum steering. However, current methods for assessing quantum network steering are constrained to specific cases. In this work, we introduce the network-Clauser-Horn-Shimony-Holt-like inequality for investigating network steering independent of entanglement source characteristics. We employ this inequality to detect full network steering in both single-node and multinode repeater networks and assess the tolerance of various noise models. Under a specific noise model, our method is used to compute the bound of semi-device-independent communication distance. Through case studies, we also demonstrate that our method, as a semi-device-independent entanglement witness, is more suitable for settings requiring Bell measurements compared to network Bell inequality. These findings open new avenues for broader ways to detect quantum steering independent of entanglement sources.}, archive = {J_PRA}, author = {Ming-Xiao Li and Yuqi Li and Ya Xi and Chang-Yue Zhang and Ying-Zheng Wang and Rui-Bin Xu and Shao-Ming Fei and Zhu-Jun Zheng}, doi = {10.1103/PhysRevA.111.012624}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012624}, shortjournal = {Phys. Rev. A}, title = {Detecting quantum steering in networks}, volume = {111}, year = {2025}, }
• (2025). Quantum state engineering in three-level systems via lewis-riesenfeld invariants. PRA, 111(1), 012623. (www)

  @article{ , abstract = {Coherent manipulation of three-level systems is of critical significance to quantum information processing. Here, we propose a scheme to achieve quantum state engineering in arbitrary three-level systems, in which the controlling Hamiltonian can be inversely engineered based on Lewis-Riesenfeld invariants and a gauge transformation. With well-designed control pulses, the three-level system continually evolves from the initial state to a desired final state in one step. The proposed scheme allows diverse optimizations, which gives it a significant advantage in robustness and fidelity over the commonly used resonant-pulse multistep method. The scheme can also be extended to produce multiqubit entangled states provided with a similar state subspace. In a particular application, we demonstrate numerically that our protocol can reliably and robustly prepare qutrit states as well as three-qubit entangled states within superconducting circuits.}, archive = {J_PRA}, author = {Xiang-Min Yu and Kun Zhou and Han-Yu Zhang and Shao-Xiong Li and Zhiguo Huang and Jingwei Wen and Runqing Zhang and Yang Yu}, doi = {10.1103/PhysRevA.111.012623}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012623}, shortjournal = {Phys. Rev. A}, title = {Quantum state engineering in three-level systems via lewis-riesenfeld invariants}, volume = {111}, year = {2025}, }
• (2025). Dissipation-induced quantum homogenization for temporal information processing. PRA, 111(1), 012622. (www)

  @article{ , abstract = {Quantum reservoirs have great potential as they utilize the complex real-time dissipative dynamics of quantum systems for information processing and target time-series generation without precise control or fine-tuning of the Hamiltonian parameters. Nonetheless, their realization is challenging as quantum hardware with appropriate dynamics, robustness to noise, and ability to produce target steady states is required. To that end, we propose the disordered quantum homogenizer as an alternative interaction model, and prove it satisfies the necessary and sufficient conditions ( stability and contractivity ) of the reservoir dynamics, necessary for solving machine learning tasks with time-series input data streams. The results indicate that the quantum homogenization protocol, physically implementable as either nuclear magnetic resonance ensemble or a photonic system, can potentially function as a reservoir computer.}, archive = {J_PRA}, author = {Alexander Yosifov and Aditya Iyer and Vlatko Vedral}, doi = {10.1103/PhysRevA.111.012622}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012622}, shortjournal = {Phys. Rev. A}, title = {Dissipation-induced quantum homogenization for temporal information processing}, volume = {111}, year = {2025}, }
• (2025). Shortcuts to adiabatic transducers in a hybrid spin-superconducting system. PRA, 111(1), 012621. (www)

  @article{ , abstract = {Hybrid quantum systems consisting of quantum dot spins and superconducting circuits have emerged as a promising platform for quantum information processing. However, the development of scalable architectures requires the ability to entangle different quantum systems over long distances, which remains an outstanding challenge for hybrid systems with complex interactions and multiple energy levels. Here, we devise methods to implement entangling gates by using engineered virtual photons as a transducer to couple spin-superconducting systems. We propose to tailor such transducers by tuning the driving pulse using shortcuts to adiabaticity. We demonstrate the realization of high-fidelity entangling gates of 99% in short timescales of a few tens of nanoseconds, and we show the robustness of this approach to control parameters. Furthermore, our method enables state transfer and remote entanglement between different modules of the hybrid system with fidelity exceeding the fault-tolerance threshold, thus demonstrating the scalability of this approach. These results pave the way for fast, high-fidelity quantum information processing on leading hybrid platforms.}, archive = {J_PRA}, author = {Xing-Yu Zhu and Le-Tian Zhu and Guang-Can Guo and Tao Tu and Chuan-Feng Li}, doi = {10.1103/PhysRevA.111.012621}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012621}, shortjournal = {Phys. Rev. A}, title = {Shortcuts to adiabatic transducers in a hybrid spin-superconducting system}, volume = {111}, year = {2025}, }
• (2025). Shadow-based quantum subspace algorithm for the nuclear shell model. PRA, 111(1), 012620. (www)

  @article{ , abstract = {In recent years, researchers have been exploring the applications of noisy intermediate-scale quantum (NISQ) computation in various fields. One important area in which quantum computation can outperform classical computers is the ground-state problem of a many-body system, e.g., the nucleus. However, using a quantum computer in the NISQ era to solve a meaningful-scale system remains a challenge. To calculate the ground energy of nuclear systems, we propose a new algorithm that combines classical shadow and subspace diagonalization techniques. Our subspace is composed of matrices, with the basis of the subspace being the classical shadow of the quantum state. We test our algorithm on nuclei described by the Cohen-Kurath shell model and USD shell model. We find that the accuracy of the results improves as the number of shots increases, following the Heisenberg scaling.}, archive = {J_PRA}, author = {Ruyu Yang and Tianren Wang and Bing-Nan Lu and Ying Li and Xiaosi Xu}, doi = {10.1103/PhysRevA.111.012620}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012620}, shortjournal = {Phys. Rev. A}, title = {Shadow-based quantum subspace algorithm for the nuclear shell model}, volume = {111}, year = {2025}, }
• (2025). Efficient frequency allocation for superconducting quantum processors using improved optimization techniques. PRA, 111(1), 012619. (www)

  @article{ , abstract = {Building on previous research on frequency allocation optimization for superconducting circuit quantum processors, this work incorporates several techniques to improve overall solution quality. We introduce constraints and imposed edgewise differences help to improve the optimization results. We also introduce optimization variables for the orientation of each edge, defined as the direction from the control qubit to the target qubit, to be chosen during optimization. To scale up to larger processors, multimodule designs are employed with various boundary conditions, thereby enhancing the collective yield. These enhancements allow for greater flexibility in processor design by eliminating the need for handpicked orientations. We support the efficient assembly of large processors with dense connectivity by choosing the best boundary conditions. Examples demonstrate that, at low computational cost, this optimization approach finds a frequency configuration for a square chip with over 1000 qubits and over 10% yield at much larger dispersion levels than required by previous approaches.}, archive = {J_PRA}, author = {Zewen Zhang and Pranav Gokhale and Jeffrey M. Larson}, doi = {10.1103/PhysRevA.111.012619}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012619}, shortjournal = {Phys. Rev. A}, title = {Efficient frequency allocation for superconducting quantum processors using improved optimization techniques}, volume = {111}, year = {2025}, }
• (2025). Cascaded multiparameter quantum metrology. PRA, 111(1), 012618. (www)

  @article{ , abstract = {We present an innovative, platform-independent concept for multiparameter sensing where the measurable parameters are in series, or cascaded, enabling measurements as a function of position. With temporally resolved detection, we show that squeezing can give a quantum enhancement in sensitivity over that of classical states by a factor of , where is the squeezing parameter. As an example, we have modeled an interferometer that senses multiple phase shifts along the same path, demonstrating a maximal quantum advantage by combining a coherent state with squeezed vacuum. Further classical modeling with up to 100 phases shows linear scaling potential for adding nodes to the sensor. The approach can be applied to remote sensing, geophysical surveying, and infrastructure monitoring.}, archive = {J_PRA}, author = {Gregory Krueper and Lior Cohen and Juliet T. Gopinath}, doi = {10.1103/PhysRevA.111.012618}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012618}, shortjournal = {Phys. Rev. A}, title = {Cascaded multiparameter quantum metrology}, volume = {111}, year = {2025}, }
• (2025). Bit-flip errors in dissipative cat qubits: Second-order perturbation theory. PRA, 111(1), 012617. (www)

  @article{ , abstract = {Dissipative cat qubits are known for the exponential suppression of the bit-flip rate. However, there is significant discrepancy between experimental measurements and analytical predictions of the strength of the bit-flip suppression. In this paper we resolve this discrepancy for some of the perturbations, by developing a second-order perturbation theory on top of a nonlinear dissipative Lindbladian. Following this scheme, we derive an analytical expression for the exponentially small bit-flip rate due to single-photon loss, which shows good agreement with numerical simulations. We also apply our scheme to other perturbations, such as frequency detuning and the Z gate, and find the corresponding bit-flip rates, which also show good agreement with the numerical simulation.}, archive = {J_PRA}, author = {Kirill S. Dubovitskii}, doi = {10.1103/PhysRevA.111.012617}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012617}, shortjournal = {Phys. Rev. A}, title = {Bit-flip errors in dissipative cat qubits: Second-order perturbation theory}, volume = {111}, year = {2025}, }
• (2025). Secure quantum-enhanced measurements on a network of sensors. PRA, 111(1), 012616. (www)

  @article{ , abstract = {Two-party secure quantum remote sensing protocols enable quantum-enhanced measurements at remote locations with guaranteed security against eavesdroppers. This idea can be scaled up to networks of nodes where one party can directly measure functions of parameters at the different nodes using entangled states. However, the security on such networks decreases exponentially with the number of nodes. Here we show how this problem can be overcome in a hybrid protocol that utilizes both entangled and separable states to achieve quantum-enhanced measurement precision and security on networks of any size.}, archive = {J_PRA}, author = {Sean William Moore and Jacob A. Dunningham}, doi = {10.1103/PhysRevA.111.012616}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012616}, shortjournal = {Phys. Rev. A}, title = {Secure quantum-enhanced measurements on a network of sensors}, volume = {111}, year = {2025}, }
• (2025). Decoherence of surface phonons in a quantum acoustic system. PRA, 111(1), 012615. (www)

  @article{ , abstract = {Phononic resonators are becoming increasingly important in quantum information science, both for applications in quantum computing, communication, and sensing as well as in experiments investigating fundamental physics. Here, we study the decoherence of phonons confined in a surface acoustic wave (SAW) resonator strongly coupled to a superconducting transmon qubit. By comparing experimental data with numerical solutions to the Markovian master equation, we report a surface phononic energy decay rate of and a pure dephasing rate of . These rates are in good agreement with the level of decoherence we extract from qubit-assisted spectroscopic measurements of the SAW resonator. We additionally find that the timescales over which coherent driven dynamics and decoherence occur are comparable, highlighting the need to model the composite device as an open quantum system. We discuss possible sources of decoherence in SAW-based quantum acoustic devices and the application of these devices in future quantum acoustic dissipation engineering experiments. The decoherence characterization techniques we employ are broadly applicable for investigating and benchmarking the effects of loss and dephasing on mechanical resonators in the quantum regime.}, archive = {J_PRA}, author = {Camryn Undershute and Joseph M. Kitzman and Camille A. Mikolas and Johannes Pollanen}, doi = {10.1103/PhysRevA.111.012615}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012615}, shortjournal = {Phys. Rev. A}, title = {Decoherence of surface phonons in a quantum acoustic system}, volume = {111}, year = {2025}, }
• (2025). Proposal for superconducting quantum networks using multioctave transduction to lower frequencies. PRA, 111(1), 012614. (www)

  @article{ , abstract = {We propose networking superconducting quantum circuits by transducing their excitations (typically 4–8 GHz) to 200–500 MHz photons for transmission via superconducting cryogenic coaxial cables. This frequency down-conversion reduces transmission losses and, counterintuitively, reduces noise. We introduce a multioctave asymmetrically threaded superconducting quantum interference device circuit capable of the required efficient, high-rate transduction. For a 100-meter cable with at 10 mK, we theoretically show that our approach achieves single-photon fidelities of 0.962 at 200 MHz versus 0.772 at 8 GHz, and triples the lower bound on quantum channel capacity. This method enables highly efficient networking of superconducting qubits while maintaining high fidelities, combining improved performance with the practical advantages of flexible, compact coaxial cables.}, archive = {J_PRA}, author = {Takuma Makihara and Wentao Jiang and Amir H. Safavi-Naeini}, doi = {10.1103/PhysRevA.111.012614}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012614}, shortjournal = {Phys. Rev. A}, title = {Proposal for superconducting quantum networks using multioctave transduction to lower frequencies}, volume = {111}, year = {2025}, }
• (2025). Continuous-variable measurement-device-independent multipartite quantum communication via a fast-fading channel. PRA, 111(1), 012613. (www)

  @article{ , abstract = {This study investigates the implementation of measurement-device-independent multiparty quantum communication using continuous-variable Greenberger-Horne-Zeilinger (CV GHZ) states under the fast fading channel. The communication parties are connected through free space, and factors such as atmospheric turbulence cause beam drift, resulting in variations in channel transmittance according to specific probability distributions. We assume a worst-case scenario in which an eavesdropper has complete control over the channel, forcing the communicators to estimate the channel based on this probability distribution. The protocol employs CV GHZ states to achieve secure communication through quantum cryptographic conference and quantum secret sharing. For the aspect of security, independent entangling cloner attack and coherent attack are analyzed. Simulation results demonstrate that the protocol can withstand advantageous attacks from eavesdroppers.}, archive = {J_PRA}, author = {Runbo Zhao and Jian Zhou and Ronghua Shi and Jinjing Shi and Guangqiang He}, doi = {10.1103/PhysRevA.111.012613}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012613}, shortjournal = {Phys. Rev. A}, title = {Continuous-variable measurement-device-independent multipartite quantum communication via a fast-fading channel}, volume = {111}, year = {2025}, }
• (2025). Entanglement generation using single-photon pulse reflection in realistic networks. PRA, 111(1), 012612. (www)

  @article{ , abstract = {A general entanglement generation protocol between remote stationary qubits using single-photon reflection in a photonic network is explored theoretically. The nodes of the network consist of single qubits that are typically represented by the spin of a color center, each localized in a separate optical cavity and linked to other nodes via photonic links such as optical fibers. We derive a model applicable to a wide range of parameters and scenarios to describe the nodes and the local spin-photon interaction accounting for the pulsed (finite-bandwidth) nature of flying single photons while optimizing the rate and fidelity. We investigate entanglement generation between remote qubits and tailor protocols to a variety of physical implementations with different properties. Of particular interest is the regime of weak coupling and low cooperativity between the spin and cavity, which is relevant in the cases of the nitrogen- and silicon-vacancy centers in diamond. We also take into account the variability of the properties between realistic (stationary) nodes.}, archive = {J_PRA}, author = {Ferdinand Omlor and Benedikt Tissot and Guido Burkard}, doi = {10.1103/PhysRevA.111.012612}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012612}, shortjournal = {Phys. Rev. A}, title = {Entanglement generation using single-photon pulse reflection in realistic networks}, volume = {111}, year = {2025}, }
• (2025). Randomized benchmarking protocol for dynamic circuits. PRA, 111(1), 012611. (www)

  @article{ , abstract = {Dynamic circuit operations (measurements with feedforward) are important components for future quantum computing efforts, but lag behind gates in the availability of characterization methods. Here we introduce a series of dynamic circuit benchmarking routines based on interleaving dynamic circuit operation blocks in one-qubit randomized benchmarking sequences of data qubits. spans between the set of data qubits and a measurement qubit and may include feedforward operations based on the measurement. We identify six candidate operation blocks, such as preparing the measured qubit in and performing a -Pauli on the data qubit conditioned on a measurement of “1”. Importantly, these blocks provide a methodology to accumulate readout assignment errors in a long circuit sequence. We also show the importance of dynamical decoupling in reducing crosstalk and measurement-induced phase errors during dynamic circuit blocks. When measured on an IBM Eagle device with appropriate dynamical decoupling, the results are consistent with measurement assignment error and the decoherence of the data qubit as the leading error sources.}, archive = {J_PRA}, author = {Liran Shirizly and Luke C. G. Govia and David C. McKay}, doi = {10.1103/PhysRevA.111.012611}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012611}, shortjournal = {Phys. Rev. A}, title = {Randomized benchmarking protocol for dynamic circuits}, volume = {111}, year = {2025}, }
• (2025). Probing electron-photon entanglement using a quantum eraser. PRA, 111(1), 012610. (www)

  @article{ , abstract = {We propose a tangible experimental scheme for demonstrating quantum entanglement between swift electrons and light, relying on coherent cathodoluminescence for photon generation in a transmission electron microscope, and a quantum eraser setup for formation and verification of entanglement. The entanglement of free electrons with light is key to developing free-electron quantum optics and its potential applications such as quantum sensing, novel photonic and electron state generation, and entanglement between free electrons.}, archive = {J_PRA}, author = {Jan-Wilke Henke and Hao Jeng and Claus Ropers}, doi = {10.1103/PhysRevA.111.012610}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012610}, shortjournal = {Phys. Rev. A}, title = {Probing electron-photon entanglement using a quantum eraser}, volume = {111}, year = {2025}, }
• (2025). Simultaneous information and energy transmission through quantum channels. PRA, 111(1), 012609. (www)

  @article{ , abstract = {The optimal rate at which information can be sent through a quantum channel when the transmitted signal must simultaneously carry some minimum amount of energy is characterized. To do so, we introduce the quantum-classical analog of the capacity-power function, and we generalize results in classical information theory for transmitting classical information through noisy channels. We show that the capacity-power function for a classical-quantum channel, for both unassisted and private protocol, is concave, and we also prove additivity for unentangled and uncorrelated ensembles of input signals for such channels. This implies that we do not need regularized formulas for calculation. We show that these properties also hold for all noiseless channels when we restrict the set of input states to be pure quantum states. For general channels, we geometrically prove that the capacity-power function is piecewise concave, with further support from numerical simulations. Further, we connect channel capacity to properties of random quantum states. In particular, we obtain analytical expressions for the capacity-power function for the case of noiseless channels using properties of random quantum states under an energy constraint and concentration phenomena in large Hilbert spaces.}, archive = {J_PRA}, author = {Bishal Kumar Das and Lav R. Varshney and Vaibhav Madhok}, doi = {10.1103/PhysRevA.111.012609}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012609}, shortjournal = {Phys. Rev. A}, title = {Simultaneous information and energy transmission through quantum channels}, volume = {111}, year = {2025}, }
• (2025). One-decoy-state quantum key distribution with advantage distillation based on planar-lightwave-circuit-integration modules. PRA, 111(1), 012608. (www)

  @article{ , abstract = {Photonics integrated circuits provide a stable, compact and robust platform for the implementation of quantum key distribution (QKD), which can generate information-theoretic secure keys between distant parties. Here, we present a high-speed QKD tests with silica planar lightwave circuits based asymmetric Mach-Zehnder interferometer modules. To further enhance system performance and reduce system complexity, we employ the advantage distillation (AD) algorithm alongside the one-decoy method. The AD algorithm can effectively extract strongly correlated bit pairs from weakly correlated bit pairs, thereby significantly improving the key rate over long distances, where traditional post-processing methods fail to generate keys. With a clock rate of 625 MHz, our system achieves composable secret key rates of 3.32 Mbps at 2 dB loss and 1.85 kbps at 18 dB loss, respectively. These results represent the first experimental validation of AD algorithm, and pave the way for the development of QKD networks with photonic integration.}, archive = {J_PRA}, author = {Jiali Zhu and Xingyu Zhou and Huajian Ding and Jingyang Liu and Chunhui Zhang and Jian Li and Junming An and Qin Wang}, doi = {10.1103/PhysRevA.111.012608}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012608}, shortjournal = {Phys. Rev. A}, title = {One-decoy-state quantum key distribution with advantage distillation based on planar-lightwave-circuit-integration modules}, volume = {111}, year = {2025}, }
• (2025). Quantum estimation for improving optomechanical coupling strength. PRA, 111(1), 012607. (www)

  @article{ , abstract = {Enhanced quantum metrology is of vital importance for revealing the distinct features of quantum phenomena. Here we propose an effective scheme to significantly improve the quantum estimation of optomechanical coupling strength (OCS) with the assistance of two-level atoms, coherent feedback loop, and squeezed vacuum injection. Our results indicate that, by selecting appropriate atomic, quantum feedback and squeezing parameters, the estimation error of the OCS parameter can be greatly reduced. We explain the physical mechanisms behind these factors enhancing estimation precision of OCS parameter and explore the ideal parameter regions for estimating it. More importantly, the estimation precision obtained by our scheme exhibits stronger robustness against mechanical damping and ambient temperature in comparison with the unassisted case. In addition, we evaluate the performance of heterodyne detection, indicating that the measurement precision obtained through this method can approach the estimation precision obtained by our scheme. Further, the experimental feasibility of our scheme is discussed. The proposed scheme for enhancing quantum sensing is quite general and can also be applied to high-precision estimation of other physical parameters.}, archive = {J_PRA}, author = {Jia-Xin Peng and P. Djorwe and H. T. Cui and Naeem Akhtar and Inaam Ul Haq and Chengsong Zhao and Dongke Li}, doi = {10.1103/PhysRevA.111.012607}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012607}, shortjournal = {Phys. Rev. A}, title = {Quantum estimation for improving optomechanical coupling strength}, volume = {111}, year = {2025}, }
• (2025). Generalized quantum parity codes for ultrafast long-distance quantum communication. PRA, 111(1), 012606. (www)

  @article{ , abstract = {To achieve an ultrafast long-distance quantum communication, the one-way quantum repeater scheme based on linear optics is a promising framework. However, photon loss becomes the dominant error in communication as the distance increases. To resolve this problem, a quantum parity code has been developed, which, however, suffers from a significant fluctuation in the success transmission probability as the code length increases. Here, to utilize all the available qubits to boost the coding gain, we propose a generalized version of quantum parity code by using the concatenated structure in a flexible way. Compared to quantum parity code, the generalized one does not increase the hardware overhead but offers superior performance with the continuous increase of code length. The gain comes from optimizing the length distribution of the inner codes. Given the current limited ability to realize quantum codes, generalized quantum parity code assisted by one-way quantum repeaters offers a promising way to achieve ultrafast long-distance quantum communication.}, archive = {J_PRA}, author = {Yun-Jiang Wang and Zhuo-Yan Xiao and Xing-Yu Xiong and Sha Shi and Dong-Sheng Wang}, doi = {10.1103/PhysRevA.111.012606}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012606}, shortjournal = {Phys. Rev. A}, title = {Generalized quantum parity codes for ultrafast long-distance quantum communication}, volume = {111}, year = {2025}, }
• (2025). General communication enhancement via the quantum switch. PRA, 111(1), 012605. (www)

  @article{ , abstract = {Recent studies have shown that quantum information may be effectively transmitted by a finite collection of completely depolarizing channels in a coherent superposition of different orders, via an operation known as the quantum . Such results are quite remarkable, as completely depolarizing channels taken in isolation and in a definite order can only output white noise. For general channels, however, little is known about the potential communication enhancement provided by the quantum . In this work, we define an easily computable quantity associated with the quantum of copies of a fixed channel, and we conjecture that is both a necessary and sufficient condition for communication enhancement via the quantum . In support of our conjecture, we derive a simple analytic expression for the classical capacity of the quantum of copies of an arbitrary Pauli channel in terms of the quantity , which we then use to show that our conjecture indeed holds in the space of all Pauli channels. Utilizing such results, we then formulate a communication protocol involving the quantum which enhances the private capacity of the BB84 channel.}, archive = {J_PRA}, author = {Zhen Wu and James Fullwood and Zhihao Ma and Si-Qi Zhou and Qi Zhao and Giulio Chiribella}, doi = {10.1103/PhysRevA.111.012605}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012605}, shortjournal = {Phys. Rev. A}, title = {General communication enhancement via the quantum switch}, volume = {111}, year = {2025}, }
• (2025). Quantum computation based on capture-and-release dynamics. PRA, 111(1), 012604. (www)

  @article{ , abstract = {High-fidelity and decoherence-insensitive quantum gates are essential for achieving universal quantum computing. In quantum information processing, decoherence arising from excited states significantly contributes to the scheme's infidelity. Therefore, minimizing the average population of the excited state is crucial when designing quantum protocols. A promising approach involves utilizing capture-and-release dynamics to induce a complex phase on the ground state in a two-level system, effectively suppressing the integrated excited-state population. By applying this dynamics protocol to a three-level system, we propose a scheme to construct arbitrary decoherence suppressed single-qubit and nontrivial two-qubit gates; meanwhile, by incorporating the Zeno dynamics process in the construction of two-qubit logic gates, the large detuning and excitation of virtual photons render the scheme insensitive to qubit decoherence and cavity dissipation. Applying our scheme to the nitrogen-vacancy (NV) center as an example, we prove our scheme with higher fidelity than conventional nonadiabatic non-Abelian geometric gates while significantly enhancing the robustness against decoherence and frequency shift errors. These studies provide alternative approaches for constructing robust quantum gate operations. We also emphasize that the scheme is feasible for three-level quantum systems, not limited to NV center systems.}, archive = {J_PRA}, author = {S.-Y. Zhang and J.-F. Wei and P.-Y. Song and L.-L. Yan and A. Kinos and Shi-Lei Su and Gang Chen}, doi = {10.1103/PhysRevA.111.012604}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012604}, shortjournal = {Phys. Rev. A}, title = {Quantum computation based on capture-and-release dynamics}, volume = {111}, year = {2025}, }
• (2025). Device-independent quantum secret sharing with advanced random key generation basis. PRA, 111(1), 012603. (www)

  @article{ , abstract = {Quantum secret sharing (QSS) enables a dealer to securely distribute keys to multiple players. Device-independent (DI) QSS can resist all possible attacks from practical imperfect devices and provide QSS the highest level of security in theory. However, DI QSS requires high-performance devices, especially for low-noise channels, which is a big challenge to demonstrate experimentally. We propose a DI QSS protocol with the advanced random key generation basis strategy, which combines the random key generation basis with the noise preprocessing and postselection strategies. We develop the methods to numerically simulate the key generation rate in an acceptable time. Our DI QSS protocol has some advantages. First, it can increase the noise tolerance threshold from an initial 7.147% to 9.231% (29.16% growth) and reduce the global detection efficiency threshold from 96.32% to 93.41%. The maximal distance between any two users increases to 1.43 km, which is about 5.5 times the initial value. Second, by randomly selecting two basis combinations to generate the key, our DI QSS protocol can reduce the entanglement resource consumption. Our protocol has potential for the experimental demonstration of DI QSS and application in the future.}, archive = {J_PRA}, author = {Qi Zhang and Jia-Wei Ying and Zhong-Jian Wang and Wei Zhong and Ming-Ming Du and Shu-Ting Shen and Xi-Yun Li and An-Lei Zhang and Shi-Pu Gu and Xing-Fu Wang and Lan Zhou and Yu-Bo Sheng}, doi = {10.1103/PhysRevA.111.012603}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012603}, shortjournal = {Phys. Rev. A}, title = {Device-independent quantum secret sharing with advanced random key generation basis}, volume = {111}, year = {2025}, }
• (2025). Memory-assisted measurement-device-independent quantum secret sharing. PRA, 111(1), 012602. (www)

  @article{ , abstract = {Measurement-device-independent quantum secret sharing (MDI-QSS) can resist all attacks on imperfect measuring devices. However, limited by the exponential increase in fiber loss, MDI-QSS has a low key rate and short communication distance. In this paper, we introduce quantum memory (QM) in MDI-QSS to increase the success probability of the three-photon synchronous projection measurement and propose a memory-assisted (MA) MDI-QSS protocol. In this protocol, the heralded single-photon source and the decoy-state method are also explored. This MA-MDI-QSS protocol has three advantages. First, the QM used here is all optical, and this protocol is feasible under current experimental conditions. Second, combined with the decoy-state method, our protocol can guarantee the security of the transmitted keys under practical experimental conditions. Third, numerical simulation results show that our protocol has a higher secure key rate and longer photon transmission distance than existing MDI-QSS protocols without QM. Our protocol provides a promising way for implementing the long-distance MDI-QSS in the near future.}, archive = {J_PRA}, author = {Cheng Zhang and Qi Zhang and Wei Zhong and Ming-Ming Du and Shu-Ting Shen and Xi-Yun Li and An-Lei Zhang and Lan Zhou and Yu-Bo Sheng}, doi = {10.1103/PhysRevA.111.012602}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012602}, shortjournal = {Phys. Rev. A}, title = {Memory-assisted measurement-device-independent quantum secret sharing}, volume = {111}, year = {2025}, }
• (2025). Quantum metrology algorithms for dark matter searches with clocks. PRA, 111(1), 012601. (www)

  @article{ , abstract = {Quantum algorithms such as dynamical decoupling can be used to improve the sensitivity of a quantum sensor to a signal while suppressing sensitivity to noise. Atomic clocks are among the most sensitive quantum sensors, with recent improvements in clock technology allowing for unprecedented precision and accuracy. These clocks are highly sensitive to variations in fundamental constants, making them ideal probes for local ultralight scalar dark matter. Further improvements to the sensitivity are expected in proposed nuclear clocks based on a nuclear transition in the thorium-229 isotope. We investigate the use of various quantum metrology algorithms in the search for dark matter using quantum clocks. We propose a broadband dynamical decoupling algorithm and compare it with quantum metrology protocols that have been previously proposed and demonstrated, namely, differential spectroscopy and narrowband dynamical decoupling. We conduct numerical simulations of scalar dark matter searches with realistic noise sources and accounting for dark matter decoherence. Finally, we propose an alternative thorium nuclear transition excitation method that bypasses the technical challenges associated with vacuum ultraviolet lasers.}, archive = {J_PRA}, author = {M. H. Zaheer and N. J. Matjelo and D. B. Hume and M. S. Safronova and D. R. Leibrandt}, doi = {10.1103/PhysRevA.111.012601}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012601}, shortjournal = {Phys. Rev. A}, title = {Quantum metrology algorithms for dark matter searches with clocks}, volume = {111}, year = {2025}, }
• (2025). Quantum eigenstate preparation assisted by a coherent link. PRA, 111(1), 012445. (www)

  @article{ , abstract = {Preparing the ground state of a local Hamiltonian is a crucial problem in understanding quantum many-body systems, with applications in a variety of physics fields and connections to combinatorial optimization. While various quantum algorithms exist which can prepare the ground state with high precision and provable guarantees from an initial approximation, current devices are limited to shallow circuits. Here we consider the setting where Alice and Bob, in a distributed quantum computing architecture, want to prepare the same Hamiltonian eigenstate. We demonstrate that the circuit depth of the eigenstate preparation algorithm can be reduced when the devices can share entanglement via a coherent link. This is especially so in the case where one of them has a near-perfect eigenstate, which is more efficiently broadcast to the other device. Our approach requires only a single auxiliary qubit per device to be entangled with the outside. We show that, in the near-convergent regime, the average relative suppression of unwanted amplitudes is improved to per run of the protocol, outperforming the average relative suppression of achieved with a single device alone for the same protocol.}, archive = {J_PRA}, author = {Benjamin F. Schiffer and Jordi Tura}, doi = {10.1103/PhysRevA.111.012445}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012445}, shortjournal = {Phys. Rev. A}, title = {Quantum eigenstate preparation assisted by a coherent link}, volume = {111}, year = {2025}, }
• (2025). Low-overhead quantum error-correction codes with a cyclic topology. PRA, 111(1), 012444. (www)

  @article{ , abstract = {Quantum error correction is an important ingredient for scalable quantum computing. Stabilizer codes are one of the most promising and straightforward ways to correct quantum errors, are convenient for logical operations, and improve performance with increasing the number of qubits involved. Here, we propose a resource-efficient scaling of a five-qubit perfect code with increasing-weight cyclic stabilizers for small distances on the ring architecture, which takes into account the topological features of the superconducting platform. We show an approach to construct the quantum circuit of a correction code with ancillas entangled with non-neighboring data qubits. Furthermore, we introduce a neural network-based decoding algorithm supported by an improved lookup table decoder and provide a numerical simulation of the proposed code, which demonstrates the exponential suppression of the logical error rate.}, archive = {J_PRA}, author = {Ilya A. Simakov and Ilya S. Besedin}, doi = {10.1103/PhysRevA.111.012444}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012444}, shortjournal = {Phys. Rev. A}, title = {Low-overhead quantum error-correction codes with a cyclic topology}, volume = {111}, year = {2025}, }
• (2025). Exploiting symmetry in variational quantum channel coding. PRA, 111(1), 012443. (www)

  @article{ , abstract = {Quantum channel coding is an effective method to reduce noise interference in quantum communication and has been extensively investigated both theoretically and practically. It is difficult, however, for ordinary channel-coding strategies to deal with scenarios in which quantum noises are completely or partially unknown. This paper introduces a solution using an equivariant variational quantum algorithm to design coding schemes for unknown channels. Our approach employs parameterized quantum channels within an equivariant Ansatz . We analyze the channel's capabilities, demonstrate the mitigation of the barren plateau, and provide convergence guarantees for our method. The numerical results highlight the following: (1) Our method achieves higher fidelity and faster convergence than naive methods in various quantum communication scenarios. (2) The equivariant method exhibits enhanced convergence and trainability, efficiently avoiding the barren-plateau issue.}, archive = {J_PRA}, author = {Jun Wu and Wei Xie and Hao Fu and Mingzheng Zhu and Xiang-Yang Li}, doi = {10.1103/PhysRevA.111.012443}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012443}, shortjournal = {Phys. Rev. A}, title = {Exploiting symmetry in variational quantum channel coding}, volume = {111}, year = {2025}, }
• (2025). Stochastic action for the entanglement of a noisy monitored two-qubit system. PRA, 111(1), 012442. (www)

  @article{ , abstract = {We study the effect of local unitary noise on the entanglement evolution of a two-qubit system subject to local monitoring and interqubit coupling by constructing a suitable stochastic path integral based on the Chantasri-Dressel-Jordan formalism. From this, we identify the optimal entanglement dynamics and deploy a diagrammatic method to find a closed-form approximation for the evolution of the average squared concurrence. We find that the optimal trajectory and diagrammatic expansion capture the oscillations of entanglement at short times. A separate numerical analysis of the long-time steady-state entanglement reveals a nonmonotonic relationship between the concurrence and noise strength.}, archive = {J_PRA}, author = {Dominic Shea and Alessandro Romito}, doi = {10.1103/PhysRevA.111.012442}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012442}, shortjournal = {Phys. Rev. A}, title = {Stochastic action for the entanglement of a noisy monitored two-qubit system}, volume = {111}, year = {2025}, }
• (2025). Barren plateaus swamped with traps. PRA, 111(1), 012441. (www)

  @article{ , abstract = {Two main challenges preventing efficient training of variational quantum algorithms and quantum machine learning models are local minima and barren plateaus. Typically, barren plateaus are associated with deep circuits, while shallow circuits have been shown to suffer from suboptimal local minima. We point out a simple mechanism that creates exponentially many low-quality local minima specifically in the barren plateau regime. These local minima are trivial solutions that optimize only a few terms in the loss function, leaving the rest on their barren plateaus. More precisely, we show the existence of approximate local minima, optimizing a single loss term, and conjecture the existence of exact local minima, optimizing only a logarithmic fraction of all loss function terms. One implication of our findings is that many, if not most, regions with large gradients are vicinities of poor local minima. This highlights additional challenges in finding efficient initialization strategies.}, archive = {J_PRA}, author = {Nikita A. Nemkov and Evgeniy O. Kiktenko and Aleksey K. Fedorov}, doi = {10.1103/PhysRevA.111.012441}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012441}, shortjournal = {Phys. Rev. A}, title = {Barren plateaus swamped with traps}, volume = {111}, year = {2025}, }
• (2025). Retrieving nonstabilizerness with neural networks. PRA, 111(1), 012440. (www)

  @article{ , abstract = {Quantum computing's promise lies in its intrinsic complexity, with entanglement initially heralded as its hallmark. However, the quest for quantum advantage extends beyond entanglement, encompassing the realm of nonstabilizer (magic) states. Despite their significance, quantifying and characterizing these states pose formidable challenges. Here, we introduce a different approach leveraging convolutional neural networks (CNNs) to classify quantum states based on their nonstabilizerness content. Without relying on a complete knowledge of the state, we utilize partial information acquired from measurement snapshots to train the CNN in distinguishing between stabilizer and nonstabilizer states. Importantly, our methodology circumvents the limitations of full state tomography, offering a practical solution for real-world quantum experiments. In addition, we unveil a theoretical connection between stabilizer Rényi entropies and the expectation value of Pauli matrices for pure quantum states. Our findings pave the way for experimental applications, providing a robust and accessible tool for deciphering the intricate landscape of quantum resources.}, archive = {J_PRA}, author = {Antonio Francesco Mello and Guglielmo Lami and Mario Collura}, doi = {10.1103/PhysRevA.111.012440}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012440}, shortjournal = {Phys. Rev. A}, title = {Retrieving nonstabilizerness with neural networks}, volume = {111}, year = {2025}, }
• (2025). Investigating an approach of robustly self-testing two-qubit entangled states. PRA, 111(1), 012439. (www)

  @article{ , abstract = {In a recent paper [S.-L. Chen et al. , Quantum 5 , 552 (2021) ], the authors proposed a framework for robustly self-testing steerable quantum assemblages. In this work, we apply their method to the scenario of self-testing two-qubit entangled quantum states. Our bounds on the fidelity with the reference states are compared with other methods.}, archive = {J_PRA}, author = {Chan-Ching Lien and Shin-Liang Chen}, doi = {10.1103/PhysRevA.111.012439}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012439}, shortjournal = {Phys. Rev. A}, title = {Investigating an approach of robustly self-testing two-qubit entangled states}, volume = {111}, year = {2025}, }
• (2025). Quantum teleportation between a continuous-variable optical qumode and a discrete-variable solid-state qubit. PRA, 111(1), 012438. (www)

  @article{ , abstract = {Quantum teleportation is a fundamental ingredient for quantum information science and technology. In particular, the ability to perform quantum teleportation between quantum systems with different natures and encoding types is crucial for building complex systems, such as a distributed quantum internet. Here we propose a scheme to teleport a continuous-variable optical qubit, encoded in an optical qumode by means of a superposed coherent state, onto a discrete-variable solid-state qubit, associated with a single nitrogen-vacancy-center spin in diamond, via hybrid entanglement. By using a newly developed method for Bell-state measurement which relies only on light homodyne detection and spin-polarization measurement, near-deterministic and -perfect quantum teleportation can be achieved for large coherent-state amplitude input. Taking noise effects into account, we find that the average teleportation fidelity can still exceed the classical limit, enabling substantial teleportation distances under realistic experimental conditions.}, archive = {J_PRA}, author = {Di Wang and Lei Xie and Jinfeng Liu and Yiling Song and Wei Xiong and Mingfeng Wang}, doi = {10.1103/PhysRevA.111.012438}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012438}, shortjournal = {Phys. Rev. A}, title = {Quantum teleportation between a continuous-variable optical qumode and a discrete-variable solid-state qubit}, volume = {111}, year = {2025}, }
• (2025). Hamiltonian-based graph-state ansatz for variational quantum algorithms. PRA, 111(1), 012437. (www)

  @article{ , abstract = {One promising application of near-term quantum devices is to prepare trial wave functions using short circuits for solving different problems via variational algorithms. For this purpose, we introduce a circuit design that combines graph-based diagonalization circuits with arbitrary single-qubit rotation gates to get a Hamiltonian-based graph states ansatz. We test the accuracy of the proposed ansatz in estimating ground-state energies of various molecules of size up to 12 qubits. Additionally, we compare the gate count and parameter number complexity of the proposed ansatz against previously proposed schemes and find an order magnitude reduction in gate count complexity with a slight increase in the number of parameters. Our work represents a significant step towards constructing compact quantum circuits with good trainability and convergence properties and applications in solving chemistry and physics problems.}, archive = {J_PRA}, author = {Abhinav Anand and Kenneth R. Brown}, doi = {10.1103/PhysRevA.111.012437}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012437}, shortjournal = {Phys. Rev. A}, title = {Hamiltonian-based graph-state ansatz for variational quantum algorithms}, volume = {111}, year = {2025}, }
• (2025). Device-independent certification of multipartite distillable entanglement. PRA, 111(1), 012436. (www)

  @article{ , abstract = {Quantum networks consist of various quantum technologies, spread across vast distances, and involve various users at the same time. Certifying the functioning and efficiency of the individual components is a task that is well studied and widely used. However, the power of quantum networks can only be realized by integrating all the required quantum technologies and platforms across a large number of users. In this work, we demonstrate how to certify the distillable entanglement available in multipartite states produced by quantum networks, without relying on the physical realization of its constituent components. We do so by using the paradigm of device independence.}, archive = {J_PRA}, author = {Aby Philip and Mark M. Wilde}, doi = {10.1103/PhysRevA.111.012436}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012436}, shortjournal = {Phys. Rev. A}, title = {Device-independent certification of multipartite distillable entanglement}, volume = {111}, year = {2025}, }
• (2025). Scalable embedding of parity constraints in quantum annealing hardware. PRA, 111(1), 012435. (www)

  @article{ , abstract = {One of the main bottlenecks in solving combinatorial optimization problems with quantum annealers is the qubit connectivity in the hardware. A possible solution for larger connectivity is minor embedding. This technique makes the geometrical properties of the combinatorial optimization problem, encoded as a Hamiltonian, match the properties of the quantum annealing hardware. The embedding itself is a hard computational problem, and therefore heuristic algorithms are required. In this work we present fixed, modular, and scalable embeddings that can be used to embed any combinatorial optimization problem described as an Ising Hamiltonian. These embeddings are the result of an extension of the well-known parity mapping, which has been used in the past to map higher-order Ising Hamiltonians to quadratic Hamiltonians, which are suitable for existing quantum hardware. We show how our new embeddings can be mapped to existing quantum annealers and that the embedded Hamiltonian physical properties match the original Hamiltonian properties.}, archive = {J_PRA}, author = {Michele Cattelan and Jemma Bennett and Sheir Yarkoni and Wolfgang Lechner}, doi = {10.1103/PhysRevA.111.012435}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012435}, shortjournal = {Phys. Rev. A}, title = {Scalable embedding of parity constraints in quantum annealing hardware}, volume = {111}, year = {2025}, }
• (2025). Improved quantum power method and numerical integration using a quantum singular-value transformation. PRA, 111(1), 012434. (www)

  @article{ , abstract = {Quantum singular-value transformation (QSVT) is a framework that has been shown to unify many primitives in quantum algorithms. In this work we leverage the QSVT framework in two directions. We first show that the QSVT framework can accelerate one recently introduced quantum power method, which substantially improves its running time. Additionally, we incorporate several elementary numerical integration techniques, such as the rectangular method, Monte Carlo method, and quadrature method, into the QSVT framework, which results in polynomial speedup with respect to the size or the number of points of the grid. Our results thus provide further examples to demonstrate the potential of the QSVT and how it may enhance quantum algorithmic tasks.}, archive = {J_PRA}, author = {Nhat A. Nghiem and Hiroki Sukeno and Shuyu Zhang and Tzu-Chieh Wei}, doi = {10.1103/PhysRevA.111.012434}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012434}, shortjournal = {Phys. Rev. A}, title = {Improved quantum power method and numerical integration using a quantum singular-value transformation}, volume = {111}, year = {2025}, }
• (2025). Circuit knitting facing exponential sampling-overhead scaling bounded by entanglement cost. PRA, 111(1), 012433. (www)

  @article{ , abstract = {Circuit knitting, a method for connecting quantum circuits across multiple processors to simulate nonlocal quantum operations, is a promising approach for distributed quantum computing. While various techniques have been developed for circuit knitting, we uncover fundamental limitations to the scalability of this technology. We prove that the sampling overhead of circuit knitting is exponentially lower bounded by the exact entanglement cost of the target bipartite dynamic, even with the asymptotic amount of resources using the parallel cut strategy. Specifically, we prove that the regularized sampling overhead assisted with local operations and classical communication of any bipartite quantum channel is lower bounded by the exponential of its exact entanglement cost under separable preserving operations. Furthermore, we develop the faithful lower bounds for the regularized sampling overhead based on channels' 𝜅 entanglement and max-Rains information, providing efficiently computable benchmarks. Our work reveals a profound connection between virtual quantum information processing via quasiprobability decomposition and quantum Shannon theory, highlighting the critical role of entanglement in distributed quantum computing.}, archive = {J_PRA}, author = {Mingrui Jing and Chengkai Zhu and Xin Wang}, doi = {10.1103/PhysRevA.111.012433}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012433}, shortjournal = {Phys. Rev. A}, title = {Circuit knitting facing exponential sampling-overhead scaling bounded by entanglement cost}, volume = {111}, year = {2025}, }
• (2025). Hamiltonian forging of a thermofield double. PRA, 111(1), 012432. (www)

  @article{ , abstract = {We address the variational preparation of the thermofield double as the ground state of a suitably engineered Hamiltonian acting on the doubled Hilbert space. Through the use of the Entanglement Forging ansatz, we propose a solution that involves only circuits of width . We illustrate the method with generic fermionic Hamiltonians. The free fermion case can be solved in closed form and yields a warm start state for the variational circuits whenever interactions are present. As an important side product, this method returns the complete energy spectrum and eigenbasis of the system.}, archive = {J_PRA}, author = {Daniel Faílde and Juan Santos-Suárez and David A. Herrera-Martí and Javier Mas}, doi = {10.1103/PhysRevA.111.012432}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012432}, shortjournal = {Phys. Rev. A}, title = {Hamiltonian forging of a thermofield double}, volume = {111}, year = {2025}, }
• (2025). Hybrid nonlocality via atom-photon interactions with and without impurities. PRA, 111(1), 012431. (www)

  @article{ , abstract = {To obtain Bell statistics from hybrid systems composed of finite- and infinite-dimensional systems, we propose a hybrid measurement scheme, in which the continuous mode is measured using the generalized pseudospin operators, while the finite (two)-dimensional system is measured in the usual Pauli basis. Maximizing the Bell expression with these hybrid measurement settings leads to the violations of local realism in the hybrid system, which is referred to as hybrid nonlocality . We demonstrate the utility of our strategy in a realistic setting of cavity quantum electrodynamics, where an atom interacts resonantly with a single mode of an electromagnetic field under the Jaynes-Cummings Hamiltonian. We dynamically compute the quenched averaged value of hybrid nonlocality in imperfect situations by incorporating disorder in the atom-cavity coupling strength. In the disordered case, we introduce two kinds of measurement scenarios to determine the Bell statistics—in one situation, experimentalists can tune the optimal settings according to the interaction strength, while such controlled power is absent in the other case. In contrast to the oscillatory behavior observed in the ordered case, the quenched averaged violation saturates to a finite value in some parameter regimes in the former case. We also examine the connection between Wigner negativity and hybrid nonlocality.}, archive = {J_PRA}, author = {Pritam Halder and Ratul Banerjee and Saptarshi Roy and Aditi Sen(De}, doi = {10.1103/PhysRevA.111.012431}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012431}, shortjournal = {Phys. Rev. A}, title = {Hybrid nonlocality via atom-photon interactions with and without impurities}, volume = {111}, year = {2025}, }
• (2025). Construction and classification of all equioverlapping measurements in qubit and qutrit systems. PRA, 111(1), 012430. (www)

  @article{ , abstract = {The overlap between quantum measurement operators is a fundamental quantity, and the notion of an equioverlapping measurement captures a symmetric feature of quantum measurements in terms of overlap. Such equioverlapping measurements, as a special class of quantum measurements, interpolate between von Neumann measurements and symmetric informationally complete positive operator-valued measures (SIC-POVMs), and exhibit a rich and subtle structure. In this work, we classify and completely determine all equioverlapping measurements in qubit and qutrit systems.}, archive = {J_PRA}, author = {Zhihua Guo and Yan Liu and Tsung-Lin Lee and Shunlong Luo}, doi = {10.1103/PhysRevA.111.012430}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012430}, shortjournal = {Phys. Rev. A}, title = {Construction and classification of all equioverlapping measurements in qubit and qutrit systems}, volume = {111}, year = {2025}, }
• (2025). Three-parameter symmetric quantum joint measurement on two qubits. PRA, 111(1), 012429. (www)

  @article{ , abstract = {A standard two-qubit joint measurement is the well-known Bell state measurement, in which each reduced state (traced out one qubit) is the completely mixed state. Recently, a novel quantum joint measurement known as the elegant joint measurement (EJM) has been proposed, where the reduced states of the EJM basis have tetrahedral symmetry. In this paper, we first propose a five-parameter entangled state and reveal its inherent symmetry. Based on this, we define a generalized EJM parametrized by z , φ , and θ , and provide the quantum circuits for preparing and detecting these basis states. There are three main results: (i) The previous single-parameter EJM can be directly derived by specifying the parameters z and φ ; (ii) the initial unit vectors related to the four vertices of the regular tetrahedron are not limited to the original choice and not all the unit vectors in cylindrical coordinates are suitable for forming the EJM basis; and (iii) the reduced states of the present EJM basis can always form two mirror-image tetrahedra, robustly preserving its elegant properties. We aim to determine what kind of states the EJM basis belongs to and to provide a method for constructing the generalized three-parameter EJM, which may contribute to the multisetting measurement and the potential applications for quantum information processing.}, archive = {J_PRA}, author = {Ying-Qiu He and Dong Ding and Ting Gao and Zan-Jia Li and Feng-Li Yan}, doi = {10.1103/PhysRevA.111.012429}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012429}, shortjournal = {Phys. Rev. A}, title = {Three-parameter symmetric quantum joint measurement on two qubits}, volume = {111}, year = {2025}, }
• (2025). Multiscale quantum approximate optimization algorithm. PRA, 111(1), 012427. (www)

  @article{ , abstract = {The quantum approximate optimization algorithm (QAOA) is one of the canonical algorithms designed to find approximate solutions for combinatorial optimization problems on current noisy intermediate-scale quantum (NISQ) devices. The primary focus of ongoing research is to exhibit its speed advantage over classical algorithms. However, the performance of QAOA is restricted at lower depths, while higher depths are limited by current experimental techniques. We propose an algorithm that amalgamates the capabilities of QAOA and the real-space renormalization group transformation. Numerical simulations indicate that our proposed algorithm can deliver precise solutions for specific randomly generated instances using QAOA at shallow depths, even at the lowest depth. This algorithm is particularly suitable for current NISQ devices, offering the potential to demonstrate a quantum advantage.}, archive = {J_PRA}, author = {Ping Zou}, doi = {10.1103/PhysRevA.111.012427}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012427}, shortjournal = {Phys. Rev. A}, title = {Multiscale quantum approximate optimization algorithm}, volume = {111}, year = {2025}, }
• (2025). Efficient ground-state-energy estimation and certification on early fault-tolerant quantum computers. PRA, 111(1), 012426. (www)

  @article{ , abstract = {A major thrust in quantum algorithm development over the past decade has been the search for the quantum algorithms that will deliver practical quantum advantage first. Today's quantum computers—and even early fault-tolerant quantum computers—are limited in the number of operations they can implement per circuit. We introduce quantum algorithms for ground-state-energy estimation (GSEE) that accommodate this design constraint. The first algorithm estimates ground-state energies, offering a quadratic improvement on the ground-state overlap parameter compared to other methods in this regime. The second algorithm certifies that the estimated ground-state energy is within a specified error tolerance of the true ground-state energy, addressing the issue of gap estimation that beleaguers several ground-state preparation and energy estimation algorithms. We note, however, that the scaling of this certification technique is currently less favorable than that of the GSEE algorithm. To develop the certification algorithm, we propose an alternative use of quantum computers to facilitate rejection sampling. After a classical computer generates initial samples, the quantum computer is used to accept or reject these samples, resulting in a set of accepted samples that approximate draws from a target distribution. Although we apply this technique specifically for ground-state-energy certification, it may find broader applications. Our paper pushes the boundaries of what operation-limited quantum computers can achieve, bringing the prospect of quantum advantage closer to realization.}, archive = {J_PRA}, author = {Guoming Wang and Daniel Stilck França and Gumaro Rendon and Peter D. Johnson}, doi = {10.1103/PhysRevA.111.012426}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012426}, shortjournal = {Phys. Rev. A}, title = {Efficient ground-state-energy estimation and certification on early fault-tolerant quantum computers}, volume = {111}, year = {2025}, }
• (2025). Generalizing measurement-induced phase transitions to information exchange symmetry breaking. PRA, 111(1), 012425. (www)

  @article{ , abstract = {Probing a quantum system disrupts its state in a phenomenon known as backaction. In this work we investigate the conditions for this disruption to result in a phase transition in the information dynamics of a monitored system. We introduce a framework that captures a wide range of experiments encompassing probes comprised of projective measurements and probes which more generally transfer quantum information from the system to a quantum computer. The latter case is relevant to the recently introduced quantum-enhanced experiments in which quantum postprocessing is performed on a quantum computer and which can offer an exponential sampling advantage over projective measurements and classical postprocessing. Our framework explicitly considers the effects of an environment using a model of unitary evolution which couples the system, apparatus, and environment. Information dynamics is investigated using the Rényi and von Neumann entropies of the evolving state, and we construct a replica theory for studying these quantities. We identify the possible replica symmetries an experiment can possess and discuss the meaning of their spontaneous symmetry breaking. In particular, we identify a minimum subgroup whose spontaneous symmetry breaking results in an entanglement transition. This symmetry is only possible when the information in the apparatus is as informative about the dynamics of the system as the information transferred to the environment. We call this requirement the information exchange symmetry and quantify it by a relationship between the entropies. We then introduce a generalized notion of spontaneous symmetry breaking such that the entanglement transition can be understood as the spontaneous breaking of the information exchange symmetry and without referring to the replica theory. Information exchange symmetry breaking is then shown to generalize the phenomenology of the measurement-induced phase transition (MIPT). We apply this theory to a quantum-enhanced experiment probing the unitary dynamics of a Haar brickwork quantum circuit, and we determine that the universality class of the critical point is distinct from that for the MIPT. This notion of information exchange symmetry breaking generalizes the MIPT and provides a framework for understanding the dynamics of quantum information in quantum-enhanced experiments.}, archive = {J_PRA}, author = {Shane P. Kelly and Jamir Marino}, doi = {10.1103/PhysRevA.111.012425}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012425}, shortjournal = {Phys. Rev. A}, title = {Generalizing measurement-induced phase transitions to information exchange symmetry breaking}, volume = {111}, year = {2025}, }
• (2025). Accelerating quantum imaginary-time evolution with random measurements. PRA, 111(1), 012424. (www)

  @article{ , abstract = {Quantum imaginary-time evolution (QITE) is a promising tool to prepare thermal or ground states of Hamiltonians, as convergence is guaranteed when the evolved state overlaps with the ground state. However, its implementation using a a hybrid quantum-classical approach, where the dynamics of the parameters of the quantum circuit are derived by McLachlan's variational principle, is impractical as the number of parameters increases, since each step in the evolution takes state preparations to calculate the quantum Fisher information matrix (QFIM). In this work, we accelerate QITE by rapid estimation of the QFIM, while conserving the convergence guarantees to the extent possible. To this end, we prove that if a parameterized state is rotated by a 2-design and measured in the computational basis, then the QFIM can be inferred from partial derivative cross correlations of the probability outcomes. One sample estimate costs only state preparations, leading to rapid QFIM estimation when a few samples suffice. The second family of estimators takes greater liberties and replace QFIMs with averaged classical Fisher information matrices (CFIMs). In an extreme special case optimized for rapid (over accurate) descent, just one CFIM sample is drawn. We justify the second estimator family by proving rapid descent. Guided by these results, we propose the random-measurement imaginary-time evolution algorithm, which we showcase and test in several molecular systems, with the goal of preparing ground states.}, archive = {J_PRA}, author = {Ioannis Kolotouros and David Joseph and Anand Kumar Narayanan}, doi = {10.1103/PhysRevA.111.012424}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012424}, shortjournal = {Phys. Rev. A}, title = {Accelerating quantum imaginary-time evolution with random measurements}, volume = {111}, year = {2025}, }
• (2025). Creation and manipulation of surface code defects with quantum optimal control. PRA, 111(1), 012423. (www)

  @article{ , abstract = {The surface code is a stabilizer code whose ground space degeneracy depends on defects in the lattice. The protocols developed to create defects in the system have previously relied on adiabatic dynamics. In this work we use techniques of quantum optimal control to overcome the requirement for adiabaticity and achieve defect creation and implemention of other important operations required for topological quantum computation at much faster timescales.}, archive = {J_PRA}, author = {Omar Raii and Anirban Dey and Florian Mintert and Daniel Burgarth}, doi = {10.1103/PhysRevA.111.012423}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012423}, shortjournal = {Phys. Rev. A}, title = {Creation and manipulation of surface code defects with quantum optimal control}, volume = {111}, year = {2025}, }
• (2025). Classically simulating intermediate-scale instantaneous quantum polynomial circuits through a random graph approach. PRA, 111(1), 012422. (www)

  @article{ , abstract = {Quantum advantage is a demonstration of a computation by a quantum computer that cannot be performed by the best classical computer in a reasonable time. A well-studied approach to demonstrating this on near-term quantum computers is to use random circuit sampling. It has been suggested that a good candidate for demonstrating quantum advantage with random circuit sampling is to use instantaneous quantum polynomial (IQP) circuits . These are quantum circuits where the unitary it implements is diagonal. In this paper, we introduce improved techniques for exactly classically simulating random IQP circuits. We find a simple algorithm to calculate an amplitude of an -qubit IQP circuit with dense random two-qubit interactions in time , which for sparse circuits (where each qubit interacts with other qubits) runs in for any given polynomial. Using a more complicated stabilizer decomposition approach we improve the algorithm for dense circuits to where . We further discuss how our techniques also lead to improved simulation times for IQP circuits on restricted architectures. We benchmarked our main algorithm and found that we can simulate up to 50-qubit circuits in a couple of minutes on a laptop, with 68-qubit sparse circuits taking a couple of hours. We estimate dense 70-qubit circuits are in range for large computing clusters.}, archive = {J_PRA}, author = {Julien Codsi and John van de Wetering}, doi = {10.1103/PhysRevA.111.012422}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012422}, shortjournal = {Phys. Rev. A}, title = {Classically simulating intermediate-scale instantaneous quantum polynomial circuits through a random graph approach}, volume = {111}, year = {2025}, }
• (2025). Entanglement and coherence dynamics in photonic quantum memristors. PRA, 111(1), 012421. (www)

  @article{ , abstract = {Memristive systems exhibit dynamics that depend on their past states, making them useful as memory units. Recently, quantum memristor models have been proposed, and notably, a photonic quantum memristor (PQM) has been experimentally proven. In this work, we explore and characterize various quantum properties that emerge from this specific model of PQM. First, we find that a single PQM displays memristive dynamics on its quantum coherence. Second, we analytically show that a network made of two independent PQMs can manifest memory effects on the dynamics of both entanglement and coherence of correlated photons traveling through the network, regardless of their distance, in the hypothesis of negligible external disturbances. Additionally, we build and run a circuit-model of the PQM on a real qubit-based quantum computer (IBM-Q), showing that (1) this system can effectively be used for nonlinear quantum computing under specific conditions and (2) digital quantum simulations can reproduce the dynamics of a memristive quantum system in a non-Markovian regime.}, archive = {J_PRA}, author = {Alberto Ferrara and Rosario Lo Franco}, doi = {10.1103/PhysRevA.111.012421}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012421}, shortjournal = {Phys. Rev. A}, title = {Entanglement and coherence dynamics in photonic quantum memristors}, volume = {111}, year = {2025}, }
• (2025). Designing three-way-entangled and nonlocal two-way-entangled single-particle states via alternate quantum walks. PRA, 111(1), 012420. (www)

  @article{ , abstract = {Entanglement with single-particle states is advantageous in quantum technology because of the states' ability to encode and process information more securely than their multiparticle analogs. Three-way- and nonlocal two-way-entangled single-particle states are desirable in this context. Herein we generate genuine three-way entanglement from an initially separable state involving three degrees of freedom of a quantum particle, which evolves via a two-dimensional alternate quantum walk employing a resource-saving single-qubit coin. We achieve maximum possible values for the three-way entanglement quantified by the -tangle between the three degrees of freedom. We also generate optimal nonlocal two-way entanglement, quantified by the negativity between the nonlocal position degrees of freedom of the particle. This prepared architecture using quantum walks can be experimentally realized with a photon.}, archive = {J_PRA}, author = {Dinesh Kumar Panda and Colin Benjamin}, doi = {10.1103/PhysRevA.111.012420}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012420}, shortjournal = {Phys. Rev. A}, title = {Designing three-way-entangled and nonlocal two-way-entangled single-particle states via alternate quantum walks}, volume = {111}, year = {2025}, }
• (2025). Enhancing quantum memory lifetime with measurement-free local error correction and reinforcement learning. PRA, 111(1), 012419. (www)

  @article{ , abstract = {Reliable quantum computation requires systematic identification and correction of errors that occur and accumulate in quantum hardware. To diagnose and correct such errors, standard quantum error-correcting protocols utilize global error information across the system obtained by mid-circuit readout of ancillary qubits. We investigate circuit-level error-correcting protocols that are measurement-free and based on local error information. Such a local error correction (LEC) circuit consists of faulty multi-qubit gates to perform both syndrome extraction and ancilla-controlled error removal. We develop and implement a reinforcement learning framework that takes a fixed set of faulty gates as inputs and outputs an optimized LEC circuit. To evaluate this approach, we quantitatively characterize an extension of logical qubit lifetime by a noisy LEC circuit. For the two-dimensional (2D) classical Ising model and four-dimensional toric code, our optimized LEC circuit performs better at extending a memory lifetime compared with a conventional LEC circuit based on Toom's rule in a subthreshold gate error regime. We further show that such circuits can be used to reduce the rate of mid-circuit readouts to preserve a 2D toric code memory. Finally, we discuss the application of the LEC protocol on dissipative preparation of quantum states with topological phases.}, archive = {J_PRA}, author = {Mincheol Park and Nishad Maskara and Marcin Kalinowski and Mikhail D. Lukin}, doi = {10.1103/PhysRevA.111.012419}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012419}, shortjournal = {Phys. Rev. A}, title = {Enhancing quantum memory lifetime with measurement-free local error correction and reinforcement learning}, volume = {111}, year = {2025}, }
• (2025). Quantum estimation bound of the gaussian matrix permanent. PRA, 111(1), 012418. (www)

  @article{ , abstract = {Exact calculation and even multiplicative error estimation of matrix permanent are challenging for both classical and quantum computers. Regarding the permanents of random Gaussian matrices, the additive error estimation is closely linked to boson sampling and achieving multiplicative error estimation requires exponentially many samplings. Our formula for matrix permanents and its corresponding quantum expression have enabled better estimation of the average additive error for random Gaussian matrices compared to Gurvits' classical sampling algorithm. The well-known Ryser formula has been converted into a quantum permanent estimator. When dealing with real random Gaussian square matrices of size , the quantum estimator can approximate the matrix permanent with an additive error smaller than , where is the estimation precision. In contrast, Gurvits' classical sampling algorithm has an estimation error of , which is exponentially larger ( ) than the quantum method. As expected, the quantum additive error bound fails to reach the multiplicative error bound of . Additionally, the quantum permanent estimator can be up to quadratically faster than the classical estimator when using quantum phase estimation-based amplitude estimation.}, archive = {J_PRA}, author = {Joonsuk Huh}, doi = {10.1103/PhysRevA.111.012418}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012418}, shortjournal = {Phys. Rev. A}, title = {Quantum estimation bound of the gaussian matrix permanent}, volume = {111}, year = {2025}, }
• (2025). Inherent quantum resources in stationary spin chains. PRA, 111(1), 012417. (www)

  @article{ , abstract = {The standard way to generate many-body quantum correlations is via a dynamical protocol: an initial product state is transformed by interactions that generate nonclassical correlations at later times. Here, we show that many-body Bell correlations are inherently present in the eigenstates of a variety of spin-1/2 chains. In particular, we show that the eigenstates and thermal states of the collective Lipkin-Meshkov-Glick model possess many-body Bell correlations. We demonstrate that the Bell correlations present in the eigenstates of the Lipkin-Meshkov-Glick model can take on quantized values that change discontinuously with variations in the total magnetization. Finally, we show that these many-body Bell correlations persist even in the presence of both diagonal and off-diagonal disorder.}, archive = {J_PRA}, author = {Marcin Płodzień and Jan Chwedeńczuk and Maciej Lewenstein}, doi = {10.1103/PhysRevA.111.012417}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012417}, shortjournal = {Phys. Rev. A}, title = {Inherent quantum resources in stationary spin chains}, volume = {111}, year = {2025}, }
• (2025). Hybrid quantum-classical unsupervised data clustering based on the self-organizing feature map. PRA, 111(1), 012416. (www)

  @article{ , abstract = {Unsupervised machine learning is one of the main techniques employed in artificial intelligence. We introduce an algorithm for quantum-assisted unsupervised data clustering using the self-organizing feature map, a type of artificial neural network. The complexity of our algorithm scales as 𝑂 ⁡ ( 𝐿 ⁢ 𝑁 ) , in comparison to the classical case which scales as 𝑂 ⁡ ( 𝐿 ⁢ 𝑀 ⁢ 𝑁 ) , where 𝑁 is the number of samples, 𝑀 is the number of randomly sampled cluster vectors, and 𝐿 is the number of the shifts of cluster vectors. We perform a proof-of-concept demonstration of one of the central components on the IBM quantum computer and show that it allows us to reduce the number of calculations in the number of clusters. Our algorithm exhibits exponential decrease in the errors of the distance matrix with the number of runs of the algorithm.}, archive = {J_PRA}, author = {I. D. Lazarev and Marek Narozniak and Tim Byrnes and A. N. Pyrkov}, doi = {10.1103/PhysRevA.111.012416}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012416}, shortjournal = {Phys. Rev. A}, title = {Hybrid quantum-classical unsupervised data clustering based on the self-organizing feature map}, volume = {111}, year = {2025}, }
• (2025). Separability and lower bounds of quantum entanglement based on realignment. PRA, 111(1), 012415. (www)

  @article{ , abstract = {The detection and estimation of quantum entanglement are the essential issues in the theory of quantum entanglement. We construct matrices based on the realignment of density matrices and the vectorization of the reduced density matrices, from which a family of separability criteria are presented for both bipartite and multipartite systems. Moreover, tighter lower bounds of concurrence and convex-roof extended negativity are derived. Criteria are also given to detect the genuine tripartite entanglement. Lower bounds of the concurrence of genuine tripartite entanglement are presented. By detailed examples we show that our results are better than the corresponding ones in identifying and estimating quantum entanglement as well as genuine multipartite entanglement.}, archive = {J_PRA}, author = {Jiaxin Sun and Hongmei Yao and Shao-Ming Fei and Zhaobing Fan}, doi = {10.1103/PhysRevA.111.012415}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012415}, shortjournal = {Phys. Rev. A}, title = {Separability and lower bounds of quantum entanglement based on realignment}, volume = {111}, year = {2025}, }
• (2025). Exact quantum fisher matrix results for distributed phases using multiphoton polarization greenberger-horne-zeilinger states. PRA, 111(1), 012414. (www)

  @article{ , abstract = {Recently, distributed sensing has been extensively studied using squeezed states. While this is an excellent development, it is desirable to investigate the use of other quantum probes, such as entangled states of light. In this paper, we focus on distributed sensing, i.e., estimating multiple unknown phases at different spatial nodes using multiphoton polarization-entangled Greenberger-Horne-Zeilinger states distributed across different nodes. We utilize tools of quantum metrology and calculate the quantum Fisher information matrix (QFIM). However, the QFIM turns out to be singular, hindering the determination of quantum Cramér-Rao bounds for the parameters of interest. Recent experiments have contended with a weaker form of the Cramér-Rao bound, which does not require the inversion of the QFIM. It is desirable to understand how relevant these weaker bounds are and how closely they approach the exact Cramér-Rao bounds. We thus analyze the reason for this singularity and, by removing a redundant phase, obtain a nonsingular QFIM, allowing us to derive exact quantum Cramér-Rao bounds. Using the nonsingular QFIM, we show that the arithmetic average of the distributed phases is Heisenberg limited. We demonstrate that quantum metrological bounds can be saturated by projective measurements, enabling us to determine the Fisher information matrix, which is also singular. We then show how this singularity can be resolved.}, archive = {J_PRA}, author = {Jiaxuan Wang and Girish S. Agarwal}, doi = {10.1103/PhysRevA.111.012414}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012414}, shortjournal = {Phys. Rev. A}, title = {Exact quantum fisher matrix results for distributed phases using multiphoton polarization greenberger-horne-zeilinger states}, volume = {111}, year = {2025}, }
• (2025). Unbounded recycling of genuine multiparty entanglement for any number of qubits. PRA, 111(1), 012413. (www)

  @article{ , abstract = {We show that genuine multipartite entanglement of an arbitrary number of qubits can be witnessed sequentially for an arbitrary number of times. In the simplest scenario where only one qubit is subjected to sequential measurements, we show that genuine multiparty entanglement can be detected arbitrarily many times starting from generalized Greenberger-Horne-Zeilinger, cluster, graph, and a class of mixed states. For the case where multiple qubits are subjected to sequential measurements, we again show that detection of genuine multiparty entanglement is possible for an arbitrary number of times for multipartite Greenberger-Horne-Zeilinger and a class of mixed states.}, archive = {J_PRA}, author = {Chirag Srivastava and Mahasweta Pandit and Ujjwal Sen}, doi = {10.1103/PhysRevA.111.012413}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012413}, shortjournal = {Phys. Rev. A}, title = {Unbounded recycling of genuine multiparty entanglement for any number of qubits}, volume = {111}, year = {2025}, }
• (2025). Enhancement in the temperature sensing of a reservoir by a kerr-nonlinear resonator. PRA, 111(1), 012412. (www)

  @article{ , abstract = {The challenge of developing high-precision temperature sensors is an important issue that has recently received a lot of attention. In this work, we introduce an estimation technique to precisely measure the temperature of a quantum reservoir using a Kerr-nonlinear resonator with drive. Thermalization in our suggested protocol is assessed using Uhlmann-Jozsa fidelity, then we utilize quantum Fisher information to evaluate the metrological potential of our thermometery scheme. We observe that increasing the Kerr-nonlinearity coefficient and driving amplitude significantly enhances precision in the temperature estimation. Furthermore, we also explore the underlying physical mechanisms by analyzing probe purity in the steady state and evaluating the performance of homodyne versus heterodyne detection methods. Our results demonstrate that neither of these Gaussian measurements is optimal; instead, optimal homodyne detection always surpasses heterodyne detection.}, archive = {J_PRA}, author = {Naeem Akhtar and Jia-Xin Peng and Xiaosen Yang and Yuanping Chen}, doi = {10.1103/PhysRevA.111.012412}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012412}, shortjournal = {Phys. Rev. A}, title = {Enhancement in the temperature sensing of a reservoir by a kerr-nonlinear resonator}, volume = {111}, year = {2025}, }
• (2025). Quantum sensing from gravity as a universal dephasing channel for qubits. PRA, 111(1), 012411. (www)

  @article{ , abstract = {We investigate the interaction of a transmon qubit with a classical gravitational field. Exploiting the generic phenomena of the gravitational redshift and Aharonov-Bohm phase, we show that entangled quantum states dephase with a universal rate. The gravitational phase shift is expressed in terms of a quantum computing noise channel. We give a measurement protocol based on a modified phase estimation algorithm which is linear in the phase drift, which is optimal for measuring the small phase that is acquired from the gravitation channel. Additionally, we propose qubit-based platforms as quantum sensors for precision gravitometers and mechanical strain gauges as an example of this phenomenon's utility. We estimate a sensitivity for measuring the local gravitational acceleration to be . This paper demonstrates that classical gravitation has a nontrivial influence on quantum computing hardware and provides an illustration of how quantum computing hardware may be utilized for purposes other than computation. While we focus on superconducting qubits, we point to the universal nature of gravitational phase effects for all quantum platforms.}, archive = {J_PRA}, author = {Alexander V. Balatsky and Pedram Roushan and Joris Schaltegger and Patrick J. Wong}, doi = {10.1103/PhysRevA.111.012411}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012411}, shortjournal = {Phys. Rev. A}, title = {Quantum sensing from gravity as a universal dephasing channel for qubits}, volume = {111}, year = {2025}, }
• (2025). Quantum synchronization and dissipative quantum sensing. PRA, 111(1), 012410. (www)

  @article{ , abstract = {We study the phenomenon of quantum synchronization from the viewpoint of quantum metrology. By interpreting quantum self-sustained oscillators as dissipative quantum sensors, we develop a framework to characterize several aspects of quantum synchronization. We show that the quantum Fisher information (QFI) serves as a system-agnostic measure of quantum synchronization that also carries a clear operational meaning, viz., it quantifies the precision with which the amplitude of a weak synchronizing drive can be measured. We extend our analysis to study many-body oscillators subjected to multiple drives. We show how the QFI matrix can be used to determine the optimal drive that maximizes quantum synchronization, and also to quantitatively differentiate the synchronization responses induced by different drives. Our work highlights multiple connections between quantum synchronization and quantum metrology, paving a route toward finding quantum technological applications of quantum synchronization.}, archive = {J_PRA}, author = {Gaurav M. Vaidya and Simon B. Jäger and Athreya Shankar}, doi = {10.1103/PhysRevA.111.012410}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012410}, shortjournal = {Phys. Rev. A}, title = {Quantum synchronization and dissipative quantum sensing}, volume = {111}, year = {2025}, }
• (2025). Formal bounds of entanglement purification via entanglement swapping. PRA, 111(1), 012409. (www)

  @article{ , abstract = {We study the entanglement purification via entanglement swapping in terms of optimal output state concurrence. A strict formula that governs the process is first given analytically for the case where both input entangled pairs are in arbitrary pure states. Then, it is generalized, with strong numerical evidence, to the case with one of the entangled pairs being in an arbitrary mixed state. The formula subsequently gives a formal upper bound of entanglement purification via entanglement swapping, as well as how the maximum entanglement purification can be attained by engineering the pure state entangled pair. Moreover, the formalism of the upper bound in turn suggests that entanglement swapping is most suited for reducing the influence of pure dissipative noise, which can be applied to extend the lifespan of stationary qubits in quantum communications.}, archive = {J_PRA}, author = {Run-Ze Cong and Shuang Xu}, doi = {10.1103/PhysRevA.111.012409}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012409}, shortjournal = {Phys. Rev. A}, title = {Formal bounds of entanglement purification via entanglement swapping}, volume = {111}, year = {2025}, }
• (2025). Curvature of quantum evolutions for qubits in time-dependent magnetic fields. PRA, 111(1), 012408. (www)

  @article{ , abstract = {In the geometry of quantum-mechanical processes, the time-varying curvature coefficient of a quantum evolution is specified by the magnitude squared of the covariant derivative of the tangent vector to the state vector. In particular, the curvature coefficient measures the bending of the quantum curve traced out by a parallel-transported pure quantum state that evolves in a unitary fashion under a nonstationary Hamiltonian that specifies the Schrödinger evolution equation. In this paper, we present an exact analytical expression of the curvature of a quantum evolution for a two-level quantum system immersed in a time-dependent magnetic field. Specifically, we study the dynamics generated by a two-parameter nonstationary Hermitian Hamiltonian with unit speed efficiency. The two parameters specify the constant temporal rates of change of the polar and azimuthal angles used in the Bloch sphere representation of the evolving pure state. To better grasp the physical significance of the curvature coefficient, showing that the quantum curve is nongeodesic since the geodesic efficiency of the quantum evolution is strictly less than 1 and tuning the two Hamiltonian parameters, we compare the temporal behavior of the curvature coefficient with that of the speed and the acceleration of the evolution of the system in projective Hilbert space. Furthermore, we compare the temporal profile of the curvature coefficient with that of the square of the ratio between the parallel and transverse magnetic field intensities. Finally, we discuss the challenges in finding exact analytical solutions when extending our geometric approach to higher-dimensional quantum systems that evolve unitarily under an arbitrary time-dependent Hermitian Hamiltonian.}, archive = {J_PRA}, author = {Carlo Cafaro and Leonardo Rossetti and Paul M. Alsing}, doi = {10.1103/PhysRevA.111.012408}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012408}, shortjournal = {Phys. Rev. A}, title = {Curvature of quantum evolutions for qubits in time-dependent magnetic fields}, volume = {111}, year = {2025}, }
• (2025). Entanglement degradation in the presence of markovian noise: A statistical analysis. PRA, 111(1), 012407. (www)

  @article{ , abstract = {Adopting a statistical approach we study the degradation of entanglement of a quantum system under the action of an ensemble of randomly distributed Markovian noise. This enables us to address scenarios where only limited information is available on the mechanisms that rule the noisy evolution of the model. As an application, we characterize the statistic of entanglement deterioration for a quantum memory formed by qudits that undergo randomly distributed local, uniform, Markovian noise evolution.}, archive = {J_PRA}, author = {Nunzia Cerrato and Giacomo De Palma and Vittorio Giovannetti}, doi = {10.1103/PhysRevA.111.012407}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012407}, shortjournal = {Phys. Rev. A}, title = {Entanglement degradation in the presence of markovian noise: A statistical analysis}, volume = {111}, year = {2025}, }
• (2025). Universal perspective on nonadiabatic quantum control. PRA, 111(1), 012406. (www)

  @article{ , abstract = {A stable and fast path linking two arbitrary states of a quantum system is generally required for state-engineering protocols, such as stimulated Raman adiabatic passage, shortcuts to adiabaticity, and holonomic transformation. Such a path is also fundamental to the exact solution of the time-dependent Schrödinger equation. We construct a universal control framework using an ancillary picture, in which the time-dependent Hamiltonian can be diagonalized. Multiple desired paths can be derived by the von Neumann equation for parametric ancillary projection operators. No transition exists among the ancillary basis states during the time evolution. Under various conditions, our control framework reduces to the nonadiabatic holonomic transformation, the Lewis-Riesenfeld theory for invariants, and counterdiabatic driving methods. In addition, it is applicable to the cyclic transfer of system populations that could be a hard problem for existing methods. Our work can provide a full-rank time-evolution operator for a time-dependent quantum system with a finite number of dimensions.}, archive = {J_PRA}, author = {Zhu-yao Jin and Jun Jing}, doi = {10.1103/PhysRevA.111.012406}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012406}, shortjournal = {Phys. Rev. A}, title = {Universal perspective on nonadiabatic quantum control}, volume = {111}, year = {2025}, }
• (2025). Pauli spectrum of quantum channels and the related magic-channel distillation bounds. PRA, 111(1), 012405. (www)

  @article{ , abstract = {Nonstabilizerness (“magic”) is an essential part of quantum computation, so the quantitative study of nonstabilizerness has become a very important issue. Since researchers have defined the Pauli spectrum of quantum states, they can use it to calculate other nonstabilizerness measures such as stabilizer Rényi entropy and stabilizer nullity. At the same time, the study of the magic-channel resource theory has become a main direction in recent years. In this article we extend the definition of the Pauli spectrum to quantum channels and define the definitions of stabilizer Rényi entropy and stabilizer nullity for quantum channels based on the Pauli spectrum. Meanwhile, we study the properties of stabilizer Rényi entropy and stabilizer nullity of quantum channels and give the corresponding proofs. Additionally, this article gives the necessary and sufficient condition that the depolarizing channel is a completely stabilizer-preserving operation (CSPO), and we can calculate other channels. Furthermore, we verify that stabilizer Rényi entropy of quantum channels satisfies the amortization inequality so that the maximum value of the distillation bounds of the magic channels provided by the stabilizer Rényi entropy can be established. Therefore, we can give an alternative method to calculate the magic-channel distillation bounds. Moreover, we compare the channel distillation rate provided by stabilizer Rényi entropy with that provided by thauma and find that the channel distillation rate proposed in this article has higher distillation efficiency. Finally, the nonstabilizerness cost of the gate synthesis is given.}, archive = {J_PRA}, author = {Yiran Wang and Yongming Li}, doi = {10.1103/PhysRevA.111.012405}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012405}, shortjournal = {Phys. Rev. A}, title = {Pauli spectrum of quantum channels and the related magic-channel distillation bounds}, volume = {111}, year = {2025}, }
• (2025). Finite-temperature detection of quantum critical points via internal quantum teleportation. PRA, 111(1), 012404. (www)

  @article{ , abstract = {We show that the teleportation protocol can be efficiently used to detect quantum critical points using finite-temperature data even if all resources needed for its implementation lie within the system under investigation. Contrary to a previous proposal, there is no need to use an external qubit as the input state to be teleported to one of the qubits within the system. Here we use a pair of nearest-neighbor spins from an infinite spin- chain in equilibrium with a heat bath as the entangled resource of the quantum-teleportation protocol and a third adjacent qubit within the chain itself as the input state to be teleported. For several spin-chain models subjected to an external magnetic field, we show that the efficiency of the teleportation protocol is severely affected as we cross the quantum critical points associated with those spin chains. This abrupt change in efficiency gives us a clear indication of a quantum phase transition.}, archive = {J_PRA}, author = {G. A. P. Ribeiro and Gustavo Rigolin}, doi = {10.1103/PhysRevA.111.012404}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012404}, shortjournal = {Phys. Rev. A}, title = {Finite-temperature detection of quantum critical points via internal quantum teleportation}, volume = {111}, year = {2025}, }
• (2025). Coherence based on positive operator-valued measures for standard and concatenated quantum state discrimination with inconclusive results. PRA, 111(1), 012403. (www)

  @article{ , abstract = {The optimal measurement that discriminates nonorthogonal quantum states with fixed rates of inconclusive outcomes (FRIO) can be decomposed into an assisted separation of the inputs, yielding conclusive and inconclusive outputs, followed by a minimum-error (ME) measurement for the conclusive ones (standard FRIO) or both ones (concatenated FRIO). The implementation of these measurements is underpinned by quantum resources, and here we investigate coherence based on positive operator-valued measures (POVMs) as a resource for both strategies in discriminating equally probable symmetric states of arbitrary dimension. First, we show that the POVM coherence in the assisted separation stage decomposes into the coherence of the ancillary state and the quantum discord between the system and the ancilla, evidencing coherence as a more elementary resource than quantum correlations. Next, it is demonstrated that the POVM coherence for standard and concatenated FRIO decomposes into the POVM coherence measures for state separation and ME measurement, weighted by the probabilities of occurrence of each event. Due to the ME discrimination of inconclusive states, the coherence required for the concatenated scheme is shown to be greater than that of the standard one. We discuss other general aspects of our results by characterizing the POVM coherence in the discrimination of qutrit states, with respect to the distinguishability of the inputs and the inconclusive rate. Finally, by exploiting POVM-based coherence as a quantifier of cryptographic randomness gain, we discuss the standard and concatenated FRIO strategies from the perspective of generating random bits that are secret to an eavesdropper.}, archive = {J_PRA}, author = {L. F. Melo and O. Jiménez and L. Neves}, doi = {10.1103/PhysRevA.111.012403}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012403}, shortjournal = {Phys. Rev. A}, title = {Coherence based on positive operator-valued measures for standard and concatenated quantum state discrimination with inconclusive results}, volume = {111}, year = {2025}, }
• (2025). Conditional acceleration of entanglement generation enabled by dissipation. PRA, 111(1), 012402. (www)

  @article{ , abstract = {Dissipation is usually considered a negative factor for observing quantum effects and for harnessing them for quantum technologies. Here, we propose a scheme for conditionally speeding up the generation of quantum entanglement between two coupled qubits by introducing a strong dissipation channel to one of these qubits. The maximal entanglement is established by evenly distributing a single excitation between these two qubits in a probabilistic manner. When the excitation is initially held by the qubit with stronger dissipation, the dissipation accelerates the excitation redistribution process for the quantum state trajectory without quantum jumps. Our results show that the time needed to conditionally attain the maximal entanglement is monotonously decreased as the dissipative rate is increased, at the price of a quickly decreasing success probability. We further show that this scheme can be generalized to accelerate the production of the state for the three-qubit system, where one qubit with strong dissipation is symmetrically coupled to two qubits with weak dissipation.}, archive = {J_PRA}, author = {Xiao-Wei Zheng and Jun-Cong Zheng and Xue-Feng Pan and Li-Hua Lin and Pei-Rong Han and Peng-Bo Li}, doi = {10.1103/PhysRevA.111.012402}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012402}, shortjournal = {Phys. Rev. A}, title = {Conditional acceleration of entanglement generation enabled by dissipation}, volume = {111}, year = {2025}, }
• (2025). Performance upper bound of a grover-mixer quantum alternating operator ansatz. PRA, 111(1), 012401. (www)

  @article{ , abstract = {The quantum alternating operator ansatz (QAOA) represents a branch of quantum algorithms for solving combinatorial optimization problems. A specific variant, the Grover-mixer (GM) QAOA, ensures uniform amplitude across states that share equivalent objective values. This property makes the algorithm independent of the problem structure, focusing instead on the distribution of objective values within the problem. In this work we provide an alternative proof for the upper bound on the probability of measuring a computational basis state from a GM QAOA circuit with a given depth, which is a critical factor in QAOA cost. Using this, we derive the upper bounds for the probability of sampling an optimal solution and for the approximation ratio of maximum optimization problems, both dependent on the objective value distribution. Through numerical analysis, we link the distribution to the problem size and build the regression models that relate the problem size, QAOA depth, and performance upper bound. Our results suggest that the GM QAOA provides a quadratic enhancement in sampling probability and requires circuit depth that scales exponentially with problem size to maintain consistent performance.}, archive = {J_PRA}, author = {Ningyi Xie and Jiahua Xu and Tiejin Chen and Xinwei Lee and Yoshiyuki Saito and Nobuyoshi Asai and Dongsheng Cai}, doi = {10.1103/PhysRevA.111.012401}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012401}, shortjournal = {Phys. Rev. A}, title = {Performance upper bound of a grover-mixer quantum alternating operator ansatz}, volume = {111}, year = {2025}, }
• (2025). Cluster property and bell inequalities. PRA, 111(1), 012224. (www)

  @article{ , abstract = {Among the many loopholes that might be invoked to reconcile local realism with the experimental violations of Bell inequalities, the space dependence of the correlation functions appears particularly relevant for its connections with the so-called cluster property, one of the basic ingredients of axiomatic quantum field theory. The property states that the expectation values of products of observables supported within spacelike separated space-time regions factorize. Actually, in some massive models the factorization is exponentially fast with respect to the distance between the systems possibly involved in actual experiments. It is then often argued that considering the space dependence of the quantities involved in the Bell-like inequalities would eventually not violate them and thus support the reproducibility of the quantum behavior by a suitable local hidden variable model. In this paper, we show when this is actually the case and how nonlocal effects can still be visible.}, archive = {J_PRA}, author = {F. Benatti and R. Floreanini and H. Narnhofer}, doi = {10.1103/PhysRevA.111.012224}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012224}, shortjournal = {Phys. Rev. A}, title = {Cluster property and bell inequalities}, volume = {111}, year = {2025}, }
• (2025). Maximal non-kochen-specker sets and a lower bound on the size of kochen-specker sets. PRA, 111(1), 012223. (www)

  @article{ , abstract = {The challenge of determining bounds for the minimal number of vectors in a three-dimensional Kochen-Specker (KS) set has captivated the quantum foundations community for decades. This paper establishes a weak lower bound of 10 vectors, which does not surpass the current best-known bound of 24 vectors. By exploring the complementary concept of large non-KS sets and employing a probability argument independent of the graph structure of KS sets, we introduce a technique that could be applied in the future to derive tighter bounds. Additionally, we highlight an intriguing connection to a generalization of the moving sofa problem in navigating a right-angled hallway on the surface of a two-dimensional sphere.}, archive = {J_PRA}, author = {Tom Williams and Andrei Constantin}, doi = {10.1103/PhysRevA.111.012223}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012223}, shortjournal = {Phys. Rev. A}, title = {Maximal non-kochen-specker sets and a lower bound on the size of kochen-specker sets}, volume = {111}, year = {2025}, }
• (2025). Relativistic quantum field theory approach to electron wave-packet tunneling: A fully causal process. PRA, 111(1), 012222. (www)

  @article{ , abstract = {Recent results on electron tunneling across a potential barrier, inferred from observations or obtained from theoretical models, have suggested superluminal or instantaneous barrier traversal times. In this work we investigate relativistic wave-packet dynamics for an electron tunneling through a potential barrier employing space-time resolved solutions to relativistic quantum field theory (QFT) equations. We prove by linking the QFT property of microcausality to the wave-packet behavior that the tunneling dynamics is fully causal, precluding instantaneous or superluminal effects. We illustrate these results by performing numerical computations for an electron tunneling through a potential barrier for standard tunneling as well for Klein tunneling. In all cases (Klein tunneling or regular tunneling across a standard or a supercritical potential) the transmitted wave packet remains in the causal envelope of the propagator, even when its average position lies ahead of the average position of the corresponding freely propagated wave packet.}, archive = {J_PRA}, author = {M. Alkhateeb and X. Gutierrez de la Cal and M. Pons and D. Sokolovski and A. Matzkin}, doi = {10.1103/PhysRevA.111.012222}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012222}, shortjournal = {Phys. Rev. A}, title = {Relativistic quantum field theory approach to electron wave-packet tunneling: A fully causal process}, volume = {111}, year = {2025}, }
• (2025). Stronger sum uncertainty relations for non-hermitian operators. PRA, 111(1), 012221. (www)

  @article{ , abstract = {The uncertainty relations (URs) of two arbitrary Hermitian and non-Hermitian incompatible operators represented by the product of variances have been confirmed theoretically and experimentally in various physical systems. However, the lower bound of the product uncertainty inequality can be null even for two noncommuting operators, i.e., a trivial case. Therefore, for two incompatible operators over the measured system state, the associated URs regarding the sum of variances are valid in a state-dependent manner, and the lower bound is guaranteed to be nontrivial. Although the sum URs formulated for Hermitian and unitary operators have been affirmed, the general forms for arbitrary non-Hermitian operators have not yet been investigated. This study presents the sum URs for non-Hermitian operators acting on system states using an appropriate Hilbert-space metric. The compatible forms of our sum inequalities with the conventional quantum mechanics are also provided via the -metric formalism. Concrete examples illustrate the validity of the proposed sum URs in both -symmetric and -broken phases. The developed methods and results can help give an in-depth understanding of the usefulness of -metric formalism in non-Hermitian quantum mechanics and the sum URs of incompatible operators within.}, archive = {J_PRA}, author = {Xiao-Feng Song and Yi-Fang Ren and Shuang Liu and Xi-Hao Chen and Yusuf Turek}, doi = {10.1103/PhysRevA.111.012221}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012221}, shortjournal = {Phys. Rev. A}, title = {Stronger sum uncertainty relations for non-hermitian operators}, volume = {111}, year = {2025}, }
• (2025). High-dimensional monitoring and the emergence of realism via multiple observers. PRA, 111(1), 012220. (www)

  @article{ , abstract = {Correlation is the basic mechanism of every measurement model, as one never accesses the measured system directly. Instead, correlations are created, codifying information about the measurable property into the environment. Here, we address the problem of the emergence of physical reality from the quantum world by introducing a model that interpolates between weak and strong nonselective measurements for qudits. By utilizing Heisenberg-Weyl operators, our model suggests that independently of the interaction intensity between the system and the environment, full information about the observable of interest can always be obtained by making the system interact with many environmental qudits, following a quantum Darwinism framework.}, archive = {J_PRA}, author = {Alexandre C. Orthey, Jr and Pedro R. Dieguez and Owidiusz Makuta and Remigiusz Augusiak}, doi = {10.1103/PhysRevA.111.012220}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012220}, shortjournal = {Phys. Rev. A}, title = {High-dimensional monitoring and the emergence of realism via multiple observers}, volume = {111}, year = {2025}, }
• (2025). Quantum harvester enabling energy transfer without entropy transfer. PRA, 111(1), 012219. (www)

  @article{ , abstract = {We consider a foundational question in energy harvesting: Given a partly random energy source, is it possible to extract the energy without also transferring randomness or accepting another thermodynamical cost? We answer this in the positive, describing scenarios and protocols where in principle energy is extracted from a field with randomness but without any randomness being transferred and without energy dissipation. We explain why these protocols do not violate basic physical principles. Such protocols fundamentally outperform existing methods of rectification which dissipate power or demonlike feedback protocols which transfer randomness to the feedback system. The protocols exploit the possibility of the harvesting system taking several trajectories that lead to the same final state at a given time. A key example involves Rabi oscillations between energy levels, exploiting the multitude of rotation axes in the state space. The quantum system is deterministically excited to the highest energy level after interacting with the source for a fixed amount of time, irrespective of the random initial phase of the external potential. These realizations show the value of Rabi-oscillation-type techniques for enhancing energy harvesting.}, archive = {J_PRA}, author = {Fei Meng and Junhao Xu and Xiangjing Liu and Oscar Dahlsten}, doi = {10.1103/PhysRevA.111.012219}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012219}, shortjournal = {Phys. Rev. A}, title = {Quantum harvester enabling energy transfer without entropy transfer}, volume = {111}, year = {2025}, }
• (2025). Robustness of perfect transmission resonances to asymmetric perturbation. PRA, 111(1), 012218. (www)

  @article{ , abstract = {We investigate the impact of asymmetric perturbations on the perfect transmission resonances (PTRs) of one-dimensional finite periodic systems. With no perturbations, the scattering region consists of identical cells, and the transmission spectrum exhibits at least PTRs in each passband of the Bloch dispersion of the unit cell. By introducing a perturbation, the periodic structure is broken, which a priori results in the elimination of all PTRs. However, we demonstrate that PTRs can still arise under asymmetric perturbations when the unperturbed system possesses mirror symmetry, utilizing the symmetry of the unperturbed reflectionless eigenvalue problem. We also reveal an intriguing connection between two seemingly independent PTRs that lies in the symmetry of the unperturbed unit cell: If one PTR is preserved, then a dual one is necessarily also preserved. Our findings offer insights for the design of, for example, a robust antireflection setup at multiple wavelengths or all-optical diode devices.}, archive = {J_PRA}, author = {Ioannis Kiorpelidis and Panayotis Kalozoumis and Georgios Theocharis and Vassos Achilleos and Fotios K. Diakonos and Vincent Pagneux}, doi = {10.1103/PhysRevA.111.012218}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012218}, shortjournal = {Phys. Rev. A}, title = {Robustness of perfect transmission resonances to asymmetric perturbation}, volume = {111}, year = {2025}, }
• (2025). Statistical model for quantum spin and photon number states. PRA, 111(1), 012217. (www)

  @article{ , abstract = {The most irreducible way to represent information is a sequence of two symbols. In this paper, we construct quantum states using this basic building block. Specifically, we show that the probabilities that arise in quantum theory can be reduced to counting more fundamental ontic states, which we interpret as event networks and model using sequences of 0's and 1's. A completely self-contained formalism is developed for the purpose of organizing and counting these ontic states, which employs the finite cyclic group Z 2 = { 0 , 1 } , basic set theory, and combinatorics. This formalism is then used to calculate probability distributions associated with particles of arbitrary spin interacting with sequences of two rotated Stern-Gerlach detectors. These calculations are compared with the predictions of nonrelativistic quantum mechanics and shown to deviate slightly. This deviation can be made arbitrarily small and does not lead to violations of relevant no-go theorems, such as Bell's inequalities, the Kochen-Specker theorem, or the Pusey-Barrett-Rudolph theorem. The proposed model is then extended to an optical system involving photon number states passing through a beam splitter. Leveraging recent advancements in high-precision experiments on these systems, we then propose a means of testing the model using a tabletop experiment.}, archive = {J_PRA}, author = {Sam Powers and Guangpeng Xu and Herbert Fotso and Tim Thomay and Dejan Stojkovic}, doi = {10.1103/PhysRevA.111.012217}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012217}, shortjournal = {Phys. Rev. A}, title = {Statistical model for quantum spin and photon number states}, volume = {111}, year = {2025}, }
• (2025). Quantum entanglement as an extremal kirkwood-dirac nonreality. PRA, 111(1), 012216. (www)

  @article{ , abstract = {Understanding the relationship between various different forms of nonclassicality and their resource character is of great importance in quantum foundation and quantum information. Here we discuss a quantitative link between quantum entanglement and the anomalous or nonclassical nonreal values of Kirkwood-Dirac (KD) quasiprobability in a bipartite setting. We first construct an entanglement monotone for a pure bipartite state based on the nonreality of the KD quasiprobability defined over a pair of orthonormal bases, in which one of them is a product, and optimizations over these bases. It admits a closed expression as a Schur concave function of the state of the subsystem having a form of nonadditive quantum entropy. We then construct a bipartite entanglement monotone for generic quantum states using the convex roof extension. Its normalized value is upper bounded by the concurrence of formation, and for two-qubit systems, they are equal. We also derive lower and upper bounds in terms of different forms of uncertainty in the subsystem quantified by an extremal trace-norm asymmetry and a nonadditive quantum entropy, respectively. The entanglement monotone can be expressed as the minimum total state disturbance due to a nonselective local binary measurement. Finally, we discuss its estimation using weak value measurement and classical optimization, and its connection with strange weak value and quantum contextuality.}, archive = {J_PRA}, author = {Agung Budiyono}, doi = {10.1103/PhysRevA.111.012216}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012216}, shortjournal = {Phys. Rev. A}, title = {Quantum entanglement as an extremal kirkwood-dirac nonreality}, volume = {111}, year = {2025}, }
• (2025). Nonadiabatic quantum optimization for crossing quantum phase transitions. PRA, 111(1), 012215. (www)

  @article{ , abstract = {We consider the optimal driving of the ground state of a many-body quantum system across a quantum phase transition in finite time. In this context, excitations caused by the breakdown of adiabaticity can be minimized by adjusting the schedule of the control parameter that drives the transition. Drawing inspiration from the Kibble-Zurek mechanism, we characterize the timescale of onset of adiabaticity for several optimal control procedures. Our analysis reveals that schedules relying on local adiabaticity, such as Roland-Cerf's local adiabatic driving and the quantum adiabatic brachistochrone, fail to provide a significant speedup over the adiabatic evolution in the transverse-field Ising and long-range Kitaev models. As an alternative, we introduce a framework, nonadiabatic quantum optimization (NAQO), that, by exploiting the Landau-Zener formula and taking into account the role of higher-excited states, outperforms schedules obtained via both local adiabaticity and state-of-the-art numerical optimization. NAQO is not restricted to exactly solvable models, and we further confirm its superior performance in a disordered nonintegrable model.}, archive = {J_PRA}, author = {András Grabarits and Federico Balducci and Barry C. Sanders and Adolfo del Campo}, doi = {10.1103/PhysRevA.111.012215}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012215}, shortjournal = {Phys. Rev. A}, title = {Nonadiabatic quantum optimization for crossing quantum phase transitions}, volume = {111}, year = {2025}, }
• (2025). Speed limits and thermodynamic uncertainty relations for quantum systems with the non-hermitian hamiltonian. PRA, 111(1), 012214. (www)

  @article{ , abstract = {Non-Hermitian Hamiltonians play a crucial role in describing open quantum systems and nonequilibrium dynamics. In this paper, we derive trade-off relations for systems governed by non-Hermitian Hamiltonians, focusing on the Margolus-Levitin-type and Mandelstam-Tamm-type bounds, which are originally derived as quantum speed limits in isolated quantum dynamics. While the quantum speed limit for the Mandelstam-Tamm bound in general non-Hermitian systems was derived in the literature, we obtain a Mandelstam-Tamm quantum speed limit for continuous measurement using the continuous matrix product state formalism. Moreover, we derive a Margolus-Levitin quantum speed limit in the non-Hermitian setting. We derive additional bounds on the ratio of the standard deviation to the mean of an observable, which take the same form as the thermodynamic uncertainty relation. As an example, we apply these bounds to the continuous measurement formalism in open quantum dynamics, where the dynamics is described by discontinuous jumps and smooth evolution induced by the non-Hermitian Hamiltonian. Our work provides a unified perspective on the quantum speed limit and thermodynamic uncertainty relations in open quantum dynamics from the viewpoint of the non-Hermitian Hamiltonian, extending the results of previous studies.}, archive = {J_PRA}, author = {Tomohiro Nishiyama and Yoshihiko Hasegawa}, doi = {10.1103/PhysRevA.111.012214}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012214}, shortjournal = {Phys. Rev. A}, title = {Speed limits and thermodynamic uncertainty relations for quantum systems with the non-hermitian hamiltonian}, volume = {111}, year = {2025}, }
• (2025). Single-measurement bell analysis. PRA, 111(1), 012213. (www)

  @article{ , abstract = {We examine the satisfaction of Bell criteria for single realizations of quantum systems. This is possible via the joint noisy measurement of all observables involved in the Bell test. We readily find that every outcome violates Bell bounds for local hidden-variable models. This agrees with the idea that to reveal nonclassical effects a necessary condition is that the measuring scheme itself must be nonclassical.}, archive = {J_PRA}, author = {Alfredo Luis}, doi = {10.1103/PhysRevA.111.012213}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012213}, shortjournal = {Phys. Rev. A}, title = {Single-measurement bell analysis}, volume = {111}, year = {2025}, }
• (2025). Parallel ergotropy: Maximum work extraction via parallel local unitary operations. PRA, 111(1), 012212. (www)

  @article{ , abstract = {Maximum quantum work extraction is generally defined in terms of the ergotropy functional, no matter how experimentally complicated is the implementation of the optimal unitary allowing for it, especially in the case of multipartite systems. In this framework, we consider a quantum battery made up of many interacting subsystems and study the maximum extractable work via concurrent local unitary operations on each subsystem. We call the resulting functional parallel ergotropy . Focusing on the bipartite case, we first observe that parallel ergotropy outperforms work extraction via egoistic strategies, in which the first agent A extracts locally on its part the maximum available work and the second agent B, subsequently, extracts what is left on the other part. For the agents, this showcases the need of cooperating for an overall benefit. Second, from the informational point of view, we observe that the parallel capacity of a state can detect entanglement and compare it with the statistical entanglement witness that exploits fluctuations of stochastic work extraction. Additionally, we face the technical problem of computing parallel ergotropy. We derive analytical upper bounds for specific classes of states and Hamiltonians and provide recipes to obtain numerical upper bounds via semidefinite programming in the generic case. Finally, extending the concept of parallel ergotropy, we demonstrate that system's free-time evolution and application of local unitaries allow one to saturate the gap with the ergotropy of the whole system.}, archive = {J_PRA}, author = {Riccardo Castellano and Ranieri Nery and Kyrylo Simonov and Donato Farina}, doi = {10.1103/PhysRevA.111.012212}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012212}, shortjournal = {Phys. Rev. A}, title = {Parallel ergotropy: Maximum work extraction via parallel local unitary operations}, volume = {111}, year = {2025}, }
• (2025). Quantum geometry in many-body systems with precursors of criticality. PRA, 111(1), 012211. (www)

  @article{ , abstract = {We analyze the geometry of the ground-state manifold in parameter-dependent many-body systems with quantum phase transitions (QPTs) and describe finite-size precursors of the singular geometry emerging at the QPT boundary in the infinite-size limit. In particular, we elucidate the role of diabolic points in the formation of first-order QPTs, showing that these isolated geometric singularities represent seeds generating irregular behavior of geodesics in finite systems. We also demonstrate that established approximations, namely the mean-field approximation in many-body systems composed of mutually interacting bosons and the two-level approximation near a diabolic point, are insufficient to provide a reliable description of geometry. The outcomes of the general analysis are tested and illustrated by a specific bosonic model from the Lipkin-Meshkov-Glick family.}, archive = {J_PRA}, author = {Jan Střeleček and Pavel Cejnar}, doi = {10.1103/PhysRevA.111.012211}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012211}, shortjournal = {Phys. Rev. A}, title = {Quantum geometry in many-body systems with precursors of criticality}, volume = {111}, year = {2025}, }
• (2025). Stationary states of boundary-driven quantum systems: Some exact results. PRA, 111(1), 012210. (www)

  @article{ , abstract = {We study finite-dimensional open quantum systems in contact with macroscopic equilibrium systems at their boundaries such that the system density matrix evolves via a Lindbladian, . Here is the Hamiltonian of the system and is the dissipator. We consider the case where the system consists of two parts, the “boundary” and the “bulk” , and acts only on , so , where is the identity superoperator on part . Let be ergodic, so only for one unique density matrix . We show that any stationary density matrix on the full system which commutes with must be of the product form for some . This rules out finding any that has the Gibbs measure as a stationary state with , unless there is no interaction between parts and . We give criteria for the uniqueness of the stationary state for systems with interactions between and . Related results for nonergodic cases are also discussed.}, archive = {J_PRA}, author = {Eric A. Carlen and David A. Huse and Joel L. Lebowitz}, doi = {10.1103/PhysRevA.111.012210}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012210}, shortjournal = {Phys. Rev. A}, title = {Stationary states of boundary-driven quantum systems: Some exact results}, volume = {111}, year = {2025}, }
• (2025). Transient effects in quantum refrigerators with finite environments. PRA, 111(1), 012209. (www)

  @article{ , abstract = {We explore a small quantum refrigerator consisting of three qubits, each of which is kept in contact with an environment. We consider two settings: one is when there is necessarily transient cooling and the other is when both steady-state and transient coolings prevail. Our primary focus, however, is on the transient cooling phenomena. We show that in the transient regime, the temperature of the cold qubit can decrease further compared to the case where all qubits are connected to Markovian environments, by replacing the environment attached to the cold qubit with a finite-size spin environment, modeled by a few quantum spins interacting with the cold qubit. We also consider refrigeration with more than one finite-size spin environment of the three-qubit refrigerating device. As expected, a steady temperature is reached only if there are at least two Markovian baths, regardless of whether the cold qubit is attached to an environment. However, distinct envelopes of temperature oscillations are observed in all cases. We investigate the effects of the finite-size environments on the cooling of the cold qubit when one, two, or all Markovian baths are replaced by finite-size environments. Additionally, we examine this effect in two- and single-qubit self-sustained devices connected to one or more finite-size environments. In deriving the dynamical equations for the qubits connected to finite-size environments, we made no assumptions about the Markovian nature of the environment. As a result, these finite-size environments inherently exhibit information backflow from the environment to the system, a hallmark of non-Markovianity. Hence, we propose a witness to detect non-Markovianity in such systems. Finally, the cooling processes are studied in presence of Markovian noise, and we analyze the response on the refrigeration of the noise strength. In particular, we find the noise strength until which refrigeration remains possible.}, archive = {J_PRA}, author = {Aparajita Bhattacharyya and Ahana Ghoshal and Ujjwal Sen}, doi = {10.1103/PhysRevA.111.012209}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012209}, shortjournal = {Phys. Rev. A}, title = {Transient effects in quantum refrigerators with finite environments}, volume = {111}, year = {2025}, }
• (2025). State swapping via semiclassical gravity. PRA, 111(1), 012208. (www)

  @article{ , abstract = {The prediction of nonlocal phenomena is a key attribute of quantum mechanics that distinguishes it from classical theories. It was recently suggested that state swapping is one such effect that a fundamentally classical gravitational field cannot give rise to. The reasoning was that the phenomenology of classical fields is restricted to local operations and classical communication (LOCC), whereas swapping is a non-LOCC effect, so gravity must not be a classical channel if it can give rise to such a phenomenon. Here, we show that the Hamiltonian of semiclassical gravity results in an evolution of coherent states that is virtually indistinguishable from swapping them, both theoretically and experimentally. Our results indicate that drawing a definitive conclusion about the nature of gravity based solely on its ability to swap a pair of coherent states would be premature. We discuss the implications of these results regarding proposed experimental tests for the quantum nature of gravity and clarify some conceptual issues.}, archive = {J_PRA}, author = {Praveer K. Gollapudi and M. Kemal Döner and André Großardt}, doi = {10.1103/PhysRevA.111.012208}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012208}, shortjournal = {Phys. Rev. A}, title = {State swapping via semiclassical gravity}, volume = {111}, year = {2025}, }
• (2025). Generating multipartite nonlocality to benchmark quantum computers. PRA, 111(1), 012207. (www)

  @article{ , abstract = {We show that quantum computers can be used for producing large -partite nonlocality, thereby providing a method to benchmark them. The main challenges to overcome are as follows: (i) The interaction topology might not allow arbitrary two-qubit gates. (ii) Noise limits the Bell violation. (iii) The number of combinations of local measurements grows exponentially with . To overcome (i), we point out that graph states that are compatible with the two-qubit connectivity of the computer can be efficiently prepared. To mitigate (ii), we note that for specific graph states, there are -partite Bell inequalities whose resistance to white noise increases exponentially with . To address (iii) for any and any connectivity, we introduce an estimator that relies on random sampling. As a result, we propose a method for producing -partite Bell nonlocality with unprecedented large . This allows one, in return, to benchmark nonclassical correlations regardless of the number of qubits or the connectivity. We test our approach by using a simulation for a noisy IBM quantum computer, which predicts -partite Bell nonlocality for at least qubits.}, archive = {J_PRA}, author = {Jan Lennart Bönsel and Otfried Gühne and Adán Cabello}, doi = {10.1103/PhysRevA.111.012207}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012207}, shortjournal = {Phys. Rev. A}, title = {Generating multipartite nonlocality to benchmark quantum computers}, volume = {111}, year = {2025}, }
• (2025). Local friendliness polytopes in multipartite scenarios. PRA, 111(1), 012206. (www)

  @article{ , abstract = {Recently, the local friendliness (LF) no-go theorem has attracted considerable interest due to its deep foundational implications. This no-go theorem applies to scenarios which combine Bell experiments with Wigner's friend-type setups, containing spacelike separated superobservers assumed to be capable of performing quantum operations on a local observer, also known as their “friend.” The theorem shows that a set of assumptions termed “local friendliness”—weaker than the set of assumptions required for proving Bell's theorem—constrains the space of probabilistic behaviors in extended Wigner's friend scenarios to the “local friendliness (LF) polytope,” and that quantum correlations can, in principle, violate those constraints. In this work, we extend the study of local friendliness to multipartite scenarios—with arbitrary but finite numbers of superobservers, friends, measurements, and outcomes—and fully characterize the corresponding LF polytopes, their relationships with each other, with the Bell polytope, the no-signaling polytope, and the quantum set of correlations. In particular, we identify, via constructive proofs, all the canonical LF scenarios where the LF polytope coincides with the Bell polytope—hence identifying all the scenarios where “genuine LF inequalities” may arise. Among other results, we also show that whenever the LF polytope is distinct from the Bell and the no-signaling polytope, it also is neither contained in nor contains the quantum set of correlations. Apart from the foundational motivation of better understanding the constraints from local friendliness, our results may also find use in a priori unrelated contexts of device-independent information processing, where the LF polytopes have also been shown to arise, under the name of “partially deterministic polytopes.”}, archive = {J_PRA}, author = {Marwan Haddara and Eric G. Cavalcanti}, doi = {10.1103/PhysRevA.111.012206}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012206}, shortjournal = {Phys. Rev. A}, title = {Local friendliness polytopes in multipartite scenarios}, volume = {111}, year = {2025}, }
• (2025). Certifying the activation of bell nonlocality with finite data. PRA, 111(1), 012205. (www)

  @article{ , abstract = {The activation of Bell nonlocality is a protocol that enables the violation of a Bell inequality from a system that initially did not allow for any such violation because the state of the system was Bell-local. This activation of hidden Bell nonlocality has been demonstrated in experiments; however, while the certification of Bell nonlocality is conceptional straightforward, a statistically rigorous verification that the initial state is Bell-local has not yet been achieved. This is due to two key obstacles: The lack of a method to establish a suitable confidence region from the measured data and the need for an efficient technique to verify Bell locality of all states within the confidence region. In this work, we address both challenges. We introduce a confidence polytope in the form of a hyperoctahedron and provide a computationally efficient method to verify whether a quantum state admits a local hidden state model, thus being unsteerable and, consequently, Bell-local. Using these methods, we find that a statistically rigorous certification of hidden Bell nonlocality needs of the order of samples.}, archive = {J_PRA}, author = {Jonathan Steinberg and H. Chau Nguyen and Matthias Kleinmann}, doi = {10.1103/PhysRevA.111.012205}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012205}, shortjournal = {Phys. Rev. A}, title = {Certifying the activation of bell nonlocality with finite data}, volume = {111}, year = {2025}, }
• (2025). Quantum work extraction efficiency for noisy quantum batteries: The role of coherence. PRA, 111(1), 012204. (www)

  @article{ , abstract = {Quantum work capacitances and maximal asymptotic work/energy ratios are figures of merit characterizing the robustness against noise of work extraction processes in quantum batteries formed by collections of quantum systems. In this paper we establish a direct connection between these functionals and, exploiting this result, we analyze different types of noise models mimicking self-discharging (amplitude damping channels), thermalization (generalized amplitude damping channels), and dephasing effects (simultaneous phase-amplitude damping channels). In this context we show that input quantum coherence can significantly improve the storage performance of noisy quantum batteries and that the maximum output ergotropy is not always achieved by the maximum available input energy.}, archive = {J_PRA}, author = {Salvatore Tirone and Raffaele Salvia and Stefano Chessa and Vittorio Giovannetti}, doi = {10.1103/PhysRevA.111.012204}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012204}, shortjournal = {Phys. Rev. A}, title = {Quantum work extraction efficiency for noisy quantum batteries: The role of coherence}, volume = {111}, year = {2025}, }
• (2025). Feedback-driven quantum otto-like engines. PRA, 111(1), 012203. (www)

  @article{ , abstract = {An analytical study of a feedback-driven quantum engine based on a two-level system is presented. This engine is similar to a quantum Otto engine but substitutes the quantum isochoric process with a feedback-driven operation based on a measured observable , whose eigenstates are coherent superpositions of energy eigenstates. Projective measurements control the feedback operations, while work extraction or heat absorption occurs during driven operations. We derive the general time-dependent efficiency, power, and power fluctuations. Quantum coherence is examined through three mechanisms: (i) coherence associated with , (ii) residual coherence after incomplete thermalization, and (iii) coherence generated by the interaction between the system and a coherent laser pulse on resonance. We investigate how the parameter , quantum coherence, and timing of unitary and feedback-driven strokes influence engine performance. We demonstrate that quantum coherence can significantly enhance power output and efficiency while reducing fluctuations through optimal cycle parameter adjustments.}, archive = {J_PRA}, author = {Dehua Liu and Yingying Hong and Shaolin Luo and Xian He and Zhaoqi Wu and Jianhui Wang}, doi = {10.1103/PhysRevA.111.012203}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012203}, shortjournal = {Phys. Rev. A}, title = {Feedback-driven quantum otto-like engines}, volume = {111}, year = {2025}, }
• (2025). Lie-algebraic quantum phase reduction based on heterodyne detection. PRA, 111(1), 012202. (www)

  @article{ , abstract = {Measurement backaction inherently alters observed dynamics in quantum physics. In the realm of quantum synchronization, this backaction induces a phase bias, making the assessment of synchronization critically dependent on the choice of the observables. In this study we extend the quantum phase reduction approach [W. Setoyama and Y. Hasegawa, Phys. Rev. Lett. 132 , 093602 (2024) ] into heterodyne detection, offering a comprehensive theoretical framework for analyzing quantum synchronization dynamics through uniform continuous measurement over all possible quadrature observables. This method averages out the backaction, allowing for unbiased evaluation of synchronization between quantum oscillators while avoiding measurement-induced phase bias. Furthermore, by defining the phase and limit-cycle solution independently of specific observables, our proposed method consistently adapts to the scenario where the observables are freely modified during the time evolution. Through simulations of noise-induced synchronization, our method reveals that the number of phase clusters between oscillators is restricted by their bosonic levels.}, archive = {J_PRA}, author = {Wataru Setoyama and Yoshihiko Hasegawa}, doi = {10.1103/PhysRevA.111.012202}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012202}, shortjournal = {Phys. Rev. A}, title = {Lie-algebraic quantum phase reduction based on heterodyne detection}, volume = {111}, year = {2025}, }
• (2025). Probability-based approach to hybrid classical-quantum systems of any size: Generalized gleason and kraus theorems. PRA, 111(1), 012201. (www)

  @article{ , abstract = {Hybrid classical-quantum systems are of interest in numerous fields from quantum chemistry to quantum information science. A fully quantum effective description of them is straightforward to formulate when the classical subsystem is discrete. But it is not obvious how to describe them in the general case. We propose a probability-based approach starting with four axioms for hybrid classical-quantum probability measures that readily generalize the usual ones for classical and quantum probability measures. They apply to discrete and nondiscrete classical subsystems and to finite- and infinite-dimensional quantum subsystems. A generalized Gleason theorem that gives the mathematical form of the corresponding hybrid states is shown. This form simplifies when the classical subsystem probabilities are described by a probability density function with respect to a natural reference measure, for example the familiar Lebesgue measure. We formulate a requirement for the transformations, that is, the finite-time evolutions, of hybrid probability measures analogous to the complete positive assumption for quantum operations. For hybrid systems with reference measure, we prove a generalized Kraus theorem that fully determines the considered transformations provided they are continuous with respect to an appropriate metric. Explicit expressions for these transformations are derived when the classical and quantum subsystems are noninteracting, the classical subsystem is discrete, or the Hilbert space of the quantum subsystem is finite dimensional. We also discuss the quantification of the correlations between the classical and quantum subsystems and a generalization of the quantum operations usually considered in the study of quantum entanglement.}, archive = {J_PRA}, author = {S. Camalet}, doi = {10.1103/PhysRevA.111.012201}, journal = {Physical Review a}, month = {1}, number = {1}, pages = {012201}, shortjournal = {Phys. Rev. A}, title = {Probability-based approach to hybrid classical-quantum systems of any size: Generalized gleason and kraus theorems}, volume = {111}, year = {2025}, }